UNDP/GEF Danube Regional Project
Strengthening the Implementation Capacities for Nutrient
Reduction and Transboundary Cooperation
in the Danube River Basin
Five-years Report on Water Quality in
the Danube River Basin Based on
Trans-National Monitoring Network
1996-2000
Project Component 2.2: Development of operational tools for
monitoring, laboratory and information management with
particular attention to nutrients and toxic substances
October 31, 2003
Prepared by: Rodeco Consulting GmbH
Authors: Juliana
Adamková
Carmen
Hamchevici
Peter
Litheraty
Jarmila
Makovinská
Miroslava
Metelková
Liviu Popescu
Alfred
Rauchbüchl
Birgit
Wolf
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 3
Table of contents
1. Introduction ............................................................................................................................ V - 7
2.
Objectives of the report .......................................................................................................... V - 8
3. History
of
TNMN ................................................................................................................... V - 9
4.
Description of TNMN .......................................................................................................... V - 10
4.1.
Objectives of TNMN............................................................................................... V - 10
4.2.
Network of monitoring locations............................................................................. V - 10
4.3. Determinands........................................................................................................... V
- 13
4.4.
TNMN data management ........................................................................................ V - 13
5. Quality
System ..................................................................................................................... V - 14
5.1. Introduction ............................................................................................................. V - 14
5.2.
Quality Assurance in Water Quality Data Collection.............................................. V - 15
5.2.1. Quality
and
Accuracy Targets .................................................................... V - 15
5.2.2. Analytical Methodologies .......................................................................... V - 16
5.3.
Performance testing in the Danubian laboratories................................................... V - 18
5.3.1. Perspectives
of
Proficiency Testing ........................................................... V - 19
5.3.2. QualcoDanube, AQC in Water Labs in the Danube River Basin............... V - 20
5.3.3. Other Proficiency Testing Schemes ........................................................... V - 21
5.4.
Main achievements.................................................................................................. V - 21
5.4.1. Lessons learnd from the 5 year QA/QC Activies ....................................... V - 21
5.4.2. Need for continuation of interlaboratory comparison studies .................... V - 22
6.
Five Years of Monitoring a Statistical Overview .............................................................. V - 23
7.
Description of Methodology of Assessment in the Report................................................... V - 26
7.1. Water
Quality
Classification ................................................................................... V - 26
7.2.
Assessment of spatial changes of physico-chemical determinands......................... V - 28
7.3.
Trend Analysis......................................................................................................... V - 32
7.4.
Evaluation of biological determinands .................................................................... V - 33
7.5.
Comparison of TNMN results 1996-2000 with Environmental Quality Standards
of EU legislation...................................................................................................... V - 36
7.5.1. Introduction ................................................................................................ V - 36
7.5.2. Testing for compliance ............................................................................... V - 39
8.
Assessment of Water Quality ............................................................................................... V - 41
8.1. Assessment of water quality based on physico-chemical determinands ....................... V - 41
8.1.1. General
Characteristics............................................................................... V - 41
8.1.2. Nutrients
................................................................................................ V - 59
8.1.3. Heavy Metals.............................................................................................. V - 88
8.1.4. Oxygen Regime ........................................................................................ V - 138
8.1.5. Organic Micropollutants........................................................................... V - 168
8.1.6. Results of Comaprison of TNMN data with Environmental Quality
Standards of EU legislation ...................................................................... V - 193
8.1.6.1.
General comments regarding analytical data ........................ V - 193
8.1.6.2.
Atrazine................................................................................. V - 193
8.1.6.3.
Cadmium (total).................................................................... V - 193
8.1.6.4.
Cadmium (dissolved)............................................................ V - 193
8.1.6.5.
p,p'-DDT ............................................................................... V - 194
8.1.6.6.
Lead (dissolved).................................................................... V - 194
8.1.6.7.
Lindane (gamma - Hexachlorocyclohexane) ........................ V - 194
8.1.6.8.
Mercury (total)...................................................................... V - 195
8.1.6.9.
Mercury (dissolved).............................................................. V - 195
8.1.6.10.
Nickel (dissolved) ................................................................. V - 195
8.1.6.11.
Chlorinated compounds (Tetrachlorethane,
Tetrachlormethane, Trichlorethene, Trichloromethane) ....... V - 195
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UNDP/GEF Danube Regional Project
8.1.6.12.
Recommendations for future changes in TNMN regarding
the needs of the EU WFD ..................................................... V - 195
8.2.
Evaluation of Biological Determinands ................................................................ V - 204
8.2.1. Phytoplankton biomass concentration of the chlorophyll-a .................. V - 204
8.2.2. Saprobic index of macrozoobenthos......................................................... V - 206
8.2.3. Microbiological determinands.................................................................. V - 208
9.
Conclusions and recommendations .................................................................................... V - 211
10. Abbreviations ..................................................................................................................... V - 218
11. References .......................................................................................................................... V - 219
Annex 1: Classification Tables
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 5
Executive summary
The objective of this report was to assess water quality in Danube River basin, including classification
and identification of spatial and temporal changes. The basis for assessment is data on physico-
chemical and biological determinands collected in the frame of TNMN in five-years period 1996
2000. The main assessment objectives were as follows:
· Checking of compliance with water quality target values expressed by joint
classification prepared for Danube River Basin;
· Identification of water quality changes along the Danube River;
· Detection of trends in water quality;
· Assessment of dangerous substances content in water in accordance to EQS
established or proposed for use in EU.
In general, following facts concerning classification and trend evaluation of the processed TNMN data
should be highlighted:
Nutrients
Ammonium-N and nitrite-N concentrations increase from upper to lower Danube. In the Danube
River, 53.3 % of ammonium-N and 37.2 % nitrite-N values were found to be above the target limits
for these determinands. A special concern should be paid to the ammonium-N content recorded on the
Arges river, where all five yearly values of C90 in time period 1996-2000 were above the limit for
Class V; these extremely high values, correlated with BOD5 values, show the impact of untreated or
insufficiently treated waste waters from municipalities. In the Danube River, occurrence of
ammonium-N shows a decreasing tendency from 1996 to 2000 in the upper part and in the middle
section in Slovak monitoring sites.
The spatial distribution of nitrate-N concentrations shows a decrease from upper/middle to lower
Danube. Tributaries with the highest content of nitrate-N are Morava, Dyje, Sio in the upper/middle
part, and Iskar, Russenski Lom, Arges and Prut in the lower part of river basin. For nitrate-N
concentrations the fluctuations in time profile are low for the Danube River, but rather high for the
tributaries.
Orthophosphate-P shows a spatial pattern similar to that of total phosphorous characterized by a slight
increasing profile from upper to lower Danube. In the upper/middle part of the Danube a decreasing
tendency in P concentration is seen in the section from Danube-Bratislava (km 1869) down to
Danube-Szob (km 1708) with an exception at Danube-Medvedov/Medve (km 1806). In general, the
time variance of total P concentrations is much higher than that of ortho-phosphates.
Heavy metals
Except of manganese, for which a maximum of the spatial profile is present in the middle Danube
reach, for most of the discussed heavy metals the general pattern is an increase from the upper and
middle to the lower Danube. Furthermore, the heavy metals content in some tributaries mainly those
located in the lower Danube - is higher than the content in the Danube River itself.
The contamination of the Danube River by lead and copper was found rather high. A slightly better
was the situation for cadmium and mercury with 47.4% of values exceeding cadmium target level and
36.6% of values exceeding mercury target level. In general, relatively high fluctuations of heavy metal
concentrations were observed along the Danube. Despite these uncertainties the development of heavy
metal content in some tributaries was found positive a decrease is indicated in Drava river
(cadmium, chromium, copper, lead, nickel and zinc), in Arges (cadmium, chromium, copper, lead),
Prut (cadmium, chromium, lead) and in Siret (chromium, copper, lead).
In general, five years trends of heavy metal pollution can hardly been evaluated because a relatively
high deviation of results occurred. High values of heavy metals often result from high loads of
suspended solids caused by flood events. The statistical parameter used in this report (90% percentile)
V 6
UNDP/GEF Danube Regional Project
was certainly influenced by such hydrological processes. For this five-years evaluation report the
data on total concentration of heavy metals in water samples had been used because data related to
dissolved fraction was not available in sufficient amount. Therefore, it must be stressed that such a
rather scattered pattern of the heavy metal pollution data for the water matrix clearly supports future
orientation of TNMN activities on the solid phase, i.e., in TNMN planning activities the analysis of
suspended solids and sediments should be preferred.
Oxygen regime
Dissolved oxygen concentrations show positive results, with only 7.4% of values being below the
quality target in the Danube River and 8.6% being below the quality target in monitored tributaries.
Oxygen concentration decreases from upper to lower part of the Danube River, lowest values being in
the section from Danube-Bazias to Danube-Novo Selo/Pristol. As for the tributaries, rather low
oxygen content was identified in those located in the lower part of the river basin.
As for BOD values 13.3% of them are above the target value in the Danube River (mainly in the
middle and in the lower sections) and 35.9% exceed the target value in tributaries. Organic pollution
expressed by BOD increases along the Danube, reaching its maximum in the secion from Danube-
Dunafoldvar (rkm 1560, H04) to Danube-Pristol/Novo Selo (rkm 834, RO02). The tributaries most
polluted by degradable organic matter are Morava, Dyje and Sio in the upper/middle part of the
Danube mainstream and Russenski Lom and Arges in the lower part.
For CODCr, 22.4% of all values for the Danube mainstream and 39.7% for tributaries were found
above the quality target; the situation is more positive in case of CODMn - no value above this limit
for the Danube River and 18.2% for tributaries. In principle, the results obtained for CODCr and
CODMn show the highest values in the lower part of the Danube River.
Organic micropollutants
The organochlorine compounds (Lindan and p,p'-DDT) showed similar spatial profile, with an
increasing pattern from upper/middle to lower Danube. The polar pesticide Atrazine was undetectable
at most of the monitoring sites along the Danube River, only 12.5% of the data were found above the
target limit. In tributaries, 30% of Atrazine values were above the quality target, the maximum values
were found in rivers Sio and the Sajo.
For the volatile organic compounds, data is available for upper and middle Danube only. Chloroform
and tetrachloroethylene show values above the target limits in a following pattern: 29.0% of the
Danube samples and 39.5% of the samples taken from tributaries exceeded the target values for
chloroform, for tetrachloroethylene the respective numbers were 13.6% for the Danube and 7% for
tributaries. The situation was found to be better for tetrachloromethane and trichloroethylene - in the
Danube River mainstream no value was detected above the target limit for these compounds, while in
tributaries only a small percentage of all data (2.3%) was above the target limits for both these
determinands.
Biological determinands
Evaluation of saprobic index of macrozoobenthos using Austrian standard ÖNORM M6232 showed
that the Danube River and most of its tributaries correspond to classes II II-III. Only Sava River was
characterized by a worse quality class (III III-IV), however, within the years the situation improved.
In 1996 2000 the microbiological water quality corresponded to classes I IV in the Danube River
mainstream. Some tributaries, as e.g., Vah, Tisza and Siret can be characterized as extensively
polluted, however, data from many other relevant tributaries is missing. It was observed that
sedimentation had positive effects to number of total coliforms below Gabcíkovo Reservoir, Iron
Gates and in Danube Delta as well.
For biological determinands a slightly positive time trend appeared in case of saprobic index of
macrozoobenthos, but no significant trend in microbiological determinands was observed.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 7
1. Introduction
The Danube River flows through ten countries, and its large river basin of 817 000 km2 is shared
between 17 countries. The waters in Danube River Basin serve people for many purposes drinking
water preparation, use for industrial and agricultural activities, recreation, hydropower generation, and
navigation. Very important function of the rivers in Danube River Basin is ecological function, to
which attention is growing also due to the latest development of EU legislation. On the other hand
human activities result in discharging of waste waters, release of pollutants from diffuse sources,
change of natural habitats for aquatic biota and risk of accidental pollution. To protect waters in the
Danube River Basin and to ensure their functions and sustainable human uses, cooperation of
Danubian states is inevitable.
The Danube River Protection Convention (DRPC), signed in 1994 and entering into force in 1998,
creates the basis for such cooperation. Its main objective is to achieve sustainable and equitable water
management, including conservation, improvement and the rational use of surface and ground waters.
Danubian countries shall take all appropriate legal, administrative and technical measures to at least
maintain and improve environmental and water quality conditions of the Danube River and of waters
in its catchment area.
To be able to assess the progress in improvement of environmental conditions of waters in Danube
River basin, and to assess effectiveness of measures set up, the role of information from water quality
monitoring is crucial. The Danube River Protection Convention says that the Contracting Parties shall
cooperate in the field of monitoring and assessment. For this aim they shall harmonise or make
comparable their monitoring and assessment methods and shall periodically assess the quality
conditions of Danube River and the progress made by taken measures.
As one of the tools for implementation of DRPC, Joint Action Programme for the Danube River Basin
(JAP) had been prepared defining the integrated measures for improvement of the environment related
to the waters in the Danube River Basin. Danubian States and Permanent Secretariat of ICPDR had
developed JAP for period of years 2001-2005. In relation to basin-wide cooperation in the field of
monitoring JAP stresses necessity to prepare the data in such a way that allows using them in
comparative way and serving as a reliable basis for making decisions throughout the Basin.
Presented report would like to contribute to fulfil the above-mentioned requirements on information
related to the quality of waters in Danube River Basin. It contains assessment of the data, collected by
Danubian countries in the period of years 1996-2000 in the frame of joint Trans-national monitoring
network (TNMN).
V 8
UNDP/GEF Danube Regional Project
2.
Objectives of the report
The process of assessing of water quality in this report is an evaluation of the physico-chemical and
biological status of waters based on the results collected in the frame of TNMN in five-years period
1996 2000, with the following main assessment objectives:
checking of compliance with water quality target values expressed by joint classification
prepared for Danube River Basin;
identification of water quality changes along the Danube River;
detection of trends in water quality;
assessment of dangerous substances content in water in accordance to EQS established or
proposed for use in EU.
Load assessment generally belongs to main assessment objectives and is of concern also in Danube
River Basin. As the load assessment programme started in year 2000, it is not included in the 5-years
summarising report.
This is the first time, when complete data sets from 5-years operation of TNMN will be processed. For
the first time these data will be used for classification of water quality in accordance to joint
classification system prepared for the Danube river basin; and for assessment of temporal and spatial
changes in water.
The results of this activity should have not been seen as a self-standing activity, but should be seen in
a broader context to recognise the needs for TNMN improvements. On one hand, in the report TNMN
data from the first phase of its operation are evaluated, which can be used in identification of possible
weak points in the monitoring programme and the following suggestions for future TNMN
improvement. On the other hand it has to be mentioned that improvement of TNMN has to be strongly
connected to continuous implementation of Water Framework Directive, which entered in force in EU
in 2000 and Danube countries agreed on its joint implementation in the river basin.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 9
3.
History of TNMN
The first steps towards joint water quality monitoring network in Danube River basin were taken when
governments of the Danube countries signed the Bucharest Declaration. The monitoring network used
for the purposes of the Declaration consisted of eleven monitoring locations and were located on the
Danube River itself where the river formed or crossed the border between the countries.
In 1991 the Danubian countries started preparation of the Convention on cooperation for the protection
and sustainable use of the Danube River (DRPC), which was signed in 1994.
The Environmental Programme for the Danube River Basin, lead by a Task Force, also started in 1991
with the main objective to strengthen the operational basis for environmental management in the
Danube River Basin and to support the Danubian countries to implement the DRPC.
In 1992, the Task Force agreed a three-year Work Plan (1992-95) with monitoring, laboratories and
information management having between the main Programme actions. In 1992 the Monitoring,
Laboratory and Information Management Sub-Group (MLIM-SG) was established to deal with this
topic.
The main outcome of the three-year Work Plan was the Strategic Action Plan (SAP). Its approval
marked the end of the first phase of the EPDRB (1992-95) and implementation was scheduled to start
in the next phase (1996-2000).
The TNMN was originally designed in 1993 during the project "Monitoring, Laboratory Analysis and
Information Management for the Danube River Basin", conducted by the WTV Consortium in close
cooperation with MLIM-SG.
The responsibility for TNMN was assigned to MLIM-SG, which consisted of three Working Groups
Monitoring WG, Laboratory Management WG and Information Management Working Group. MLIM-
SG should address the development of water quality monitoring network in Danube River Basin;
introduce harmonised sampling procedures and enhanced laboratory analysis capabilities; and form
the core of a Danube information system on the status of in-stream water quality. The 1996 and 1997
budgets of Phare Multi-Country Environmental Programme allocated substantial funds to EPDRB
projects to support further development of the monitoring and assessment programme and the launch
of TNMN into operation.
After entry of the DRPC into force in October 1998, MLIM-Expert Group was incorporated in the
organisational structure of International Commission for the Protection of the Danube River (ICPDR)
and has been working on the basis of TORs agreed by the ICPDR Plenary Meeting. In accordance
with the TORs, the overall objective of the MLIM-EG is to create a strengthened and more strategic
approach to monitoring, laboratory and information management for surface waters. The key role of
the Group is to address the organisational and operational aspects related to the monitoring of water
riverine conditions in the Danube River Basin and to provide basic data as an input to the ICPDR
information system.
V 10
UNDP/GEF Danube Regional Project
4.
Description of TNMN
4.1. Objectives
of
TNMN
TNMN has been designed with purpose to meet the main objectives defined for monitoring network in
Danube River basin by the Work Plan of EPDRB. The Work Plan states that the monitoring network
shall:
strengthen the existing network set up by the Bucharest Declaration;
be capable of supporting reliable and consistent trend analysis for concentrations and loads for
priority pollutants;
support the assessment of water quality for water use;
assist in the identification of major pollution sources;
include sediment monitoring and bioindicators;
include quality control.
Furthermore, the Work Plan provides that:
the monitoring network shall provide outputs compatible with those in other major
international river basins in Europe;
the monitoring network shall in future comply with standards used in the western part of
Europe;
the monitoring network shall be designed in a way to reflect immediate and long-term needs -
starting with practical and routine functions already performed.
As was already mentioned, the TNMN was originally designed in 1993 during the project conducted
by WTV Consortium. The implementation was agreed by MLIM-SG, but the design was further
simplified for operation in the first phase, starting in 1996. The first phase is seen as a period with:
the operation of a limited number of stations with defined objectives already included in
national monitoring networks according to defined objectives;
a determinand list reflecting the Bucharest Declaration and EU-Directives;
an information management based on a simple data exchange file format between the
countries.
4.2.
Network of monitoring locations
The monitoring network in the frame of TNMN builds on national surface water monitoring networks.
To select monitoring locations for the purposes of international network in Danube River Basin,
respecting also the above-mentioned TNMN objectives, the following concrete selection criteria had
been set up:
located just upstream/downstream of an international border
located upstream of confluences between Danube and main tributaries or main tributaries and
larger sub-tributaries (mass balances)
located downstream of the biggest point sources
located according to control of water use for drinking water supply
Monitoring location included in TNMN should meet at least one of the selection criteria.
The selection procedure has lead to preparation of a final list of 61 monitoring locations. These are
given in Map.1. and Table 4.2.1 with basic information characterising the location. The monitoring
locations in the Table 4.2.1 are grouped in accordance to countries and not as they are ordered along
the Danube River.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 11
10o
12o 30'
15o
17 30
o
'
20o
22o 30'
25o
27o 30'
30o
50o
Praha
M
PL
o
UA
rava
D
Svita
CZ
Becva
O
va
nda
A
aab
v
ltm
N
Sv
H
a
P
J
r
o
ru
ü
i
a
r
h
n
t
h
a
l
t
d
l
MD01
R
a
k
e
v
g
a
a
en
Dy
D
j
Vah
S
e
y
l
Sire
47o 30'
Morava
Nitra
Hron
an
je
a
t
Jijia
MD
CZ01
SK
Rimava
D02
Tisza
Danube
CZ02
Bodrog
H09
A03
B
ajo
r
D01
Isar
Bratislava
Pr
S
ut
ig
Inn
A02
Ipel
Ta
Tisza
S
o
r
ome
A01
SK01
n
s
c
M
h
ch
Wien
a
old
A04
SK04
o
C
va
Kishinev
Le
Sa
Danube
rasn
lz
H
a
SK03
B
München
a
Letha
Z
D04
o
reg
i
ss
c
g
h
y
A
v
R
H01
a
B
r
H03
istr
D03
H02
it
Berethlyd
j
I
l
e
a
MD04
47o 30'
Enns
Budapest
aba
Crisul Repede
Somes
R
Kühtreiber-
stream
S
Inn
i
S
r
io
Körös
et
H04
Crisul Negr
D03
o
P
M
e
Zala
T
lovitz
sn
i
ic
s
E
a
channel
C
Ismail
Drava
Danube
z
risul
SL01
M
a
Alb
ura
Kapos
H08
H06
45o
Sa
Dra
v
vin
i
a
n
RO
j
Mures
S
a
a
R
v
O
a
D
0
HR03
r
5
av
H05
a
Aranca
HR04
Ljubljana
H07
I
Zagreb
Bega
Tamis
HR01
SL
HR
HR06
Sa
HR05
Ialomita
v
HR02
BLACK
a HR07
Arges
Kupa
Bucuresti
SEA
HR08
BIH01
J
RO04
i
RO01
u
RO09
BIH02
Beograd
45o
S
Una
a
BIH03
BIH04
krina
O
n
B
BG05
a
l
V
U
o
t
r
s
b
n
Sava
RO03
a
a
RO02
BG04
s
M
BG02
BG08 B
o
e
r
Danube
li
a
L
v
BG01
om
a
Ru
BIH
FRY
s
BG03
.
J
L
a
Lom
n
o
S
tr
m
J
a
u
k
z
ű
sam
.
Ogosta
t
O
42o 30'
Sarajevo
M
Rosica
o
i
t
r
Drina
a
Iskar
V
va
Z
T
a
a
p
ra
. M
Piva
ora
Sofia
va
BG
FYROM
0
50
100
150
250
250 km
Monitoring location
on the Danube River
on the tributary
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 12
Each monitoring location can have up to three sampling points, located on the left side, right side or in
the middle of a river. More than one sampling point was proposed for selected monitoring locations in
the middle and lower part of the Danube River and for large tributaries like Tisza and Prut Rivers are.
In spite of the fact, that monitoring locations from Bosnia and Herzegovina create a part of the
network, no data had been provided from them in evaluated period 1996-2000.
Table 4.2.1: List of monitoring sites.
Country River
Town/Location
Latitude
Longitude Distance Altitude
Catch-
DEFF Loc.in
Code
Name
Name
d. m. s.
d. m. s.
[Km]
[m]
ment
Code profile
[km2]
D01
Danube
Neu-Ulm
48 25 31
10 1 39
2581
460
8107
L2140 L
D02
Danube
Jochenstein
48 31 16
13 42 14
2204
290
77086
L2130 M
D03
/Inn
Kirchdorf
47 46 58
12 7 39
195
452
9905
L2150 M
D04
/Inn/Salzach
Laufen
47 56 26
12 56 4
47
390
6113
L2160 L
A01
Danube
Jochenstein
48 31 16
13 42 14
2204
290
77086
L2220 M
A02
Danube
Abwinden-Asten
48 15 21
14 25 19
2120
251
83992
L2200 R
A03
Danube
Wien-Nussdorf
48 15 45
16 22 15
1935
159
101700
L2180 R
A04
Danube
Wolfsthal
48 8 30
17 3 13
1874
140
131411
L2170 R
CZ01
/Morava
Lanzhot
48 41 12
16 59 20
79
150
9725
L2100 R
CZ02
/Morava/Dyje Pohansko
48 48 12
16 51 20
17
155
12540
L2120 R
SK01
Danube
Bratislava
48 8 10
17 7 40
1869
128
131329
L1840 M
SK02
Danube
Medvedov/Medve
47 47 31
17 39 6
1806
108
132168
L1860 M
SK03
Danube
Komarno/Komarom
47 45 17
18 7 40
1768
103
151961
L1870 M
SK04
/Váh
Komarno
47 46 41
18 8 20
1
106
19661
L1960 M
H01
Danube
Medve/Medvedov
47 47 31
17 39 6
1806
108
131605
L1470 M
H02
Danube
Komarom/Komarno
47 45 17
18 7 40
1768
101
150820
L1475 M
H03
Danube
Szob
47 48 44
18 51 42
1708
100
183350
L1490 LMR
H04
Danube
Dunafoldvar
46 48 34
18 56 2
1560
89
188700
L1520 LMR
H05
Danube
Hercegszanto
45 55 14
18 47 45
1435
79
211503
L1540 LMR
H06
/Sio
Szekszard-Palank
46 22 42
18 43 19
13
85
14693
L1604 M
H07
/Drava
Dravaszabolcs
45 47 00
18 12 22 78
92
35764
L1610 M
H08
/Tisza
Tiszasziget
46 9 51
20 5 4
163
74
138498
L1700 LMR
H09
/Tisza/Sajo
Sajopuspoki
48 16 55
20 20 27
124
148
3224
L1770 M
Sl01
/Drava
Ormoz
46 24 12
16 9 36
300
192
15356
L1390 L
Sl02
/Sava
Jesenice
45 51 41
15 41 47
729
135
10878
L1330 R
HR01
Danube
Batina
45 52 27
18 50 03
1429
86
210250
L1315 M
HR02
Danube
Borovo
45 22 51
18 58 22
1337
89
243147
L1320 R
HR03
/Drava
Varazdin
46 19 21
16 21 46
288
169
15616
L1290 M
HR04
/Drava
Botovo
46 14 27
16 56 37
227
123
31038
L1240 M
HR05
/Drava
D.Miholjac
45 46 58
18 12 20
78
92
37142
L1250 R
HR06
/Sava
Jesenice
45 51 40
15 41 48
729
135
10834
L1220 R
HR07
/Sava
us. Una Jasenovac
45 16 02
16 54 52
525
87
30953
L1150 L
HR08
/Sava
ds. Zupanja
45 02 17
18 42 29
254
85
62890
L1060 MR
BlH01
/Sava
Jasenovac
45 16 0
16 54 36
500
87
38953
L2280 M
BlH02
/Sava/Una
Kozarska Dubica
45 11 6
16 48 42
16
94
9130
L2290 M
BlH03
/Sava/Vrbas
Razboj
45 3 36
17 27 30
12
100
6023
L2300 M
BlH04
/Sava/Bosna
Modrica
44 58 17
18 17 40
24
99
10308
L2310 M
RO01
Danube
Bazias
44 47
21 23
1071 70 570896
L0020 LMR
55,57,58
24,40,54
RO02
Danube
Pristol/Novo Selo Harbour
44 11
22 45
834 31 580100
L0090 LMR
18,23,29
57,64,69
RO03
Danube
us. Arges
44 4 25
26 36 35
432
16
676150
L0240 LMR
RO04
Danube
Chiciu/Silistra
44 7 18
27 14 38
375
13
698600
L0280 LMR
RO05
Danube
Reni-Chilia/Kilia arm
45 28 50
28 13 34
132
4
805700
L0430 LMR
RO06
Danube
Vilkova-Chilia arm/Kilia arm 45 24 42
29 36 31
18
1
817000
L0450 LMR
RO07
Danube
Sulina - Sulina arm
45 9 41
29 40 25
0
1
817000
L0480 LMR
RO08
Danube
Sf.Gheorghe-Ghorghe arm
44 53 10
29 37 5
0
1
817000
L0490 LMR
RO09
/Arges
Conf. Danube
44 4 35
26 37 4
0
14
12550
L0250 M
RO10
/Siret
Conf. Danube Sendreni
45 24 10
28 1 32
0
4
42890
L0380 M
RO11
/Prut
Conf.Danube Giurgiulesti
45 28 10
28 12 36
0
5
27480
L0420 M
BG01
Danube
Novo Selo Harbour/Pristol
44 09
22 47
834 35 580100
L0730 LMR
50,58,66
36,47,58
BG02
Danube
us. Iskar - Bajkal
43 42 58
24 24 45
641
20
608820
L0780 R
BG03
Danube
Downstream Svishtov
43 37 50
25 21 11
554
16
650340
L0810 MR
BG04
Danube
us. Russe
43 48 06
25 54 45
503
12
669900
L0820 MR
BG05
Danube
Silistra/Chiciu
44 7 02
27 15 45
375
7
698600
L0850 LMR
BG06
/Iskar
Orechovitza
43 35 57
24 21 56
28
31
8370
L0930 M
BG07
/Jantra
Karantzi
43 22 42
25 40 08
12
32
6860
L0990 M
BG08
/Russ.Lom
Basarbovo
43 46 13
25 57 34
13
22
2800
L1010 M
MD01
/Prut
Lipcani
48 16 0 26 50 0
658
100
8750
L2230 L
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 13
Country River
Town/Location
Latitude
Longitude Distance Altitude
Catch-
DEFF Loc.in
Code
Name
Name
d. m. s.
d. m. s.
[Km]
[m]
ment
Code profile
[km2]
MD02
/Prut
Leuseni
46 48 0
28 9 0
292
19
21890
L2250 M
MD03
/Prut
Conf. Danube-Giurgiulesti
45 28 10
28 12 36
0
5
27480
L2270 LMR
UA01
Danube
Reni - Kilia arm/Chilia arm
45 28 50
28 13 34
132
4
805700
L0630 M
UA02
Danube
Vilkova-Kilia arm/Chilia arm 45 24 42
29 36 31
18
1
817000
L0690 M
Distance:
The distance in km from the mouth of the mentioned river
Sampling location in profile:
Altitude:
The mean surface water level in meters above sea level
L: Left bank
Catchment:
The area in square km, from which water drains through the station
M: Middle of river
ds.
Downstream
of
R:
Right
bank
us.
Upstream of
Conf.
Confluence
tributary/main
River
/
Indicates tributary to river in front of the slash. No name in front of the slash means Danube.
4.3. Determinands
To be able to fulfil TNMN objectives listed in chapter 4.1, determinands to be measured in monitoring
network of Danube River basin should be indicative to human uses, functions of the rivers and
problems identified in the river basin. On the other hand, the scope of determinands was limited by
available and affordable methods of measurements.
The original determinand list for the first phase of TNMN prepared to reflect also existing EU
directives and the riparian countries own demands had to be reduced after discussions held in MLIM-
SG. The resulting list is given in Tables 5.2.1.1 and 5.2.1.2 for water and sediment phase, respectively.
The agreed frequency of measurements for determinands in water was 12 per year and 2 per year for
biomonitoring and determinands analysed in sediments.
Sampling and analysis were carried out on the national level, respecting agreed quality system, which
is described in more details in the chapter 5.
4.4.
TNMN data management
The primary purpose of data management is to transform raw data to needed information, coming
from monitoring objective. The basic assumption for this process is to have got standard procedure for
collection, validation, merging, storage, and processing of the data.
The importance of TNMN data management was recognised in very early stage of TNMN operation
and well-defined structure for data storage had been prepared. The data are organised in a system of
joined tables, containing information related to monitoring locations, determinands, methods of
sampling, methods of analysis, remarks and information on taken samples and results of analysis.
From 1996, several parts of the database had been modified to adjust the system to the new needs, or
to increase efficiency of the system.
The procedure of TNMN data collection starts on a national level of each country. Nominated
National Information Managers (NIMs) are responsible for collection of the data from National
Reference Laboratories and other national laboratories involved in TNMN, where the data from
sampling and analysis are generated. In the next step the NIMs are responsible for data checking,
preparation in agreed data exchange file format (DEFF) and sending to the Central Point. Here the
data are checked again and suspicious data are consulted with NIMs. After the consultation process the
data from TNMN are merged and stored in one relational database for further use.
Collection of TNMN data started in 1996, TNMN data have been regularly collected from Germany,
Austria, the Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Bulgaria and Romania. Data from
Ukraine and Moldova have been available since 1998.
Basic processing and presentation of the TNMN data is done on a yearly basis in the form of Danube
Yearbook, first of which was prepared from 1996 data.
V 14
UNDP/GEF Danube Regional Project
5. Quality
System
5.1. Introduction
Before 1985, water quality monitoring in the Danube river basin had been carried out independently in
the different countries, in several cases as part of bilateral agreements. In 1985, the Bucharest
Declaration was the first sign of a basin-wide international cooperation. The gaps in existing
knowledge and the problems of the comparability of the monitoring results have been recognized. The
Environmental Programme for the Danube River Basin (EPDRB), started in 1991, provided a
framework to extend and upgrade the monitoring program. One of the major tasks of the EPDRB was
to establish the Trans-National Monitoring Network (TNMN) using accepted methodologies and
appropriate quality control. The mission of the established Monitoring, Laboratory and Information
Management Expert Group (MLIM-EG), and particularly of its Laboratory Management Working
Group (LMWG), included the harmonization of the sampling and analytical methods for use in the
TNMN and establishment of an appropriate, effective quality assurance system. In the late 90s, after
ratification of the International Convention for the Protection of the Danube River Basin (ICPDR) the
water quality/pollution monitoring became one of the important activities, and the monitoring and
laboratory experts further improved the operational elements of the TNMN.
The most difficult issue in the monitoring of international rivers is to obtain reliable information,
comparable data on the different pollutants. Therefore, implementation of monitoring programmes in
international river basins requires harmonization and coordination. Harmonization should be first of
all during the design period when target determinands and matrices for monitoring are identified,
sampling locations and frequencies, sampling and analytical methodologies, the quality control
measures particularly for the analytical quality control (AQC) are selected and agreed.
Evaluation of the quality of the river system, the realistic description of the concentrations and trends
of pollution the analytical results should be of the same high quality, irrespective of the laboratory that
provided the results. The appropriate operation of the TNMN was an important part of the monitoring
strategy ensured throughout harmonization sampling and analytical methodologies, establishment of
quality targets and appropriate quality assurance scheme. This was a prerequisite to the proper
operation of the monitoring network which includes selected monitoring sites along the Danube and its
tributaries. In each country, a National Reference Laboratory (NRL) was nominated and additional
national laboratories were involved in the implementation of the TNMN. The LMWG took the
responsibility to harmonize the monitoring methodologies and coordinate the AQC among the 11
NRLs and the additional 18 national laboratories.
In addition to the preparation of Standard Operational Procedures (SOPs) to be followed during
sample collection and analysis, the quality assurance program in the Danube river basin laboratories
included: (a) recommendations for similar laboratory facilities, (b) provision of necessary analytical
instrumentation in the laboratories, (c) implementation of integrated training programs, and (d)
proficiency testing carried out in interlaboratory comparison studies.
The implementation plan for the TNMN was prepared and agreed. This included provision of
sampling equipment and analytical instruments for the eligible countries from the EU PHARE
programme. As far as the laboratory work is concerned, harmonization of the related activities,
coordinated by the LMWG of MLIM-EG, included:
·
Selection of determinands and matrices for the TNMN in the Danube river basin;
·
Selection of appropriate sampling and sample handling procedures for water, sediment and
biota;
·
Selection of reference and optional analytical methods for determination of the identified
physical, chemical, radiochemical, biological and microbiological determinands;
·
Establishment of the AQC, performance testing system;
·
Regular revision of the methodologies;
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 15
·
Harmonization of laboratory facilities, instrumentation;
·
Identification of training needs and implementation; and
·
Co-ordination of the laboratory work through regular meetings of the National Reference
Laboratories.
During 1998-2000, in the frame of the EU supported projects on "Water Quality Enhancement in the
Danube River Basin" and "Strengthening Capabilities in the Danube River Basin" significant efforts
were devoted to the development of the quality assurance elements of the Danube TNMN. In the
second project, the Volume 2 of the Guidance Notes dealt with all quality assurance issues pertaining
to the sampling, sample preparation and analysis of TNMN determinands.
5.2.
Quality Assurance in Water Quality Data Collection
The measurement cycle for the implementation of the monitoring starts with the collection of samples
and closes with reporting the analytical results and the reliability of the results depends on the
effectiveness of the quality assurance as shown in Fig. 5.2.1.
Monitoring programs
Data handling
Data collection
Quality assurance/control
Sampling and
Measurement results
analytical protocols
Field measurements
Laboratory
Sample collection
measurements
Fig. 5.2.1. Quality assurance/control in the data collection/measurement cycle
Quality assurance/control in monitoring programme design as well as in the data handling is
considered in the relevant chapters of this review report. Here, major emphasise is given to the
laboratory work, particularly to the analytical quality control.
5.2.1. Quality and Accuracy Targets
Water/sediment quality targets, objectives and standards are set to evaluate the quality of the water
resources, both surface and subsurface water bodies, to characterise chemical and ecological status
(for surface waters) and to establish satisfactory condition for intended uses of the aquifer. The
laboratory data define whether that condition is being met, and whether the water is at acceptable
quality to fit for the purpose. If the laboratory results indicate a violation of the standard, action is
required by the pollution control authorities. The analyst must be aware that his professional
V 16
UNDP/GEF Danube Regional Project
competence, the procedures he has used, and the reported values are reliable and may be used with
confidence.
The approach adopted in proposing the analytical accuracy targets for monitoring the quality of water
(Table 5.2.1.1) and sediment (Table 5.2.1.2) in the Danube river basin is summarized as follows:
· Two key concentration levels have been defined for each determinand. These are: (i) the
lowest level likely to be encountered in the waters / sediments of interest (the minimum level
of interest); and (ii) the concentration which represents the likely level at which most
monitoring (for example, for the assessment of trends or compliance with water quality
standards) will be carried out (the principal level of interest). These levels define the aims of
the program; they can be used to establish the performance needed from analytical systems
used in the laboratories.
· It is then assumed that the aims of the program will be satisfied provided: (i) that relatively
few results are reported as "less than" the minimum level and (ii) that the accuracy achieved at
the principal level is not worse than ± 20% of the principal level. This assumption has been
tested in a wide range of environmental monitoring laboratories. Experience suggests that it is
usually appropriate to set a required limit of detection which is at least one tenth of the
principal level of interest. A subsidiary aim is that the limit of detection should be at least one
third of the minimum level of interest.
· Any practical approach to monitoring must take into account the current capabilities of
analytical science. This means that if some targets are recognized as very difficult to achieve,
it may be necessary to set more relaxed, interim targets and to review performance and data
use in the course of the monitoring program.
5.2.2. Analytical Methodologies
The analytical methodologies for the determinands applied in TNMN are based on a list containing
reference and optional analytical methods. The National Reference Laboratories (NRLs) have been
provided with a set of ISO standards (reference methods) reflecting the determinand lists, but taking
into account the current practice in environmental analytical methodology in the EU. It has been
decided not to require each laboratory to use the same method, providing the laboratory would be able
to demonstrate that the method in use (optional method) meets the required performance criteria.
Therefore, the minimum concentrations expected and the tolerance required of actual measurements
have been defined for each determinand (as reported in Tables 5.2.1.1 and 5.2.2.2), in order to enable
laboratories to determine whether the analytical methods currently in use are acceptable.
Table 5.2.1.1: Accuracy targets of water quality variables selected for the TNMN
Level of Interest
Analytical Accuracy Targets
DETERMINANDS Minimum likely
Principal
Limit of Detection
Tolerance
in Water
(Note 1)
(Note 2)
(Note 3)
(Note 4)
Physical, Chemical Parameters
Temperature, °C
- 0-25 - 0.1 °C
Suspended Solids, mg/l
1
10
1
1mg/l or 20%
Dissolved Oxygen, mg/l
0.5
5
0.2
0.2 or 10%
pH -
7.5
-
0.1
Conductivity µS/cm, @ 20°C
30
300
5
5 or 10%
Alkalinity, mmol/l
1
10
0.1
0.1
Chloride, mg/l
5
50
1
1 or 10%
Sulphate, as SO4 mg/l
5
50
5
5 or 20%
Nutrients
Ammonium (NH4) as N mg/l
0.05
0.5
0.02
0.02 or 20%
Nitrite (NO2) as N mg/l
0.005 0.02 0.005
0.005 or 20%
Nitrate (NO3) as N mg/l
0.2
1
0.1
0.1 or 20%
Organic Nitrogen as N mg/l
0.2
2
0.1
0.1 or 20%
Total - Nitrogen as N mg/l
0.2
2
0.5
0.5
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 17
Level of Interest
Analytical Accuracy Targets
DETERMINANDS Minimum likely
Principal
Limit of Detection
Tolerance
in Water
(Note 1)
(Note 2)
(Note 3)
(Note 4)
Orthophosphates (PO4) as P mg/l
0.02
0.2
0.005
0.005 or 20%
Total Phosphorus as P mg/l
0.05
0.5
0.01
0.01 or 20%
Elements (Metals)
Sodium mg/l
1
10
0.1
0.1 or 10%
Potassium mg/l
0.5
5
0.1
0.1 or 10%
Calcium mg/l
2
20
0.2
0.1 or 10%
Magnesium mg/l
0.5
5
0.1
0.2 or 10%
Iron mg/l
0.05
0.5
0.02
0.02 or 20%
Manganese mg/l
0.05
0.5
0.01
0.01 or 20%
Zinc mg/l
0.01
0.1
0.003
0.003 or 20%
Copper mg/l
0.01
0.1
0.003
0.003 or 20%
Chromium mg/l
0.01
0.1
0.003
0.003 or 20%
Lead mg/l
0.01
0.1
0.003
0.003 or 20%
Cadmium mg/l
0.001
0.01
0.0005
0.0005 or 20%
Mercury mg/l
0.001
0.01
0.0003
0.0003 or 20%
Nickel mg/l
0.01
0.1
0.003
0.003 or 20%
Arsenic mg/l
0.01
0.1
0.003
0.003 or 20%
Aluminium mg/l
0.01
0.1
0.01
0.01 or 20%
Organic Components
BOD5 , mg/l
0.5
5
0.5
0.5 or 20%
COD Cr , mg/l
10
50
10
10 or 20%
COD Mn , mg/l
1
10
0.3
0.3 or 20%
DOC, mg/l
0.3
3
0.3
0.3 or 20%
Phenol index, mg/l
0.005
0.05
0.005
0.005 or 20%
Anionic surfactants, mg/l
0.1
1
0.03
0.03 or 20%
Petroleum hydrocarbons, mg/l
0.02
0.2
0.05
0.05 or 20%
AOX, µg/l
10 100 10
10 or 20%
Lindane, µg/l
0.05 0.5 0.01
0.01
or30%
pp'DDT, µg/l
0.05 0.5 0.01
0.01
or30%
Atrazine, µg/l
0.1 1 0.02
0.02
or30%
Chloroform, µg/l
0.1 1 0.02
0.02
or30%
Carbontetrachloride, µg/l
0.1 1 0.02
0.02
or30%
Trichloroethylene, µg/l
0.1 1 0.02
0.02
or30%
Tetrachloroethylene, µg/l
0.1 1 0.02
0.02
or30%
V 18
UNDP/GEF Danube Regional Project
Table 5.2.1.2. Accuracy targets of sediment quality variables selected for the TNMN
Level of Interest
Analytical Accuracy Targets
DETERMINANDS
(for <63 µm size fraction)
in Sediment
Minimum likely
Principal
Limit of Detection Tolerance (Note
(Note 1)
(Note 2)
(Note 3)
4)
Elements
Organic Nitrogen, mg/kg
50
500
10
10 or 20%
Total Phosphorus, mg/kg
50
500
10
10 or 20%
Calcium, mg/kg
1000
10000
300
300 or 20%
Magnesium, mg/kg
1000
10000
300
300 or 20%
Iron, mg/kg
50
500
20
20 or 20%
Manganese, mg/kg
50
500
20
20 or 20%
Zinc, mg/kg
250
500
50
50 or 20%
Copper, mg/kg
2
20
1
1 or 20%
Chromium, mg/kg
2
20
1
1 or 20 %
Lead, mg/kg
2
20
1
1 or 20 %
Cadmium, mg/kg
0.05
0.5
0.05
0.05 or 20%
Mercury, mg/kg
0.05
0.5
0.01
0.01 or 20%
Nickel, mg/kg
2
20
1
1 or 20 %
Arsenic, mg/kg
2
20
1
1 or 20 %
Aluminium, mg/kg
50
500
50
50 or 20%
Organic pollutants
TOC, mg/kg
50000
500000
10000
10000 or 20%
Petroleum Hydrocarbons, mg/kg
10
100
1
1 or 20 %
Total Extractable Matter, mg/kg
100
1000
10
10 or 20 %
PAH - 6 (each), mg/kg
0.01
0.1
0.003
0.003 or 30%
Lindane, mg/kg
0.01
0.1
0.003
0.003 or 30%
pp' DDT, mg/kg
0.01
0.1
0.003
0.003 or 30%
PCBs - 7 (each), mg/kg
0.01
0.1
0.003
0.003 or 30%
Note 1 - The minimum likely level of interest is the lowest concentration considered likely to be encountered or
important in the Danube monitoring program.
Note 2 - The principal level of interest is the concentration at which it is anticipated that most monitoring will
be carried out.
Note 3 - The required limit of detection is the target limit of detection (LD) which laboratories are asked to
achieve. This has been set, wherever practicable, at one third of the minimum level of interest. This is intended
to ensure that the best possible precision is achieved at the principal level of interest and that relatively few less
than results will be reported for samples at or near the lowest level of interest. (N.B. Where the performance of
current analyses is not likely to meet the criterion of a LD of one third if the lowest level of interest, the LD has
been revised to reflect best practice. In these cases, the targets have been entered in italics).
Note 4 - The tolerance indicates the largest allowable analytical error which is consistent with the correct
interpretation of the data and with current analytical practice. The target is expressed as "x concentration units or
P%". The larger of the two values applies for any given concentration. For example, if the target is 5 mg/l or
20% - at a concentration of 20 mg/l the maximum tolerable error is 5 mg/l (20% is 4 mg/l); at a concentration of
100 mg/l, the tolerable error is 20 mg/l (i.e. 20%) because this value exceeds the fixed target of 5 mg/l.
5.3.
Performance testing in the Danubian laboratories
As part of the AQC, a performance testing scheme under the name of QualcoDanube has been
established and implemented as the primary inter-laboratory quality control program in the Danube
basin, started in 1993 with the participation of the laboratories involved in the Danube water quality
monitoring in the framework of the Bucharest Declaration. In 1995, it was extended, in the frame of
the TNMN, to the 11 National Reference Laboratories and in 1996 to another 19 national laboratories
within the Danube river basin implementing the TNMN. Since 1996, the QualcoDanube performance
testing intercalibration results demonstrate significant improvement.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 19
5.3.1. Perspectives of Proficiency Testing
One of the most important parts of the sustainable AQC is the design of an organisational structure for
proficiency testing that can ensure continuity of analytical quality control in the Danube TNMN and
the following points had to be considered: (a) the determinands of interest and type of matrix, (b) the
level of concentration of determinands, (c) sample preparation, (d) analysis and reporting, and (e)
evaluation of the results.
The key agreed requirements for the performance testing scheme are as follows:
· The sample should be considered to be adequately representative of a real test material.
Determinands and matrix depend on parameters and sample type analysed routinely by the
laboratories of Danube River Basin. Care needs to be taken to ensure that no sample is lost during
shipment and that the sample is well homogenised.
· Concentration level of determinands depends on parameters and sample type analysed routinely
by the laboratories in the Danube river basin. In the case of real surface water, sediment samples
or biota, concentration range is limited. In other cases (e.g., synthetic sample) concentrations vary
depending on the target level of contamination.
· The number of samples should be sufficient to distribute sample-pairs according to the Youden-
technique, to each of the 29 TNMN implementing laboratories. As it is anticipated that other
laboratories in Danubian countries should have the opportunity to take advantage of the respective
performance testing exercises, an additional sample set should be prepared per material.
· Sampling should ideally be at a frequency of four-times per year according to the distribution
schedule. Samples should be accompanied with clear instructions on the procedures for the PT
analysis and the reporting procedure.
· The results reported back from the analytical laboratories should be evaluated and fed back to the
laboratories within two weeks. Laboratories are identified by code numbers.
The sample preparation, distribution and evaluation schemes of the performance testing is
demonstrated in Fig. 5.3.1.1. Laboratories receive selected well homogenized environmental samples
for analysis. The reported analytical results are compared with the assigned reference values.
The test materials to be distributed in the scheme must be similar to the materials that are routinely
analysed (in respect of composition of the matrix and the concentration range or quality of the
determinand) including the type of samples as follows:
· synthetic water samples as concentrate-pairs (according to the Youden-technique),
· real-world water and sediment samples and their spikes ensuring sample-pairs again according to
the Youden-technique,
reference materials (water and sediment). Sediment references materials shall be prepared from
samples collected at different representative sites in the Danube river basin in a relatively large
quantity allowing to use these samples for internal quality control as in-house RM.
V 20
UNDP/GEF Danube Regional Project
Selection of Determinands and Matrix
Preparation of AQC Samples
Synthetic Sample
Real-world Sample
In-house RM
(concentrate)
(water/sediment)
(concentrate/sediment)
Homogenisation
(testing homogeneity)
Distribution of Samples
Sending Samples According to Schedule
Requesting Results by Strict Deadline
Evaluation of the Results
(e.g. Youden-pairs, Z-score)
Evaluate Laboratory
Evaluate Method
Assigned Values for
Performance
Performance
Reference Material
Follow-up
(actions, utilization)
In-house Reference
Initiate Actions if
Method Modification or
Material Available
Performance is Poor
Replacement if Needed
for AQC
Figure 5.3.1.1: Sample preparation and evaluation scheme for AQC in the Danube river basin
5.3.2. QualcoDanube, AQC in Water Labs in the Danube River Basin
The organisation of interlaboratory comparison in the Bucharest Declaration Danube monitoring was
agreed in 1992. The Institute for Water Pollution Control of VITUKI, Budapest, Hungary, offered and
took the responsibility for organising the first study under the name of QualcoDanube. The first
distribution in 1993 included samples for the analysis of three determinands: pH, conductivity and
total hardness. By the end of 1995, four more distributions had been made for the analysis of the
following determinands: chlorides, COD, nutrients (ammonium, nitrate, Kjeldahl-nitrogen,
orthophosphate and total-P) as well as different metals, including Fe, Mn, Ca, Mg, Cd, Cu, Hg, Pb, Ni,
Zn.
In 1996 the QualcoDanube proficiency testing scheme was extended to the National Reference
Laboratories (NRL) in the Trans-National Monitoring Network (TNMN) and the 1996/2 distribution
already included all Danubian laboratories - 11 NRLs and 18 national laboratories - implementing the
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 21
TNMN. This distribution was further extended to 6 Black Sea laboratories responsible for pollution
monitoring in their area.
Since 1996 QualcoDanube check samples are distributed quarterly in each year.
5.3.3. Other Proficiency Testing Schemes
In addition to the QualcoDanube, another interlaboratory comparison, the AQUACHECK
performance testing scheme, organized by WRc (UK), was conducted for the NRLs, mainly aiming at
the analysis of specific micropollutants.
5.4. Main
achievements
The described approach supports the work of harmonising the analytical activities within the Danube
Basin related to the TNMN as well as the implementation and operation of an Analytical Quality
Control (AQC) programme. Therefore, it has been used in development of the training needs required
to improve the laboratory performance of the National Reference Laboratories as well as the other
laboratories involved in the implementation of the TNMN. The result is that managers and personnel
of the involved laboratories have been provided with practical training for analytical instrumentation
and on-site sampling as well as with theoretical aspects of AQC.
Interlaboratory studies - organized regularly - help to improve analytical performances because the
participants can review their own performance concerning the accuracy of the analytical results and
where necessary, investigate the sources of error and take corrective actions.
5.4.1. Lessons learnd from the 5 year QA/QC Activies
The four QualcoDanube distributions in each year provided information on the analytical performance
of the participating laboratories implementing the TNMN in the Danube river basin. The overall
output of the results is the demonstration of the comparability of the analytical data on the studied
determinands as well as the possible methodological problems during the analysis.
Since the start of the QualcoDanube AQC programme nutrients were included in several distributions
and therefore it was possible to assess the quality improvement in the analytical work by comparing
the performance during the different distributions.
The results in 1996 showed the quality improvement in most of the determinands. Although the
number of laboratories during the first distributions was almost one third of the other distributions the
performance significantly improved during the study period, particularly in the case of Nitrate-N.
Variation in the Orthophosphate-P and the Total-P was significant, therefore, improvement is needed
before the monitoring data of these determinands could be considered reliable in the entire Danube
basin. The results of the heavy metal analysis were promising because with very few exceptions they
were within an acceptable range.
It was expected that the performance of the Danube basin laboratories as well as of the additional
laboratories from the Black Sea region would further improve which would ensure the comparability
of the water quality monitoring results in the river basin and related marine regions.
Most of the data provided by the laboratories during the 1997 QualcoDanube intercalibration study
were satisfactory, when comparing to error thresholds.
While the results in 1996 showed the quality improvement in most of the determinands, further
improvement could not be observed in 1997. The performance for the general parameters was
V 22
UNDP/GEF Danube Regional Project
satisfactory. Some problems arose due to stability of the samples (e.g. MBAS, PO4-P) and a relatively
long analysis time which can influence the variation between results. In the case of metals different
digestion methods were used and there were some problems for less commonly measured metals (e.g.
Hg, As) and at low concentration level (e.g. Cd, Ni, Pb).
In 1998, the analytical results of synthetic samples were better than results of real water samples. In
the latter case, due to matrix effect, results were influenced by both systematic and random errors,
while systematic error characterized mainly the results of the synthetic samples. Among the nutrients
Kjeldahl-N (1998/2) and among the organic pollutants the Chemical Oxygen Demand with dichromate
method (1998/1) were analysed. In general, the results of the metals were satisfactory, especially of
zinc, and only the results of mercury were scattered. Similarly to the real water samples, the results of
the sediment samples were also influenced by both random and systematic errors.
In addition to regularly analysed determinands, distributions in 1999 included specific trace organic
determinands in waters for quantitative determinations as being involved in the TNMN for the River
Danube, (e.g. lindane, DDT). The results of these determinands were poor, unsatisfactory together
with the results of petroleum hydrocarbons in both water and sediment. In the case of water samples
solvent extracts were distributed so the discrepancies in the results most likely originated from
incorrect analyses and/or unsuitable analytical methods.
In 2000, the analytical results of synthetic samples were again better than results obtained from real
water samples. Results of general determinands, nutrients in synthetic samples and metals were
relatively good, but results of nutrients in real water samples were influenced by significant systematic
error and slight random error. Analysis of organic compounds proved to be a field requiring
improvement, especially of micropollutants, in case of which the performance was not sufficient.
In summary, there was significant quality improvement in most of the determinands during the five
years. For further improvement more attention should be paid particularly to:
· the distributed samples were preserved (regularly by acid and/or by sterilization depending on
determinands), so before analyses pH checking and adjustment should have been done. This
simple but important step might have been left out of consideration, e.g., at NO -3-N
determination. The results of some laboratories could be out of range due to this reason.
· In the case of determination of metals, particularly in sediment, the reason for discrepancies
could be the different way of mineralization, or systematic errors during analyses.
· Most of the measurements were influenced by systematic error which is calling for more
attention in the sample preparation and calibrations.
· There were some laboratories which regularly reported outlying results for certain
determinands. They should pay attention to the whole process of analysis of these
determinands (analytical method, standard materials, etc.).
5.4.2. Need for continuation of interlaboratory comparison studies
Intercalibration studies organised regularly present an important part of QA/QC system. They help to
improve analytical performances because the participants can review their own performance
concerning the accuracy of the analytical results and, where necessary, investigate the sources of error
and take corrective actions.
It is expected that performance of laboratories analysing samples in the frame of TNMN will further
improve and the comparability of the water quality monitoring results in the river basin and related
regions will be ensured. To achieve this goal regular performance testing and the continuation of the
interlaboratory comparison studies are of paramount importance.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 23
6.
Five Years of Monitoring a Statistical Overview
Over the five years period the number of sampling sites where data have been provided has increased
from 75 (1996) to 81 (2000). Most of the sites have been maintained only a few sites were shifted
from one river side to another: BG03 from middle to right, HR08 from right to middle, HR06 from
right to left.
The amount of investigations differs, not all determinands were analysed at all monitoring sites. Table
6.1 gives an overview on the number of monitoring sites where data of a specific determinand is
available. Comparing the years an upward trend can be stated. At the same time the number of
samples per year increased. As an example, in Fig. 6.1 the percentage of sites with the number of
nitrate measurements in 1996-2000 is shown.
However, there are big differences regarding the determinands. As to basic descripters, currently many
samples are taken but for specific organic pollutants the number of samples is still very low. Seasonal
fluctuations and particular situations like flood events or algae blooms can not be detected and for this
reason data processing and data interpretation is rather limited for several determinands.
Fig.6.1: Nitrate percentage of sites with number of
measurements per year.
100%
80%
> 20
60%
11 - 20
6 - 10
40%
0 - 5
20%
0%
1996
1997
1998
1999
2000
Concerning analytical methods changes over time have been reported for every data delivery.
Frequently these changes have been affected the detection limit. This has to be beared in mind when
processing the data of determinands, which usually occur in low concentrations. For the five-years
period table 6.2 shows the overall range of detection limits reported by countries, which are stored in
the TNMN database.
V 24
UNDP/GEF Danube Regional Project
Table 6.1: Number of monitoring sites where data are available
Determinand
Number of monitoring sites
1996 1997 1998 1999 2000
Basic Descriptors
Water
temperature
Dissolved oxygen *
74 75 77 81 71
Conductivity
72 74 71 75 77
Suspended
solids
66 74 74 81 81
pH
74 75 77 81 81
Alkalinity
62 67 71 75 80
Nutrient regime
Ammonium-N
70 75 77 81 81
Nitrite-N
71 76 76 79 79
Nitrate-N
75 75 77 81 81
Organic
N
29 24 22 33 34
Total-N
4
Ortho-phosphate-P
72 74 75 76 69
Total-P
65 66 67 79 78
Chlorophyll-a
Pollution
indicators
BOD5
73 71 77 81 82
CODMn
72 74 74 78 78
CODCr
64 70 73 77 79
AOX
8 8 23 22 14
Heavy Metals (total)
Zinc
70 70 73 73 77
Copper
70 70 73 73 77
Chromium (Cr-III+VI)
64 65 68 68 68
Lead
66 69 68 68 74
Cadmium
65 66 66 68 74
Mercury
52 34 33 29 35
Nickel
69 42 42 63 74
Arsenic
29 30 31 31 39
Manganese
67 71 71 75 68
Iron
68 73 74 80 70
Toxic
substances
Lindane
28 51 56 66 69
p,p´-DDT
28 47 59 66 69
Atrazine
37 27 28 36 62
Trichloromethane
9 15 23 28 29
Tetrachloromethane
9 15 23 28 29
Trichloroethene
9 15 23 28 27
Tetrachloroethene
9 15 23 28 27
PAL
A
29 53 73 73 77
NES
28 37 44 48 51
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 25
Table 6.2: Range of detection limits in 1996-2000, reported by countries.
Determinands
Range of detection limits 1996-2000
Units
(all monitoring sites)
Basic Descriptors
Suspended solids
0,2 - 10
mg.l-1
Alkalinity
0,01 - 0,4
mmol.l-1
Ca
0,003 - 10
mg.l-1
Mg
0,0005 5
mg.l-1
Na
0,005 1,0
mg.l-1
K
0,005 1,0
mg.l-1
Nutrient regime
Ammonium-N
0,008 - 0,05
mg.l-1
Nitrite-N
0,001 - 0,02
mg.l-1
Nitrate-N
0,002 - 1
mg.l-1
Organic N
0,05 - 1
mg.l-1
Total-N 0,2
mg.l-1
Ortho-phosphate-P
0,003 - 0,05
mg.l-1
Total-P
0,005 - 0,05
mg.l-1
Pollution indicators
BOD5
0,01 - 1
mg.l-1
CODMn
0,01 - 0,8
mg.l-1
CODCr
0,01 - 15
mg.l-1
AOX
0,01 - 10
µg.l-1
Heavy Metals (total)
Zinc
0,003 - 20
µg.l-1
Copper
0,003 - 3
µg.l-1
Chromium (Cr- 0,03 - 10
µg.l-1
III+VI)
Lead
0,003 - 2
µg.l-1
Cadmium
0,01 - 5
µg.l-1
Mercury
0,01 - 3
µg.l-1
Nickel
0,003 - 2,5
µg.l-1
Arsenic
0,02 - 2
µg.l-1
Manganese
0,00001 - 0,5
mg.l-1
Iron
0,00002 - 0,2
mg.l-1
Toxic substances
Lindane
0,001 - 0,1
µg.l-1
p,p´-DDT
0,001 - 0,05
µg.l-1
Atrazine
0,001 - 1
µg.l-1
Trichloromethane
0,01 - 1
µg.l-1
Tetrachloromethane
0,01 - 1
µg.l-1
Trichloroethene
0,01 - 1
µg.l-1
Tetrachloroethene
0,01 - 1
µg.l-1
PAL A
0,005 - 0,1
mg.l-1
NES
0,005 - 0,2
mg.l-1
V 26
UNDP/GEF Danube Regional Project
7.
Description of Methodology of Assessment in the Report
Reffering to objectives of the report, there is a need to obtain information on water quality in the
Danube River and its main tributaries based on data from five-years joint monitoring of Danubian
states. The questions regarding the water quality, its compliance with set up target values, spatial
changes along the river and questions whether and where the water quality is improving or
deteriorating, are of concern for not only decision makers, but also for public.
Assessment in the report consists of several parts:
classification of surface water quality in accordance to classification system developed for TNMN,
methodology of which is described in chapter 7.1.;
assessment of spatial changes and trend assessment of physico-chemical determinands, approach
for which is described in chapter 7.2 and 7.3, respectively;
assessment of biological determinands measured in TNMN, for which methodology described in
chapter 7.4.;
assessment of dangerous substances content in waters in accordance to Environmental Quality
Standards established or proposed for use in EU, methodology of which is described in chapter
7.5.
7.1.
Water Quality Classification
The first attempt to come up with proposal of joint water quality classification for Danube river basin
had been done in 1997 by PHARE Applied Research Project EU/AR/203/91 "Water Quality Targets
and Objectives for Surface Waters in the Danube basin" (WRRC, Vituki, Plc., 1997).
The proposed classification has not been applied for evaluation of results from TNMN, it was only
partly used by means of using its limit values for illustration of BOD
3-
-
5, PO4 -P and NO3 -N
concentrations on the maps in the TNMN-Yearbooks 1996-2000.
In 1999 the EU PHARE Programme contributed to the EPDRB by initiating the project "Danube
River Basin Water Quality Enhancement". One of its objectives was to make a proposal for a unified
water quality classification for the entire Danube River basin region based on
review of existing water quality and sediment quality classification methods in Danubian
countries
review of EU legislation
experience within the different countries
The activity was realised by IWACO BV Consultants for water and environment in Rotterdam.
Although the attention was given to Water Famework Directive (WFD) (at that time still under
preparation), it was concluded that to come to ecologically based and regionally differentiated water
quality criteria according to WFD in Danube River Basin will take considerable effort and time. In the
meantime interim water quality classification scheme had been proposed. This proposal was further
discussed and adjusted by Monitoring, Laboratory and Information Management Sub-Group and
approved finally in 2001.
The classification scheme as presented in Table 7.1.1 is meant to serve international purposes for the
presentation of current status and improvements of water quality in Danube river and its main
tributaries and is not to be a tool for implementation of a national water policy.
Five classes are used for assessment, with target value being the limit value of class II. The class I
should represent reference conditions or background concentrations. For number of determinands it
was not possible to establish real reference values due to existence of many types of water bodies in
Danube river basin differing in its physico-chemical characteristics naturally. For synthetic substances
the detection limit or minimal likely level of interest was chosen as limit value for class I.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 27
The classes III V are on the "non-complying" side of the classification scheme and their limit values
are usually 2-5-times the target values. They should indicate the seriousness of the exceedance of the
target value and help to recognise the positive tendency in water quality development.
For compliance testing 90-perentile value of at least 11 measurements in a particular year is used.
Table 7.1.1: Water Quality Classification used for for TNMN purposes.
Determinand Unit
Class
I II III IV V
TV
Class limit values
Oxygen/Nutrient regime
Dissolved oxygen * mg.l-1
7 6 5 4 <
4
BOD5 mg.l-1
3 5 10 25 >
25
CODMn mg.l-1
5 10 20 50 >
50
CODCr mg.l-1
10 25 50 125 >
125
pH -
>
6.5* and
< 8.5
Ammonium-N mg.l-1
0.2 0.3 0.6 1.5 >
1.5
Nitrite-N mg.l-1
0.01 0.06 0.12 0.3 >
0.3
Nitrate-N mg.l-1
1 3 6 15 >
15
Total-N mg.l-1 1.5
4
8
20
>
20
Ortho-phosphate-P mg.l-1
0.05 0.1 0.2 0.5 >
0.5
Total-P mg.l-1
0.1 0.2 0.4 1 >
1
Chlorophyll-a
µg.l-1
25 50 100 250 >
250
Metals (dissolved) **
Zinc
µg.l-1
- 5 - - -
Copper
µg.l-1
- 2 - - -
Chromium (Cr-III+VI)
µg.l-1
- 2 - - -
Lead
µg.l-1
- 1 - - -
Cadmium
µg.l-1
- 0.1
- - -
Mercury
µg.l-1
- 0.1
- - -
Nickel
µg.l-1
- 1 - - -
Arsenic
µg.l-1
- 1 - - -
Metals (total)
Zinc
µg.l-1
bg 100 200 500 >
500
Copper
µg.l-1
bg 20 40 100 >
100
Chromium (Cr-III+VI)
µg.l-1
bg 50 100 250 >
250
Lead
µg.l-1
bg 5 10 25 >
25
Cadmium
µg.l-1
bg 1 2 5 >
5
Mercury
µg.l-1
bg 0.1 0.2 0.5 >
0.5
Nickel
µg.l-1
bg 50 100 250 >
250
Arsenic
µg.l-1
bg 5 10 25 >
25
Toxic
substances
AOX
µg.l-1
10 50 100 250 >
250
Lindane
µg.l-1
0.05 0.1 0.2 0.5 >
0.5
p,p´-DDT
µg.l-1
0.001 0.01 0.02 0.05 >
0.05
Atrazine
µg.l-1
0.02 0.1 0.2 0.5 >
0.5
Trichloromethane
µg.l-1
0.02 0.6 1.2 1.8 >
1.8
Tetrachloromethane
µg.l-1
0.02
1 2 5 >
5
Trichloroethene
µg.l-1
0.02
1 2 5 >
5
Tetrachloroethene
µg.l-1
0.02
1 2 5 >
5
Biology
Saprobic index -
-
1.8
1.81 2.3 2.31 2.7 2.71 3.2 > 3.2
macrozoobenthos
*
values
concern
10-percentile
value
bg
background
values
**
for dissolved metals only guideline values are indicated
TV
target value
V 28
UNDP/GEF Danube Regional Project
For the purpose of classification, the data 1996-2000 had been processed and are presented in tables of
Annex 1. The classification scheme originally covers 37 determinands, out of which 29 are presented
in the report. The tables showing results of each determinand are sequenced in the Annex in the same
order as determinands in the classification scheme, given in Table 7.1.1. The group of metals in
dissolved phase is missing because number of available data in evaluated period 1996-2000 is not
sufficient to provide representative picture along the Danube River. Similarly in case of some other
determinands, like are AOX and volatile hydrocarbons there are parts of Danube River basin covered
rather sparsely.
The results of classification are given in tables prepared separately for each water quality determinand.
The rows of tables present sampling points, ordered in a way as they occur in a reality from the most
upper sampling point in Germany down to the mouth to Black Sea. Italic letters used for name of river
and location indicate tributaries.
Results characterising each year in a period from 1996-2000 are given in columns of tables. Both
calculated mean annual value and so-called "testing value" are given in a cell for each sampling site in
a year. Testing value was equal to 90 %-ile (10 %-ile for dissolved oxygen and lower limit of pH
value), if number of measurements in a year was at least eleven. If number of measurements in a year
was lower than eleven, the testing value was represented by maximum value from a data set (a
minimum value for dissolved oxygen and a lower limit of pH value).
Water quality classes in sampling points for each year were expressed by using the following colours:
blue colour
class I
green colour
class II
yellow colour
class III
orange colour
class IV
red colour
class V
It happened in some cases (Cd, Hg, p,p DDT, atrazine, trichloromethane) that limit of detection used
by country was higher than limit value for class II, representing the target value. In these cases only
statistics was calculated and presented in a table, but classification has not been done.
An agreed frequency of measurements has not always been kept in monitoring programme. Using blue
colour for figures presenting the statistical haracteristics in tables of Annex 1 expresses those results of
classification, which are based on very few (less than three) measurements and therefore are not
sufficiently reliable. An exception is saprobic index of macrozoobenthos, in case of which agreed
frequency of measurements is two times per year.
7.2.
Assessment of spatial changes of physico-chemical determinands
In each profile of the river the water quality reflects the effects of both natural and antropogenic
origin. In accordance to the type and extent of these processes water is differently affected in
particular sections along the river. To indicate the changes between locations or sections of the river,
visualisation by using the charts for each evaluated determinand is provided in the report. Where it is
relevant, the charts are also accomplished by target value indication for respective determinands,
providing also visualisation of the distance of real situation from this value.
In assessment ofspatial changes in water quality 57 monitoring stations are included, out of which 31
sites are located on the main course of the Danube River and 26 on the first and second tributaries.
They are illustrated in Table 7.2.1. in the order of their occurrence along the Danube River. This order
was also used in graphical presentations illustrating situation along the river.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 29
Table 7.2.1: List of Monitoring Sites located on the Danube River and its tributaries.
Country
River
Town/Location
Distance
River
Location
Section
Code
(km)
km
in
Profile
D01 Danube
Neu-Ulm
2581 2581 L
D03
/ Inn
Kirchdorf
195
/ 2225
M
D04
/ Inn / Salzach
Laufen
47
-
M
D02 Danube
Jochenstein
2204 2204 M
A01 Danube
Jochenstein
2204 2204 M
A02 Danube
Abwinden-Asten 2120 2120 R
A03 Danube
Wien-Nussdorf
1935 1935 R
CZ01
/ Morava
Lanzhot
79
/ 1880
R
UPPER
CZ02
/ Morava / Dyje
Breclav
17
-
R
A04 Danube
Wolfsthal
1874 1874 R
SK01 Danube
Bratislava
1869 1869 M
SK02 Danube
Medvedov/Medve 1806 1806 M
H01 Danube
Medve/Medvedov 1806 1806 M
SK03 Danube
Komarno/Komarom 1768 1768 M
H02 Danube
Komarom/Komarno
1768 1768 M
SK04 /
Vah
Komarno 1
/
1766
M
H03 Danube
Szob
1708 1708 LMR
H04 Danube
Dunafoldvar
1560 1560 LMR
H06
/ Sio
Szekszard - Palank
13
/ 1497
M
H05 Danube
Hercegszanto
1435 1435 LMR
HR01 Danube
Batina
1429 1429 M
SL01 /
Drava
Ormoz
300 -
L
HR03 /
Drava
Varazdin
288
-
M
HR04 /
Drava
Botovo
227
-
M
HR05
/ Drava
D. Miholjac
78
/ 1379
R
MIDDLE
H07
/ Drava
Dravaszabolcs
78
/ 1379
M
HR02 Danube
Borovo
1337 1337 R
H08
/ Tisza
Tiszasziget
163
/ 1215
LMR
H09
/ Tisza/ Sajo
Sajopuspoki
124
-
M
SL02 /
Sava
Jesenice
729 -
R
HR06 /
Sava
Jesenice
729
-
R
HR07
/ Sava
Us. Una Jasenovac
525
-
L
HR08
/ Sava
Ds. Zupanja
254
/ 1170
M
RO01 Danube
Bazias
1071 1071 LMR
RO02
Danube
Pristol/Novo Selo
834
834
LMR
BG01 Danube
Novo
Selo/Pristol 834
834
LMR
BG02
Danube
Us. Iskar - Bajkal
641
641
M
BG06 /
Iskar
Orechovitza
28
637
M
BG03 Danube
Ds.
Svishtov
554
554
MR
BG07 /
Jantra
Karantzi
12
537
M
BG04 Danube
Us.
Russe
503
503
MR
BG08 /
Russenski
Lom
Basarbovo
13
498
M
RO03 Danube
Us.
Arges
432
432
LMR
RO04 Danube
Chiciu/Silistra
375
375
LMR
RO09
/ Arges
Conf. Danube
0
/ 432
M
BG05
Silistra/Chiciu
375
LMR
LOWER
RO10 /
Siret
Conf.
Danube
-
0 /
154
M
Sendreni
MD01 /
Prut
Lipcani
658
-
L
MD02
/ Prut
Leuseni
292
-
M
MD03 /
Prut
Conf. Danube -
0 /
135
M
Giurgiulesti
V 30
UNDP/GEF Danube Regional Project
Country
River
Town/Location
Distance
River
Location
Section
Code
(km)
km
in
Profile
RO11 /
Prut
Conf.
Danube
-
0 /
135
M
Giurgiulesti
RO05 Danube
Reni-Chilia/KiliaArm
132
132
LMR
UA01 Danube
Reni-Kilia
Arm/Chilia
132 132 M
Arm
RO06 Danube
Vilkov-Chilia
18 18 LMR
Arm/Kilia Arm
UA02 Danube
Vilkov-Kilia
18 18 M
Arm/Chilia Arm
RO07
Danube
Sulina Sulina Arm
0
0
LMR
RO08
Danube
Sf. Gheorghe Sf. 0 0 LMR
Gheorghe Arm
Legend for Table 7.2.1:
-
River: The water course where the sampling site is located
-
Distance: The distance (km) from the mouth of the considered river
-
River km (rkm): The Danube River km (from confluence with the Black Sea) where the sampling site
is located
-
/ Tributary
-
Us. Upstream of
-
Ds. Downstream of
-
Conf.: Confluence tributary / main river
-
Location in profile:
o L left bank of the river
o M middle of the river
o R right bank of the river
-
Section:
o Upper Danube
o Middle Danube
o Lower Danube
According to a previous approach (Joint Danube Survey Technical Report, 2002) and to a regional
agreement among the Danube countries, the Danube Basin was divided into three main sections for the
purpose of assessmen (Fig. 7.2.1):
- Upper Section: from Danube-Neu Ulm (km 2581, D01) to Danube-Wolfsthal (km 1874, A04),
comprising of 6 monitoring sites;
- Middle Section: from Danube-Bratislava (km 1869, SK01) to Danube-Borovo (km 1337,
HR02), comprising of 10 monitoring sites;
- Lower Section: from Danube-Bazias (km 1071, RO01) to Danube-Sf. Gheorghe/Sf. Gheorghe
arm (km 0, RO08) comprises 15 monitoring sites. In order to make the charts more clear and
due to the fact that entire lower section has more than 1000 km length, this section was further
divided into two parts. Second part of the lower section starts in Danube-Us. Arges (km 432,
RO03).
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 31
v
a
ra
h
t
t
i
sza
r
ges
e
u
Va
T
Mo
A
Sir
Pr
r
n
o
v
a
In
a
v
a
r
a
Si
I
ska
Dr
Sa
2800
2400
2000
1600
1200
800
s
s
.
Lom
J
ant
u 400
0
R
Lower I
Lower II
Upper
Middle
rkm
Tributaries-L
Danube-L
Danube M
Danube-R
Tributaries-R
Fig. 7.2.1: Selected monitoring sites
Legend for Fig. 7.2.1:
-
Danube-L: the left bank of the Danube River
-
Danube-R: the right bank of the Danube River
-
Tributary-L: tributary for which the confluence is located on the left side of the Danube River
- Tributary-R: tributary for which the confluence is located on the right side of the Danube River
Physico-chemical determinands selected for the assessment have been divided to five groups in
accordance to Table 7.2.2.
Table 7.2.2.: List of selected physico-chemical determinands for water quality assessment
Group of
determinands
Determinand
Unit
General
Suspended Solids (SS)
mg/l
characteristics
pH -
Conductivity µS/cm
Alkalinity mmol/l
Nutrients
Ammonium-N (N-NH +
4 ) mg/l
Nitrite-N (N-NO -2) mg/l
Nitrate-N (N-NO -3) mg/l
Ortho-phosphate-P (P-PO 3-
4 ) mg/l
Total Phosphorous
mg/l
Oxygen regime
Dissolved oxygen (concentration)
mg/l
Biochemical Oxygen Demand (BOD5) mg/l
Chemical Oxygen Demand by K2Cr2O7 (CODCr) mg/l
Chemical oxygen demand by KMnO4 (CODMn) mg/l
Heavy Metals
Iron (Fe)
mg/l
Manganese (Mn)
mg/l
Zinc (Zn)
µg/l
Copper (Cu)
µg/l
Chromium total (Cr)
µg/l
Lead (Pb)
µg/l
Cadmium (Cd)
µg/l
Mercury (Hg)
µg/l
V 32
UNDP/GEF Danube Regional Project
Group of
determinands
Determinand
Unit
Nickel (Ni)
µg/l
Arsenic (As)
µg/l
Organic
Lindan µg/l
micropollutants
pp'-DDT µg/l
Atrazine µg/l
Chloroform µg/l
Carbon tetrachloride
µg/l
Trichloroethylene
µg/l
Tetrachloroethylene
µg/l
The basis for the evaluation was 90 %-ile (c90) for each considered determinand (90 percentile
method has the advantage that extreme values caused by exceptional conditions or measuring errors
are not taken into account, but still represents "unfavourable" situation that occurred in monitoring site
in a year). For dissolved oxygen content 10%-ile data were considered, but maximum and minimum
values were also taken into account.
Here is necessary to stress that whilst for assessment of spatial and temporal changes c90 was used, in
classification c90 value was used in all those cases when frequency of measurements of determinand
in a year was at least 11. In case of lower frequency, testing value as a basis for classification was
maximum value from a data set, as was explained in a chapter 7.1. Therefore, c90 value in charts
presented in evaluation part of the report can differ from numerical value given in classification tables
at a place of "testing value".
There are two main types of the charts used for illustration of determinands. The first type is a bar
chart presenting 90 %-iles calculated for each year in all monitoring sites measured in TNMN (it
means that in case of measurements made on right side, left side and in the middle of a profile the data
from all three sites are presented). The distance between monitoring sites is proportional on the x-axis.
This type of chart is made separately for Danube River and for tributaries.
The second type is x/y chart with river kilometres on x-axis. The chart is prepared separately for
Danube River itself and for tributaries again. In case of presenting tributaries concentrations are
plotted at the river km of the confluence of the tributary with the Danube. Therefore, in the Table
7.2.1. also river km of confluence with Danube is given for tributaries. In this type of chart a lne is
added displaying the target value equal to class II limit value. By comparing the real values against the
distance from target value can be seen.
7.3.
Trend Analysis
After five years of monitoring the question rises whether water quality in the Danube River Basin
improves, remains stable or get worse. Many changes took place regarding the economic situation in
the countries, industrial production, agricultural methods, land use and protection of environment. The
human impact on rivers might differ now from that of 1996. In the meantime the physical, chemical
and biological characteristics of the Danube and its tributaries have also varied because they are
dependent on hydrological conditions and climate. There are the natural trends in water quality that
reflect either short-term or long-term changes and cyclic repetitions like daily, seasonal or longer
periodicity. Taking this in consideration five years are not very much for trend analysis.
Several methods for trend analysis are described in literature. Nearly every software used for
calculation or data base has a tool for adding trend line to time-series plots. However without having
any information on the behaviour of the determinands no serious evaluation can be done. To calculate
trend lines as a precondition periodic cycles have to be substracted from the time-series. Afterwards
the quality of the so called trend model has to be proved e.g. by checking the distribution frequency of
the square deviations from the line. To apply these procedures for time-series analysis sufficient data
of high quality is needed and much information on the processes, which steer the environmental
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 33
turnover of a substance, should be available. Within the TNMN network about 60 samples should be
stored for every determinand, but actually there are much less particularly for specific pollutants. For
some determinands few samples may be sufficient if there is no seasonal periodicity and if fluctuations
of values are either random or very strong dependent on a known predicting variable. While only few
determinands fulfil these preconditions it was decided to firstly use a very simple approach for trend
analysis comparing to the models mentioned above.
The simple approach for trend assessment is based on the comparison of statistical parameters of
yearly data sets. According to the parameter different situations can be evaluated, the choice is
dependent on the target of the analysis. Critical situations can be expressed best by the 90percentile (or
10percentile for pH and dissolved oxygen) of a yearly data set. As they occur naturally or as a result of
human impacts it often appears difficult to interpret the year-on-year variations. To calculate
90percentiles mathematically reliable a sufficient number of samples per year are required, too.
Although all data sets, which consist of more than five samples, were considered, valid statements can
only be given for some determinands where more samples are available.
The trend assessment was carried out for all monitoring sites of the TNMN. At sites where samples are
taken from left, middle and right only the middle was used. In general the different riversides fit quite
well together. For the year 1996 the differences are often higher than for other years and for some
nutrients (ammonia, ortho-phosphate phosphorus and total phosphorus) and heavy metals greater
deviations have to be observed, too. A systematic difference is monitored for Kilia-arm at Reni: values
of CODCr of the left side exceed that of the right side.
7.4.
Evaluation of biological determinands
An integral part of TNMN are biological determinands and MLIM-EG exerted a big effort to
harmonise methodologies of their measurements and evaluation to assure their comparability
throughout the River basin and to utilise their potential of being good indicators of water quality. In
TNMN Phase I chlorophyll-a, macrozoobenthos and microbiological determinands had been
measured.
Phytoplankton biomass concentration of the chlorophyll-a
Chlorophyll-a is the essential photosynthetic pigment present in all green plants. The chlorophyll
content in surface water is an indicator of its trophic state. The determination of the chlorophyll-a
concentration provides information concerning the quantity and potential photosynthetic activity of the
algae in the water column. The ratio of chlorophyll to phaeopigments (important metabolites of
chlorophylls) is indicative of the physiological state of the algae.
Phytoplankton together with phytobenthos and water macrophytes reflect the primary production in
the watercourses. Therefore it is important community to investigate it. Increase of the phytoplankton
biomass is one of the characteristics of the eutrophication in the rivers. Eutrophication of the large
rivers is caused by input of the nutrients in excess in combination with other factors like suitable light,
temperature, transparency. High level of eutrophication lead to negative consequences for the river
itself and reservoirs in particular (Wetzel, 1983).
Development of the phytoplankton biomass can be measured also as a concentration of the
chlorophyll-a. For this purpose the method of ISO 10260 (1992) was recommended. Method consists
of four steps (collection of algae from water by filtration; extraction of algal pigments from the filter
residue into hot ethanol; spectrometric determination of chlorophyll-a concentration in the extract and
evaluation of the chlorophyll-a and phaeopigment from the difference in absorbance prior to and after
acidification of the extract).
V 34
UNDP/GEF Danube Regional Project
Based on the TNMN database from the period 1996-2000 the statistical processing of selected
characteristic values was used for individual year. In case of less than 3 measurements existing in a
year, no value was used. Up to 10 measurements a maximum was used as a characteristic value. If
more data were available 90 percentile was calculated. If the chlorophyll-a was measured at cross
section of the river (left, middle and right), the mean value of three sites was taken into account.
Characteristic values categorized individual TNMN stations according to the classification scheme
(tab. 7.4.1).
Tab.7.4.1: Classification scale of the quality class for the chlorophyll-a concentration.
CLASSIFICATION SCALE
I.
II.
III.
IV.
V.
High
Good
Moderate
Bad
Very bad
status
status
status
status
status
µg/l of the chlorophyll-a
25
50
100
250 >250
Saprobic index of macrozoobenthos
Macroscopic organisms macroinvertebrates create the important part of the aquatic community. In
accordance with specific autecological demands for life in the aquatic environment, individual species
react in different ways to variations in its physical and chemical state like diffuse and point sources
pollution, light, temperature, flow velocity, oxygen condition and the structure of the river bed.
Macrozoobenthos taxa are space and/or food competitors with different feeding habitats and they are
capable to self-regulate their population size. They also depend on other biological compartments, in
particular on micro-organisms, whose metabolic activity can lead to negative effect on the oxygen
budget of the water body and its fauna during decomposition of great amounts of organic substances
(saprobity).
Within the TNMN the standard operational procedure have been proposed to monitor
macrozoobenthos in the Danube river and its tributaries. The SOP covered macroinvertebrates only and
was focused on the numerical evaluation for the system of saprobity by means of the Saprobic Index.
The macroinvertebrates sampling and biological assessment was a first step in the development of a
more comprehensive ecological assessment of the river water quality. There were a few sampling
methods, level of taxa identification and numerical evaluation suggested. For TNMN it was
recommended to use the Pantle & Buck formula, modified by Zelinka & Marvan:
i
h si iI
SI =
i
h iI
with: hi = quantity of species i in sample
Ii = weight of species i in sample.
si = saprobic index of species i.
The quantity (h) in the formula can be expressed as an estimation of the number of individuals in the
sample based on 5 class scale. The Saprobic Index ranges from 1 to 4 and is in current practice divided
into 4 or 7 classes covering the range from xenosaprobic to polysaprobic. SOP proposed five class
scale to evaluate biological results for TNMN (see table 7.4.2).
Tab. 7.4.2: Proposal for classification of Saprobic Index in the natural rivers in Danube basin.
Class
I II III IV V
Saprobic Index
< 1.8
1.81-2.3
2.31-2.7
2.71-3.2
>3.2
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 35
Whilst the results of saprobic index classification in accordance to TNMN classification scheme are
presented in Annex 1, in the special chapter dedicated to biological determinands (chapter 8.2) the
seven-class scale was used based on the Saprobic Index in accordance to Austrian standard ÖNORM
M6232. The reason is that this scale is more detailed, mainly in the range of the first three classes (see
table 7.4.3).
Tab. 7.4.3: Classification scale based on the Saprobic Index (in accordance to Austrian standard
ÖNORM M6232).
I.
I.-II.
II.
II.-III.
III.
III.-IV.
IV.
CLASSIFICATION
moderately criticaly strongly very high extensively
SCALE
unpolluted low
polluted polluted
polluted polluted
polluted
polluted
1,25
1,75
2,25
2,75
3,25
3,75 >3,75
Based on the TNMN database from the period 1997-2000 the statistical processing of selected
characteristic values was used for individual year. Usually 3-4 measurements were done by the
individual countries. Characteristic values (maximum for individual year) categorized individual
TNMN stations according to the above mentioned classification scale.
Microbiological determinands
Heterotrophic bacteria play a decisive role in river ecosystem in degrading organic matter. Their
contribution to self purification processes of rivers is of great interest within a scope of water quality
assessment. Bacteria are ideal sensors because of their fast response to changing environmental
conditions (Kavka, 2002).
Bacterial indicators such as total coliforms, faecal coliforms (thermotolerant coliforms), E.coli, faecal
streptococci (enterococci) and colony counts are widely applied to the assessment of water quality. On
one hand, because of their mainly allochthonous origin, these standard parameters are used as
indicators of change in the natural stage of rivers. On the other hand, they indicate anthropogenic
impact such as faecal pollution in the water. E.coli and faecal coliform bacteria are the best indicators
for assessment of faecal pollution, mainly caused by raw and treated sewage and e.g. diffuse impact
from farmlands and pastures. Faecal indicators are excreted by humans and warm-blooded animals
treated to a large extent in sewage treatment plants and ultimately found in aquatic environment where
they survive for a relatively long time. E.coli and faecal coliforms also indicate the potential presence
of pathogenic bacteria, viruses and parasites (Kavka, 2002).
For the TNMN database Total Coliforms, Faecal Coliforms, Faecal Streptococci (enterococci) and
Salmonella sp. were proposed for monitoring. However data on Faecal Streptococci and Salmonella
sp. are for evaluated period (1996-2000) insufficient. Therefore only Total Coliforms and Faecal
Coliforms were processed for the purpose of this report.
Total Coliforms usually contained typical coliform bacteria (Escherichia coli, Klebsiella sp.,
Citrobacter sp., Enterobacter sp.). For TNMN the proposed method was according to the ISO 9308-
1:1990. Method is based on membrane filtration, cultivation (mEndo-Agar LES, Difco) and incubation
of 24 hours at 37şC.
For the Faecal Coliforms (thermotolerant coliform bacteria) the method of ISO 9308-1:1990 was
recommended. Method is based on membrane filtration, cultivation (mFC medium, Difco) and
incubation of 24 hours at 44şC.
Base on the TNMN database from the period 1996-2000 the statistical processing of selected
characteristic values was used for individual year. In case of less than 3 measurements exist in a year,
no value was used. Up to 10 measurements a maximum was used as a characteristic value. If more
V 36
UNDP/GEF Danube Regional Project
data were available 90 percentile was calculated. If the analyses of bacteria were provided at cross
section of the river (left, middle and right), the mean value of three sites was taken into acount.
TNMN classification does not contain limit values for microbiological deterinands. Therefore, the
classification scale given in table 7.4.4 was used to categorize water quality from the point of view of
microbiological pollution in TNMN stations.
Table 7.4.4: Classification system of Kohl (1975), the EU-Bathing Water Quality Directive 76/160
EEC and new EU expert proposals (verbal information) were taken into account.
CLASSIFICATION SCALE
I.
II.
III.
IV.
V.
POLLUTION Low
Moderate
Critical
Strong
Extensive
Total Coliforms (CFU/100 ml)
500
10000
100000
1000000 >1000000
Faecal Coliforms (CFU/100 ml)
100
1000
10000
100 000
>100000
7.5.
Comparison of TNMN results 1996-2000 with Environmental Quality
Standards of EU legislation
7.5.1. Introduction
With the publication of the Water Framework Directive (EC 2000) in December 2000 a new legal
basis for the protection of ground and surface waters within the European Union has been put into
force. One of the objectives of the Water Framework Directive (WFD) is to achieve a "good surface
water status" for all surface waters irrespective of their size until 2015. Regarding dangerous
substances this means that all environmental quality standards (EQS) "established
· in Annex IX
· and under Article 16(7) of the WFD
· and under other relevant Community legislation setting EQS at Community level" have to be
met.
Annex IX of the WFD lists the daughter directives of the Dangerous Substances Directive (EEC 1976,
EEC 1982, EEC 1983, EEC 1984/1, EEC 1984/2, EEC 1986). This legislation stipulates the EQS for
the seventeen so called List 1 substances (see Table 7.5.1.1).
Table 7.5.1.1 Environmental Quality Standards for List 1 substances according to the daughter
directives of Council Directive 76/464/EEC (Dangerous Substances Directive, EEC
1976)
List 1 Substance
CAS number
Directive
EQS water
EQS
EQS
µg/l
sediment
biota
Cadmium 7440-43-9
83/514
1
a), b) Standstill e) Standstill
c)
DDT total
86/280
d)
0,025
Standstill e) Standstill
f)
1,2-Dichloroethane 107-06-2 86/280 10
Drins
86/280
g)
0,01
Standstill e) Standstill
f)
Hexachlorobenzene 118-74-1 86/280 0,03
Standstill
e) Standstill
f)
Hexachlorobutadiene 87-68-3 86/280
0,1
Hexachlorocyclohexane
608-73-1 84/491
h)
0,05
Standstill e) Standstill
f)
Pentachlorophenol 87-86-5 86/280 2
Standstill
e) Standstill
f)
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 37
List 1 Substance
CAS number
Directive
EQS water
EQS
EQS
µg/l
sediment
biota
0.3 mg/kg i)
Mercury 7439-97-6
82/176,
84/156
1
b)
Standstill e)
Standstill j)
Tetrachloroethene 127-18-4
86/280 10
Tetrachloromethane 56-23-5 86/280 12
Trichlorobenzene 120-82-1
86/280 k)
0,4
Standstill e) Standstill
f)
Trichloroethene 79-01-6
86/280
10
Trichloromethane
127-18-4
86/280
12
a) Without direct impact of a discharge, otherwise 5 µg/l
b) Total metal concentration
c) Mollusks and shellfish (if possible, mytilus edulis)
d) p,p'-DDT 0,01 µg/l, DDT total comprises p,p'-DDT, o,p'-DDT, p,p'-DDE and p,p'-DDD
e) optional to standstill in biota
f)
Standstill in Fish and/or mollusks and/or shellfish
g) Endrin and Isodrin 0,005 µg/l
h) Without direct impact of a discharge, otherwise 0,1 µg/l. The directive does not specify to which isomer the
limit value relates
i)
For Fish, wet weight
j)
Mollusks and shellfish (optional to sediments)
k) Related to the sum of three isomers
Article 16 of the WFD summarizes the strategies against pollution of water. In 16(2) the European
Commission is obliged to submit a list of priority substances "which present a significant risk to or via
the aquatic environment". With Decision 2455/2001/EEC (EC 2001) this obligation was fullfilled and
a first list of priority substances published. For the time being no binding EQS have been set for these
compounds but on behalf of the European Commission the Fraunhofer-Institute (FHI) for Molecular
Biology and Applied Ecology (Schmallenberg, Germany) carried out a study which aimed to derive
EQS for the priority substances based on ecotoxicological data according to the procedure laid down
in Annex V, 1.2.6 of the WFD (FHI 2002). This proposal is available now and the EQS will be put
into force with minor modifications in 2003/2004. The priority substances and the proposed quality
objectives are given in Table 7.5.1.2.
Table 7.5.1.2: List of Priority Substances according to Decision 2455/2001/EC and Overall
Environmental Quality Standards for Inland and Transitional Waters proposed by FHI
Priority Substance
CAS number
EQS FHI
[µg/l]
Alachlor 15972-60-8
0,035
Anthracene 120-12-7
0,063
Atrazine 1912-24-9
0,34
Benzene 71-43-2
16
a)
Brominated diphenylethers
32534-81-9
0,0005 b)
Cadmium and its compounds
7440-43-9
0,08 c)
C10-13-chloroalkanes 85535-84-8
0,41
Chlorfenvinphos 470-90-6
0,01
Chlorpyrifos 2921-88-2
0,00046
1,2-Dichloroethane 107-06-2
10
d)
Dichloromethane
75-09-2
8,2
Di(2-ethylhexyl)phthalate (DEHP)
117-81-7
0,33
V 38
UNDP/GEF Danube Regional Project
Priority Substance
CAS number
EQS FHI
[µg/l]
Diuron 330-54-1
0,046
Endosulfan
115-29-7
0,004
alpha-Endosulfan
959-98-8
Fluoranthene 206-44-0
0,12
Hexachlorobenzene 118-74-1
e)
Hexachlorobutadiene 87-68-3
0,003
Hexachlorocyclohexane
608-73-1
0,042
(gamma-isomer,
Lindane)
58-89-9
0,02
Isoproturon 34123-59-6
0,32
Lead and its compounds
7439-92-1
1 c)
Mercury and its compounds
7439-97-6
0,036 c), f)
Naphthalene 91-20-3
2,4
Nickel and its compounds
7440-02-0
0,6 c)
Nonylphenols
25154-52-3
(4-(para)-nonylphenol)
104-40-5
0,33
(4-nonylphenol,
branched)
84852-15-3
Octylphenols
1806-26-4
0,1
(para-tert-octylphenol)
140-66-9
Pentachlorobenzene 608-93-5
0,05
Pentachlorophenol 87-86-5
0,1
Polyaromatic hydrocarbons
(Benzo(a)pyren)
50-32-8
(Benzo(b)fluoroanthene)
205-99-2
e)
(Benzo(g,h,i)perylene)
191-24-2
(Benzo(k)fluoroanthene)
207-08-9
(Indeno(1,2,3-cd)pyrene)
193-39-5
Simazine 122-34-9
1
Tributyltin compounds
688-73-3
0,0001
(Tributyltin-cation)
36643-28-4
Trichlorobenzenes
12002-48-1
(1,2,3-Trichlorobenzene)
87-61-6
1,8
(1,2,4-Trichlorobenzene)
120-82-1
(1,3,5-Trichlorobenzene)
108-70-3
Trichloromethane (Chloroform)
67-66-3
3,85
Trifluralin 1582-09-8
0,03
a) No proposal for an overall QS was made in the FHI study. Specific QS derived for the protection of aquatic
life is given.
b) Individual substances are very different regarding their physico-chemical properties and toxic potential. QS
for the most harmful individual compound Pentabromo diphenylether is given.
c) Maximum permissible addition (MPA) according to the "Added Risk" approach for the QS derivation of
metals, for details see text.
d) No proposal for an overall QS was made in the FHI study. EQS of CD 86/280/EEC currently in force is
given (see also Table 1)
e) No proposal for an overall QS was made in the FHI study.
f)
No proposal for an overall MPA was made in the FHI study.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 39
The other, above-mentioned "Community legislation setting EQS at Community level" comprises
application-oriented directives containing EQS for specific water uses, which are of regional and not
of general significance. These EQS are not further considered within this report.
In 1996-2000 a number of List 1 and Priority Substances were analysed within TNMN in Danube
River and tributaries (see Table 7.5.1.3).
Table 7.5.1.3: List 1 and Priority Substances observed within TNMN in the time period
1996- 2000 and TNMN substance code
Substance
List 1
Priority
TNMN Code
Substance
Substance
Atrazine
X
4.75
Cadmium (total)
X
3.65
Cadmium (dissolved)
X
3.66
p,p'-DDT X
4.65
Lead (dissolved)
X
3.61
Lindane (gamma-Hexachlorcyclohexane)
X
X
4.60
Mercury (total)
X
3.70
Mercury (dissolved)
X
3.71
Nickel (dissolved)
X
3.76
Tetrachloroethene X
4.95
Tetrachloromethane (Carbon tetrachloride)
X
4.85
Trichloroethene X
4.90
Trichloromethane (Chloroform)
X
4.80
With respect to the fact that two riparian countries of the Danube River are member states of the
European Union and another four will join the community in near future and therefore are obliged to
implement the WFD it seems very interesting to compare these results with already valid and future
EQS.
Motivation for such an assessment is
· identification of possible problems with exceeding substance concentrations
· identification of data gaps
· recommendations for the analysis of List 1 substances and PS in future based on experiences
in compliance checking of this report
7.5.2. Testing
for
compliance
Choice of statistical quantity
In Annex V, 1.2.6 of the WFD dealing with the derivation procedure for EQS is stated that quality
objectives should be laid down by "setting of a maximum annual average concentration". No further
guidance is given for compliance checking. For List 1 substances this is specified in more detail in the
daughter directives of CD 76/464/EEC: the arithmetic annual mean of analytical results shall be used
to check the compliance with EQS. On EC level the Expert Advisory Forum Priority Substances (EAF
- an expert advisory panel supporting the European Commission in implementing the WFD) has
agreed to use the arithmetic mean at least for the discussion of the proposal of EQS for Priority
Substances. There are still other statistical quantities in discussion for compliance checking, namely a
combination of mean and a maximum allowable concentration (MAC) and the 90 percentile, but for
V 40
UNDP/GEF Danube Regional Project
the time being the annual arithmetic mean is the preferred statistical quantity. For this reason the mean
was selected too to compare TNMN data with EQS for the purpose of this report. (Note: Due to the
fact that for comparison of TNMN data with EQS of EU legislation the the mean was used, the values
presented in chapter 8.1.6 are different than those presented by charts in chapters 8.1.3 and 8.1.5,
where c90 was used).
Dealing with "less than" values
For the time being no information can be found in EC legislation or guidance documents how to
handle data below the detection limit when calculating the mean. This is a very important detail
because in certain cases (EQS close to the limit of detection of the analytical method, many less than
values) the chosen convention resp. method can influence the results of the compliance check
dramatically. It is common practice to use simple substitution methods for taking into account less
than values. The problem associated with this methods is that they have no theoretical basis and are
defined by convention. The mean is biased and deviates more or less from the real location (HELSEL
2002). In TNMN yearbooks the mean is calculated by substituting the less than values with the limit of
detection (LOD) of the specific analytical method. Although this is a very pesimistic approach because
the mean is definitely shifted to higher concentrations in comparison with its true location this method
was used for the purpose of this report to keep comparability with the yearly evaluations (this
convention is named "LOD-method"). For some substances an additional evaluation using the most
optimistic approach for calculation of the mean by setting the less then values to zero has been
included to show the influence of the averaging method (called "Zero-method" in the following text).
Dealing with EQS lower than LOD
Derivation of EQS on a ecotoxicological basis sometimes results in a very low concentration as limit
value which is out of range of the available analytical methodologies. Although this problem is evident
for a number of Priority Substances it hasn't been tackled on EU level. One proposal to be discussed is
to use the LOD as substitute for the actual EQS value. Of course this approach needs a harmonisation
of methods or at a least the definition of minimum requirements regarding the LOD to avoid different
limit values in the respective states. Whether a data set including some less than values gives
compliance or non-compliance again depends on the convention used for calculating the mean. The
"LOD-method" results in a non-compliance with only one figure above LOD (see also related text in
an evaluation part of the report).
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 41
8.
Assessment of Water Quality
The assessment of water quality in Danube River basin in the report is divided into two basic parts
assessment on the basis of physico-chemical determinands and assessment of biological determinands.
Chapter 8 is dedicated to assessment on the basis of physico-chemical determinands. It is structured in
a way, that for each evaluated determinand information on results of classification are given (on the
basis of tables with results of classification in the Annex 1), followed by information on spatial
changes and trend assessment in Danube River itself and tributaries. This chapter is supplemented by
sub-chapter 8.1.6 dealing with comparison of available TNMN data on hazardous substances with
Environmental Quality Standards of European Union legislation and with proposed EQS for priority
substances.
Results of water quality assessment based on biological determinands are given in chapter 8.2.
8.1. Assessment of water quality based on physico-chemical determinands
8.1.1. General
Characteristics
Suspended solids
Suspended matter comprises the quantity of insoluble substances in water that can be separated by
filtration, centrifugal action and sedimentation. Insoluble substances, composed by organic and
inorganic particles, can be both rough dispersions (particles size above 0.1 mm) and fine dispersions
(particle size between 0.1 mm and 0.1 µm). Depending on size and specific gravity these particles are
settling, remaining in suspended form or floating on the water surface.
In assessment of river water quality, strong correlation of suspended solids content with the flow
discharge conditions must be taken into account. Several determinands measured in frame of TNMN
are highly dependent on suspended solids content in waters, like total P, heavy metals (if sample is
not filtered before analysis) and specific organic micropollutants with affinity to solid particles.
For the Danube River itself, the spatial pattern of suspended solids variation is shown in Fig. 8.1.1.1a
and Fig. 8.1.1.1b.
As it can be seen, in the upper section of the Danube River, excepting the first monitoring station,
Danube-Neu Ulm (km 2581, D01), where the concentration values are below 35 mg/l, all the other
values show a relative uniform profile of spatial pattern. Still, an increasing spatial line is noticeable
along this stretch.
For the middle section, suspended solids concentrations decrease from Danube-Bratislava (km 1869,
SK01) down to Danube-Medvedov/Medve (km 1806, SK02) due to sedimentation process in
Gabcikovo dam. For the following part of this stretch, the spatial pattern remains constant down to
Danube-Hercegszanto (km 1435, H05). Slight higher concentrations, exceeding 100 mg/l in 2000, are
present at Danube-Batina (km1429, HR01) and Danube-Borovo (km 1337, HR02), in conditions of
discharge of 4305 m3/s and 4464 m3/s, respectively.
In the first part of lower section, most of the suspended solids concentration values are higher than in
the middle section, but a decreasing tendency from Danube-Bazias (km 1071, RO01) down to
Danube-us. Russe (km 503, BG04) can be noticed.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 42
160
140
120
100
/l
g
80
m
60
40
20
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
0
1
0
2
0
1
0
2
0
3
0
4
0
3
0
4
0
5
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A0
A0
A0
A0
SK0
SK0
H0
SK0
H0
H0
H0
H0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
lower I
lower II
Monitoring site
upper
middle
1996
1997
1998
1999
2000
Fig. 8.1.1.1a: Spatial variation of Suspended Solids content Danube River
160
140
120
100
/
l
80
mg
60
40
20
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
Fig. 8.1.1.1b: Spatial variation of Suspended Solids content Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 43
The second part of the lower Danube section shows a relative constancy, but the suspended solids
level is higher than in the previous part: here many values exceed 80 mg/l, while just a few of them are
above this value in the first part. A few higher values are recorded at Danube-us. Arges (km 432,
RO03) and at Danube-Chiciu/Silistra (km 375, RO04), but these concentration values are not very
well in correlation with those reported for the same location but different site - Danube-Silistra/Chiciu
(km 375, BG05).
The maximum values from this stretch belong to Danube-Silistra/Chiciu (km 375, BG05) and to
Danube-Vilkov-Kilia arm/Chilia arm (km 18, UA02): 140.0 and 141.4 mg/l, respectively.
Selected tributaries generally present a higher suspended solids content than the Danube itself Fig.
8.1.1.2a, 8.1.1.2b and 8.1.1.3:
- in the upper section, the Inn-Kirchdorf (D03) - 315 mg/l in 2000 and 158.4 mg/l in 1996 and
the Morava-Lanzhot (CZ01) - 154.8 in 1996 versus 83.1 mg/l, represent the maximum value
in the Danube River in this section;
- in the middle section, the Sio-Szekszard-Palank (H06) shows 140.8 mg/l in 1999 and 116.0
mg/l in 1998 versus approx. 50.0 mg/l for the upstream/downstream monitoring sites, Danube-
Dunafoldvar (H04) and Danube-Hercegszanto (H05); but the maximum values for tributaries
located in this stretch belong to the Tisza-Tiszasziget (H08) 336.6 mg/l (L), 372.9 mg/l (M)
and 414.0 mg/l (R) in 1998. The values above 100 mg/l appear also on the Sava-Jesenice
(HR06) and Sava-us. Una Jasenovac (HR07), in 1998;
- from tributaries the highest suspended solids content belongs to those from the lower section,
where the Russenski Lom-Basarbovo (BG08) is characterized by values ranging between
252.6 mg/l and 569.8 mg/l. Also the Siret-Conf. Danube-Sendreni (RO10) and Prut-Conf.
Danube Giurgiulesti present rather high concentrations 308.3 mg/l in 1998 and 278.0 mg/l
respectively, in 2000.
V 44
UNDP/GEF Danube Regional Project
600
500
400
g
/l 300
m
200
100
0
3
4
1
2
4
6
3
4
7
5
8
9
6
7
8
6
7
8
9
0
1
0
0
1
2
1
2
3
0
0
0
0
0
0
1
0
0
1
0
D0
D0
H0
H0
H0
H0
CZ
CZ
SK0
Sl
HR0
HR0
HR0
Sl
HR0
HR0
HR0
BG
BG
BG
RO
RO
MD
MD
RO
MD
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring sites / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.1.2a: Spatial variation of Suspended Solids content Tributaries
600
500
400
300
g
/l
m
200
100
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
Fig. 8.1.1.2b: Spatial variation of Suspended Solids content Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 45
400
350
300
mg/l
250
200
150
100
50
0 D03
D04
CZ01 CZ02 SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06 HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.1.3:
Temporal trends of Suspended Solids content Tributaries
V 46
UNDP/GEF Danube Regional Project
pH
Hydrogen ion concentration, expressed in the form of pH value, is an important property of natural
waters influenced by the substances dissolved in the water and influencing chemical reactions and the
ability of water to bring other substances into solution. Beside, it represents an important factor that
determines the water reactivity, its aggressiveness and its capacity of supporting life and growth of
different organisms. Between the pH value and alkalinity or acidity value, no identity can be
emphasized: increasing in either alkalinity or acidity is not visible in increasing or decreasing of pH
value, due to the buffer capacity of natural waters, particularly. The main buffer system of natural
water is composed by acid carbonates/carbonates, for a pH range of 6.50 8.50 (Varduca, 1997).
Concerning the Quality Classification System in the Danube River Basin applied to pH values (Fig.
8.1.1.4), the following remarks can be done:
- the evaluation is based on data recorded from 87 monitoring sites (it means that out of the
assessment is 16 monitoring sites from Phase I List of Monitoring Sites, in which no
measurements of pH had been done in 1996-2000);
- more than 70 % of considered monitoring sites belong to Class II, with a maximum of 90.8 %
in 1999;
- Class III is represented in all five studied years, with a maximum of 16.1 % in 1997;
excluding Danube-Bazias (RO01-middle, rkm 1071), all cases of non-compliance with class II
are caused by exceedance of upper limit set up for pH value. Therefore, the figures illustrating
pH are concentrated on the "upper" border of target value.
- the percentage for monitoring sites with no reported data slowly decreases from 1996 to 2000.
pH
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.1.4: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for pH
The spatial variation of pH values along the Danube River, shown in Fig. 8.1.1.5a, has the following
pattern:
In the upper section, pH values show a slight alkaline medium; with the exception of only one value -
8.14 - in 1999 at Danube-Jochenstein (km 2204, D02), all the other values are in the range 8.20 8.60.
Spatial distribution shows also that between Danube-Jochenstein (km 2204, D02) down to Danube-
Wien-Nussdorf (km 1935, A03) an increasing tendency is present.
Taking into account the spatial pattern of 90%-iles of pH along the Danube River, just in the middle
section is the majority of values not-satisfying the upper limit of pH target values. Between Danube-
Medve (km 1806, H01) down to Danube-Hercegszanto (km 1435, H05) a maximum values were
observed - pH in the range 8.6-8.8 - followed by a decreasing tendency of pH values down to 7.80 at
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 47
Danube-Borovo (km 1337, HR02). These long-term monitoring values correlate well with previous
data (Joint Danube Survey Technical Report, 2002), this variation being caused mainly by the balance
between the increased primary production followed by the increased organic matter decomposition.
The decreasing visible in the last part of the middle stretch seems to be valid also for the first part of
the lower Danube, between Danube-Bazias (km 1071, RO01) and Danube-Pristol/NovoSelo (km 834,
RO02), although a few values exceed pH 8.20. (Still, differences of 0.20-0.40 pH units could be
detected between the recorded values for the same cross section - km 834: RO02/BG01). For the
stretch located between Danube-ds. Svishtov (km 554, BG03) and Danube-us. Russe (km 503, BG04)
spatial distribution presents a scattered profile: rather different values are recorded at the same location
but in different years - 7.49 in 1996 and 8.52 in 1997 at Danube-us. Russe (km 503, BG04 M and R).
In the second part of the lower Danube, between Danube-us. Arges (km 432, RO03) down to the main
arms of the Danube Delta (km 0, RO07 and RO08) an increasing tendency in pH values is recorded,
especially in year 2000, when most pH values are within the range 8.42 8.50, showing the same
slightly alkaline medium.
Selected tributaries do not show significant differences among the pH values Fig. 8.1.1.6a.
- Concerning the number of pH values exceeding the target value (8.50) during the five
evaluated years, 21 values are above this limit in the Danube itself and 7 values in selected
tributaries - Fig. 8.1.1.5b and 8.1.1.6b. In the Danube River can be seen that most of the pH
values that exceed the target value are recorded in 1997, 1998 and rarely in 2000. Values
exceeding the target value in tributaries are recorded in 1996 and 2000, on Dyje-Pohansko
(CZ02), Sio-Szekszard-Palank (H06) and Prut-Lipcani (MD01).
The temporal pattern of pH values in the Danube River is illustrated in Fig. 8.1.1.7 and in selected
tributaries in Fig. 8.1.1.8.
The following remarks can be done in this respect:
- the upper section is practically without any trends;
- similarly in the middle section, temporal variation is rather scattered and no systematic trend
is detectable;
- in the first part of the lower Danube, a decreasing tendency from 1996 to 2000 is visible at
Danube-Bazias (km 1071, RO01); an increasing, also from 1996 to 2000 is visible at Danube-
ds. Svishtov (km 554, BG03),;
- in the second part of the lower Danube, no temporal changes are present at Danube-us. Arges
(km 432, RO03); most of the remaining sites in this stretch shows a tendency of increasing
from 1996 to 2000 , maximum values reaching mostly in 2000.
Selected tributaries present the following temporal changes:
- an increasing was observed for the Arges-Conf. Danube (RO09) and Siret-Conf. Danube-
Sendreni (RO10);
- a decreasing tendency is indicated in Sava-Jesenice (SL02).
V 48
UNDP/GEF Danube Regional Project
9.00
8.50
8.00
7.50
7.00
6.50
1
2
1
2
3
4
5
1
2
0
1
0
2
0
3
0
4
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A01
A02
A03
A04
SK01
SK02
H0
SK03
H0
H0
H0
H0
HR0
HR0
RO
RO
BG01
BG02
BG03
BG04
RO
RO
BG05
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.1.5a: Spatial variation of pH Danube River
9
8.8
8.6
8.4
8.2
8
7.8
7.6
7.4
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.1.5b: Spatial variation of pH Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 49
9.00
8.50
8.00
7.50
7.00
6.50
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ.
Arges
Siret
Prut
Lom
1996
1997
1998
1999
2000
Monitoring sites / Tributary
Fig. 8.1.1.6a: Spatial variation of pH Tributaries
9.00
8.80
8.60
8.40
8.20
8.00
7.80
7.60
7.40
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.1.6b: Spatial variation of pH Tributaries
V 50
UNDP/GEF Danube Regional Project
9.00
8.80
8.60
8.40
8.20
8.00
7.80
7.60
7.40
7.20
7.00
6.80
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
Sulina/0
Georghe/0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitorings sites / distance from the mouth [km]
Fig. 8.1.1.7: Temporal trends of pH Danube River
9.00
8.50
8.00
7.50
7.00
6.50 D03
D04
CZ01 CZ02 SK04 H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06 HR07 HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites / distance from the mouth [km]
Fig. 8.1.1.8: Temporal trends of pH Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 51
Conductivity
Conductivity is one of the most frequently used determinands for assessing the mineralization degree
of a natural watercourses as it is a measure of total dissolved salts in water column.
The spatial distribution of the conductivity values along the Danube River is shown in Fig. 8.1.1.9a
and 8.1.1.9b.
For the monitoring points located on the Danube in the upper section of the Danube itself,
conductivity is within the range 400 539 µS/cm. From the above-mentioned figures can be seen the
influence that the low salts content of the Inn-Kirchdorf (D03) has upon the downstream stretch.
The middle section of the river is characterized by small spatial variation. Only at Danube-Szob (km
1708, H03), a slight increasing pattern is noticeable, probably caused by an anthropogenic influence.
The first part of the lower Danube section shows no significant variation in spatial distribution
between Danube-Bazias (km 1071, RO01) and Danube-us. Russe (km 503, BG04), only two values
exceed the level of 500 µS/cm.
The pattern for the second part of the lower Danube is characterized by slightly higher values than in
the first part; e.g. values increase from 405µS/cm in 2000 at Danube-us. Arges (km 432, RO03)up to
598µS/cm at Danube-Sulina/Sulina arm (km 0, RO07) in the same year.
Tributaries are generally characterized by higher conductivity levels than the Danube itself Fig.
8.1.1.10a and 8.1.1.10b:
- in the upper section, relatively higher values (637 µS/cm in 1996 784 µS/cm in 1998) were
recorded on the Dyje but they are due to the low values of the flow (123.2 and 37.3 m3/s,
respectively). In 1997 there was higher conductivity than in 1996.
- the highest conductivity values belong to the Sio-Szekszard-Palank (H06), in the middle
section (992 µS/cm in 1998 - 1195 µS/cm in 1997) in good correlation with flow discharges
in respective years (63.9 m3/s in 1998 and 49.0 m3/s in 1997);
- in the lower Danube, the conductivity levels increase (e.g.: two c90 values, characterising
Russenski Lom-Basarbovo (BG08), exceed 800 µS/cm - in 1997 and 1999). However, the
highest values for tributaries along this stretch belong to the Prut-Conf. Danube Giurgiulesti
(RO11) - 1100 µS/cm and 1110 µS/cm in 1997 and 1998, respectively.
The temporal trend for conductivity values in the Danube River is shown in Fig. 8.1.1.11, and in Fig.
8.1.1.12 for selected tributaries:
- in the upper and the middle Danube, the general trend is decreasing from 1996 to 2000;
- in the first part of lower Danube, no general trend was observed; in the second part, the
general tendency is increasing from 1996 to 1998 or 1999;
- selected tributaries from the upper river show a relative uniform temporal distribution of
conductivity values; on the Morava-Lanzhot (CZ01) and Djye-Pohansko (CZ02) higher values
are recorded in 1997 and 1998 respectively;
- the same uniform temporal pattern is valid also for the tributaries from the middle section,
with few exceptions: on the Sio-Szekszard-Palank (H06), the maximum value appears in 1997
and on the Sava-us. Jesenovac (HR07) a decreasing trend from 1996 to 2000 is detectable.
- tributaries from the lower Danube present a scattered temporal profile, with no visible
systematic trend.
V 52
UNDP/GEF Danube Regional Project
700
600
500
400
/
c
m
µS 300
200
c
100
0
1
2
1
2
3
4
5
1
2
0
1
0
2
0
3
0
4
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A01
A02
A03
A04
SK01
SK02
H0
SK03
H0
H0
H0
H0
HR0
HR0
RO
RO
BG01
BG02
BG03
BG04
RO
RO
BG05
RO
UA
RO
UA
RO
RO
upper
Monitoring site
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.1.9a: Spatial variation of Conductivity Danube River
700
600
500
400
/
c
m
300
µS
200
100
0
2700
2400
2100
1800
1500
1200
900
600
300
0
1996
1997
1998
1999
2000
Distance from the mouth [km]
Fig. 8.1.1.9b: Spatial variation of Conductivity Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 53
1400
1200
1000
800
/
c
m
µS
600
400
200
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.1.10a: Spatial variation of Conductivity Tributaries
1400
1200
1000
800
/
c
m
600
µS
400
200
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
Fig. 8.1.1.10b: Spatial variation of Conductivity Tributaries
V 54
UNDP/GEF Danube Regional Project
µS/cm
600
500
400
300
200
100
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.1.11: Temporal trends of Conductivity Danube River
µg/l
1400
1200
1000
800
600
400
200
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites / distance from the mouth
[k ]
Fig. 8.1.1.12: Temporal trends of Conductivity Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 55
Alkalinity
Alkalinity is conditioned by the presence of acid carbonate, carbonate, hydroxide and only rarely by
borate and silicate ions in water column. Values of "p" alkalinity (given by hydroxide and carbonate)
and "m" alkalinity (given by acid carbonate) show the equilibrium status among the above-mentioned
ions in water.
Spatial variation of alkalinity values along the Danube River is shown in Fig. 8.1.1.13a and 8.1.1.13b.
For the upper section, unlike the first monitoring point, Danube-Neu-Ulm (km 2581, D01) where the
alkalinity is in the range 4.6-4.8 mmol/l, all the other monitoring sites from this stretch are
characterized by values in the range 3.5-3.9 mmol/l.
In the middle section, excepting two values, the range of alkalinity is 3.4 4.1 mmol/l. The exceptions
are recorded at Danube-Batina (km 1429, HR01), where alkalinity values are 7.4 and 8.1 mmol/l in
1998 and 2000, respectively.
The spatial pattern of alkalinity in the first part of the lower section shows a slight increasing line from
Danube-Bazias (km 1071, RO01) down to Danube-us. Iskar-Bajkal (km 641, BG02); at the following
monitoring site, higher alkalinity value is recorded in 2000 (5.4 mmol/l).
In the second part of this lower stretch a slight increasing tendency of alkalinity values is present as
well, with a maximum 4.9 mmol/l in 2000, at Danube-Silistra/Chiciu (km375, BG05).
The profile characteristic to selected tributaries presents maximum values on the Sio-Szekszard-
Palank (H06), where the alkalinity values are within the range 6.4 8.5 mmol/l. Also the Jantra-
Karantzi (BG07) and Russenski Lom-Basarbovo (BG08) show relatively higher values in 1999 and
2000 - between 5.6 and 7.5 mmol/l (see Fig. 8.1.1.14a and 8.1.1.14b).
From the temporal point of view, the following can be concluded based on illustration on Fig.
8.1.1.15, for the Danube River and in Fig. 8.1.1.16 for selected tributaries:
- a uniform profile for upper and middle Danube, slight variations being noticeable at Danube-
Medve/Medvedov (km1806, H01) and at Danube-Komarom/Komarno (km 1768, H02);
- in the first part of the lower Danube, a slight increasing trend from 1996 to 1999 or 2000 is
present at Danube-Novo Selo/Pristol (km 834, BG01);
- in the second part of lower Danube, the temporal view is inhomogeneous, but it can be seen
that higher values are recorded in 1997, 1998 or 2000, depending on the monitoring site.
V 56
UNDP/GEF Danube Regional Project
9.0
8.0
7.0
6.0
5.0
l
/
l
mmo 4.0
3.0
2.0
1.0
0.0
1
2
1
2
3
4
5
1
2
0
1
0
2
0
3
0
4
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A01
A02
A03
A04
SK01
SK02
H0
SK03
H0
H0
H0
H0
HR0
HR0
RO
RO
BG01
BG02
BG03
BG04
RO
RO
BG05
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.1.13a: Spatial variation of Alkalinity Danube River
9.0
8.0
7.0
6.0
5.0
l
/
l
4.0
mmo
3.0
2.0
1.0
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
Fig. 8.1.1.13b: Spatial variation of Alkalinity Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 57
9.0
8.0
7.0
6.0
5.0
l
/
l
mmo 4.0
3.0
2.0
1.0
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.1.14a: Spatial variation of Alkalinity Tributaries
9.0
8.0
7.0
6.0
5.0
l
/
l
4.0
mmo
3.0
2.0
1.0
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
Fig. 8.1.1.14b: Spatial variation of Alkalinity Tributaries
V 58
UNDP/GEF Danube Regional Project
mmol/l
10
8
6
4
2
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06 RO07/Sulina RO08/
UA01/Kilia
UA02/
Georghe
Kilia
Monitoring sites / distance from the mouth
[k ]
Fig. 8.1.1.15: Temporal trends of Alkalinity Danube River
mmol/l
10
8
6
4
2
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites
Fig. 8.1.1.16: Temporal trends of Alkalinity Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 59
8.1.2. Nutrients
Assessment of nutrients levels in water column has a particulate importance due to the fact that the
input of nutrients into surface waters (mainly nitrogen and phosphorous), either from natural or
anthropogenic sources, leads to the process being known as eutrophication. The direct consequences
of eutrophication increased algal bloom, accelerated biological activity (metabolism and
decomposition), widespread reduction in dissolved oxygen concentration, growth of higher plants,
changes in aquatic food chain and, eventually, a disturbed ecosystem and a deteriorated water quality
make the assessment of nutrients level to be one of the most important issue in assessment of water
quality. Although the associated effects of eutrophication are characteristic particularly to lakes,
reservoirs, coastal areas and large slowly flowing rivers as well, it could also be apparent in the case of
the various conditions specific to the Danube River.
From the different fractions analyzed within the TNMN Programme, ammonium-N, nitrite-N, nitrate-
N, ortho-phosphate-P and total phosphorous were chosen for spatial pattern assessment and trend
assessment in the report.
Nitrogen
Dissolved inorganic nitrogen, particularly ammonium and nitrate, constitutes most of the total nitrogen
in river waters. They derive mainly from the decomposition of protein compounds that enter the
surface water along with urban and industrial waste discharge. Among the indirect sources of various
nitrogen forms, erosion/runoff from agriculture and effluents from animal farms can be mentioned.
As it will be shown, nitrogen levels have a characteristic concentration distribution along the Danube
and its tributaries.
Ammonium
Ammoniacal-nitrogen occurs in two forms: ammonia (NH
+
3) and ammonium (NH4 ); the first one is a
dissolved gas with much higher toxicity on aquatic ecosystem than the ionized form. The equilibrium
between the two species depends on pH. Mediated by microorganisms, decomposition of protein
organic matter has as final result release of ammonium. It can also emerge from decomposition of
mineral and vegetal matters. Dissolved ammonium is further oxidized to nitrites and nitrates.
The distribution of monitoring sites according to the Classification System in the DRB for ammonium-
N is shown in Fig. 8.1.2.1:
N-NH4
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
V 60
UNDP/GEF Danube Regional Project
Fig. 8.1.2.1: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for N-NH4
The quality assessment within the five-class system is made based on data reported from 85
monitoring sites (out of the assessment are 18 monitoring sites from Phase I List of Monitoring Sites,
in which no measurements had been done in 1996-2000) and the following remarks can be done in this
respect:
- the temporal distribution of monitoring sites within quality classes is generally uneven during
five studied years, with no percentage above 50 % in one class;
- The percentage of sites in Class I varies between 10.6 % in 1996 and 31.8 % in 1998;
- The percentage of sites corresponding to Class II is in the range from 7 % (1998) to 26 %
(1996);
- The maximum percentage of sites in Class III is in 1999 (36.5 %) and in Class IV in 1998
(29.4%)
- Only few monitoring sites (1.2 4.7 %) correspond to Class V;
- the number of measurements was increasing from 1996 to 2000.
The spatial variation of ammonium-N along the Danube River is shown in Fig. 8.1.2.2a and 8.1.2.2b.
In the upper section of the river, ammonium-N concentrations have a homogenous level, with no value
above the target value (0.30 mg/l).
In the middle section most of the concentrations are below 0.30 mg/l, too. Slightly higher values were
recorded at Danube-Bratislava (km 1869, SK01), Danube-Medvedov/Medve (km 1806, SK02) and
Danube-Komarno/Komarom (km 1768, SK03). It has to be mentioned that at the last two mentioned
cross-sections (SK02/H01 and SK03/H02) results reported by the Hungarian part are significantly
lower than results from Slovakia. Along this middle stretch, 18 c90 values are indicated as above the
target value.
The ammonium-N spatial pattern changes in the first part of the lower Danube section, where the
concentration level rises up to 0.75 mg/l between Danube-Bazias (km 1071, RO01) and Danube-
Pristol/NovoSelo (km 834, RO02). An even higher value (1.09 mg/l) was observed at Danube-us.
Iskar Bajkal (km 641, BG02).
In the second part of lower Danube section, the general pattern shows an increasing of concentrations.
Thus, the ammonium-N values recorded in 1998 in two arms of the Danube Delta (Sulina/Sulina arm
and Sf. Gheorghe/Sf. Gheorghe arm) are 1.39 and 1.44 mg/l, respectively. For the entire lower
Danube, 151 values were above the quality target in the period 1996-2000.
The large differences of the upper and the middle section ammonium-N levels against the ones from
the lower Danube section are mainly attributable to the anthropogenic influence upon lower Danube
on one hand (sewage effluent and runoff from agriculture) and to the general improvement in waste
water treatment in the upper and the middle sections on the other hand.
Remarkable is high year-to-year variability in ammonium-N values in the monitoring sites of lower
Danube section.
The spatial distribution of ammonium-N level for selected tributaries is illustrated in Fig. 8.1.2.3a and
8.1.2.3b.
As it can be seen, for tributaries located in the upper and the middle section, rather high ammonium-N
concentrations were recorded on the Morava-Lanzhot (CZ01), Dyje-Pohansko (CZ02), Vah-Komarno
(SK04) and Sio-Szekszard-Palank (H06); most of these ammonium-N values (above 0.60 mg/l the
limit value for Class III) are mainly attributable both to urban waste waters and agricultural inputs. on
In case of Tisza and Sava tributaries, with only few exceptions the ammonium-N c90 level is below
0.60 mg/l. The water quality is totally different in tributaries located in the lower Danube: if in Iskar-
Orechovitza (BG06) and Jantra-Karantzi (BG07) only one value correspond to Class IV and Class V,
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 61
respectively, in Arges-Conf. Danube (RO09), all ammonium-N concentrations - between 2.49 7.68
mg/l - are within Class V. These extreme high values, correlated with BOD5 values, are mostly caused
by non- or insufficiently treated waste waters from municipalities. Still very high ammonium-N
concentrations (above 1.50 mg/l in 1996 1998) were observed on the Siret-Conf. Danube Sendreni
(RO10) and Prut-Conf. Danube Giurgiulesti (RO11). In all selected tributaries, 67 concentrations are
above the quality target for ammonium-N.
The temporal trends for ammonium-N concentrations along the Danube River are shown in Fig.
8.1.2.4 and for tributaries in Fig. 8.1.2.5:
- for the upper Danube, a decreasing trend from 1996 to 2000 is visible;
- in the middle Danube, for monitoring sites located on left side of the river (the Slovakian part)
there is a decreasing trend from 1996-1997 to 1998, followed by a stationary state until 2000;
for the rest of monitoring sites located along this stretch, a relatively constant temporal profile
is observed;
- in the first lower part of Danube River, temporal pattern is very scattered, with higher values
recorded in 1997, 1998 and 2000. In the second part, situation is similar, with higher
concentrations characteristic mainly to 1996, 1997 and 1998;
- in majority of tributaries located in the upper and middle Danube, generally ammonium N
seems to decrease, excepting Croatian sites located on the Sava River;
- for tributaries located in the lower Danube, the Arges-Conf. Danube (RO09) shows most
critical ammonium-N values in 1996 and 2000; in Siret-Conf. Danube (RO10) and Prut-
Conf. Danube Giurgiulesti (RO11) values observed in 1999-2000 were significantly lower
than those measured in 1997 and 1998.
V 62
UNDP/GEF Danube Regional Project
1.60
1996
1997
1998
1999
2000
1.40
1.20
1.00
0.80
N-NH4
mg/l 0.60
0.40
0.20
0.00
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
0
1
0
2
0
3
0
4
3
4
0
5
5
1
6
2
7
8
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO0
RO0
BG
BG
BG
BG
RO0
RO0
BG
RO0
UA0
RO0
UA0
RO0
RO0
Monitoring site
upper
middle
lower I
lower II
Fig. 8.1.2.2a: Spatial variation of N-NH4 Danube River
1.60
1.40
1.20
1.00
0.80
N-NH4
0.60
mg/l
0.40
0.20
0.00
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.2b: Spatial variation of N-NH4 Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 63
9.00
8.00
7.00
6.00
5.00
l
N-NH4 4.00
mg/
3.00
2.00
1.00
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.2.3a: Spatial variation of N-NH4 Tributaries
9.00
8.00
7.00
6.00
5.00
N-NH4
4.00
mg/l
3.00
2.00
1.00
0.00
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.3b: Spatial variation of N-NH4 Tributaries
V 64
UNDP/GEF Danube Regional Project
1.60
1.40
1.20
1.00
mg/l
0.80
0.60
0.40
0.20
0.00
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07/Sulina
RO08/ Georghe
UA01/Kilia
UA02/ Kilia
Monitoring sites / distance from the mouth [km]
Fig. 8.1.2.4: Temporal trends of N-NH4 Danube River
9.00
8.00
7.00
mg/l 6.00
5.00
4.00
3.00
2.00
1.00
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites
Fig. 8.1.2.5: Temporal trends of N-NH4 Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 65
Nitrite
Nitrite is an intermediate nitrogen form in the oxidation/reduction process of the nitrogen dissolved
forms.
The distribution of monitoring sites according to the Classification System in the DRB for nitrite-N is
shown in Fig. 8.1.2.6:
N-NO2
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.2.6: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for N-NO2
From the above-mentioned figure, based on data reported from 86 monitoring sites, (out of the
assessment is 17 monitoring sites from Phase I List of Monitoring Sites, in which no measurements
had been done in 1996-2000), it can be seen that:
- no site presents nitrite values corresponding to Class I
- more than 50 % of all sites are within Class II each year. The respective percentages increase
from 1996 to 1999 and then decrease in 2000 in favour of Class III;
- the temporal profile corresponding to Class III is opposite to the previous one: decreases from
1996 to 1999 and increases in 2000;
- there are no sites corresponding to Class IV in 1997, the values representing other years are
very low, with a maximum of 4.7 % in 1998;
- Class V is represented during 1996 1998 only, by a percentage of less than 3 % of all sites
each year;
- number of measurements increased in evaluation period in a similar pattern as ammonium-N.
The spatial pattern for nitrite-N concentrations for the Danube River is shown in Fig. 8.1.2.7a and
8.1.2.7b and it has the following features:
In the upper part of the Danube, almost no value exceeds 0.040 mg/l, which is less than the quality
target (0.060 mg/l).
Approximately the same spatial pattern is present in the middle section of the river, where the nitrite-N
concentrations vary within the range 0.020 0.051 mg/l. Apart an extreme value (0.233 mg/l)
observed in 1998 at Danube-Bratislava (km 1869, SK01), along this stretch an increasing spatial
variation is present; only 8 nitrite-N concentrations are above the target value.
In the first part of the lower Danube, nitrite-N concentrations are higher than in the middle stretch,
reaching the 0.071 mg/l in 1996 at Danube-Pristol/Novo Selo (km 834, RO02).
V 66
UNDP/GEF Danube Regional Project
In the second part of the lower Danube section, nitrite-N concentrations continue to rise up to 0.126
mg/l at Danube-Reni/Kilia arm/Chilia arm (km 132, UA01).
For the entire lower Danube, 58 values are above target value 0.060 mg/l.
For selected tributaries, (the spatial variation in Fig. 8.1.2.8a and 8.1.2.8b), the concentrations vary
within the range 0.009 0.720 mg/l. In the upper part, the Morava-Lanzhot (CZ01) and Dyje-
Pohansko (CZ02) show values exceeding 0.060 mg/l in all five studied years. In the middle Danube,
the Sio-Szekszard-Palank (H06) is characterized by high nitrite-N concentrations ranging between
0.147 and 0.435 mg/l. In a smaller extent, the Vah-Komarno (SK 04), Sajo-Sajopuspoki (H09), Sava-
Jesenice and Sava-us. Una Jasenovac (HR06 and HR07) present concentrations above 0.060 mg/l.
The nitrite-N levels are different for the Jantra-Karantzi (BG07), Prut-Leuseni (MD02) and
particularly for the Siret-Conf. Danube Sendreni (RO10): if for the first two ones the concentration
reaches 0.280 mg/l in 1997 and 0.282 mg/l in 1998 respectively, the last one is characterized by a
value of 0.720 mg/l recorded in 1998.
The total number of nitrite-N c90 values exceeding the target value in selected tributaries is 45.
The temporal trend (Fig. 8.1.2.9) shows no significant variation during 1996 2000 for upper Danube.
In the middle Danube, a slight decreasing trend from 1996 to 2000 is present for Slovak results (SK02
and SK03), while for Hungarian results at the same cross sections the trend is quite opposite. In the
first part of the lower Danube, a zigzag profile characterizes the Danube-Bazias and Danube-us. Iskar-
Bajkal monitoring sites. At the cross section from Danube-Pristol/NovoSelo/Pristol (km 834 -
RO02/BG01), temporal trends are different: according to RO02 results, higher values are recorded in
1996 and 1997 and according to BG01, in 1999. In the second part of the lower Danube section, the
temporal profile is unevenly distributed among the five years, most of the sites showing a decreasing
line from 1996 to 1999, followed by an increasing in 2000.
For selected tributaries, the temporal variation of the nitrite-N concentrations (Fig. 8.1.2.10) shows
that for the Morava-Lanzhot (CZ01), Dyje-Pohansko (CZ02) and Vah-Komarno (SK04) a decreasing
trend from 1996 to 2000 can be seen. For the Sio-Szekszard-Palank (H06) high values are recorded in
1996 and 1997, followed by decreasing values until 2000. The other tributaries from the middle
section present no significant temporal variation during the studied period. In the lower Danube, the
Arges-Conf. Danube (RO09) shows an increasing tendency from 1996 to 1999, while for the Siret-
Conf. Danube Sendreni (RO10) the trend is opposite from 1996 to 2000.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 67
0.15
0.233
0.12
2 0.09
NO
/
l
N-
g
m 0.06
0.03
0.00
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
0
1
0
2
0
1
0
2
0
3
0
4
0
3
0
4
0
5
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A0
A0
A0
A0
SK0
SK0
H0
SK0
H0
H0
H0
H0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
lower I
lower II
Monitoring site
upper
middle
1996
1997
1998
1999
2000
Fig. 8.1.2.7a: Spatial variation of N-NO2 Danube River
0.15
0.233
0.12
0.09
2
g
/
l
N-NO
0.06
m
0.03
0.00
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.7b: Spatial variation of N-NO2 Danube River
V 68
UNDP/GEF Danube Regional Project
0.80
0.70
0.60
0.50
2
NO 0.40
/
l
N-
g
m 0.30
0.20
0.10
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
1996
1997
1998
1999
2000
Monitoring site / Tributary
Fig. 8.1.2.8a: Spatial variation of N-NO2 Tributaries
0.80
0.70
0.60
0.50
2
O
-
N
0.40
g
/l
N
0.30
m
0.20
0.10
0.00
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.8b: Spatial variation of N-NO2 Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 69
0.20
0.18
0.16
0.14
0.12
mg/l 0.10
0.08
0.06
0.04
0.02
0.00
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.2.9: Temporal trends of N-NO2 Danube River
0.80
0.70
0.60
0.50
mg/l
0.40
0.30
0.20
0.10
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.2.10: Temporal trends of N-NO2 Tributaries
V 70
UNDP/GEF Danube Regional Project
Nitrate
Nitrate is the final product of oxidation of N-components. Potential sources of nitrate include
industrial wastes, animal wastes and fertilizers applied to agricultural crop land.
The distribution of monitoring sites according to the Classification System in the DRB for nitrate-N is
shown in Fig. 8.1.2.11.
N-NO3
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
20.0
CL V
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.2.11: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for N-NO3
Based on data measured at 87 monitoring sites (therefore out of the assessment is 16 monitoring sites
from Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following pattern is valid:
- the number of sites within Class I is very low, actually between from 2.3 -3.4 %
- more than 50 % of all sites correspond to Class II each year, with a maximum of 67.8 % in
1998; almost 60 % of sites are characterised by this quality class during 1999 2000;
- representation of Class III has an inhomogeneous temporal variation, with a minimum
percentage of 13.8 % in 1998 and a maximum of 28.7 in 1999;
- Class IV has less than 5 % of all sites during 1996 2000 and 5.7 % in 2000;
- Class V is present in 1998 only, with 1.1 % of sites.
The spatial variation for nitrate-N concentrations is shown in Fig. 8.1.2.12a and 8.1.2.12b:
In the upper part of the Danube, 25 nitrate-N concentrations are above the quality target (3.00 mg/l),
with the maximum value (4.76 mg/l) at Danube-Neu-Ulm (km 2581, D01). Probably the main cause of
this profile is the base flow (Nutrient Balances for Danube Countries Project, 1991). Downstream this
location, the concentrations level remains constant down to Danube-Wolfsthal (km 1874, A04).
In the middle section, the nitrate-N concentration level is quite homogenous, with 47 values exceeding
the quality target.
In the first part of the lower Danube, nitrate-N level is lower than in the middle one, the influence of
the Iron Gate reservoir being visible in this area. Rather high values appear at Danube-us. Iskar-Bajkal
(km 641, BG02) and at Danube-ds. Svishtov (km 554, BG03) 3.27 and 5.28 mg/l respectively. In the
second part of the lower Danube, avoiding three high values within the range 4.70 5.80 mg/l,
recorded at Danube-us. Arges (km 432, RO03), all the other concentrations are within the range 1.16
2.99 mg/l.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 71
Tributaries are illustrated in Fig. 8.1.2.13a and 8.1.2.13b. As it has already been shown also in case of
previous nutrient forms, the tributaries from the upper and the middle Danube that are characterized by
higher nitrate-N concentrations values are Morava-Lanzhot (CZ01), Dyje-Pohansko (CZ02), Sio-
Szekszard-Palank (H06) and in a smaller extent Vah-Komarno (SK04). Thus, on Dyje and Sio rivers,
nitrates level exceeds 6 mg/l, the limit value for Class III. (7.50 and 9.54 mg/l respectively). The next
tributaries from the middle Danube present a uniform level of variation - below 3.00 mg/l - with
exceptions occurring on the Sajo-Sajopuspoki (H09) and Sava-Jesenice (HR06), where several values
are above this limit. As far as concerns the tributaries located in the lower Danube, the nitrates-N
values are the highest from those observed in tributaries in Russenski Lom-Basarbovo (BG08) - 10.39
mg/l, Arges-Conf. Danube (RO09) - 10.40 mg/l and Prut-Conf. Danube Giurgiulesti (RO11 and
MD03) - 10.37 and 11.10 mg/l, respectively. In all tributaries, there are 43 values above the quality
target in evaluated period.
The temporal trend for the Danube River is shown in Fig. 8.1.2.14 and for selected tributaries in Fig.
8.1.2.15. Thus, the following general trends are visible:
- for the upper Danube, no significant temporal changes of nitrate-N values are observed;
- in the middle Danube the situation is the same, but can be mentioned that in majority of
monitoring sites in this section nitrate-N values were highest in 1996;
- in the lower Danube, temporal variation shows that in the first part the most elevated values
are recorded in 1998 and 2000, while in the second part, the general trend is increasing from
1996 to 1999;
- tributaries from the upper Danube present a relatively stable state for Inn-Kirchdorf (D03) and
Salzach-Laufen (D04); in Morava-Lanzhot (CZ01) and Dyje-Pohansko (CZ02) the nitrate-N
values decrease;
- in the middle section, a decreasing trend from 1996 to 1998 followed by an increasing until
1999 or 2000 is valid for the Vah-Komarno (SK04) and for several monitoring sites located on
Drava (Ormoz-SL01, Varazdin-HR03, Botovo-HR04 and D. Miholjac-HR05). A clear
decreasing trend from 1996 to 1999 is visible on the Sio-Szekszard-Palank (H06). An opposite
temporal variation appears on the Sajo-Sajopuspoki (H09). For the Sava tributary, no
systematic temporal trend is noticeable;
- tributaries located in the first part of the lower Danube do not indicate any trend; in the second
part, in Arges-Conf. Danube (RO09) an increasing trend from 1996 to 2000 is visible. For the
Siret-Conf. Danube Sendreni (RO10) a relatively stable state is characteristic, while for the
Prut tributary, two different monitoring sites (RO11 and MD03) show the highest values
recorded in 2000 and 1998, respectively.
V 72
UNDP/GEF Danube Regional Project
7.00
6.00
5.00
3 4.00
g
/
l
N-NO
m 3.00
2.00
1.00
0.00
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
0
1
0
2
0
1
0
2
0
3
0
4
0
3
0
4
0
5
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A0
A0
A0
A0
SK0
SK0
H0
SK0
H0
H0
H0
H0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
lower I
Monitoring site
upper
middle
lower II
1996
1997
1998
1999
2000
Fig. 8.1.2.12a: Spatial variation of N-NO3 Danube River
7.00
6.00
5.00
3
4.00
3.00
g
/
l
N-NO
m
2.00
1.00
0.00
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.12b: Spatial variation of N-NO3 Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 73
12.00
10.00
8.00
3
6.00
g
/
l
N-NO
m
4.00
2.00
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.2.13a: Spatial variation of N-NO3 Tributaries
12.00
10.00
8.00
3
NO
6.00
g
/
l
N-
m
4.00
2.00
0.00
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.13b: Spatial variation of N-NO3 Tributaries
V 74
UNDP/GEF Danube Regional Project
6
4
mg/l
2
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.2.14: Temporal trends of N-NO3 Danube River
12
10
8
mg/l
6
4
2
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites
Fig. 8.1.2.15: Temporal trends of N-NO3 Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 75
Phosphorous
Phosphorous is one of the main components in organic matter. It generally originates from
mineralization from the soil and rocks (as natural sources) and from waste effluents, municipal
wastewaters or drainage that contain fertilizers (as anthropogenic sources). Although phosphorous
tends to be the nutrient that mostly limits plant growth in lakes in reservoirs, its presence assessment in
flowing rivers is not of a less importance. If the natural background concentration of dissolved
phosphorous is about 0.025 mg/l P, the polluted segment of a watercourse may contain up to 1 mg/l P
or even more (The Dobris Assessment, 1991).
In TNMN Programme, phosphorous is measured both as total phosphorous and soluble reactive
phosphate or ortho-phosphate. The latter form is the only biologicaly available form of phosphorous.
Ortho-phosphate
The distribution of monitoring sites according to the Classification System in the DRB for ortho-
phosphate-P is shown in Fig. 8.1.2.16.
P-PO4
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.2.16: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for P-oPO4
On the bases on data reported from 85 monitoring sites (out of the assessment are 18 monitoring sites
from Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following can be concluded:
- the number of monitoring sites within Class I shows an uneven temporal variation, with a
minimum of 7.1 % in 1998 and a maximum of 20% in 2000;
- Class II comprises the maximum percentages in each year, with an increasing line from 1996
to 1998, followed by a decreasing until 2000. Percentage of sites in Class II varies from 38%
(2000) to 58% (1998);
- the percentage of monitoring sites within Class IV is low, with maximum value of 9.4% in
1999;
- similarly low percentage if sites correspond to Class V, with a maximum of 7.1% in 1996.
The spatial assessment of orthophosphate-P concentration along the Danube River is shown in Fig.
8.1.2.17a and 8.1.2.17b.
In the upper Danube, ortho-phosphate concentrations level is nearly 0.050 mg/l at all monitoring sites,
so no value is above the target value for this nutrient (0.10 mg/l).
V 76
UNDP/GEF Danube Regional Project
In the middle Danube, spatial profile is slightly changed, with most of the values within the range
0.060 0.126 mg/l. Comparing with the quality target value, there are 18 values above it.
In the first part of the lower Danube, the ortho-phosphate-P concentrations are higher than in the
middle Danube, the variation range of c90 is 0.070 0.186 mg/l for the first 200 km of this stretch.
Although high values from Danube-Bazias (km 1071, RO01) were recorded in 2000, the previous four
years do not show many values above the 0.100 mg/l level. An extreme high value (0.446 mg/l) was
observed at Danube-us. Russe (km 503, BG04) in 1996.
In the second part of the lower Danube, ortho-phosphate-P c90 values seldom exceed 0.100 mg/l level.
However, the big difference between the recorded data at the same cross section (RO04/BG05 and
RO06/UA02) gives an inhomogeneous picture of the spatial distribution. Leaving apart this
incoherence, a slight decreasing spatial tendency is visible from Danube-us. Arges (km 432, RO03)
down to the three main arms of the Danube Delta (RO06, RO07 and RO08).
Along the entire lower Danube, 51 ortho-phosphate-P concentrations are above the quality target.
The spatial pattern of ortho-phosphate-P concentrations in selected tributaries is shown in Fig.
8.1.2.18a and 8.1.2.18b.
- in the upper and middle section of the Danube, in two tributaries only ortho-phosphate values
exceed 0.20 mg/l (the limit value for Class III) in evaluated period: Dyje-Pohansko (CZ02)
and the Sio-Szekszard-Palank (H06). In strong correlation with other data from the group of
nutrients, these values are caused mainly by anthropogenic inputs.
- in the lower section, there are far more elevated values for ortho-phosphate, characteristic to
Class V: 1.322 and 1.072 mg/l in 1996 and 1998 on the same tributary - Iskar-Orechovitza
(BG06). High values were also recorded in 1996 and 1999 on the Jantra-Karantzi (BG07)
0.460 and 0.484 mg/l, Russenski Lom-Basarbovo (BG08) 0.850 mg/l and Arges-Conf.
Danube (RO09) 0.675 mg/l and 0.850 mg/l;
- in TNMN tributaries, 57 values are above the target value in period 1996-2000.
Temporal trend for ortho-phosphate-P is shown in Fig. 8.1.2.19 for the Danube River and in Fig.
8.1.2.20 for selected tributaries. The following can be concluded:
- for monitoring sites located in the upper Danube, no significant temporal variation is visible;
- in the middle Danube, a decreasing trend from 1996 to 1999 is characteristic from Danube-
Bratislava (km 1869, SK01) down to Danube-Szob (km 1708, H03); an exception appears at
Danube-Medvedov/Medve (km 1806, SK02). For the rest of the sites in this stretch, the
temporal distribution is almost stationary.
- as regards the first part of the lower Danube section, from Danube-Bazias (km 1071, RO01)
down to Danube-Pristol/Novo Selo (km 834, RO02) an increasing tendency from 1996 to
2000 is present if the Romanian results are taken into account; according to the Bulgarian
data, the temporal trend for Danube-Novo Selo/ Pristol (km 834, BG01) is opposite -
decreasing from 1996 to 1999;
- in the second part of lower Danube section, in most of the monitoring points the values are
reather varying. In addition, rather high differences exist between the reported data for the
same cross section Danube-Silistra/Chiciu/Silistra (RO04/BG03, km 375). At the Danube-
us. Arges (km 432, RO03) an increasing line from 1997 to 2000 is noticeable;
- selected tributaries show inhomogeneous temporal trends: the Morava-Lanzhot (CZ01) and
Dyje-Pohansko (CZ02) have high values recorded in 1996 and 1998 respectively, while the
Sio-Szekszard (H06) is characterized by high values in 1997 and 2000. Except a decreasing
trend observed in Drava-Varazdin (HR03) the rest of monitoring sites located on this tributary
present a relatively stable state. No temoral changes were observed in Tisza tributary, even the
variation between years is low. The picture shows differently for the Sava, where no
systematic temporal trend is detectable, but year-to-year variation is much higher there.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 77
0.50
0.45
0.40
0.35
0.30
-
P
0.25
/l
PO4
mg 0.20
0.15
0.10
0.05
0.00
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
0
1
0
2
0
3
0
4
3
4
0
5
5
6
7
8
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO0
RO0
BG
BG
BG
BG
RO0
RO0
BG
RO0
UA0
RO0
UA0
RO0
RO0
lower I
Monitoring site
upper
middle
lower II
1996
1997
1998
1999
2000
Fig. 8.1.2.17a: Spatial variation of P-oPO4 Danube River
0.50
0.45
0.40
0.35
0.30
4
PO
0.25
g
/l
P-
0.20
m
0.15
0.10
0.05
0.00
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.17b: Spatial variation of P-oPO4 Danube River
V 78
UNDP/GEF Danube Regional Project
1.40
1.20
1.00
mg/l
0.80
0.60
0.40
0.20
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.2.18a: Spatial variation of P-oPO4 Tributaries
1.40
1.20
1.00
4
0.80
PO
/
l
P-
0.60
g
m
0.40
0.20
0.00
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.18b: Spatial variation of P-oPO4 Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 79
0.70
0.60
mg/l 0.50
0.40
0.30
0.20
0.10
0.00 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18
0
0
132
18
D01
D02
A01
A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.2.19: Temporal trends of P-oPO4 Danube River
1.20
1.00
0.80
mg/l 0.60
0.40
0.20
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.2.20: Temporal trends of P-oPO4 Tributaries
V 80
UNDP/GEF Danube Regional Project
Total Phosphorous
The distribution of monitoring sites according to the Classification System in the DRB for Total P is
shown in Fig. 8.1.2.21.
Total P
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.2.21: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Total P.
Based on data recorded at 824 monitoring sites (it means that out of the assessment is 21 monitoring
sites from Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000),
the following remarks can be done:
- Class I comprises less than 20 % of all monitoring sites, with a minimum of 6.0 % in 1996 and
1998;
- during 1996 1999, more than 40 % of all sites belong to Class II, but in 2000 the percentage
decreases to 38.1 %;
- the number of sites within Class III increases from 1996 to 2000, the maximum value being
21.4 %;
- the number of sites within Class IV decreases during 1996 1998 and from 1999 to 2000 and
increases from 1998 1999; the variation range is 1.2 % - 8.3 %;
- Class V is represented in 1998 and 1999 only, by 1.2 % and 4.8 % of all sites respectively;
- "no data" category" from 84 monitoring sites has a constant variation around 20 %, excepting
1999 when only 6 % of all sites are included in this category.
The spatial variation of Total P concentration along the Danube River is shown in Fig. 8.1.2.22a and
8.1.2.22b.
Unlike the spatial variation for ortho-phosphate in the upper Danube, the total P concentrations
increase from Danube-Neu-Ulm (km 2581, D01), where the variation range is 0.106-0.140 mg/l to
Danube-Wolfsthal (km1874, A04), where the range is 0.120-0.302 mg/l. There are five c90 values of
total P above the quality target (0.200 mg/l) .
In the middle section of the river the maximum value was located in Danube-Szob (km 1708, H03L)
0.310 mg/l in 1998, being the sampling site where Danube leaves Slovakia. Along this stretch, 23
values are above the target limit.
In the first part of the lower Danube, after Danube-Bazias (km 1071, RO01) where the concentrations
values reach 0.240 mg/l, a decreasing is observed down to Danube-us. Iskar-Bajkal (km 641, BG02),
where the concentration is 0.144 mg/l. Although the missing data cannot provide enough information
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 81
for the next stretch, a high value (0.765 mg/l) is visible at Danube-ds. Svishtov (km 554, BG03) in
1999.
In the second part of the lower Danube, Total P values follow a relatively uniform line regarding
spatial variation, only three values being outside of this profile, recorded at Danube-Silistra/Chiciu
(km 375, BG05). However, a slight decreasing is noticeable below Danube-us. Arges (km 432, RO03)
down to the three main arms of the Danube Delta.
For the entire lower Danube, 21 values are above the quality target 0,2 mg/l.
Total P in the selected tributaries has an inhomogeneous profile, mainly in accordance to extent of
human influences in the river basins of these tributaries Fig. 8.1.2.23a and 8.1.2.23b. Thus,
relatively high Total P values, corresponding to Class IV and V, were recorded on the following
watercourses:
- the Dyje-Pohansko (CZ02) all values exceeding 0,5 mg/l with maximum 0.917 mg/l in
1998;
- the Sio-Szekszard-Palank (H06) all values exceeding 0,9 mg/l with maximum 1.370 mg/l in
1998;
- the Jantra-Karantzi (BG07) with c90 value of 0.942 mg/l in 1999 (only the data from this
year available);
- the Russenski Lom-Basarbovo (BG08) with c90 value of 1.805 mg/l in 1999 (only the data
from this year available);
- the Arges-us. Arges (RO09) with c90 value of 0.865 mg/l in 1996.
There are 63 Total P values above the quality target.
Temporal trend for Total P concentrations is illustrated in Fig. 8.1.2.24 for the Danube River and in
Fig. 8.1.2.25 for selected tributaries. Concerning total phosphorus the variance between the years is
much higher than that of orthophosphates because of its connection to short-time process. When
samples are taken during high-flow period, 90 %-iles of that year are supposed to be on a higher level.
In many cases the years showing high values of suspended solids have high values of total
phosphorus, too. Regarding temporal assessment, the following can be concluded:
- in the upper Danube, slight continuous increasing is visible in Danube Wien-Nussdorf (A03,
rkm 1935)
- in the middle part of the Danube, Total P temporal distribution is rather scattered, with no
indication of general increasing or decreasing trend;
- similar situation is in the first part of the lower Danube; at the cross section Danube-Pristol
NovoSelo/ Pristol, the changes in time are opposite, depending on whether results provided by
Romania or Bulgaria are taken into account;
- in the second part of the lower Danube, if at Danube-us. Arges (km 432, RO03) Total P
concentrations increase from 1997 to 2000 and at Danube-Reni-Chilia/kilia arm (km 132,
RO05) values decrease from 1997 to 2000; for almost all remaining sites, the maximum
values are recorded in 1996 and 1998;
- there is only one tributary, in which an indication of an increase is observable - Inn
Kirchdorf (D03), but this "change" in time can be explained by suspended solids content in a
water in 2000 (see also Fig. 8.1.1.4). The decrease is visible in Arges (RO09) and Siret
(RO10), especially taking into account high values reached in 1996 that did not occur later in
the evaluated period.
V 82
UNDP/GEF Danube Regional Project
0.90
0.80
0.70
0.60
0.50
g
/l
P
m 0.40
0.30
0.20
0.10
0.00
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK
SK
SK
HR
HR
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
lower I
upper
middle
lower II
Monitoring site
1996
1997
1998
1999
2000
Fig. 8.1.2.22a: Spatial variation of Total P Danube River
0.90
0.80
0.70
0.60
0.50
g
/l
P
0.40
m
0.30
0.20
0.10
0.00
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.22b: Spatial variation of Total P Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 83
2.000
1.600
1.200
/l
P
mg
0.800
0.400
0.000
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H09
H08
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
2225
1880
1766
1497
1379
1215
1170
637
537
498
432
154
135
Inn
Morava
Vah
Sio
Drava
Tisza
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring sites / confluence at Danube km
1996
1997
1998
1999
2000
Fig. 8.1.2.23a: Spatial variation of Total P Tributaries
0.9
0.8
0.7
0.6
mg/l
0.5
0.4
0.3
0.2
0.1
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.2.23b: Spatial variation of Total P Tributaries
V 84
UNDP/GEF Danube Regional Project
0.9
0.8
0.7
0.6
0.5
/
l
mg
0.4
0.3
0.2
0.1
0.0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.2.24: Temporal trends of Total P Danube River
2.00
1.80
1.60
1.40
mg/l
1.20
1.00
0.80
0.60
0.40
0.20
0.00 D03
D04
CZ01 CZ02 SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06 HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites / distance from the mouth [km]
Fig. 8.1.2.25: Temporal trends of Total P Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 85
Regarding exceedance of the target limit of Total-P, set up on the level of 0.2 mg/l, 18.0 % of c90
values are above this limit in the Danube River and 57.3 % in selected tributaries Fig. 8.1.2.22b and
8.1.2.23b.
If the orthophosphate is a reliable indicator of bioavailability, total phosphorous concentration can be
related with suspended solids content, due to the fact that phosphorous compounds tend to be adsorbed
on particulate matter. In this respect, the charts illustrating the spatial distribution of suspended solids
versus so-called "particulate phosphorous", approximated as the difference between total P and ortho-
phosphate P (where available), was done for each studied year (see Fig. 8.1.2.26 - 8.1.2.30). Results
present a large variability in longitudinal profile of the Danube itself and the only conclusive data are
visible for several sites, listed in Table 8.1.2.1.
Table 8.1.2.1: Several correlations between the particulate phosphorous (PP) and suspended solids
content (SS):
Year Monitoring
site PP
SS
(mg/l)
(mg/l)
H08 0.247 138.4
1996
RO09 0.190 147.5
RO10 0.420 261.5
1997 HO8 0.372 153.4
1998 D03 0.169 131.0
1999
H06 0.805 140.8
H08 0.254 125.3
BG08 0.955 300.6
UA01 0.194 108.7
2000
D03 0.335 315.0
H08 0.183 217.4
Fig. 8.1.2.26 - 8.1.2.30: Suspended solids content vs. particulate phosphorous
mg/l
1996
SS
mg/l P
300
0.60
250
0.50
200
0.40
150
0.30
100
0.20
50
0.10
0
0.00
1
4
1
3
1
2
3
3
4
6
1
5
8
0
2
0
1
0
1
0
1
0
2
0
1
0
1
0
6
0
3
0
4
0
8
0
3
0
9
0
4
0
5
0
5
1
1
0
5
0
5
0
6
0
6
0
7
0
7
0
8
D0
D0
A0
A0
H0
H0
H0
H0
H0
H0
H0
CZ
SK
HR0
HR0
RO
RO
RO
BG
BG
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
RO
RO
RO
RO
RO
RO
RO
Monitoring site
SS
PP
V 86
UNDP/GEF Danube Regional Project
mg/l
1997
SS
mg/l P
600
0.40
0.35
500
0.30
400
0.25
300
0.20
0.15
200
0.10
100
0.05
0
0.00
1
4
1
3
1
5
0
2
0
1
1
2
3
3
4
6
8
0
1
0
1
0
2
0
1
0
1
0
6
0
3
0
4
0
8
0
3
0
9
0
4
0
5
0
5
1
1
0
5
0
5
0
6
0
6
0
7
0
7
0
8
D0
D0
A0
A0
H0
H0
H0
H0
H0
H0
H0
CZ
SK
HR0
HR0
RO
RO
RO
BG
BG
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
RO
RO
RO
RO
RO
RO
RO
Monitoring site
SS
PP
mg/l
1998
SS
mg/l P
400
1.00
350
0.90
0.80
300
0.70
250
0.60
200
0.50
150
0.40
0.30
100
0.20
50
0.10
0
0.00
1
4
1
3
2
1
1
2
3
3
4
6
1
5
8
0
0
1
1
2
3
9
4
1
5
5
6
6
7
7
8
0
0
0
0
1
0
1
0
6
0
3
0
4
0
8
0
0
0
0
5
0
5
1
0
0
0
0
0
0
0
D0
D0
A0
A0
H0
H0
H0
H0
H0
H0
H0
CZ
SK
HR0
HR0
RO
RO
RO
BG
BG
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
RO
RO
RO
RO
RO
RO
RO
Monitoring site
SS
PP
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 87
1999
mg/l
SS
mg/l P
350
1.20
300
1.00
250
0.80
200
0.60
150
0.40
100
50
0.20
0
0.00
1
4
1
3
0
2
1
1
2
3
3
4
6
1
5
8
0
1
0
1
0
2
0
1
0
1
0
6
0
3
0
4
0
8
0
3
0
9
0
4
0
5
0
5
1
1
0
5
0
5
0
6
0
6
0
7
0
7
0
8
D0
D0
A0
A0
CZ
H0
H0
H0
H0
H0
H0
H0
SK0
HR0
HR0
RO
RO
RO
BG
BG
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
RO
RO
RO
RO
RO
RO
RO
Monitoring site
SS
PP
mg/l
2000
SS
mg/l P
350
0.40
300
0.35
0.30
250
0.25
200
0.20
150
0.15
100
0.10
50
0.05
0
0.00
1
4
1
3
2
1
1
2
3
3
4
6
1
5
8
0
0
1
1
2
3
9
4
1
5
5
6
6
7
7
8
0
0
0
0
1
0
1
0
6
0
3
0
4
0
8
0
0
0
0
5
0
5
1
0
0
0
0
0
0
0
D0
D0
A0
A0
H0
H0
H0
H0
H0
H0
H0
CZ
SK
HR0
HR0
RO
RO
RO
BG
BG
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
RO
RO
RO
RO
RO
RO
RO
Monitoring site
SS
PP
V 88
UNDP/GEF Danube Regional Project
8.1.3. Heavy
Metals
All heavy metals exist in surface waters in colloidal, particulate and dissolved phases, although
dissolved concentrations are generally low (Kennish, 1992). The colloidal and particulate metal may
be found in hydroxides, oxides, silicates and sulfides or adsorbed to clay, silica or organic matter. The
soluble forms are generally ions or unionized organometallic chelates or complexes. The solubility of
trace metals in surface waters is predominately controlled by pH, the type and concentration of ligands
on which the metal could adsorb and the oxidation state of the mineral components and redox
environment of the system (Connel et al., 1984). The water chemistry also controls the rate of
adsorption and desorption of metals to and from sediment. Thus, metals can be desorbed from the
sediment if the water increases in salinity, decreases in redox potential or decreases in pH.
In surface waters system, heavy metals can be from natural and anthropogenic sources, but currently
human inputs of metals exceed the natural ones. As natural sources, chemical and physical weathering
of rocks and soils can be mentioned, further decomposition of plants and animal detritus, wind
erosion, atmospheric deposition of airborne particles (Kennish, 1992). As antropogenic non-point
sources, the most important are surface runoff from mining operations, urban storm water runoff,
combustion of fossil fuels; as anthropogenic point sources, among the most important are domestic
wastewater effluents, corrosion of water pipes and industrial effluents (Connel et al., 1984).
Within the TNMN Programme, a number of 11 heavy metals are routinely analyzed in water samples,
both as total water concentration and as dissolved fraction. The ration of these fractions in water varies
from substance to substance. The concentration of heavy metals is strongly dependent on quantity and
nature of suspended solids. This is the reason of natural variations and trends which hide the effect of
anthropogenic contaminations. High values often reflect situations with high loads of suspended solids
and flood events statistical parameters ike 90 %-ile, using also in the assessment in this report, are
therefore influenced by these processes. To eliminate such effects it is preferred to determine heavy
metals dissolved in water as well as concentrations in suspended solids.
Referring to the five-years synthesis report, the main focus is directed to the total heavy metals content
in water samples during 1996 2000, because dissolved fraction data are available for recent years
only, and collected data do not even cover the whole river basin.
Iron
The spatial distribution of Iron concentrations along the Danube River is shown in Fig. 8.1.3.1a and
8.1.3.1b:
In the upper section, Iron concentrations vary within the range 0.208 1.190 mg/l, with a slight spatial
increasing from Danube-Neu Ulm (km 2581, D01) down to Danube-Wolfsthal (km 1874, A04),
reaching 1.19 mg/l.
In the middle section, the spatial profile is relatively constant down to Danube-Szob (km 1708 H03),
where the highest values range between 0.82 0.99 mg/l. Downstream this monitoring site, a
significant decreasing is visible.
In the first part of the lower section, iron concentration profile is higher than in the middle stretch. The
maximum recorded value from the whole Danube River appears at Danube-Bazias (km 1071, RO01)
4.40 mg/l.
In the second part of the lower Danube, iron concentrations generally increase. Taking into account
whole Danube River, here are the highest concentration of iron, increasing frequently over 1.00 mg/l.
The highest c90 values from this sub-section (2.78 mg/l) is present at Danube-Silistra/Chiciu (km 375,
BG05)
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 89
Iron concentrations for selected tributaries is shown in Fig. 8.1.3.2a and 8.1.3.2b:
- for those located in the upper section, the Inn-Kirchdorf (D03) and, in a smaller extent, the
Salzach-Laufen (D04) and Morava-Lanzhot (CZ01) present values above 2.00 mg/l;
- most of the tributaries located in middle stretch of the Danube are characterized by low Iron
concentrations, only on the Tisza-Tiszasziget (H08) and the Sava-ds. Zupanja (HR08) two
values exceed 2.00 mg/l;
- there is a change in the lower section, where three tributaries show quite high concentration
levels, as follows:
- the Russenski Lom-Basarbovo (BG08) 6.59 and 6.86 mg/l;
- the Arges-Conf. Danube (RO09) 8.14 mg/l;
- the Siret-Conf. Danube Sendreni (RO10) with the maximum recorded value for
tributaries - 18.73 mg/l.
The temporal trends for the Danube River are shown in Fig. 8.1.3.3a and 8.1.3.3b for the Danube
River and in Fig. 8.1.3.4 for selected tributaries:
- from sites located in Danube River, only in Danube-Szob (rkm 1708, H03) there is an
indication of increase;
- from tributaries, decreasing in period 1996-2000 is observable in Morava-Lanzhot
(CZ01), Drava-Varazdin (HR03), Drava-Botovo (HR04), Arges (RO09) and Siret (RO10).
V 90
UNDP/GEF Danube Regional Project
5.0
4.5
4.0
3.5
3.0
/
l 2.5
mg
2.0
1.5
1.0
0.5
0.0 1
1
1
1
2
1
1
1
3
4
3
5
1
2
8
81
3
35
0
69
4
60
29
0
71
0
4
0
4
0
3
0
2
0
5
0
2
0
0
0
D0
A0
18
25
A0
19
SK
18
H0
H0
H0
15
83
55
50
43
37
13
HR0
14
RO
10
BG
BG
BG
RO
BG
UA
UA
RO
Monitoring sites / distance from the mouth [km]
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.3.1a: Spatial variation of Fe Danube River
5.0
4.5
4.0
3.5
3.0
/
l
2.5
mg
2.0
1.5
1.0
0.5
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
Fig. 8.1.3.1b: Spatial variation of Fe Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 91
20
16
12
l
mg/
8
4
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.2a: Spatial variation of Fe Tributaries
20
18
16
14
12
/
l
10
mg
8
6
4
2
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
Fig. 8.1.3.2b: Spatial variation of Fe Tributaries
V 92
UNDP/GEF Danube Regional Project
2.50
2.00
mg/l 1.50
1.00
0.50
0.00
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.3: Temporal trends of Fe Danube River
20
18
16
14
mg/l
12
10
8
6
4
2
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Fig. 8.1.3.4: Temporal trends of Fe Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 93
Manganese
For the Danube River itself, the spatial distribution of manganese concentrations is shown in Fig.
8.1.3.5a and 8.1.3.5b.
In the upper section of the Danube, spatial distribution is relative uniform, with only one concentration
value reaching 0.10 mg/l, at Danube-Wolfsthal (km 1874, A04).
In the middle stretch, spatial variation assessment depends on which data are taken into account: it
results in a uniform spatial pattern in accordance to Slovak data (SK02 and SK03), but higher values
in accordance to the Hungarian ones (H01 and H02). A significant decreasing of manganese values is
visible from Danube-Szob (km 1708, H03) to Danube-Borovo (km 1337, HR02). Taking into account
Hungarian data, in the section between rkm 1800 1700 are the highest manganase values along the
Danube River.
The first part of the lower Danube shows a scattered profile of manganese concentrations: from
Danube-Bazias (km 1071, RO01) to Danube-us. Iskar Bajkal (km 641, BG02), nearly half of the
values are equal to or exceed the 0.10 mg/l level. The next two monitoring sites in this sub-section,
Danube-ds. Svishtov (km 554, BG03) and Danube-us. Russe (km 503, BG04), indicate much lower
values.
The second part of the lower Danube section is characterized by a relatively uniform distribution, with
few exceptions. Thus, the maximum manganese value (0.27 mg/l in 2000) is recorded at Danube-us.
Arges (km 432, RO03); also several values along this stretch exceed the 0.20 mg/l level.
The spatial distribution of manganese c90 values on selected tributaries is shown in Fig. 8.1.3.6a and
8.1.3.6b. Regarding those located in the upper Danube, the Morava-Lanzhot (CZ01) and Dyje-
Pohansko (CZ02) present concentration above 0.20 mg/l. In the middle stretch, only the Tisza-
Tiszasziget (H08) shows rather high values, reaching 0.87 mg/l in 1996. In the lower section, majority
of tributaries is characterized by high values, but some of them exceed 1.00 mg/l: 1.02 mg/l on the
Iskar-Orechovitza (BG06), 1.01 and 1.26 mg/l on the Siret-Conf. Danube Sendreni (RO10).
The temporal trends of manganese concentrations are shown in Fig. 8.1.3.7 for the Danube River and
in Fig. 8.1.3.8 for selected tributaries:
- in the upper Danube, temporal pattern is without significant changes, also variation
between years is rather low there;
- in the middle Danube, increase of iron in Danube-Szob (rkm 1708, H03) is in coincidence
with increse of manganese;
- in the lower Danube, an increasing is observed in Danube-Bazias (km 1071, RO01), and
decrease in Danube-Novo Selo/Pristol /rkm 834, BG01);
- for two tributaries located in the upper Danube, the Morava-Lanzhot (CZ01) and Dyje-
Pohansko, the temporal trends are opposite: decreasing for the first one and increasing in
the same sense for the second. Also relative decreasing trends are valid for tributaries
located in the middle and lower Danube: the Vah-Komarno (SK04), Arges-Conf. Danube
(RO09) and the Prut-Conf. Danube Giurgiulesti (RO11).
V 94
UNDP/GEF Danube Regional Project
0.5
0.4
0.4
0.3
0.3
mg/l 0.2
0.2
0.1
0.1
0.0
1
2
3
4
1
2
3
01
02
0
1
0
2
0
3
0
4
03
04
0
5
05
01
06
02
07
08
D01
D02
A0
A0
A0
A0
H01
H02
H03
H04
H05
SK0
SK0
SK0
HR01
HR02
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
lower I
Monitoring site
upper
middle
lower II
1996
1997
1998
1999
2000
Fig. 8.1.3.5a: Spatial variation of Mn Danube River
0.45
0.40
0.35
mg/l
0.30
0.25
0.20
0.15
0.10
0.05
0.00
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
Fig. 8.1.3.5b: Spatial variation of Mn Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 95
1.40
1.20
1.00
0.80
/
l
mg 0.60
0.40
0.20
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.6a: Spatial variation of Mn Tributaries
1.4
1.2
1.0
0.8
/
l
mg
0.6
0.4
0.2
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
Fig. 8.1.3.6b: Spatial variation of Mn Tributaries
V 96
UNDP/GEF Danube Regional Project
0.40
0.35
0.30
0.25
mg/l 0.20
0.15
0.10
0.05
0.00
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.7: Temporal trends of Mn Danube River
1.40
1.20
1.00
mg/l
0.80
0.60
0.40
0.20
0.00
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites
Fig. 8.1.3.8: Temporal trends of Mn Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 97
Arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc in unfiltered
water samples (total forms)
The heavy metals like arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc are of a
particular concern to surface water systems. The Water Quality Classification for DRB set up limit
values for five classes for total forms and only guidelines values for dissolved forms at the border
between class II and class III.
For heavy metals in unfiltered water samples (total forms) data are available for the entire time period
1996 2000 and for dissolved forms during 1998-2000 only. In addition, data on dissolved forms are
available only for part of river basin.
Arsenic
Arsenic can be found naturally in small concentrations. It occurs in soil and minerals and it may enter
air, water and land by wind-blown dust and water run-off. Arsenic is a component that is extremely
hard to convert to water-soluble or volatile products. Because arsenic is naturally a quite mobile
component, it means that large concentrations are not likely to appear on one specific site. However,
the negative fact is that arsenic pollution becomes a wider issue because it easily spreads. In the
aquatic systems, arsenic ends up through effluents from industrial production of copper, lead and zinc
and also through insecticide applications on land. Although arsenic may be found in surface water,
ground water is the main source of arsenic in water.
The distribution of monitoring sites according to the Classification System in the DRB for arsenic is
shown in Fig. 8.1.3.9:
As
100.0
80.0
CL I
60.0
CL II
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.9: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for As
Based on data reported from 41 monitoring sites (out of the assessment is 62 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), it can be
concluded that most of the monitoring sites are within Class II (61.0 % 73.2 %). Other classes are
represented in very small percentages, with an exeption 30 % of sites in Class III in 2000.
The spatial pattern for arsenic concentrations along the Danube River is shown in Fig. 8.1.3.10a and
8.1.3.10b and in Fig. 8.1.3.11a and 8.1.3.11b for selected tributaries.
In the upper section, arsenic is detectable starting from Danube-Jochenstein (km 2204, A01), but no
monitoring site from this section has arsenic concentration exceeding the target value (5 µg/l).
V 98
UNDP/GEF Danube Regional Project
In the middle section, an increasing spatial pattern is present from Danube-Bratislava (km 1869,
SK01) to Danube-Szob (km 1708, H03), followed by a decreasing to Danube-Borovo (km 1337,
HR02); along this stretch no value is above the target limit as well.
Lower section is characterized mainly by lack of reported data for arsenic. However, the existing
values are higher than in previous river sections, the maximum concentration (11.02 µg/l) being
recorded at Danube-us. Iskar Bajkal (km 641, BG02). Along the entire part of lower Danube 9
values exceed the target value set up for arsenic.
Selected tributaries present 8 concentration values exceeding the target value:
- the Salzach-Laufen (D04) 8.00 µg/l (in 2000);
- the Vah-komarno (SK04) 5.17 µg/l (in 2000);
- the Sio-Szekszard-Palank (H06) 90 %-iles during the whole period exceeded target value
and were in a range from 5.24 - 12.32 µg/l;
- the Iskar-Orechovitza (BG06) 79.36 µg/l (in 2000);
- the Russenski Lom-Basarbovo (BG08) 10.00 µg/l (in 2000).
The temporal trends for the Danube River are illustrated in Fig. 8.1.3.12a and 8.1.3.12b and in Fig.
8.1.3.13 for selected tributaries:
- for upper Danube, Austrian sites show slight increasing tendency;
- for middle Danube, most of the sites show a decreasing trend from 1997 to 2000;
- for entire lower Danube, even if the missing data cannot give a complete picture, it can be
seen that all the high values are specific to year 2000;
- from tributaries, a slight increasing was in Dyje-Pohansko (CZ02) and Tisza-Tiszasziget
(H08); a decreasing trend in the same sense in Inn-Kirchdorf (D01) and Sajo-Sajopuspoki
(H09).
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 99
12.0
10.0
8.0
6.0
µg/l
4.0
2.0
0.0
01
02
03
04
05
06
07
08
D01
D02
A01
A02
A03
A04
H01
H02
H03
H04
H05
SK01
SK02
SK03
HR01
HR02
lower I
RO
RO
BG01
BG02
BG03
BG04
RO
RO
BG05
RO
UA01
RO
UA02
RO
RO
upper
middle
lower II
Monitoring site
1996
1997
1998
1999
2000
Fig. 8.1.3.10a: Spatial variation of As Danube River
12
10
8
µg/l
6
4
2
0
2700
2400
2100
1800
1500
1200
900
600
300
0
1996
1997
1998
1999
2000
TV
Distance from the mouth [km]
Fig. 8.1.3.10b: Spatial variation of As Danube River
V 100
UNDP/GEF Danube Regional Project
90
80
70
60
µg/l 50
40
30
20
10
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999 2000
Fig. 8.1.3.11a: Spatial variation of As Tributaries
100
80
60
µg/l
40
20
0
2500
2000
1500
1000
500
0
1996
1997
1998
1999
2000
Confluence at Danube km
TV
Fig. 8.1.3.11b: Spatial variation of As Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 101
µg/l
12
10
8
6
4
2
0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01
D02
A01 A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.12: Temporal trends of As Danube River
µg/l
14
12
10
8
6
4
2
0 D03 D04 CZ01 CZ02 SK04 H06 Sl01 HR03 HR04 HR05 H07 H08 H09 Sl02 HR06 HR06 HR07 HR08 HR08 BG06 BG07 BG08 RO09 RO10 MD01 MD02 RO11 MD03
Monitoring sites
Fig. 8.1.3.13: Temporal trends of As Tributaries
V 102
UNDP/GEF Danube Regional Project
Cadmium
Cadmium is one of the most hazardous heavy metal pollutants. Naturally, it can mainly be found in the
earth's crust and it always occurs in combination with zinc. Cadmium enters the environment mainly
through the ground, because it is found in manure and pesticides. Cadmium is released into rivers
through weathering of rocks and human activities, such as manufacturing. An important source of
cadmium emission is also the production and applying of phosphate fertilizers. In natural waters,
unaffected by anthropogenic impacts, the cadmium concentration is less than 1 µg/l (The Dobris
Assessment, 1991).
The distribution of monitoring sites according to the Classification System in the DRB for cadmium is
shown in Fig. 8.1.3.14:
Cd
100.0
80.0
CL I
60.0
CL II
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.14: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Cd
Based on data reported from 79 monitoring sites (out of the assessment is 24 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), it can be
concluded that:
- most of monitoring sites belongs to Class II (39.2 % - 62.0%) and this percentage increases
from 1997 to 2000
- percetage of sites corresponding to Class III decreases from 1998 to 2000;
- distribution corresponding to Class IV is uneven during the five years period;
- in 1999 more than 30% of the monitoring points are within Class V, but this figure decreased
in 2000.
The spatial distribution of cadmium concentrations is shown in Fig. 8.1.3.15a and 8.1.3.15b for the
Danube River and in for tributaries.
In the upper section, level of cadmium is low at all monitoring points; the maximum value recorded on
this stretch is 0.66 µg/l at Danube-Abwinden-Asten (km 2120, A02), but no value is above the target
limit for cadmium (1 µg/l).
In the middle section, between Danube-Medve/Medvedov (km 1806, H01) and Danube-Szob (km
1708, H03), 9 cadmium c90 values exceed the target value. Downstream to Danube-Szob, cadmium
level is again very low.
First part of the lower section is characterized by high values from Danube-Bazias (km 1071, RO01)
to Danube-Pristol/Novo Selo (km 834, RO02), but also with very high variability among the years.
Cadmium c90 values reach up to 16.81 µg/l and 17.70 µg/l there according the Romanian data. On the
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 103
other hand, at the cross section from km 834, the Bulgarian data show undetectable cadmium
concentrations. For the rest of the stretch, excepting one high value of 8.00 µg/l, recorded at Danube-
us. Russe (km 503, BG04), cadmium presence is also undetectable. From the reported data, only three
values along this stretch are below the target value.
The second part of the lower Danube section shows even higher cadmium concentrations than the first
one: thus, 76 values are above the target limit. The highest c90 value for this stretch, which is also the
highest value for the entire Danube - 29.10 µg/l - was recorded at Danube-us. Arges (km 432, RO03)
in 1997.
The spatial variation for selected tributaries, shown in Fig. 8.1.3.16a and 8.1.3.16b. It is seen that 34
values exceeded the target value. It is also visible that tributaries at the lower part of river basin are
characterised by much higher cadmium values than those in the upper and middle section. Going to
more details, it can be concluded that:
- in the upper section, only on the Dyje-Pohansko (CZ02) concentrations slightly exceed the
target value;
- in the middle Danube, in Sava-ds. Zupanja (HR08) and Drava River excepting Drava-
Ormoz (SL01), cadmium concentrations are above 1µg/l;
- as was already indicated, the situation is much worse regarding the tributaries from the
lower Danube, where actually all of them are characterized by very high cadmium
concentrations, leading to the following c90 values:
o the Iskar-Orechovitza (BG06) 10.00 µg/l in 1996;
o the Jantra-Karantzi (BG07) 9.10 µg/l in 1996;
o the Russenski Lom-Basarbovo (BG08) 8.00 µg/l in 2000;
o the Arges-Conf. Danube (RO09) 24.18 µg/l (1996), 9.25 µg/l (1997) and 8.96
µg/l (1999);
o the Siret-Conf. Danube Sendreni (RO10) 8.46 µg/l in 1999);
o the Prut-Conf. Danube Giurgiulesti (RO11) 8.36 µg/l (in 1998).
The temporal trend for cadmium concentrations is shown in Fig. 8.1.3.17 for the Danube River and in
Fig. 8.1.3.18 for selected tributaries:
- for the upper Danube, no systematic temporal trend is visible;
- a slight decreasing tendency from 1997 to 2000 is valid for most of the sites located in the
middle Danube from Danube Medve/Medvedov (rkm 1806, H01) to Danube-Szob (rkm
1708, H03);
- in the lower Danube, most of monitoring sites are characterized by high values recorded in
1997 and 1999, significant decrease is observed in 2000;
- from selected tributaries, only several monitoring sites indicate temporal changes:
decreasing is observed in Drava River, Jantra (BG07), Arges (RO09) and Prut-Conf.
Danube-Giurgiulesti (RO11).
JDS results from analysis of cadmium (0.2 0.8 µg/l in total sample) indicated that Danube River can
be regarded as unpolluted by this metal. However, TNMN results does not confirm this finding, great
differences are especially in the lower part of the Danube River.
V 104
UNDP/GEF Danube Regional Project
30
25
20
/
l 15
µg
10
5
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
middle
lower I
lower II
Monitoring site
1996
1997
1998
1999
2000
Fig. 8.1.3.15a: Spatial variation of Cd Danube River
30
25
20
/
l
15
µg
10
5
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.15b: Spatial variation of Cd Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 105
30
25
20
/
l 15
µg
10
5
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.16a: Spatial variation of Cd Tributaries
30
25
20
/
l
15
µg
10
5
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.16b: Spatial variation of Cd Tributaries
Note: In HR08 (2000) the value in the graph represents limit of detection that is higher than the target value.
V 106
UNDP/GEF Danube Regional Project
30
25
20
µg/l
15
10
5
0
2581
2204
2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071
834 834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01 A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the
Fig. 8.1.3.17: Temporal trends of Cd Danube River
30
25
20
µg/l
15
10
5
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring sites
Fig. 8.1.3.18: Temporal trends of Cd Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 107
Chromium
There are two kinds of chromium with different effects upon environment: chromium (III) and
chromium (VI). If the first one is an essential nutrient for humans, the second one is dangerous to
health. Both forms can enter the environment through both natural sources and human activities. The
main activities that increase the chromium (III) content are steel and leather manufacturing; for
chromium (VI) chemical, textile manufacturing, electro-painting and other industrial applications of
this form. In water, chromium is adsorbed on sediment and becomes immobile. That is why only a
small part of chromium that ends up in water eventually dissolves.
In TNMN Programme, chromium is measured as total chromium (III + VI).
The distribution of monitoring sites according to the Classification System in the DRB for chromium
is shown in Fig. 8.1.3.19.
Cr
100.0
80.0
CL I
60.0
CL II
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.19: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Cr
Based on data reported from 78 monitoring sites (out of the assessment is 25 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following remarks can be done:
-
during 1997 2000, more than 80% of the monitoring points belong to Class II;
-
very few monitoring sites are within Class III and IV (less than 6 %).
The spatial pattern for chromium concentrations along the Danube River is shown in Fig. 8.1.3.20a
and 8.1.3.20b:
Excepting the first and the last monitoring site from the upper section - Danube-Neu-Ulm (km 2581,
D01) and Danube-Wolfsthal (km 1874, A04) - where chromium is detectable in very low
concentrations, all the other monitoring sites reported data below the declared detection limit.
In the middle section, even though the spatial pattern shows significantly higher values according to
the Hungarian data, no value from this stretch exceeds the target value for chromium (50 µg/l).
Maximum values are around 20 µg/l there.
In the first part of the lower Danube, an increasing is observed between Danube-Bazias (km 1071,
RO01) and Danube-Pristol/Novo Selo (km 834, RO02), followed by a decreasing profile down to
Danube-us. Russe (km 503, BG04). Along this part of the river, no value is above the target limit.
V 108
UNDP/GEF Danube Regional Project
In the second part of the lower section, chromium concentrations increase from Danube-Chiciu/Silistra
(km 375, RO04) down to the Danube Delta. Three values exceed the quality target there: 82.00 µg/l at
Danube-us. Arges (km 432, RO03), 79.45 µg/l at Danube-Sulina/ Sulina arm (km 0, RO07) and 97.00
at Danube-Sf. Gheorghe/Sf. Gheorghe arm (km 0, RO08), all characterising year 1996.
The spatial distribution of chromium concentrations for selected tributaries is shown in Fig. 8.1.3.21a
and 8.1.3.21b: even if higher values appear on tributaries located in the lower section of the Danube -
the Arges-Conf. Danube (RO09), the Siret-Conf. Danube Sendreni (RO10) and Prut-Conf. Danube
Giurgiulesti (RO11) - no chromium concentration is above the target limit.
The temporal trend for chromium is shown in Fig. 8.1.3.22 for the Danube River and in Fig. 8.1.3.23
for selected tributaries:
- in the upper and partially in the middle Danube, the general trend is a relative stationary
state during the studied years; however, a slight decreasing tendency from 1996 to 2000
can be mentioned at Danube-Neu-Ulm (km 2581, D01);
- Hungarian sites located in the middle Danube, are characterized by higher chromium
concentration values in 1999 and 2000;
- in the lower Danube, a decreasing decreasing tendency from 1998 to 2000 in Danube-
Bazias (km 1071, RO01) and Danube-Sulina-Sulina arm (km 0, RO07) is observed;
- from tributaries in the upper Danube, in Morava-Lanzhot (CZ01) and Dyje-Pohansko
(CZ02), a slight decreasing trend from 1996 to 2000 is present;
- a relatively common decreasing trend is visible at three monitoring sites located on the
Drava tributary: the Drava-Varazdin (HR03), Drava-Botovo (HR04) and Drava-D.
Miholjac (HR05);
- for the Arges-Conf. Danube (RO09), Siret (RO10) and Prut-Conf.Danube-Giurgiulest
(RO11) also a decreasing tendency is observed.
In the frame of JDS maximum concentration of chromium was 7 µg/l. This value was exceeded
frequently inTNMN, even reaching values higher by one order.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 109
120
100
80
/
l
60
µg
40
20
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK
SK
SK
HR
HR
RO
lo ROwer I
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
middle
lower II
Monitoring site
1996
1997
1998
1999
2000
Fig. 8.1.3.20a: Spatial variation of Cr Danube River
120
100
80
/
l
60
µg
40
20
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.20b: Spatial variation of Cr Danube River
V 110
UNDP/GEF Danube Regional Project
45
36
27
/
l
µg
18
9
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
1996
1997
1998
1999
2000
Monitoring site / Tributary
Fig. 8.1.3.21a: Spatial variation of Cr Tributaries
60
50
40
/
l
30
µg
20
10
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.21b: Spatial variation of Cr Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 111
120
100
80
µg/l 60
40
20
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.22: Temporal trends of Cr Danube River
45
40
35
30
µg/l 25
20
15
10
5
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.3.23: Temporal trends of Cr Tributaries
V 112
UNDP/GEF Danube Regional Project
Copper
Copper is a very common substance that occurs naturally in the environment. Examples of natural
sources are wind-blown dust, decaying vegetation, forest fires and sea spray. Humans widely use
copper, because it is applied in industry and agriculture. That is why copper is often found near mines,
industrial settings, landfills and waste disposals. In surface water, copper can be transported along
great distances, either adsorbed on particles or as free ions. In catchments with no human inputs, the
copper concentration is generally lower than 2 to 5 µg/l (The Dobris Assessment, 1991).
The distribution of monitoring sites according to the Classification System in the DRB for copper is
shown in Fig. 8.1.3.24:
Cu
100.0
80.0
CL I
60.0
CL II
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.24: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Cu
Based on data reported from 85 monitoring sites (out of the assessment is 18 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following remarks can be done:
- a relative uniform temporal distribution appears for Class II (more than 40% of monitoring
sites) each year;
- percentage of sites within Class III decreases from 1996 to 2000, but percentage within Class
IV increases in the same period;
- a small part of sites belongs to Class V (the maximum percentage is recorded in 1999 5.9%);
The spatial pattern for copper concentrations along the Danube River is shown in Fig. 8.1.3.25a and
8.1.3.25b:
In the upper part of the Danube River, the distribution of the copper c90 values is uniform, with the
maximum value hardly reaching half of the target value for this heavy metal (20 µg/l).
In the middle stretch, excepting only one value, the same spatial pattern as in the upper section is
present. Exception occurs at Danube-Medve/Medvedov (km 1806, H01), where the copper
concentration exceeds more than two times the quality target in 1996.
In the lower section, the first part is characterized by an elevated profile between Danube-Bazias (km
1071, RO01) and Danube-Pristol/Novo Selo (km 834, RO02). Differences between the reported data
from Romania and Bulgaria at the same cross section are still noticeable. Downstream km 834, a
decreasing spatial pattern is present, even if two high values appear at Danube-ds. Svishtov (km 554,
BG03) and at Danube-us. Russe (km 503, BG04): 117.0 µg/l and 138.20 µg/l, respectively, in 1997.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 113
In the second part of the lower Danube, copper concentrations begin to increase along the entire
stretch. Thus, the maximum values appear at Danube-Silistra/Chiciu (km 375, BG05), ranging
between 162.10 and 213.10 µg/l. It has to be mentioned that in the lower section, during 1996 2000,
139 values exceed the target value.
The spatial pattern for selected tributaries is shown in Fig. 8.1.3.26a and 8.1.3.26b:
- copper
concentrations
have a relatively uniform distribution in tributaries located in the
upper and in the middle sections, with two exceptions: the Salzach-Laufen (D04) with one
value exceeding the target limit and the Tisza-Tiszasziget (H08) with 4 values above this
limit
- as regarding the tributaries from the lower Danube, six of them are characterized by values
above 20µg/l.
The temporal distribution for copper concentrations is shown in Fig. 8.1.3.27 for the Danube River
and in Fig. 8.1.3.28 for tributaries. The following can be concluded:
- in the upper Danube, an increasing tendency is observed in Danube-Wolfsthal (km 1874,
A04), for the rest of monitoring sites a relatively steady state is present excluding Danube
Neu-Ulm (D01), being the site with higher variability of copper content in comparison
with other sites in this section;
- in the middle Danube, a slight decreasing trend appears from Danube-Bratislava (km
1869, SK01) down to Danube-Komarno/Komarom (km 1768, SK03). In Danube-
Hercegszanto (km 1435, H05) a slight increasing in time is present;
- in the first part of the lower Danube, the temporal trends are different from one site to
another: Danube-Bazias (km 1071, RO01) is characterized by an increasing tendency,
similarly as Danube-Chiciu-Silistra (RO04) and Danube Vilkov-Chilia Arm/Kilia Arm
(RO06). A decrease is observed in Danube-Novo Selo/Pristol (BG01);
- in the second part of the lower section, an increasing trend from 1996 to 2000 is observed
in Danube-Chiciu/Silistra (km 375, RO04) and Danube-Vilkov-Chilia arm/Kilia arm (km
18, RO06); Monitoring sites like Danube-Ds.Svishtov (km 554, BG03), Danube-Us.Russe
(km 503, BG04), Danube-Silistrta/Chiciu (km 375, BG05) and Danube-
Sf.Gheorghe/Sf.Gheorghe arm (km 0, RO08) show high yearly variability without
indication general tendency of development in time;
- for tributaries from the upper section, excepting the Salzach-Laufen (D04), where the
maximum copper value appears in 1998, a relatively constant temporal profile is valid;
- for tributaries located in the middle Danube, different trends are present: a decreasing in
Drava River, an increasing in Tisza-Tiszasziget (H08) and Sajo-Sajopuspoki (H09);
- for tributaries from the lower Danube, a decreasing trend is observed in Arges-Conf.
Danube (RO09) and from 1997 in Siret-Conf. Danube Sendreni (RO10) and increase in
Russenski Lom (BG08). For the rest of the tributaries in this section, the existing data
cannot provide a clear temporal tendency.
Similarly to other heavy metals, in accordance to JDS results copper was found in much lower
concentrations in the Danube River. In the frame of TNMN, concentrations are much higher.
Generally, concentrations of copper increase significantly along the Danube. Also in case of
tributaries, those located in the lower part of Danube River Basin are characteristic by higher
concentrations.
V 114
UNDP/GEF Danube Regional Project
250
200
150
/l
µg
100
50
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
6
7
8
0
0
0
0
0
1
2
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO0
RO0
BG
BG
BG
BG
RO0
RO0
BG
RO0
UA0
RO0
UA0
RO0
RO0
upper
middle
lower I
Monitoring site
1996
1997
1998
1999
2000
lower II
Fig. 8.1.3.25a: Spatial variation of Cu Danube River
250
200
150
/
l
µg
100
50
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.25b: Spatial variation of Cu Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 115
120
90
/
l
60
µg
30
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.26a: Spatial variation of Cu Tributaries
120
100
80
µg/l
60
40
20
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.26b: Spatial variation of Cu Tributaries
V 116
UNDP/GEF Danube Regional Project
120
100
80
µg/l
60
40
20
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.27: Temporal trends of Cu Danube River
120
100
80
µg/l 60
40
20
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.3.28: Temporal trends of Cu Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 117
Lead
Lead is a particularly dangerous chemical. Most lead concentrations that are found in the environment
are a result of human activities. Due to the application of lead in gasoline, through burning in car
engines, lead salts (chlorine, bromines and oxides) enter the environment: the larger particles drop to
ground immediately and pollute soils and surface waters, the smaller particles are transported long
distances through air and fall back by raining. In water and soils lead can also end up through
corrosion of leaded pipelines in a water transporting system and through corrosion of leaded paints
(more likely to happen when the water is slightly acidic).
The distribution of monitoring sites according to the Classification System in the DRB for lead is
shown in Fig. 8.1.3.29:
Pb
100.0
80.0
CL I
60.0
CL II
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.29: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Pb
Based on data reported from 79 monitoring sites (out of the assessment is 24 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following remarks can be done:
- the highest percentage of sites within Class II is observed in years 1996-1999;
- year 2000 is the only one in which with percentage of sites corresponding to Class IV (39 %)
exceed percentage of sites in Class II (37 %);
- the number of sites within Class III increases from 1996 to 1999, followed by a decreasing in
- lead is actually the only heavy metal which is represented by high percentage in Class V -
even more than 30 % of the monitoring points in 1998), but this situation became better in
2000 (with 6.3 % of monitoring sites);
The spatial pattern of lead concentrations along the Danube River is illustrated in Fig. 8.1.3.30a and
8.1.3.30b.
Similarly to the already discussed heavy metals, lead concentrations in the upper section present a
uniform distribution, all values are below the target limit (5 µg/l).
This profile is valid also for the middle stretch; excepting one value 17.45 µg/l at Danube-
Dunafoldvar (km 1560, HO4) - all the others are below 5µg/l.
Spatial variation of lead concentration is totally different in the first part of the lower Danube. There is
dramatic increase of lead concentrations from the beginning of this section and maximum is detected
between Danube-Bazias (km 1071, RO01) Danube-Pristol/Novo Selo (km 834, RO02); along this
V 118
UNDP/GEF Danube Regional Project
stretch, excepting the value from 2000, all the others are above two times target value. Here are also
the highest values along the Danube River, the lead c90 value reaches up to 82.00 µg/l. Downstream
this location, the existing data shows a decreasing spatial pattern.
The second part of the lower Danube is also characterised by rather high lead concentrations,
especially at Danube-Chiciu/Silistra (km 375, RO04), where according to Romanian data the lead c90
value reaches up to 57.30 µg/l.
Concerning the exceeding of the target value, along the entire lower stretch, 136 values are above this
limit. Most of the values are actually characteristic to Quality Class V.
The spatial distribution of lead concentrations in the selected tributaries is shown in Fig. 8.1.3.31a and
8.1.3.31b. It can be seen that 55 values exceed the target value. Target limit for lead is exceeded in
majority of monitoring sites. The highest concentrations are observed in the tributaries of the lower
part of river basin. Maximum c90 values had been observed in Arges (RO09), Siret (RO10) and Prut
(RO11), reaching values 91.00 µg/l in Arges-Conf. Danube (RO09); 88.71 µg/l in Siret-Conf. Danube
Sendreni (RO10) and 49.70 µg/l in Prut-Conf. Danube Giurgiulesti (RO11).
The temporal distribution of lead c90 values along the Danube River is shown in Fig. 8.1.3.32 and in
Fig. 8.1.3.33 for selected tributaries. It can be concluded that:
- in the upper and middle Danube, a relative constant values in evaluated period are present,
excepting the monitoring site located at Danube-Dunafoldvar (km1560, H04), where an
increasing tendency appears from 1997 to 2000;
- in the lower Danube, decreasing from 1998 is observed in all Romanian monitoring sites
from Danube-Bazias (km 1071, RO01), down to Danube-Sf. Gheorghe/Sf. Gheorghe arm
(km 0, RO08). In cross section RO02/BG01 and RO04/BG05, in accordance to existing
Bulgarian data, the trend is somehow opposite - increasing from 1996 to 2000;
- as far as concerns the temporal changes in selected tributaries, the following has been
observed:
o increasing from 1997 to 2000 in Salzach-Laufen (D04);
o decreasing in Drava-Varazdin (HR03), Drava-Botovo (HR04) and Drava-D.
Miholjac (HR05);
o decreasing in Arges-Conf. Danube (RO09), Siret-Conf. Danube Sendreni (RO10)
and Prut-Conf. Danube Giurgiulesti (RO11).
The spatial pattern of lead is the same as was in case of other heavy metals, with generally several-
times higher values in lower part of river basin, which is valid for both Danube River itself and
monitored tributaries. JDS results are much lower, TNMN data indicate values characterising lead
content in lower Danube part sometimes even higher by one order.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 119
90
80
70
60
50
l
µg/ 40
30
20
10
0
1
2
3
4
1
2
3
01
02
1
2
3
4
03
04
5
05
01
06
02
07
08
D01
D02
A0
A0
A0
A0
H01
H02
H03
H04
H05
SK0
SK0
SK0
HR01
HR02
RO
lowe ROr I
BG0
BG0
BG0
BG0
RO
RO
BG0
RO
UA
RO
UA
RO
RO
middle
lower II
Monitoring site
upper
1996
1997
1998
1999
2000
Fig. 8.1.3.30a: Spatial variation of Pb Danube River
90
80
70
60
50
/
l
µg
40
30
20
10
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.30b: Spatial variation of Pb Danube River
V 120
UNDP/GEF Danube Regional Project
100
80
60
/
l
µg
40
20
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
1996
1997
1998
1999
2000
Monitoring site / Tributary
Fig. 8.1.3.31a: Spatial variation of Pb Tributaries
100
80
60
µg/l
40
20
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.31b: Spatial variation of Pb Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 121
80
70
60
50
40
30
20
10
0
2581
2204
2204
2120 1935 1874 1869 1806 1806 1768 1768 1708
1560
1435
1429
1337
1071
834 834 641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Fig. 8.1.3.32: Temporal trends of Pb Danube River
100
90
80
70
µg/l 60
50
40
30
20
10
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.3.33: Temporal trends of Pb Tributaries
V 122
UNDP/GEF Danube Regional Project
Mercury
Mercury is a metal that occurs naturally in the environment. It can be found as mercury salts or as
organic mercury compounds. It enters the environment as a result of normal breakdown of minerals
and exposure to wind and water. From human activities, mercury is released into air through fossil fuel
combustion, mining, smelting and solid waste combustion. Some forms of human activities release
mercury directly into soil or water, for instance the application of agricultural fertilizers and industrial
waste water discharges. All mercury released into environment will eventually end up in soil and
surface water. Acidic surface waters can contain significant amounts of mercury: when the pH values
are between 5.00 and 7.00, the mercury concentrations in water increase due to mobilization of
mercury in the ground. Once it reaches the surface water, microorganism can convert it into methyl
mercury, a very dangerous organic compound.
The distribution of monitoring sites according to the Classification System in the DRB for mercury is
shown in Fig. 8.1.3.34:
Hg
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
No data
20.0
No class indication
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.34: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Hg
Based on data reported from 64 monitoring sites (out of the assessment is 49 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following remarks can be done:
- almost 50 % of the monitoring sites (in 1996) have no quality class indication, because the
limit of detection is higher than the limit value for Class II. In years 1997-2000 sites with "no
class" indication is low because data have not been provided from majority of these sites (and
therefore percentage of sites with "no data" from the basic set of 64 monitoring sites is so high
in 1997-2000) (see also Annex 1)
- in four of the five studied years, maximum percentage of sites correspond to Class II. In 1997,
maximum belongs to Class III;
- the number of sites corresponding Class IV is uniform during 1996-1998 (3.1%), absent in
1999 but increases in 2000 at 9.4 %;
- the number of sites within Class V is below 5 % during the evaluated period;
The spatial pattern for mercury concentrations along the Danube River is shown in Fig. 8.1.3.35a and
8.1.3.35b.
Mercury c90 values are between 0.100 0.416 µg/l in the upper section, being undetectable at
Danube-Neu Ulm (km 2581, D01) and Danube-Jochentein (km 2204, D02). Mercury is the only
heavy metal in case of which the upper Danube section contains 16 values above the target limit.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 123
Although mercury was mostly undetected at monitoring sites from the middle stretch, still 14 values
are above the quality target. The maximum value (0.82 µg/l) appears at Danube-Dunafoldvar (km
1560, H04).
Entire lower section of the Danube has no suitable data for assessment.1
The spatial pattern of mercury concentrations for selected tributaries is illustrated in Fig. 8.1.3.36a and
8.1.3.36b. All four tributaries from the upper section show mercury values exceeding the target value.
Those from the middle stretch also show values above 0.1 µg/l. It has to be mentioned that in the case
of the Drava-Ormoz (SL01) and the Sava-Jesenice (SL02) the represented values (0.5 µg/) are actually
the limit of detection, so mercury is undetected at those sites. The maximum mercury concentration
(1.54 µg/) appears on the Sava-ds. Zupanja (HR08). Concerning the tributaries from the lower Danube
section, no mercury data are suitable for assessment1.
The temporal distribution of mercury concentrations along the Danube River is shown in Fig. 8.1.3.37
and in Fig. 8.1.3.38 for selected tributaries. It can be concluded that:
- no tendency of development can be observed in the monitoring sites from the upper and
middle Danube section;
- for selected tributaries, slight increase in Inn-Kirchdorf (D03) and Dyje (CZ02) and slight
decrease in Morava-Lanzhot (CZ01) is observed.
1 the reported data for Romanian monitoring sites are excluded from assessment because all data are equal to
3.00µg/l, identical with the reported limit of detection
V 124
UNDP/GEF Danube Regional Project
0.9
0.8
0.7
0.6
0.5
/
l
µg 0.4
0.3
0.2
0.1
0.0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
middle
lower I
lower II
upper
1996
1997
1998
1999
2000
Monitoring site
Fig. 8.1.3.35a: Spatial variation of Hg Danube River
0.9
0.8
0.7
0.6
0.5
/
l
µg
0.4
0.3
0.2
0.1
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.35b: Spatial variation of Hg Danube River
Note: In locations A01, A02, A03, A04 (96-99), RO01, RO02, RO03, RO04, RO05, RO06, RO07, RO08 (96) the values in the graph represent limits of detection that are higher than the target
value.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 125
1.8
1.6
1.4
1.2
1.0
/
l
µg 0.8
0.6
0.4
0.2
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.36a: Spatial variation of Hg Tributaries
2.0
1.5
µg/l
1.0
0.5
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.36b: Spatial variation of Hg Tributaries
Note: In locations SL01, SL02 (96-00), RO09, RO10, RO11 (96) the values in the graph represent limits of detection that are higher than the target value.
V 126
UNDP/GEF Danube Regional Project
3.5
3.0
2.5
l 2.0
µ
g/ 1.5
1.0
0.5
0.0
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834
834 641
554 503
432 375
375 132
18
0
0
132
18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02RO01RO02 BG01 BG02 BG03 BG04 RO03RO04 BG05RO05RO06 RO07RO08 UA01 UA02
Monitoring sites / distance f rom the mouth [km]
Fig. 8.1.3.37: Temporal trends of Hg Danube River
3.5
3.0
2.5
2.0
µg/l
1.5
1.0
0.5
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03
H04
H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.38: Temporal trends of Hg Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 127
Nickel
The distribution of monitoring sites according to the Classification System in the DRB for nickel is
shown in Fig. 8.1.3.39:
Ni
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.39: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Ni
Based on data reported least in one year by 82 monitoring sites (out of the assessment is 21 monitoring
sites from Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000),
it can be concluded that nickel seems to be the heavy metal for which the Danube River and its
tributaries have "the best" quality, taking into account target value given by Class II of TNMN
classification scheme. Monitoring sites correspond to Class II and Class III is represented only in 1996
by 2.4 % of monitoring sites.
The spatial distribution of nickel concentrations along the Danube River is shown in Fig. 8.1.3.40a
and 8.1.3.40b.
In the upper Danube, a slight increasing spatial profile is present from Danube-Jochenstein (km 2204,
D02) to Danube-Wolfsthal (km 1874, A04), but no nickel concentration is above the target limit for
this heavy metal (50 µg/l).
In the middle Danube, also an increasing pattern is present along Danube-Bratislava (km 1869, SK01)
to Danube-Szob (km 1708, H03), followed by a decreasing down to Danube-Borovo (km 1337,
HR02). Even the maximum value for this stretch (16.21 µg/l) is well below the target limit.
Along the first part of the lower Danube section, nickel concentrations are higher than in the middle
stretch, reaching c90 value 28.10 µg/l at Danube-Pristol/Novo Selo (km 834, RO02). However, no
value exceeds the quality target.
The second part of the lower Danube section shows several nickel concentrations higher than in the
first section. Three monitoring sites - Danube-us. Arges (km 432, RO03), Danube-Chiciu/ Silistra (km
375, RO04) and Danube-Vilkov/Chilia arm/Kilia arm - present values above 30 µg/l, The target limit
is not exceeded.
The spatial profile of nickel concentrations in the selected tributaries is shown in Fig. 8.1.3.41a and
8.1.3.41b. It can be seen that, excepting one value recorded on the Salzach-Laufen (D04), the
tributaries from the upper and middle Danube are characterized by low nickel concentrations, with no
V 128
UNDP/GEF Danube Regional Project
value above the target limit. For those located in the lower Danube, 2 values are above 50µg/l: on the
Arges-Conf. Danube (RO09) and Siret-Conf. Danube Sendreni (RO10).
The temporal trends for nickel concentrations are shown in Fig. 8.1.3.42 for the Danube River and in
Fig. 8.1.3.43 for selected tributaries:
- increasing tendency is observed in Hungarian section of the Danube River, from Danube-
Komarom/Komarno (km1768, H02) down to Danube-Hercegszanto (km 1435, H05);
- in the lower part of Danube River interpretation is rather difficult, because whilst in
Romanian sites maximum values have been observed at the beginning of the evaluated
period in 1996, in Bulgarian ones at the end of this period in 2000
- from selected tributaries decreasing from 1996 to 2000 in Salzach-Laufen (D04) and
Drava-Varazdin (HR03) is observed;
- for interpretation of tributaries in the lower part, the data available are not sufficient.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 129
50
40
30
/
l
µg
20
10
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
middle
lower I
lower II
Monitoring site
1996
1997
1998
1999
2000
Fig. 8.1.3.40a: Spatial variation of Ni Danube River
60
50
40
/
l
30
µg
20
10
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.40b: Spatial variation of Ni Danube River
V 130
UNDP/GEF Danube Regional Project
90
80
70
60
/
l 50
µg 40
30
20
100 D03 D04 CZ01 CZ02 SK04 H06 Sl01 HR03 HR04 H07 HR05 H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.41a: Spatial variation of Ni Tributaries
100
80
60
/
l
40
µg
20
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.41b: Spatial variation of Ni Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 131
40
30
µg/l
20
10
0 2581 2204 2204
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01 2120
A02 1935
A03 1874
A04 1869
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02 834
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.42: Temporal trends of Ni Danube River
100
80
60
µg/l
40
20
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.3.43: Temporal trends of Ni Tributaries
V 132
UNDP/GEF Danube Regional Project
Zinc
Zinc occurs naturally in air, water and soil. Similar to copper, zinc is widely used in human activities.
Mining of other different metals results in zinc discharging in the environment. In natural water,
unaffected by anthropogenic influence, zinc concentration is usually below 5 µg/l (The Dobris
Assessment, 1991). Due to the fact that its toxicity is generally higher in water with a low mineral
content, the Council Directive 78/659/EEC concerning water standards for fish recommends that Zn
levels to be below 300 µg//l in water with a hardness of 100 mg/l CaCO3, but below 30 µg//l in water
with a hardness of 10 mg/l CaCO3. Within the Danube River Basin, Water Quality Classification
System sets 100 µg/l as target value for zinc.
The distribution of monitoring sites according to the Classification System in the DRB for zinc is
shown in Fig. 8.1.3.44:
Zn
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.3.44: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Zn
Based on data reported from 85 monitoring sites (out of the assessment is 18 monitoring sites from
Phase I List of Monitoring Sites, in which no measurements had been done in 1996-2000), the
following remarks can be done:
- a relatively positive distribution is present, with more than 70 % of the monitoring sites within
Class II during 1996 1999 and more than 80 % in 2000;
- Class III is represented by the maximum percentage in 1998 (12.9 %);
- percentage of sites corresponding to Class IV and Class V is low, less than 10 %.
The spatial distribution of zinc concentrations along the Danube River is shown in Fig. 8.1.3.45a and
8.1.3.45b.
In the upper section, zinc concentration has an uneven spatial distribution: at first two monitoring sites
Danube-Neu Ulm (km 2581, D01) and Danube-Jochenstein (km 2204, D02) - excepting one value,
this metal is undetectable, the limit of detection being here 10 µg/l. The rest of sites from this stretch
are characterized by higher zinc concentrations, but no value is above the target limit.
In the middle stretch, the spatial distribution shows a maximum profile at Danube-Szob (km 1708
H03), where only one value exceeds the target limit. It has to be mentioned that at the cross sections
from this stretch (SK02/H01 and SK03/H02), the Hungarian data shows higher concentrations.
Downstream of Danube-Szob (H03) zinc content decreases, all c90 values are below 70 µg/l.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 133
In the first part of the lower Danube, the spatial distribution presents a significantly higher values than
in the middle stretch, with 11 values exceeding the target value. The maximum - 302.0 µg/l - appears
at Danube-ds. Svishtov (km 554, BG03).
The second part of the lower Danube is also characterized by high zinc concentrations. At Danube-us.
Arges (km 432, RO03) three values are more than two times higher than the target limit. For this part,
the total number of zinc values above this limit is 14.
The spatial distribution for selected tributaries is shown in Fig. 8.1.3.46a and 8.1.3.46b. Taking the
target limit as a criterion for assessment the zinc concentration levels in tributaries, the following
remarks can be done:
- in upper stretch, no c90 value is above the target value;
- in the middle stretch, above the target value are concentrations characterising Tisza-
Tiszasziget (H08) and Sajo-Sajopuspoki (H09);
- in the lower stretch, the Iskar-Orechovitza (BG06), Russenski Lom-Basarbovo (BG08),
Arges-Conf. Danube (RO09), Siret-Conf. Danube Sendreni (RO10) and Prut-Conf.
Danube Giurgiulesti (RO11) are the tributaries with zinc content exceeding target value.
The temporal trends for zinc concentrations are shown in Fig. 8.1.3.47 for the Danube River and in
Fig. 8.1.3.48 for selected tributaries:
- in the upper Danube, at the monitoring sites where zinc is detectable, the temporal profile
shows that higher values are recorded in 1998 and/or 1999;
- in the middle Danube, an increasing is observed in Danube-Dunafoldvar (km 1560, H04)
and Danube-Herceszanto (km 1435, H05); decreasing in Danube-Bratislava (km 1869,
SK01), and Danube-Komarno/Komarom (km 1768, SK03);
- sites in the lower Danube are characteristic with rather high variability, but decrease can
be observed in Danube-Chiciu/Silistra (km 375, RO04), Danube-Reni-Chilia/Kilia Arm
(km 132, RO05) and taking into account high value in 1997, also in Danube-Sulina-Sulina
Arm (km 0, RO07) temporal changes are going in a positive direction.
- tributaries from the upper Danube do not show significant temporal variations, only on
Dyje-Pohansko (CZ02) a decreasing trend is visible;
- in the middle Danube, increasing tendency is observed in Sio-Szekszard-Palank (H06) and
Drava-Ormoz (SL01) and decreasing tendency in the rest on monitoring sites on Drava
River and in Sajo-Sajopuspoki (H09);
- for Romanian tributaries located in the lower Danube the Arges-Conf. Danube (RO09),
Siret-Conf. Danube Sendreni (RO10) and Prut-Conf. Danube Giurgiulesti (RO11) the
general trend is decreasing, while for Iskar (BG06) and Russenski Lom (BG08) there is an
increase in evaluated period.
V 134
UNDP/GEF Danube Regional Project
350
300
250
200
µg/l
150
100
50
0
01
02
03
04
05
01
06
02
07
08
D01
D02
A01
A02
A03
A04
H01
H02
H03
H04
H05
SK01
SK02
SK03
HR01
HR02
RO
RO
BG01
BG02
BG03
BG04
RO
RO
BG05
RO
UA
RO
UA
RO
RO
lower I
Monitoring sites
upper
middle
lower II
1996
1997
1998
1999
2000
Fig. 8.1.3.45a: Spatial variation of Zn Danube River
350
300
250
200
/
l
µg
150
100
50
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.45b: Spatial variation of Zn Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 135
500
400
300
/
l
µg
200
100
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.3.46a: Spatial variation of Zn Tributaries
450
400
350
300
250
200
150
100
50
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.3.46b: Spatial variation of Zn Tributaries
V 136
UNDP/GEF Danube Regional Project
350
300
250
µg/l
200
150
100
50
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.3.47: Temporal trends of Zn Danube River
450
400
350
µg/l
300
250
200
150
100
50
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.3.48: Temporal trends of Zn Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 137
Arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc in filtered water
samples (dissolved forms)
For heavy metals in the filtered water samples (dissolved forms), data are available from 1998 to 2000
only. The monitoring sites for which dissolved forms data are available are located in the upper and in
the middle section of the Danube River, the same situation being valid also for the tributaries.
Based on existing data, the Fig. 8.1.3.49 illustrates the percentage of monitoring sites, which exceed
the target limits - for both dissolved and total forms, and for entire studied period (1996 2000).
95.55
100
84.44
84.44
82.05
80
66.66
55.55
60
54.7848.88
%
45.45
46.2
41.88
40
32.43
20
11.25
11.29
0.9
0.68
0
As
Cd
Cr
Cu
Pb
Hg
Ni
Zn
Total
Dissolved
Fig. 8.1.3.49: Total percentage of monitoring sites exceeding target values in period 1996-00
As it can be seen from the figure above, the highest differences between percentages of exceedance
based on analysis of total samples and dissolved fraction belong to nickel, chromium, arsenic and zinc,
dissolved fractions having much higher percentage of exceedance.
As an overview on heavy metals concentration levels in the Danube River and its main tributaries, the
Table 8.1.3.1 shows a comparison of TNMN data for several investigated heavy metals with literature
data on river water background concentration, quality targets of other river monitoring networks and
of those from water quality classification of MLIM Expert Group Proposal.
Table 8.1.3.1: Comparison of heavy metals concentration in the Danube River and its tributaries with
various concentration levels (the concentration ranges are valid for total heavy metals forms)
Upper
Middle
Lower
Tributaries Background Target
Target
Danube
Danube
Danube
level 2
Value 3
Value 4
a
l
(diss.)
(Total /
Met
diss.)
Range concentration (min max) µg/l
µg/l
As
1.00 3.27
0.10 4.84
0.30 11.02
1.00 79.36
-
?
5 / 1
Cd
0.10 0.66
0.02 2.25
0.14 29.10
0.02 24.18
0.009 0.036
0.072
1 / 0.1
Cr
1.00 5.00
0.43 20.17
5.00 97.00
0.10 41.00
1.3 5.0
3.1
50 / 2
2 LAWA Guide
3 Joint Danube Survey Technical Report, 2002
4 MLIM Expert Group Proposal on Water Quality Classification in Danube River Basin
V 138
UNDP/GEF Danube Regional Project
Upper
Middle
Lower
Tributaries Background Target
Target
Danube
Danube
Danube
level 2
Value 3
Value 4
a
l
(diss.)
(Total /
Met
diss.)
Range concentration (min max) µg/l
µg/l
Cu
2.00 10.20
0.73 46.98
2.00 213.1
0.02 102.5
0.5 2.0
3
20 / 2
Pb
1.00 4.70
0.55 17.45
1.00 82.00
0.05 91.00
0.4 1.7
3.4
5 / 1
Hg
0.10 0.42
0.03 0.82
-
0.08 1.54
0.005 0.020
0.04
0.1 / 0.1
Ni
1.00 5.40
0.39 16.21
0.05 42.90
0.05 79.00
0.6 2.2
1.8
50 / 1
Zn
3.90 69.00
9.05 122.9
18.0 288.0
4.0 409.0
1.8 7.0
7
100 / 5
8.1.4. Oxygen
Regime
The natural organic matter occurring in water originates mainly from soil erosion and decomposition
of dead plants and animals; it is relatively insoluble and slowly decomposed. Organic matter evolved
from various human activities represent one of the most important pollutants discharged into a rivers;
it is generally soluble and rapidly divided and decomposed. Since the decomposition of this matter is
carried out by microorganisms and requires consumption of oxygen, the assessment of oxygen regime
indicators is of a major importance. Hence, the variation of dissolved oxygen in terms of concentration
(DO), biochemical oxygen demand (BOD5) and chemical oxygen demand both COD-Mn and COD-
Cr was taken into account:
Dissolved oxygen
The actual amount of oxygen present is an important water quality parameter. As a general rule, the
less of oxygen dissolved in water the worse is the water quality. Therefore, for oxygen low values,
described in this report by 10 %-iles, have to be examined. In general the concentration of dissolved
oxygen shows strong daily and seasonal variation. Monitoring results are therefore very much
dependent on the time of sampling. In periods of high primary production and algae growth
concentration may fluctuate for several milligrams per litre.
The distribution of monitoring sites according to the Classification System in the DRB for dissolved
oxygen is shown in Fig. 8.1.4.1:
DO
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.4.1: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for DO
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 139
The quality assessment within the five-class system is made on the basis of data reported from 87
monitoring sites (out of the assessment is 16 monitoring sites from Phase I List of Monitoring Sites, in
which no measurements had been done in 1996-2000) and the following remarks can be done in this
respect:
- the number of monitoring sites within Class I decreases from 1996 to 1998 and then increases
until 2000; values above 50% are present in 1996 and 2000 only;
- the monitoring sites within Class II show a maximum percentage in 1998 (when the
percentage for Class I is minimum);
- the number within Class III is below 10% in all five years;
- Class IV does not appear in 1997; for the other years, all values are below 5% of the
monitoring sites;
- the number of sites within Class V decreases continuously from 1996 to 1999, in 2000 being
totally absent, which demonstrates the improving in water quality from the DO point of view;
The spatial pattern of dissolved oxygen concentrations for the Danube River is shown in Fig, 8.1.4.2a
and 8.1.4.2.b.
In the upper section, dissolved oxygen values increase from Danube-Neu Ulm (km 2581, D01) to
Danube-Wien-Nussdorf (km 1935, A03). In this stretch, all concentrations are above 8.5 mg/l and no
value is below the target limit for oxygen (6 mg/l).
In the middle stretch, oxygen concentrations are slightly lower then that from the upper one, but a
uniform pattern is present along this stretch. The apparent "V" profile with minimum located at
Danube-Medve/Medvedov (km 1806, H01) is caused by the lower Hungarian data in comparison with
Slovak data in this cross section. It has to be mentioned that along this stretch no value is below the
target limit.
In the first part of the lower section, oxygen c10 values clearly decrease from Danube-Bazias (km
1071, RO01) to Danube-Novo Selo/Pristol (km 834, BG01) by more than 2 mg/l, varying in the range
4.45 7.10 mg/l O2; this situation can be mainly attributable to the Iron Gate Reservoir influence.
From Danube- us. Iskar (km 641, BG02) to Danube-us. Russe (km 503, BG04), the dissolved oxygen
regime is better, even if due to the lack of some data it is not possible to give a comprehensive picture.
The second part of the lower Danube shows a uniform spatial pattern of dissolved oxygen, the values
vary within the range 5.72 8.80 mg/l O2.
For the entire lower Danube, 19 values were below the target limit, with minimums in Danube-Novo
Selo/Pristol (km 834, BG01); but especially in 1997-1998 there are remarkable differences in the
results reported by Bulgaria and Romania in this river profile (BG01 and RO02) (see Fig. 8.1.4.2a).
The spatial distribution of dissolved oxygen concentrations in selected tributaries is illustrated in Fig.
8.1.4.3a and 8.1.4.3b. It can be mentioned that oxygen content generally decreases, from those located
in the upper to those from the lower part. For example, two tributaries from the upper Danube, the Inn-
Kirchdorf (D03) and Salzach-Laufen (D04), have a dissolved oxygen concentration ranging between
9.9 10.5 mg/l O2, while for a tributary located in the lower Danube, the Arges-Conf. Danube
(RO09), this range is 2.50 6.20 mg/l O2. Similarly, on the Siret-Conf. Danube Sendreni (RO10) and
Prut-Conf. Danube Giugiulesti (RO11), rather low values are recorded (2.95 and 2.06 mg/l O2,
respectively).
As concerning the tributaries located in the middle section, the oxygen content is generally lower than
in the Danube itself, the minimum values are recorded on the Sio-Szekszard-Palank (H06) and Sava-
ds. Zupanja (HR08) 5.13 and 5.52 mg/l O2, respectively.
From selected tributaries, 11 values of dissolved oxygen are below the target limit most of them being
in the lower Danube - the Arges-Conf. Danube (RO09), Siret-Conf. Danube Sendreni (RO10) and
Prut-Conf. Danube Giugiulesti (RO11).
V 140
UNDP/GEF Danube Regional Project
Regarding yearly variations of oxygen it can be concluded, that they do not exceed 1 mg/l at many
monitoring sites. In particular the sites at the Danube River remain rather constant. As to the
tributaries, Arges (RO09) and Siret (RO10) show the biggest differences between the years.
The temporal trends are illustrated in Fig. 8.1.4.4 for the Danube River and in Fig. 8.1.4.5 for selected
tributaries. The following trends are visible:
- increasing tendencies were observed in Danube-Neu-Ulm (D01), Danube-Jochenstein (km
2204, D02), Danube-us. Arges (km 432, RO03), Danube-Chiciu/Silistra (km 375, RO04) and
Danube-us. Iskar-Bajkal (km 641, BG02);
- slight decreasing tendencies are in Danube-Borovo (km 1337, HR02) and Danube-
Pristol/Novo Selo (km 834, RO02);
- the different tendencies at the cross sections at km 834 (RO02/BG01) and km 375
(RO04/BG05) has to be mentioned, the reason of which could be a lower frequencies of
measurements in Bulgaria;
- in selected tributaries increasing tendencies were observed in Iskar-Orechovitza (BG06),
Arges-Conf. Danube (RO09) and Siret-Conf. Danube Sendreni (RO10).
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 141
12
10
8
/l
O2
6
g
m
4
2
0
1
2
01
02
1
03
2
3
4
5
0
1
0
2
0
1
0
2
01
02
03
04
0
3
0
4
05
0
5
0
1
0
6
0
2
0
7
0
8
D0
D0
A01
A02
A03
A04
H0
H0
H0
H0
H0
SK
SK
SK
HR
HR
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.4.2a: Spatial variation of DO Danube River
12
10
8
2
6
g
/l
O
m
4
2
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.2b: Spatial variation of DO Danube River
V 142
UNDP/GEF Danube Regional Project
14
12
10
8
g
/l
O2
6
m
4
2
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.4.3a: Spatial variation of DO Tributaries
14
12
10
8
2
g
/l
O
6
m
4
2
0
2500
2000
1500
1000
500
0
Confluenece at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.3b: Spatial variation of DO Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 143
12
10
mg/l
8
6
4
2
0
2581
2204
2204
2120
1935
1874
1869
1806
1806
1768
1768
1708
1560
1435
1429
1337
1071
834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01
A02
A03
A04
SK01
SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01
RO02
BG01
BG02
BG03
BG04
RO03
RO04
BG05
RO05
RO06
RO07
RO08
UA01
UA02
Monitoring sites / distance from the mouth
[k ]
Fig. 8.1.4.4: Temporal trends of DO Danube River
12
10
mg/l
8
6
4
2
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
HR05
H07
H08
H09
Sl02
HR06
HR06
HR07
HR08
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Monitoring site
Fig. 8.1.4.5: Temporal trends of DO Tributaries
V 144
UNDP/GEF Danube Regional Project
In order to have a more comprehensive picture of the dissolved oxygen distribution along the Danube
River within the five years time period (1996-2000), beside 10 percentiles both maximum and
minimum concentration values were represented for each studied year, separately for the Danube
River itself and selected tributaries - Fig. 8.1.4.6 8.1.4.15.
Table 8.1.4.1.summarizes some relevant data related to oxygen content distribution along the Danube
and its tributaries:
Table 8.1.4.1: Ranges of maximum and minimum values for dissolved oxygen concentrations
Range of maximum values
Range of minimum values
Year
(mg/l O2)
(mg/l O2)
Danube Tributaries Danube Tributaries
1996
8.6 16.0
9.1 29.5
4.8 9.6
2.4 10.4
1997 8.3
18.3
8.1 15.2
3.9 9.4
2.3 9.9
1998
10.3 15.6
8.5 17.4
4.3 9.2
3.0 11.4
1999
8.8 15.3
6.4 15.3
4.5 9.5
2.9 9.8
2000
8.5 15.6
6.1 15.9
4.3 9.8
3.7 9.9
Based on the above mentioned figures and table, the following remarks can be done:
- apart from the extreme values, a relative constancy among the studied years for both minimum
and maximum dissolved oxygen ranges is illustrated;
- a closer look should be given to the "top" of the maximum recorded values as well as to the
"bottom" of the minimum ones.
o the maximum-recorded value for the Danube River itself (18.3 mg/l O2) appears in
1997, at Danube-Dunafoldvar (km 1560, H04);
o the maximum-recorded value for tributaries (29.5 mg/l O2) is present in 1996 on the
Sio-Szekszard (H06). Other related data - pH = 8.72, BOD5 = 9.5 mg/l O2, N-NH4 =
1.30 mg/l, N-NO3 = 9.54 mg/l (TNMN Data Base 1996 - 2000) - indicate strong
pollution by nutrients, allowing excessive growth of primary producers producing an
oxygen. Also data obtained in the frame of JDS (Joint Danube Survey 2001)
indicated a high value of oxygen content for the Sio-Szekszard (H06) tributary 18.9
mg/l O2;
o the minimum dissolved oxygen concentration on the Danube River (3.9 mg/l O2) is
present in 1997, at Danube-Novo Selo/Pristol (km 834, BG01), but is not in harmony
with the observations from Romanian side at the same cross section (6.4 mg/l O2);
o the minimum dissolved oxygen concentration for selected tributaries (2.3 mg/l O2)
appears in 1997 and, as well as the most of the minimum recorded values, is specific
to the Arges-Conf. Danube. This critical problem is mainly caused by the fact that this
tributary regularly serves as recipient of untreated and not adequately treated waste
water and its low dilution regime (discharge flows ranging within the range 34.9
102.0 m3/s) cannot compensate these pollution inputs;
- some differentiations can be made among the oxygen contents in the studied years:
o 1996, as the first year of TNMN monitoring Programme, is characterized by a
scattered profile of both minimum and maximum oxygen concentrations; apart from
the above discussed value of 29.5 mg/l O2, the maximum level of 16.0 mg/l O2 is met
at several monitoring point located on the main course of the Danube and on
tributaries: Danube-Medvedov/Medve (km 1806, SK02) even if it doesn't make a
good correlation with the cross reported data (12.2 mg/l O2 at H01), further in
Danube-Szob (km 1708, H03), Danube-Hercegszanto (km 1435, H05) and on the
alpine tributary, Drava-Dravaszabolcs (H07);
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 145
o 1997: as it was already mentioned, the maximum recorded value appears at Danube-
Dunafoldvar (km 1560, H04); the minimum values profile of the Danube is spatially
uniform;
o 1998: the maximum value (17.4 mg/l O2) is recorded on the Sio-Szekszard -Palank
(H06), but the other maximum concentrations do not exceed 16.0 mg/l O2. Excepting
one already mentioned value, all minimum ones are above 4.0 mg/l O2;
o 1999 and 2000 present a uniform spatial distribution of maximum and minimum
concentration values, ranging between 4.0 and 16.0 mg/l O2, only one value being
outside of this interval.
Fig. 8.1.4.6 8.1.4.15: Minimum, maximum and 10%-iles values for Dissolved Oxygen (Danube
River and Tributaries)
1996
20
18
16
14
12
2
10
g
/l O
m
8
6
4
2
0
1
1
2
3
4
4
1
1
2
3
3
4
5
1
6
2
7
8
8
01
01
0
0
0
01
01
03
04
0
0
0
05
05
0
0
0
0
0
0
0
D0
A01
A03
H0
H0
H0
H0
H0
SK
HR
RO
RO
RO
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
UA
RO
UA
RO
RO
RO
Monitoring site
Max
Min
10-%
1996
30
25
20
2
15
g
/l O
m
10
5
0
3
4
1
2
6
1
3
4
7
5
9
8
2
6
7
8
6
7
8
9
0
1
2
1
3
0
0
4
0
0
0
0
0
0
0
1
0
0
1
0
D0
D0
H0
H0
H0
H0
CZ
CZ
SK
Sl
HR0
HR0
HR0
Sl
HR0
HR0
HR0
BG
BG
BG
RO
RO
MD
MD
RO
MD
Monitoring site
Max
Min
10-%
V 146
UNDP/GEF Danube Regional Project
1997
20
18
16
14
12
2
10
g
/l O
m 8
6
4
2
0
1
1
3
0
1
1
2
3
4
4
01
0
1
0
1
0
2
0
1
0
1
0
3
0
4
0
3
0
3
0
4
0
5
0
5
0
5
01
0
6
02
0
7
0
8
0
8
D0
A0
A0
H0
H0
H0
H0
H0
SK
HR
RO
RO
RO
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
UA
RO
UA
RO
RO
RO
Monitoring site
Max
Min
10-%
1997
20
18
16
14
12
/
l
O2 10
mg 8
6
4
2
0
3
4
1
2
6
3
4
7
5
9
8
6
7
8
9
0
1
2
1
3
0
0
4
1
2
6
7
8
0
0
0
0
0
0
0
1
0
0
1
0
D0
D0
H0
H0
H0
H0
CZ
CZ
SK
Sl
HR0
HR0
HR0
Sl
HR0
HR0
HR0
BG
BG
BG
RO
RO
MD
MD
RO
MD
Monitoring site
Max
Min
10-%
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 147
1998
20
18
16
14
12
2
10
g
/l O
m 8
6
4
2
0
1
1
3
0
1
1
2
3
4
4
0
1
0
1
0
1
0
2
0
1
0
1
0
3
0
4
0
3
0
3
0
4
0
5
0
5
0
5
0
1
0
6
0
2
0
7
0
8
0
8
D0
A0
A0
H0
H0
H0
H0
H0
SK
HR
RO
RO
RO
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
UA
RO
UA
RO
RO
RO
Monitoring site
Max
Min
10-%
1998
20
18
16
14
12
2
10
g
/l
O
m
8
6
4
2
0
3
4
1
2
4
6
1
3
4
7
5
9
8
2
6
7
8
6
7
8
9
0
1
2
1
3
0
0
0
0
0
0
0
1
0
0
1
0
D0
D0
H0
H0
H0
H0
CZ0
CZ0
SK
Sl
HR0
HR0
HR0
Sl
HR0
HR0
HR0
BG
BG
BG
RO
RO
MD
MD
RO
MD
Monitoring site
Max
Min
10-%
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UNDP/GEF Danube Regional Project
1999
20
18
16
14
12
2
10
g
/l O
m
8
6
4
2
0
1
1
3
1
0
1
1
2
3
4
4
0
1
0
1
0
2
0
1
0
1
0
3
0
4
0
3
0
3
0
4
0
5
0
5
0
5
0
1
0
6
0
2
0
7
0
8
0
8
D0
A0
A0
H0
H0
H0
H0
H0
SK
HR0
RO
RO
RO
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
UA
RO
UA
RO
RO
RO
Monitoring site
Max
Min
10-%
1999
20
18
16
14
12
2
10
g
/l
O
m 8
6
4
2
0
3
4
1
2
6
3
4
7
5
9
8
6
7
8
9
0
1
2
1
3
0
0
4
1
2
6
7
8
0
0
0
0
0
0
0
1
0
0
1
0
D0
D0
H0
H0
H0
H0
CZ
CZ
SK
Sl
HR0
HR0
HR0
Sl
HR0
HR0
HR0
BG
BG
BG
RO
RO
MD
MD
RO
MD
Monitoring site
Max
Min
10-%
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 149
2000
20
18
16
14
12
2
10
g
/l O
m 8
6
4
2
0
1
1
3
1
0
1
1
2
3
4
4
0
1
0
1
0
2
0
1
0
1
0
3
0
4
0
3
0
3
0
4
0
5
0
5
0
5
0
1
0
6
0
2
0
7
0
8
0
8
D0
A0
A0
H0
H0
H0
H0
H0
SK
HR0
RO
RO
RO
BG
BG
BG
BG
RO
RO
RO
BG
BG
RO
UA
RO
UA
RO
RO
RO
Max
Min
10-%
Monitoring site
2000
20
18
16
14
12
2
10
g
/l
O
m
8
6
4
2
0
3
4
1
2
6
3
4
7
5
9
8
6
7
8
9
0
1
0
0
4
1
2
6
7
8
0
0
0
0
0
0
0
1
01
02
1
03
D0
D0
H0
H0
H0
H0
CZ
CZ
SK
Sl
HR0
HR0
HR0
Sl
HR0
HR0
HR0
BG
BG
BG
RO
RO
MD
MD
RO
MD
Max
Min
10-%
Monitoring site
V 150
UNDP/GEF Danube Regional Project
Biochemical and Chemical Oxygen Demand
Because microorganisms mediate the composition of organic matter and it is an oxygen consuming
process, the amount of organic matter in a water body is measured in terms of biochemical and
chemical oxygen demand. Thus, in order to evaluate the temporal variation of organic matter content
in the longitudinal profile of the Danube River and in its selected tributaries, BOD5, COD-Mn and
COD-Cr are the determinands that were taken into account in this respect.
Biochemical Oxygen Demand (BOD5)
The distribution of monitoring sites according to the Classification System in the DRB for BOD5 is
shown in Fig. 8.1.4.16:
BOD5
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.4.16: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for BOD5
The assessment is made based on data reported from 87 monitoring sites (out of the assessment is 16
monitoring sites from Phase I List of Monitoring Sites, in which no measurements had been done in
1996-2000):
- the percentage of monitoring sites within Class I is below 25% during the entire time period;
- the maximum percentages belong to Class II and the values within this quality class increase
from 44.8 % in 1997 to 58.6 % in 2000;
- the number of sites within Class III increases from 1996 to 1998 up to 27.6 % and decrease
until 2000 down to 12.6 %;
- Class IV and V are present in 1996, at 1.1 % of all monitoring sites only.
The spatial variation of BOD5 values for the Danube River is illustrated in Fig. 8.1.4.17a and
8.1.4.17b.
In the upper section of the Danube, BOD5 values increase from Danube- Neu-Ulm (km 2581, D01) to
Danube-Wolfsthal (km 1874, A04), excepting the monitoring site located at Danube-Wien Nussdorf
(km 1935, A03). It has to be mentioned that in the upper Danube two values are below 2 mg/l O2,
indicating no human activities impact (The Dobris Assessment, 1991), but two values are above the
target limit for BOD5.
In the middle stretch, a relative constancy (2.0 4.6 mg/l O2) is visible from Danube-Bratislava (km
1869, SK01) to Danube-Szob (km 1708, H03). In this point - the confluence with the Ipoly tributary
values are within the interval 4.4 5.6 mg/l O2. The spatial increasing pattern is valid also down to
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 151
Danube-Hercegszanto (km 1435, H05), where BOD5 reaches 8.2 mg/l O2, the maximum obtained
value for the Danube River. For the middle stretch, 15 BOD5 values are above the target limit, mainly
located in the stretch from Danube-Szob (km 1708, H03) to Danube-Borovo (km 1337, HR02).
Longitudinal assessment in the first part of the lower Danube shows a different spatial variation of
BOD5 values, it depends on the cross section data at which the reference is made to: a uniform spatial
profile if the Danube-Pristol/Novo Selo (km 834, RO02) data are taken into account and a spatial
decreasing if the Danube- Novo Selo/Pristol (km 834, BG01) data are considered. (Actually, the
differences between the data reported in 1997 are serious: from 6.1 mg/l O2 in RO02 to 2.1 mg/l O2 in
BG01). Even if the interpretation is quite problematic, it can be estimated that a uniform level is valid
for this stretch.
The second part presents a uniform spatial pattern from Danube-us. Arges (km 432, RO03) and the
three arms of the delta, with BOD5 values within the range 1.8 5.5 mg/l O2.
Generally can be said that along the Danube the organic pollution expressed by BOD increases,
reaching maximum values in the section from Danube-Dunafoldvar (rkm 1560, H04) to Danube-
Pristol/Novo Selo (rkm834, RO02). Here is also the highest frequency of exceedance of target value
recorded in 5-years evaluation period. In addition, in this section there is the highest year-to-year
variability of values, reaching in some cases even more than 3 mg/l.
For selected tributaries, the BOD5 values are illustrated in Fig. 8.1.4.18a and 8.1.4.18b. The following
remarks can be done:
- even if in the upper and in the middle Danube, the Morava-Lanzhot (CZ01), Dyje-Pohansko
(CZ02) and Sio-Szekszard (H06) have values above the target limit, the general spatial pattern
of BOD5 values is decreasing down to Tisza tributary, with no big differences between the
tributaries and the Danube itself;
- in the lower section, BOD5 values are slightly higher for the right side tributaries - the Iskar-
Orechovitza (BG06), Jantra-Karantzi (BG07) and Russenski Lom-Basarbovo (BG08), but the
most critical problem occurs on the Arges-Conf. Danube (RO09), where an extreme value
(60.5 mg/l O2) is recorded in 1996;
- for all selected tributaries, 46 BOD5 values exceed the target limit; most likely, the main
reason for this exceeding is existence of significant point sources of pollution in some cases in
combination with low flows.
The temporal trends of BOD5 are illustrated in Fig. 8.1.4.19 for the Danube River and in Fig. 8.1.4.20
for tributaries. Several different trends can be noticed:
- decreasing from 1997 or 1998 to 2000 from Danube-Neu Ulm (km 2581, D01) to Danube-
Abwinden-Asten (km 2120, A02), at the cross sections Danube-Medve/Medvedov/Medve
(km 1806, SK02/H01) and Danube-Komarom/Komarno/Komarom (km 1768, SK03/H02),
from Danube-Borovo (km 1337, HR02) to Danube-Bazias (km 1071, RO01), in Danube-
Reni/Chilia arm/Kilia arm (km 132, RO05), Danube-Vilkov/Kilia arm/Chilia arm (km 18,
UA02);
- increasing from 1996 to 1997 or 1998 followed by a decreasing until 2000 at Danube-
Dunafoldvar (km 1560, H04), Danube-Hercegszanto (km 1435, H05) and from Danube-
Chiciu/Silistra (RO04) to Danube-Sulina/Sulina arm (km 0, RO07);
- regarding tributaries, a decreasing trend for BOD5 can be observed in Inn (D03), Salzach
(D04), Dyje (CZ02), Vah (SK04) Drava (HR03, HR04,HR05, H07) and Arges (RO09), whilst
the sites at Tisza River (H08) ad its tributary Sajo (H09) show a reverse behaviour.
V 152
UNDP/GEF Danube Regional Project
9
8
7
6
2 5
g
/l
O
4
m
3
2
1
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.4.17a: Spatial variation of BOD5 Danube River
9
8
7
6
5
2
4
g
/l
O
m
3
2
1
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.17b: Spatial variation of BOD5 Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 153
15
12
60.5
9
/l
O2
g
m
6
3
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.4.18a: Spatial variation of BOD5 Tributaries
15
X
60.5
12
9
2
g
/l
O
m
6
3
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.18b: Spatial variation of BOD5 Tributaries
V 154
UNDP/GEF Danube Regional Project
mg/l
10
8
6
4
2
0
2581
2204
2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01 A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.4.19: Temporal trends of BOD5 Danube River
mg/l
80
60
40
20
0
D03
D04
CZ01 CZ02 SK04 H06
Sl01
HR03 HR04 HR05
H07
H08
H09
Sl02
HR06 HR06 HR07 HR08 HR08 BG06 BG07 BG08 RO09 RO10 MD01 MD02 RO11 MD03
Monitoring sites / distance from the mouth [km]
Fig. 8.1.4.20: Temporal trends of BOD5 Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 155
Chemical Oxygen Demand
COD-Mn and COD-Cr
The other two determinands that illustrate the presence of oxygen-consuming compounds in the water
column are COD by KMnO4 and K2Cr2O7 methods.
The distribution of monitoring sites according to the Classification System in the DRB for COD-Mn
is shown in Fig. 8.1.4.21:
COD-Mn
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.4.21: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for COD-Mn
For COD-Mn, the assessment is made based on data reported from 84 monitoring sites (out of the
assessment is 19 monitoring sites from Phase I List of Monitoring Sites, in which no measurements
had been done in 1996-2000):
- Class I is represented by less than 40 % of all monitoring sites;
- excepting 1996, when the number of monitoring sites within Class I is identical to that specific
to Class II (39.3%), for all the other studied years the maximum percentages belong to Class
II, in the range of 48.8 % in 1997 58.3 % in 1998;
- Class III is represented by low percentages in all five years, within the range from 2.4 % in
1998 8.3 % in 1997;
- Class IV appears only in 1996 and 1997 ( at 2.4 % and 1.2 % of sites respectively);
- no monitoring site shows values within Class V;
The distribution of monitoring sites according to the Classification System in the DRB for COD-Cr is
shown in Fig. 8.1.4.26:
V 156
UNDP/GEF Danube Regional Project
COD-Cr
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.4.26: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for COD-Cr
For COD-Cr, the assessment is made based on data reported from 83 monitoring sites (therefore, out
of the assessment is 20 monitoring sites from Phase I List of Monitoring Sites, in which no
measurements had been done in 1996-2000):
- Class I is represented by low number of sites, with a minimum of 2.4 % in 1997 and 1999 and
a maximum of 9.6 % in 1996;
- the maximum percentages from all sites belong to Class II each year: in 1997 only, less than
50 % of the monitoring sites belong to this class, all the other values are above this level;
- Class III has an uneven distribution, with percentages within the range 8.4 % in 1996 up to
34.9 % in 1997;
- only few monitoring sites show values within Class IV, the maximum being 3.6 % in 1997
and 2000;
- similarly to COD-Mn, no monitoring site is described by COD-Cr values within Class V.
The spatial distributions of COD-Mn and COD-Cr values for the Danube River are shown in Fig.
8.1.4.22a, 8.1.4.22b and Fig. 8.1.4.27a, 8.1.4.27b, respectively.
In the upper section of the Danube River, both determinands present a uniform spatial pattern, with
variation intervals of 1.8 6.1 mg/l O2 for COD-Mn and 8.9 19.2 mg/l O2 for COD-Cr. For
monitoring sites located in this stretch, no value is above the target limits (10.0 mg/l O2 for COD-Mn
and 25.0 mg/l O2 for COD-Cr).
Middle stretch is characterized by slightly higher values than the upper part for both determinands.
But, unlike the COD-Mn for which no value is above the target limit in this stretch, for COD-Cr four
values exceeded this limit.
For COD-Mn, the first part of the lower Danube is characterized by higher values than the middle
stretch, within the range 2.8 9.6 mg/l O2. A similar pattern as for BOD5 is valid at the cross section
from Danube-Pristol Novo Selo/Pristol (km 834, RO02/BG01), where again the differences between
the recorded data by two countries are noticeable. For COD-Cr spatial pattern is uniform, with values
within the range 11.5 23.9 mg/l O2, only one value reaching 30.0 mg/l O2 level.
The second part of the lower Danube shows a uniform line for COD-Mn. However, slightly increased
values are noticed at Danube-Chiciu/Silistra (km 375, RO04), with values within the range 5.5 10
mg/l O2. COD-Cr pattern is characterized by an increasing values from Danube-us. Arges (km 432,
RO03) down to the three main arms of the Danube Delta. The maximum value (58.0 mg/l O2) appears
at Danube-Sulina/Sulina arm (km 0, RO07).
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 157
For the entire lower Danube, no COD-Mn value is above the target limit, but 51 values exceed this
limit for COD-Cr few of them in the middle section, but most of them in the lower Danube section.
It also should be mentioned that yearly variation of COD-Mn and COD-Cr is much higher in the lower
Danube section than in the upper and middle ones.
The spatial pattern of COD-Mn and COD-Cr values for selected tributaries are shown in
Fig.8.1.4.23a, 8.1.4.23b and 8.1.4.28a, 8.1.4.28b respectively. The following remarks can be done in
this respect:
- in the upper section Morava-Lanzhot (CZ01) and Dyje-Pohansko (CZ02) are characterized by
rather high values, in Dyje exceeding 10.0 mg/l in COD-Mn and 40.0 mg/l in COD-Cr;
- in the middle stretch Sio-Szekszard (H06) presents relatively higher values, with intervals of
14.7 16.5 mg/l O2 for COD-Mn and 33.5 49.2 mg/l O2 for COD-Cr, but still these are not
extreme values for a tributary;
- in the first part of the lower Danube, only one tributary located in this section, the Jantra-
Karantzi (BG07) shows higher organic matter content with values up to 33.8 mg/l and 90.4
mg/l using COD-Mn and COD-Cr, respectively;
- in the second part of the lower Danube stretch, concerning COD-Mn, three tributaries along
this stretch the Arges-Conf. Danube (RO09), Siret-Conf. Danube Sendreni (RO10) and Prut-
Conf. Danube Giurgiulesti (RO11) - do not present extreme values for this determinand;
COD-Cr values are above level 50.0 mg/l O2 on the Siret-Conf. Danube Sendreni (RO10) and
Prut-Conf. Danube Giurgiulesti (RO11), but they are not much different from the values
recorded on the main delta arms;
- concerning the exceeding quality target for selected tributaries, 22 values are above this limit
for COD-Mn and 46 for COD-Cr.
The temporal trends for the Danube River are illustrated in Fig. 8.1.4.24 and 8.1.4.29. For selected
tributaries, the trends are shown in Fig. 8.1.4.25 and 8.1.4.30:
- for COD-Mn, the following temporal changes are observed for the Danube River and its
tributaries:
o slight increasing tendency in monitoring sites from Danube-Jochenstein (km 2204,
D02) to Danube-Bratislava (km 1869, SK01);
o most of the monitoring sites from the middle Danube are characterized by slight
decreasing trend from 1996 to 2000;
o in the lower Danube, most of the sites do not indicate any clear trend, high values
were observed mainly in 1997 and 1998;
o from tributaries, slight increasing trend is visible in Sajo-Sajopuspoki (H09); all the
others are characterized either by stationary state or decreasing trends;
- for COD-Cr, the following was observed for the Danube River and its tributaries:
o in the upper and middle Danube, most of the monitoring sites present a "V" temporal
profile, with lower values in 1998 and 1999 or a decreasing trend;
o concerning the sites located in the lower Danube, in its second part downstream
Danube-Chiciu/Silistra (rkm 375, RO04) increasing was observed especially in sites
measured by Romania, which was not confirmed by Bulgarian data in the same
section RO04/BG05. Bulgarian data indicate decrease in period 1998-2000 there;
o similarly to COD-Mn, slight increasing trend is observed in Sajo-Sajopuspoki (H09),
but the general trend is decreasing from 1996 to 2000; it has to be mentioned that for
three tributaries located in the lower Danube, the Arges-Conf. Danube (RO09), Siret-
Conf. Danube Sendreni (RO10) and Prut-Conf. Danube Giurgiulesti (RO11), very
high values are recorded in 1997 and 1998.
V 158
UNDP/GEF Danube Regional Project
12
10
8
2
/l
O
6
g
m
4
2
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.4.22a: Spatial variation of COD-Mn Danube River
12
10
8
2
6
g
/l
O
m
4
2
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.22b: Spatial variation of COD-Mn Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 159
40
35
30
25
mgO2/l
20
15
10
5
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.4.23a: Spatial variation of COD-Mn - Tributaries
40
35
30
25
2
20
g
/l
O
m
15
10
5
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.23b: Spatial variation of COD-Mn - Tributaries
V 160
UNDP/GEF Danube Regional Project
mg/l
12
10
8
6
4
2
0
2581
2204
2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01 A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.4.24: Temporal trends of COD-Mn Danube River
mg/l
20
15
10
5
0
D03
D04
CZ01 CZ02 SK04 H06
Sl01
HR03 HR04 HR05
H07
H08
H09
Sl02
HR06 HR06 HR07 HR08 HR08 BG06 BG07 BG08 RO09 RO10 MD01 MD02 RO11 MD03
Monitoring site
Fig. 8.1.4.25: Temporal trends of COD-Mn Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 161
70
60
50
40
/
l
2
O
mg 30
20
10
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
Monitoring site
upper
lower I
middle
lower II
1996
1997
1998
1999
2000
Fig. 8.1.4.27a: Spatial variation of COD-Cr Danube River
70
60
50
40
2
g
/l
O
30
m
20
10
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.27b: Spatial variation of COD-Cr Danube River
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UNDP/GEF Danube Regional Project
100
80
60
2
/
l
O
mg
40
20
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.4.28a: Spatial variation of COD-Cr Tributaries
100
80
60
2
g
/l
O
m
40
20
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.4.28b: Spatial variation of COD-Cr Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 163
mg/l
50
40
30
20
10
0
2581
2204
2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834
641
554
503
432
375
375
132
18
0
0
132
18
D01
D02
A01 A02 A03 A04 SK01 SK02
H01
SK03
H02
H03
H04
H05
HR01
HR02
RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Fig. 8.1.4.29: Temporal trends of COD-Cr Danube River
mg/l
70
60
50
40
30
20
10
0
D03
D04
CZ01 CZ02 SK04 H06
Sl01
HR03 HR04 HR05
H07
H08
H09
Sl02
HR06 HR06 HR07 HR08 HR08 BG06 BG07 BG08 RO09 RO10 MD01 MD02 RO11 MD03
Monitoring site
Fig. 8.1.4.30: Temporal trends of COD-Cr Tributaries
V 164
UNDP/GEF Danube Regional Project
It is well known that when a watercourse receives sewage effluent or effluent from animal farms, the
levels of organic matter and ammonium rise, while the level of oxygen falls. In order to illustrate this
relation in the Danube River and its tributaries, for each evaluated year a chart has been made in which
both the BOD-5 values and ammonium content are represented versus the minimum dissolved oxygen
values (Fig. 8.1.4.31. 8.1.4.35). Significant relations between these determinands had been identified
in monitoring sites listed in Table 8.1.4.2 below.
Table 8.1.4.2: Significant relations between the N-NH4 and BOD5 levels versus minimum dissolved
oxygen.
Year River
Country
N-NH4
BOD5
DO Min.
code
(mg/l)
(mg/l O2)
(mg/l O2)
1996
Dyje CZ02
1.18
11.0 5.9
Vah SK04
1.00
6.5 5.2
Sio H06
1.30
9.5 7.2
Arges RO09
7.68 60.5 2.4
Siret RO10
1.50 6.3 0.2
1997
Morava
CZ01
1.16
7.2
6.2
Djye CZ02
1.05 6.5 6.2
Sio H06
1.14
9.5 6.4
Jantra BG07
2.95 - 6.6
Arges RO09
2.49 9.7 2.3
Siret RO10
3.05 7.1 5.4
1998
Dyje CZ02
0.56 8.4 7.8
Arges RO09
2.86 7.0 3.0
1999
Morava CZ01
0.88 9.1 8.2
Dyje CZ02
0.89 6.7 7.1
Jantra BG07
0.46 5.0 6.5
Russenski Lom
BG08
0.19
8.8
5.6
Arges RO09
2.60 8.3 2.9
Siret RO10
0.54 5.3 5.5
2000
Sio H06
0.49
7.6 6.2
Russenski Lom
BG08
0.26
8.9
5.6
Siret RO10
0.93 7.0 6.8
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 165
Fig. 8.1.4.31 8.1.4.35: Correlation between ammonium content and biochemical oxygen demand
versus minimum of dissolved oxygen
1996
mg/l O2
mg/l N-NH4
12
5
10
60.5
7.68
4
8
3
6
2
4
1
2
0
0
3
4
0
1
0
2
6
7
9
8
0
4
0
1
0
3
0
4
0
5
0
2
0
6
0
7
0
8
0
6
0
7
0
8
0
9
1
0
0
1
0
2
1
1
0
3
D0
D0
H0
H0
H0
H0
CZ
CZ
SK
Sl
Sl
HR
HR
HR
HR
HR
HR
BG
BG
BG
RO
RO
MD
MD
RO
MD
Monitoring site
DO Min
BOD5
NH4-N
Fig. 8.1.4.31
1997
mg/l O2
mg/l N-NH4
12
5
10
4
8
3
6
2
4
1
2
0
0
1
2
4
1
3
4
5
2
6
7
8
6
7
8
1
2
3
0
0
0
0
0
0
0
0
0
0
0
0
0
09
10
0
0
11
0
D03
D04
H06
H07
H09
H08
CZ
CZ
SK0
Sl
Sl
HR
HR
HR
HR
HR
HR
BG
BG
BG
RO
RO
MD
MD
RO
MD
DO Min
BOD5
NH4-N
Monitoring site
Fig. 8.1.4.32
V 166
UNDP/GEF Danube Regional Project
1998
mg/l O2
mg/l N-NH4
12
5
10
4
8
3
6
2
4
1
2
0
0
3
4
0
1
0
2
4
6
0
1
0
3
0
4
7
0
5
9
8
0
2
0
6
0
7
0
8
0
6
0
7
0
8
0
9
1
0
0
1
0
2
1
1
0
3
D0
D0
H0
H0
H0
H0
CZ
CZ
SK0
Sl
Sl
HR
HR
HR
HR
HR
HR
BG
BG
BG
RO
RO
MD
MD
RO
MD
Monitoring site
DO Min
BOD5
NH4-N
Fig. 8.1.4.33
mg/l O2
1999
mg/l N-NH4
12
5
10
4
8
3
6
2
4
1
2
0
0
3
4
1
2
4
6
1
3
4
7
5
9
8
2
6
7
8
6
7
8
1
2
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
H0
H0
H0
H0
CZ
CZ
SK0
Sl0
Sl0
HR
HR
HR
HR
HR
HR
BG
BG
BG
RO09
RO10
MD
MD
RO11
MD
Monitoring site
DO Min
BOD5
NH4-N
Fig. 8.1.4.34
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 167
2000
mg/l O2
mg/l N-NH4
12
5
10
4
8
3
6
2
4
1
2
0
0
3
4
1
2
4
6
1
3
4
7
5
9
8
2
6
7
8
6
7
8
1
2
3
0
0
0
0
0
0
0
0
0
0
0
0
0
09
10
0
0
11
0
D0
D0
H0
H0
H0
H0
CZ
CZ
SK0
Sl
Sl
HR
HR
HR
HR
HR
HR
BG
BG
BG
RO
RO
MD
MD
RO
MD
DO Min
BOD5
NH4-N
Monitoring site
Fig. 8.1.4.35
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UNDP/GEF Danube Regional Project
8.1.5. Organic
Micropollutants
Among the main sources of organic micropollutants in surface waters industrial, urban activities and
application of pesticides in agriculture can be mentioned.
Within the TNMN Programme, organic micropollutants that are regularly monitored are Lindan, p,p'-
DDT, Atrazine, chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene. Because
of the low frequencies of measurements, trend analysis has not been possible to done for these
determinands, so only some observations related to temporal patterns are mentioned.
When assessing organic micropollutants results of classification, percentage of monitoring sites
satisfying limit values for different water quality classes is influenced very much by uneven number of
measurements in particular years. As can be seen later, the number of monitoring sites without
measurements has decreased significantly from 1996 to 2000, but still there is rather large group of
monitoring sites without measurements of organic micropollutants.
Lindan (gamma isomer of hexachlorocyclohexane)
The distribution of monitoring sites according to the Classification System in the DRB for Lindan is
shown in Fig. 8.1.5.1:
Lindan
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.1: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for Lindan
The assessment is made based on data reported from 69 monitoring sites (out of the assessment is 34
monitoring sites from Phase I List of Monitoring Sites, in which no measurements of Lindane had
been done in 1996-2000):
- the number of monitoring sites corresponding to Class I decreases from 1996 to 1998 and then
increases until 2000 up to 81.2 %;
- Class II is represented by a minimum value of 1.4 % in 1996 and 1998 and by a maximum of
15.9 % in 1997;
- no monitoring site corresponds to Class III in 1996 and 1999; in the other years Class III is
represented by 4.3 % - 33.3% of sites;
- Class IV is absent in 1996 and 2000; during 1997 1999 perentage of sites in in this Class is
in the range from 1,4 24,6 %;
- Class V is present during 1998 2000, with the minimum in 2000 (2.9 %) and the maximum
in 1999 (14.5 %);
The pattern for Lindan concentrations in the Danube River is shown in Fig. 8.1.5.2a and 8.1.5.2b.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 169
In the upper Danube, Lindan is actually undetectable at the first two monitoring sites, Danube-Neu-
Ulm (km 2581, D01) and Danube-Jochenstein (km 2204, D02), according to German results. For the
rest four sites, Lindan is also undetectable during 19971999 even though there are differences among
years, caused by the differences in reported limits of detection. According to Austrian data, from
Danube-Jochenstein (km 2204, A01) to Danube-Wolfsthal (km1874, A04), Lindan seems to be
detectable in 2000 only, at the level of 0.100 µg/l, the target value for Lindan.
In the middle section, all Lindan values are below 0.050 µg/l, the limit value for Quality Class I.
In the first part of the lower Danube, Lindan concentrations are much higher than 0.100 µg/l. From
Danube-Bazias (km 1071, RO01) down to Danube-Pristol/Novo Selo (km 834, RO02), Lindan
concentrations increase reaching c90 values up to 0.398 µg/l according to Romanian data. The higest
values from this part are recorded mainly in 1999. It has to be mentioned that, similar to some other
determinands, big differences exist between the reported data for the cross section from km 834
(RO02/BG01).
In the second part of the lower Danube Lindan c90 values are even above 0.20 µg/l, corresponding to
Class IV. This is observed in all Romanian monitoring sites mainly in 1999. Again has to be
mentioned that there are extremely high differences between Romanian and Bulgarian results in the
same cross sections.
For the entire lower Danube, 46 Lindan c90 values exceeded the level set up as a target value.
The distribution of Lindan concentrations in selected tributaries is illustrated in Fig. 8.1.5.3a and
8.1.5.3b and shows an inhomogeneous picture:
- those tributaries from the upper section, in which Lindan is detectable - the Morava-Lanzot
(CZ01) and Dyje-Pohansko (CZ02), present Lindan concentrations below 0.05 µg/l;
- in the middle stretch, in Sio-Szekszard (H06), an extreme value is recorded in 2000 (5.75
µg/l); higher values that appear on Sajo-Sajopuspoki (H09) in 1996 and 1997 do not exceed
the target limit;
- in the lower section, three tributaries - the Arges-Conf. Danube (RO09), Siret-Conf. Danube
Sendreni (RO10) and Prut-Conf. Danube Giurgiulesti (RO11), show values above 0.100 µg/l,
especially in 1999, with a maximum value of 0.321 µg/l on the Arges-Conf. Danube (RO09);
- majority of values characterising Lindan content, which were above the target limit, were
observed on tributaries from the lower Danube.
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UNDP/GEF Danube Regional Project
0.6
0.5
0.4
/
l 0.3
µg
0.2
0.1
0.0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
Monitoring site
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.5.2a: Spatial variation of Lindan Danube River
0.6
0.5
0.4
0.3
/
l
µg
0.2
0.1
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.2b: Spatial variation of Lindan Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 171
0.4
0.3
5.75
/
l 0.2
µg
0.1
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.5.3a: Spatial variation of Lindan Tributaries
0.4
0.3
5.75
0.2
/
l
µg
0.1
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.3b: Spatial variation of Lindan Tributaries
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UNDP/GEF Danube Regional Project
pp'-DDT (isomer of dichlorodiphenyltrichloroethane)
The distribution of monitoring sites according to the Classification System in the DRB for pp'-DDT is
shown in Fig. 8.1.5.4:
pp'-DDT
100.0
80.0
CL I
CL II
CL III
60.0
CL IV
%
CL V
40.0
No data
No class indication
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.4: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for pp'-DDT
The quality assessment is made based on data reported by 69 monitoring sites (out of the assessment is
34 monitoring sites from Phase I List of Monitoring Sites, in which no measurements had been done in
1996-2000):
- Class I is represented in 1996 and 2000 only, by 13.0 % and 5.8 % respectively;
- the percentage of monitoring sites within Class II is in the range from 14,5 30,4 %;
- Class III and Class IV have been represented by less than 10 % in the periond from 1996-
1999, in 2000 13.0 % and 18.8 % of monitoring sites corresponded to Class III and Class IV,
respectively;
- Class V is absent in 1996, but the number of sites within this class is approximately 40 %
during 1997 1999 and less than 20 % in 2000;
- the additional category of "no class indication" (sites, in which limit of detection of p,p'-DDT
measurement was higher than limit value for Class II, and therefore have not been classified)
is represented in all five studied years.
The spatial variation of pp'-DDT concentrations for the Danube River is illustrated in Fig. 8.1.5.5a
and 8.1.5.5b.
In the upper section of the river, the pp'-DDT concentrations level shows a similar profile with that of
Lindan: is undetectable at first two monitoring sites, Danube-Neu-Ulm (km 2581, D01) and Danube-
Jochenstein (km 2204, D02), according to German results. According to Austrian data, pp'-DDT is
undetectable during 1997 1999; the only measurable concentrations appear in 2000, from Danube-
Jochenstein (km 2204, A01) down to Danube-Wolfsthal (km 1874, A04), at the level of 0.05 µg/l.
The middle stretch is characterized by values below the limit of detection, according to Slovak results,
excepting the value recorded at Danube-Komarno/Komarom (km 1768, SK03) 0.080 µg/l in 1999.
For the rest of the stretch, values below 0.050 µg/l are present.
In the first part of the lower Danube, pp'-DDT concentrations are much higher than in the middle
stretch, They exceed 0.50 µg/l level in 1998 and 1999 from Danube-Bazias (km 1071, RO01) to
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 173
Danube-Pristol/Novo Selo (km 834, RO02), if the Romanian results are taken into account.
According to Bulgarian data, values are below 0.10 µg/l.
The second part of lower Danube section is characterized by higher values than the first part - above
0.60 µg/l, recorded mainly in 1997 and 1999 from Danube-us. Arges (km 432, RO03) to Danube-
Chiciu/Silistra (km 375, RO04). Much higher p,p'-DDT concentrations appear in three main arms of
the Danube Delta Chilia (RO06), Sulina (RO07) and Sf. Gheorghe (RO08). The maximum c90 value
(1.498 µg/l) is observed at Danube- Sf. Gheorghe/Sf. Gheorghe arm (km 0, RO08) in 1999.
Fig. 8.1.5.6a and 8.1.5.6b show p,p'-DDT c90 values in selected tributaries. It can be seen that high
p,p'-DDT concentrations are recorded only on Romanian tributaries - the Arges-Conf. Danube
(RO09), Siret-Conf. Danube Sendreni (RO10) and Prut-Conf. Danube Giurgiulesti (RO11). The
maximum value for tributaries (1.142µg/l) appears on the Siret-Conf. Danube Sendreni (RO10) in
1999.
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UNDP/GEF Danube Regional Project
1.6
1.4
1.2
1.0
/
l 0.8
µg
0.6
0.4
0.2
0.0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.5.5a: Spatial variation of pp'-DDT Danube River
1.6
1.4
1.2
1.0
0.8
/
l
µg
0.6
0.4
0.2
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.5b: Spatial variation of pp'-DDT Danube River
Note: In locations D01 (97-00), D02 (96-00), A01, A02, A03, A04 (99, 00) the values in the graph represent limits of detection that are higher than the target value.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 175
0.6
0.5
0.4
1.142
/
l 0.3
µg
0.2
0.1
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.5.6a: Spatial variation of pp'-DDT Tributaries
0.6
1.142
0.5
0.4
0.3
/
l
µg
0.2
0.1
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.6b: Spatial variation of pp'-DDT Tributaries
Note: In locations D03 (96-00), D04 (97-00), MD01, MD02, MD03 (98-00) the values in the graph represent limits of detection that are higher than the target value
V 176
UNDP/GEF Danube Regional Project
Atrazine
The distribution of monitoring sites according to the Classification System in the DRB for Atrazine is
shown in Fig. 8.1.5.7:
Atrazin
100.0
80.0
CL I
CL II
CL III
60.0
CL IV
%
CL V
40.0
No data
No class indication
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.7: Distribution of monitoring sites (%) according to the Quality Classification System in the
DRB for Atrazine
The assessment is made based on data reported from 65 monitoring sites (therefore, out of the
assessment is 38 monitoring sites from Phase I List of Monitoring Sites, in which no measurements
had been done in 1996-2000):
- Class I is constantly represented by less than 8% of the considered monitoring sites;
- percentage of sites within Class II decreases from 1996 to 1998 (reaching minimum 24,6 %)
and then increases till 2000 to the level of 70.8 %;
- the maximum percentage of sites within Class III is 6.2 % in 1999, in all other years
percentage is below 4 %;
- Class IV is represented in years 1997 2000, with maximum 10.8 % in 2000;
- Class V is represented during 1997 2000, with the maximum value in 2000 (6.2%);
- only 1.5 % of considered sites have "no class indication" in 1998 and 1999 (sites, in which
limit of detection was higher than limit value for Class II, and therefore have not been
classified).
The Atrazine concentrations in the Danube River are illustrated in Fig. 8.1.5.8a and 8.1.5.8b.
In accordance to German results, Atrazine is detectable in 1999 in Danube-Neu Ulm (km 2581, D01)
and excepting 1997, in all studied years in Danube-Jochenstein (km 2204, D02). According to
Austrian results, in the stretch from Danube-Jochenstein (km 2204, A01) to Danube-Wolfsthal (km
1874, A04) the only detectable values are recorded in 2000. In this stretch, no Atrazine concentration
is above the target value (0.10 µg/l).
In the middle stretch from Danube-Bratislava (km 1869, SK01) to Danube-Szob (km 1708, H03)
Atrazine concentrations are below 0.100 µg/l, excepting one value (0.164 µg/l) at Danube-Szob in
1997. From Danube-Dunafoldvar (km 1560, H04) to Danube-Hercegszanto (km 1435, H05), Atrazine
concentrations are higher, with the maximum at Danube-Hercegszanto (km 1435, H05) in 1997 (0.50
µg/l). In the middle Danube 4 values are above the target limit.
In the first part of the lower Danube, Atrazine is below reported limit of detection (0.06 µg/l), from
Danube-Bazias (km 1071, RO01) to Danube-Pristol/Novo Selo (km 834, RO02) in accordance to
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 177
Romanian results. On the basis of Bulgarian results, at Danube-Novo Selo/Pristol a very high c90
value (1.316 µg/l) respresents situation in 1998.
The second part of the lower Danube shows a similar pattern to the first one. In accordance to
Romanian data, Atrazine is undetectable at the respective monitoring sites - from Danube-us. Arges
(km 432, RO03) to Danube-Sf. Gheorghe arm/Sf. Gheorghe arm (km 0, RO08); if the Bulgarian data
are taken into account, high Atrazine values - 0.618 µg/l and 2.134 µg/l - appear in 1998 and 2000,
respectively, at Danube-Silistra/Chiciu (km 375, BG05). Big differences between the reported data at
cross sections make the interpretation to be rather difficult.
For the entire lower Danube, among the Atrazine values 12 of them are above the target limit of this
determinand.
Atrazine c90 values for selected tributaries are illustrated in Fig. 8.1.5.9a and 8.1.5.9b. It can be seen
that the profile is inhomogeneous, with Atrazine values corresponding to Quality Class V on the
Morava-Lanzhot (CZ02) and Tisza-Tiszasziget (H08) - 0.930 µg/l in 1998 and 0.550 µg/l in 1999,
respectively. Extremely high values appear on Sio-Szekszard (H06) and Sajo-Sajopuspoki (H09) -
4.550µg/l in 1999 and 5.250 µg/l in 1997. Concerning the measured Atrazine level in selected
tributaries against the target value, 18 of them are above this limit.
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UNDP/GEF Danube Regional Project
2.5
2.0
1.5
/
l
µg
1.0
0.5
0.0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
middle
lower I
lower II
Monitoring sites
1996
1997
1998
1999
2000
Fig. 8.1.5.8a: Spatial variation of Atrazin Danube River
2.5
2.0
1.5
/
l
µg
1.0
0.5
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.8b: Spatial variation of Atrazin Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 179
6.0
5.0
4.0
/
l 3.0
µg
2.0
1.0
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.5.9a: Spatial variation of Atrazin Tributaries
6.0
5.0
4.0
/
l
3.0
µg
2.0
1.0
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.9b: Spatial variation of Atrazin Tributaries
Note: In location MD02 (98, 99) the values in the graph represent limits of detection that are higher than the target value.
V 180
UNDP/GEF Danube Regional Project
Chloroform (trichloromethane)
The distribution of monitoring sites according to the Classification System in the DRB for
Chloroform is shown in Fig. 8.1.5.10:
Chloroform
100.0
80.0
CL I
CL II
CL III
60.0
CL IV
%
CL V
40.0
No data
No class indication
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.10: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Chloroform
Number of monitoring sites, in which chloroform was measured in 1996-2000, is very low - the
assessment is made based on data reported from only 33 monitoring sites. Even from this low number
of sites measurements were missing in more than 50 % in years 1996-97.
Completely without any measurements of chloroform during the whole period of years 1996-2000
were 70 monitoring sites.
The chloroform concentrations in the Danube River are shown in Fig. 8.1.5.11a and 8.1.5.11b.
In the upper section, chloroform is undetectable during the entire studied time period. The differences
in values exist because the reported limit of detection decreases from 1998 to 2000.
In the middle section, the concentration profile has very large limits of variation. A relevant example
appears at Danube-Bratislava (km 1869, SK01), where chloroform is undetectable in 1999 but has a
very high value in 1997 (189.1 µg/l). Downstream this monitoring site, from Danube-
Medvedov/Medve (km 1806, SK02) to Danube-Komarno/Komarom (km 1768, SK03) according to
Slovak data, chloroform shows concentrations values much higher than those reported by the
Hungarian part at the respective cross sections. In the middle stretch, 18 concentrations are above the
target limit (0.6 µg/l).
In the entire lower section, for only two monitoring sites data characterising chloroform content exist:
Danube-Novo Selo/Pristol (km 834, BG01) in 2000 and Danube-Silistra/Chiciu (km 375, BG05) in
1999. All results show that chloroform is undetectable at the reported limit of detection of 0.02 µg/l.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 181
The values of chloroform concentrations for selected tributaries are shown in Fig. 8.1.5.12a and
8.1.5.12b. The measured concentrations are quite high, with 17 values above the target limit. The most
elevated values are the following:
- the Morava-Lanzot (CZ02): 3.360 µg/l in 1997;
- the Vah-Komarno (SK04): 10.310 µg/l in 1996 and 81.800 µg/l in 1997;
- the Drava-Ormoz (SL01): 3.000 µg/l in 2000;
- the Sajo-Sajopuspoki (H09): 4.060 µg/l in 1996 and 2.900 µg/l in 1997;
- the Sava-Jesenice (SL02): 3.000 µg/l in 1999.
By comparing the results with those obtained by JDS it can be concluded that in the frame of JDS
were not detected such high values as in the TNMN in case of several monitoring sites. High values of
chloroform sporadically found in Danube River or its tributaries can indicate that sources of pollution
were still not sufficiently under control (under assumption that analysis of chloroform was correct.) As
can be seen later in the text, in Slovak section of Danube River and on Vah tributary also other
substances from the group of volatile organic compounds are sporadically recorded in high
concentrations.
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UNDP/GEF Danube Regional Project
40
35
189.1
30
25
/
l 20
µg
15
10
5
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
lower I
Monitoring site
upper
middle
lower II
1996
1997
1998
1999
2000
Fig. 8.1.5.11a: Spatial variation of Chloroform Danube River
40
35
X
189.1
30
25
20 /lµg
15
10
5
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.11b: Spatial variation of Chloroform Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 183
15
81.8
12
9
/l
µg
6
3
0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
1996
1997
1998
1999
2000
Monitoring sites / Tributary
Fig. 8.1.5.12a: Spatial variation of Chloroform Tributaries
15
X
12
81.8
9
/
l
µg
6
3
0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.12b: Spatial variation of Chloroform Tributaries
Note: In locations SL01, SL 02 (99, 00) and H08 (00) the values in the graph represent limits of detection that are higher than the target value.
V 184
UNDP/GEF Danube Regional Project
Carbon tetrachloride (tetrachloromethane)
The distribution of monitoring sites according to the Classification System in the DRB for Carbon
tetrachloride is shown in Fig. 8.1.5.13:
Carbon tetrachloride
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.13: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Carbon tetrachloride
The situation in availability of data on tetrachloromethane is the same as in case of chloroform. The
assessment is made based on data reported from only 33 monitoring sites, and absolutelly no
measurements had been done in 1996-2000 in 70 monitoring sites.
Class II was prevailing in monitoring sites, but due to the lack of data it is not possible to provide a
satisfactory picture on the occurance of the substance in water in the whole river basin.
The spatial profile for carbon tetrachloride in the Danube River is shown in Fig. 8.1.5.14a and
8.1.5.14b.
Similar to chloroform, carbon tetrachloride shows undetectable values in the upper Danube, even if the
levels look different (due to differences among limits of detection).
In the middle section of the Danube, tetrachloride is detectable in 1999 only according to Slovak data
and mainly during 1998-2000 according to Hungarian data. The measurable concentrations for this
stretch vary within the range 0.095 - 0.600 µg/l, with maximum at Danube-Dunafoldvar (km 1560,
H04).
The entire lower section of the Danube as well as the corresponding tributaries has no reported data
for this organic micropollutant, with two exceptions: Danube-Novo Selo/Pristol (km 834, BG01) in
2000 and Danube-Silistra/Chiciu (km 375, BG05) in 1999. All results show that carbon tetrachloride is
undetectable at the reported limit of detection of 0.02 µg/l.
It has to be mentioned that no concentration measured in the Danube River is above the target limit
(1.000 µg/l).
The measurable values for carbon tetrachloride in the selected tributaries are shown in Fig. 8.1.5.15a
and 8.1.5.15b. The highest value observed in Sajo/Sajopuspoki (H09) 2.460 µg/l in 1996. The
concentrations values that appear at the level of 1.00 µg/l, in Drava-Ormoz (SL01), Sava-Jesenice
(SL02) and Tisza-Tiszasziget (H08) are caused by the rather high limit of detection, equal to the target
value for this determinand.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 185
0.7
0.6
0.5
0.4
/
l
µg 0.3
0.2
0.1
0.0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
middle
lower I
lower II
Monitoring site
1996
1997
1998
1999
2000
Fig. 8.1.5.14a: Spatial variation of Carbon tetrachloride Danube River
1.2
1.0
0.8
0.6
/
l
µg
0.4
0.2
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.14b: Spatial variation of Carbon tetrachloride Danube River
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UNDP/GEF Danube Regional Project
3.0
2.5
2.0
/
l 1.5
µg
1.0
0.5
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.5.15a: Spatial variation of Carbon tetrachloride Tributaries
3.0
2.5
2.0
1.5
/
l
µg
1.0
0.5
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.15b: Spatial variation of Carbon tetrachloride Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
Trichloroethylene
The distribution of monitoring sites according to the Classification System in the DRB for
Trichloroethylene is shown in Fig. 8.1.5.16:
Trichloroethylene
100.0
80.0
CL I
CL II
60.0
CL III
%
CL IV
40.0
CL V
No data
20.0
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.16: Distribution of monitoring sites (%) according to the Quality Classification System in
the DRB for Trichloroethylene
The assessment is made based on data reported from 30 monitoring sites, therefore without any
measurement in 1996-2000 is 73 monitoring sites from Phase I List of Monitoring Sites. Number of
sites with trichloroethylene is very low, but in the sites with measurements Class II is prevailing.
The spatial profile of trichloroethylene concentrations in the Danube River is illustrated in Fig.
8.1.5.17a and 8.1.5.17b.
In the upper Danube, trichloroethylene is detectable in 1999 only at Danube-Neu Ulm (km 2581, D01)
and Danube-Wolfsthal (km 1874, A04) and in 1999-2000 at Danube-Jochenstein (km 2204, D02),
according to German data.
The middle stretch is characterized by undetectable levels of trichloroethylene, with three exceptions,
all recorded in 1998, at Danube-Bratislava (km 1869, SK01), Danube-Dunafoldvar (km 1560, H04)
and Danube-Herceszanto (km 1435, H05).
In the lower section, data for this determinand are reported from only one monitoring site - Danube-
Silistra/Chiciu (km 375, BG05) in 1999, with undetectable values.
No concentration of trichloroethylene in the Danube River is above the target limit (1.00 µg/l).
Undetectable concentrations are observed also in almost all selected tributaries, relative to the reported
limits of detection. The only measurable values appear on the Sajo-Sajopuspoki (H09); the maximum
value - 2.42 µg/l in 1996 - is the only one above the target limit for trichloroethylene in tributaries
Fig. 8.1.5.18a and 8.1.5.18b.
V 188
UNDP/GEF Danube Regional Project
0.7
0.6
0.5
0.4
/
l
µg
0.3
0.2
0.1
0.0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
Monitoring site
upper
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.5.17a: Spatial variation of Trichloroethylene Danube River
1.2
1.0
0.8
0.6
/
l
µg
0.4
0.2
0.0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.17b: Spatial variation of Trichloroethylene Danube River
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 189
3.0
2.5
2.0
/
l 1.5
µg
1.0
0.5
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.5.18a: Spatial variation of Trichloroethylene Tributaries
3.0
2.5
2.0
/
l
1.5
µg
1.0
0.5
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.18b: Spatial variation of Trichloroethylene Tributaries
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UNDP/GEF Danube Regional Project
Tetrachloroethylene
The distribution of monitoring sites according to the Classification System in the Danube River basin
for Tetrachloroethylene is shown in Fig. 8.1.5.19:
Tetrachloroethylene
100.0
80.0
CL I
60.0
CL II
%
CL III
40.0
CL IV
CL V
20.0
No data
0.0
1996
1997
1998
1999
2000
Fig. 8.1.5.19 : Distribution of monitoring sites (%) according to the Classification System in the
Danube River basin for Tetrachloroethylene
The data on occurance of tetrachloroethylene were reported from 30 monitoring sites; out of the
assessment is 73 monitoring sites, in which no measurements had been done in 1996-2000. Majority
of sites with tetrachloroethylene measurement correspond to class II, but classes III V are also
represented.
The spatial profile of tetrachloroetylene concentrations in the Danube River is illustrated in Fig.
8.1.5.19a and 8.1.5.19b. Unlike trichloroethylene, tetrachloroetylene is detectable at Danube-Neu Ulm
(km 2581, D01) in 1998-2000 and at Danube-Jochenstein (km 2204, D02) in 1996 and 1999-2000
according to German data, but no value is above the target limit for this determinand (1.000 µg/l). If
the Austrian data are taken into account, tetrachloroethylene is undetectable from Danube-Jochenstein
(km 2204, A01) to Danube-Wolfsthal (km 1874, A04).
In the middle stretch, it can be noticed that values above 2.00 µg/l from Danube-Medvedov/Medve
(km 1806, SK02) to Danube-Komarno/Komarom (km 1768, SK03), according to Slovak data.
According to Hungarian data at the same cross sectioned, tetrachloroetylene is undetectable.
Particularly at Danube-Bratislava (km 1869, SK01), an extreme high value was observed in 1999
16.5 µg/l. Also according to Slovak data, in the middle Danube 8 concentrations are above the target
limit.
The profile of tetrachloroethylene concentrations measured in selected tributaries, illustrated in Fig.
8.1.5.20a and 8.1.5.20b, presents the following features:
- tributaries from the upper Danube show undetectable levels of tetrachloroetylene, mainly during
1996 1998, even though the values are different within the five years (again, different limits of
detection);
- in the middle Danube, on the Vah-Komarno (SK04) higher concentrations appears in 1999 and
2000 1.000 µg/l and 2.26 µg/l respectively, but only the second one is above the target limit;
- two concentrations above the target limit are also recorded on Sajo-Sajopuspoki (H09) 2.420
µg/l in 1996 and 3.100 µg/l in 1997;
- it has to be mentioned that values that appear on the Drava-Ormoz (SL01), Tisza-Tiszasziget
(H08) and Sava-Jesenice (SL02) tributaries have the same explanation as in the case of
trichloroethylene - the reported values are the limits of detection, hence tetrachloroethylene was
undetected at the respective monitoring sites.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 191
18
16
14
12
10
/
l
µg
8
6
4
2
0
1
2
1
2
3
4
1
2
1
3
2
3
4
5
1
2
1
2
1
2
3
4
3
4
5
5
1
6
2
7
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
D0
A0
A0
A0
A0
H0
H0
H0
H0
H0
SK0
SK0
SK0
HR0
HR0
RO
RO
BG
BG
BG
BG
RO
RO
BG
RO
UA
RO
UA
RO
RO
upper
Monitoring site
middle
lower I
lower II
1996
1997
1998
1999
2000
Fig. 8.1.5.19a: Spatial variation of Tetrachloroethylene Danube River
18
16
14
12
10
/
l
8
µg
6
4
2
0
2700
2400
2100
1800
1500
1200
900
600
300
0
Distance from the mouth [km]
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.19b: Spatial variation of Tetrachloroethylene Danube River
V 192
UNDP/GEF Danube Regional Project
3.5
3.0
2.5
2.0
/
l
µg 1.5
1.0
0.5
0.0
D03
D04
CZ01
CZ02
SK04
H06
Sl01
HR03
HR04
H07
HR05
H08
H09
Sl02
HR06
HR07
HR08
BG06
BG07
BG08
RO09
RO10
MD01
MD02
RO11
MD03
Inn
Salzach
Morava
Dyje
Vah
Sio
Drava
Tisza
Sajo
Sava
Iskar
Jantra
Russ. Lom
Arges
Siret
Prut
Monitoring site / Tributary
1996
1997
1998
1999
2000
Fig. 8.1.5.20a: Spatial variation of Tetrachloroethylene Tributaries
3.5
3.0
2.5
2.0
/
l
µg
1.5
1.0
0.5
0.0
2500
2000
1500
1000
500
0
Confluence at Danube km
1996
1997
1998
1999
2000
TV
Fig. 8.1.5.20b: Spatial variation of Tetrachloroethylene Tributaries
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 193
8.1.6. Results of Comaprison of TNMN data with Environmental Quality Standards
of EU legislation
8.1.6.1. General
comments regarding analytical data
It has to be noted that for some of the substances discussed in the following the data base shows
considerable gaps, mainly in the lower stretch of the Danube River. If data are available the data set of
one year sometimes consists of one or two measurements only. To avoid a further restriction of the
overall picture such data have not been excluded from the evaluation.
In processing and representation of the data the following rules have been applied:
· Obviously erroneous data have been discarded
· All data sets of one year with at least one result greater than the LOD have been taken into
consideration. The mean was calculated with the "LOD-method" in selected cases in addition
with the "Zero-method"
· Data sets of one year where all data were below the LOD have not been included in the graph
· Mean values deviating from the reported LOD have been excluded when they obviously were
produced by a LOD change within one year without any result greater than LOD (in the data
base only one LOD per year and method can be stored, differing "less than" values within one
year reflect a LOD change and result in a "mean of LODs" value which deviates from the
stored LOD)
The mentioned limitations of the data base should be taken into account in the following assessment of
the results. The focus should be better on the overall picture for a substance than on a single result.
8.1.6.2. Atrazine
For Atrazine a nearly complete data set is available. The LOD ranges between 0,01 and 0,06 µg/l, in a
few cases up to 0,1 µg/l. Atrazine was included in the list of Priority Substances. With regard to the
proposed EQS of 0,34 µg/l the Atrazine concentration at all sampling sites seems to be no problem
even with the used worst case calculation of the mean (see Figure 8.1.6.2.1). In 1998 rather high
values have been measured at two sampling sites which exceed the proposed EQS, but also at this sites
the mean concentration went down below 0,34 µg/l in the consecutive years.
8.1.6.3. Cadmium
(total)
The results for Cadmium (total) are characterised by high mean values in the range of 1 to 8 µg/l in
lower part of Danube River (see Figure 8.1.6.3.1). The extreme values are caused by single data one
order of magnitude higher than the rest of the data set. But even when this data are excluded the mean
values lie very close to or even above the List 1 EQS of 1 µg/l for total Cadmium stipulated in CD
83/514/EEC (EEC 1983). Also an recalculation of the mean with the optimistic convention of setting
values below LOD to zero does not change the situation because only few results are smaller than the
method LODs (range: 0,01 - 1,0 µg/l). The results therefore indicate a severe Cadmium pollution for
this Danube stretch although the concentration seems to decrease in 2000 in comparison particularly
with 1997 and 1999. In the upper part of the river the mean concentrations are well below the EQS
with exception of a few results in 1996/97.
8.1.6.4. Cadmium
(dissolved)
For the derivation of EQS for metals FHI proposes to use the "added risk" approach, originally
introduced in the Netherlands. The reasoning behind this approach is that the adaptation of the
ecosystem in a certain region with a natural metal background concentration is part of the natural
biodiversity of this ecosystem. With the assumption that in different adapted ecosystems the same
V 194
UNDP/GEF Danube Regional Project
amount of a metal added by human activities (maximum permissible addition - MPA) causes the same
effect the EQSadd can be derived with the following equation:
EQSadd = Cbackground + MPA
where Cbackground is the natural metal background concentration of the region under concern.
Cbackground estimates can be gained e.g. by evaluating monitoring data of pristine areas for the
region. The MPA values are derived independently according to the procedure of Annex V, 1.2.6 of
the WFD.
For Cadmium FHI proposes a MPA value of 0,08 µg/l for the dissolved fraction. Due to the fact that
background concentrations may change along the Danube and may not be available for all regions, in
a first approximative evaluation only the MPA was compared with TNMN results.
For Cadmium (dissolved) only few data and only for the upper part of Danube River are available in
the data base. LOD ranges from 0,02 to 0,2 µg/l. With this very low EQS and the application of the
LOD-method the results exceed the limit value in most cases (see Figure 8.1.6.4.1).
The situation might be improved by two measures:
· taking into account Cbackground once these vaules have been determined for the different
river stretches
· using a more optimistic method for calculation of the mean
To show the influence of the second option an additional diagramm has been produced applying the
"Zero-method" (see Figure 8.1.6.4.2).
8.1.6.5. p,p'-DDT
For p,p'-DDT in the upper part of the Danube practically all data are below LOD (LODs range
between 0,005 and 0,05 µg/l). Downstream Hungary an increase in DDT concentration can be seen,
resulting in mean values up to 0,4 µg/l. In this area the EQS of 0,01 µg/l for p,p'-DDT laid down in
CD 86/280/EEC (EEC 1986) is exceeded in many cases (see Figure 8.1.6.5.1). Similar to Cadmium
(total) change of the calculation method of the mean does not improve the situation because most of
the data are above the method LODs.
8.1.6.6. Lead
(dissolved)
As for the other metals data for the dissolved fraction of lead are very scarce and are only availbale for
the upper stretch of the Danube (see figure Figure 8.1.6.6.1). The LOD ranges from 0,2 to 1 µg/l.
Because of many less than values the influence of the calculation method is significant but even with
the "LOD-method" most of the results are close to or below the MPA value of 1 µg/l proposed by the
FHI (for explanation of MPA see Cadmium (dissolved)).
8.1.6.7. Lindane (gamma - Hexachlorocyclohexane)
Going down the Danube a sharp increase in Lindane concentration is noticable. The LOD of methods
ranges from 0,001 to 0,1 µg/l. For Lindane one EQS is in force (0,05 µg/l laid down in CD
84/491/EEC (EEC 1984/2) for the sum of Hexachlorcyclohexane isomers). This value will be
substituted by the FHI proposal of 0,02 µg/l in near future. While the EQS in force is only exceeded
by the extreme values with new limit value the situation will get worse (see Figure 8.1.6.7.1). The
influence of the calculation method is shown in Figure 8.1.6.7.2.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 195
8.1.6.8. Mercury
(total)
For Mercury CD 82/176/EEC (EEC 1982) states an EQS of 1 µg/l. The data base provides only results
for the upper part of the Danube including Hungary and Croatia. For the lower part of the Danube no
data for Mercury are available at all. LODs lie mainly within 0,1 to 0,2 µg/l. The existing results show
only one exceedance of the EQS caused by an extreme concentration in 1999, which can be also
observed downstreams throughout Hungary (see Figure 8.1.6.8.1). All other mean values are well
below the List 1 EQS.
8.1.6.9. Mercury
(dissolved)
Mercury is also included in the List of Priority Substances. FHI proposes an MPA of 0,036 µg/l for the
dissolved metal fraction (for explanation of MPA see Cadmium (dissolved)). Again for the dissolved
fraction are only very few data are available (see Figure 8.1.6.9.1) which in all cases exceed the limit
value. The LODs (0,03 - 0,2 µg/l) lie very close or above the EQS which leads to high mean values
when using the LOD-method. Switching to the Zero-method (see Figure 8.1.6.9.2) changes the picture
dramatically. Mercury (dissolved) is one of the cases where the used convention for calculationg the
mean influences the results of the compliance check to a very high degree.
8.1.6.10. Nickel (dissolved)
Nickel and its compounds is the fourth metal included in the Priority Substance list. Similar to other
metals data are scarce for the dissolved fraction. Comparison with the proposed MPA of 0,6 µg/l (for
explanation of MPA see Cadmium (dissolved)) shows exceedance of the EQS to a high extent for all
results (see Figure 8.1.6.10.1). Also in this case the LODs (0,2 - 1,0 µg/l) are very close to the EQS.
Therefore the influence of the calculation method was checked out (see Figure 8.1.6.10.2).
8.1.6.11. Chlorinated compounds
(Tetrachlorethane, Tetrachlormethane, Trichlorethene, Trichloromethane)
For these four compounds the situation is very similar in many respects. For all substances EQS are
laid down in CD 86/280/EEC (EEC 1986, Tetrachloroethane, Trichlorethane: 10 µg/l,
Tetrachlormethane, Trichloromethane: 12 µg/l). Data for these compounds are only available in the
upper stretch of the Danube. LODs range from 0,01 to 0,5 µg/l. For Tetrachlorethane,
Tetrachlormethane and Trichlorethene the results are well below the respective EQS values (see
Figure 8.1.6.11.1 8.1.6.11.4). Trichloromethane exceeds the EQS of 12 µg/l in one case and shows
the highest concentration in general. Its also the only one of the four compounds which has been
included in the list of Priority Substances. FHI prosposes an EQS of 3,85 µg/l which increases the
number of exceeding concentrations to three in the five year period.
8.1.6.12. Recommendations for future changes in TNMN regarding the needs of the EU WFD
In future TNMN investigations it should be clearly distinguished between the terms limit of detection
(LOD) and limit of quantification (LOQ) should be clearly defined, following the definitions used by
the EU. A review of the ANAMETH-file having in mind this definitions should be carried out and
both quantities included in future data sets.
The discussions on EU level concerning the statistical quantity used for compliance checking and the
calculation of this quantity in the case of less than values should be carefully followed and the results
integrated in the TNMN to keep up comparability of the data and compliance with EU legislation,
which is of utmost importance for at least the half of the riparian states.
V 196
UNDP/GEF Danube Regional Project
0.8
0.6
µg/l 0.4
0.2
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
PS EQS
Figure 8.1.6.2.1: Atrazine
4.0
3.5
3.0
µg/l 2.5
2.0
1.5
1.0
0.5
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
Figure 8.1.6.3.1: Cadmium (total)
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 197
0.5
0.45
0.4
µg/l
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02
A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
PS EQS
Figure 8.1.6.4.1: Cadmium (dissolved) - LOD method
0.5
0.45
0.4
µg/l 0.35
0.3
0.25
0.2
0.15
0.1
0.05
0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
PS EQS
Figure 8.1.6.4.2: Cadmium (dissolved) - Zero-method
V 198
UNDP/GEF Danube Regional Project
0.40
0.35
0.30
µg/l 0.25
0.20
0.15
0.10
0.05
0.00 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02
A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
Figure 8.1.6.5.1: p,p-DDT
1.4
1.2
µg/l
1.0
0.8
0.6
0.4
0.2
c
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
PS EQS
Figure 8.1.6.6.1: Lead
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 199
0.30
0.25
µg/l 0.20
0.15
0.10
0.05
0.00 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
PS EQS
Figure 8.1.6.7.1: Lindane
0.30
0.25
0.20
µg/l
0.15
0.10
0.05
0.00 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
PS EQS
Figure 8.1.6.7.2: Lindane - Zero-method
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UNDP/GEF Danube Regional Project
µg/l 1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
List 1 EQS
PS EQS
Figure 8.1.6.8.1: Mercury (total)
0.2
µg/l
0.15
0.1
0.05
0
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0
0
132
18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
PS EQS
Figure 8.1.6.9.2: Mercury (dissolved) - Zero method
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 201
4.5
4.0
µg/l 3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0
0
132
18
D01 D02 A01 A02 A03 A04 SK01SK02 H01 SK03 H02 H03 H04 H05 HR01HR02 RO01 RO02 BG01BG02 BG03 BG04 RO03RO04 BG05 RO05 RO06 RO07RO08 UA01UA02
Monitoring sites / distance from the mouth
1996
1997
1998
1999
2000
PS EQS
Figure 8.1.6.10.1: Nickel (dissolved)
4.50
4.00
3.50
3.00
1996
l 2.50
1997
µ
g/ 2.00
1998
1.50
1999
1.00
2000
0.50
PS EQS
0.00
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834
834
641
554
503
432
375
375
132
18
0
0
132
18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
Figure 8.1.6.10.1: Nickel (dissolved) -Zero method
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UNDP/GEF Danube Regional Project
µg/l
3.0
10.0
2.5
2.0
8.0
1.5
1.0
0.5
6.0
0.0
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435
4.0
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05
2.0
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01
D02
A01
A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
1996
1997
1998
1999
2000
List 1 EQS
Figure 8.1.6.11.1: Tetrachloroehtene
12.0
0.30
µg/l 10.0
0.20
8.0
0.10
6.0
0.00
4.0
1869
1806
1806
1768
1768
1708
1560
1435
SK01
SK02
H01
SK03
H02
H03
H04
H05
2.0
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02
A01
A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
1996
1997
1998
1999
2000
List 1 EQS
Figure 8.1.6.11.2: Tetrachloromethane
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 203
µg/l
0.6
12.0
0.5
0.4
10.0
0.3
0.2
8.0
0.1
0.0
6.0
2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05
4.0
2.0
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02 A01 A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
1996
1997
1998
1999
2000
List 1 EQS
Figure 8.1.6.11.3: Trichloroethene
2.5
µg/l 12.0
2.0
1.5
10.0
1.0
8.0
0.5
0.0
6.0
1869
1806
1806
1768
1768
1708
1560
1435
4.0
SK01
SK02
H01
SK03
H02
H03
H04
H05
2.0
0.0 2581 2204 2204 2120 1935 1874 1869 1806 1806 1768 1768 1708 1560 1435 1429 1337 1071 834 834 641 554 503 432 375 375 132 18 0 0 132 18
D01 D02
A01
A02 A03 A04 SK01 SK02 H01 SK03 H02 H03 H04 H05 HR01 HR02 RO01 RO02 BG01 BG02 BG03 BG04 RO03 RO04 BG05 RO05 RO06 RO07 RO08 UA01 UA02
Monitoring sites / distance from the mouth [km]
1996
1997
1998
1999
2000
List 1 EQS
PS EQS
Figure 8.1.6.11.4: Trichloromethane
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UNDP/GEF Danube Regional Project
8.2.
Evaluation of Biological Determinands
8.2.1. Phytoplankton biomass concentration of the chlorophyll-a
First of all it should be stated that results of the measurements within TNMN database during period
1996 2000 are very heterogenious (Tab.8.2.1.1). Almost all data from the 1996 are missing (only
upper two sites data are present). Upper part of the Danube and upper tributaries are covered by data
(1997-2000) completely (up to 1439 r.km of the Danube). Part of the Danube from 1337 r.km was
monitored very sporadicaly, only a few data from Bulgaria are present.
Interpretation of the results can be only based on data which are at disposal from the TNMN database.
Therefore the only upper part of the Danube and selected tributaries can be evaluated (r.km 2581
1435).
The Danube stretch between Neu-Ulm and Wolfsthall belongs to the class I - II, the characteristic
values ranged from 2,0 to 43,4 µg/l. Last station of the Austrian part of the Danube (Wolfsthal)
belongs to class III (50,8 µg/l) in the year 1998. Other investigated years (1999 2000) show class I.
Left side tributary Morava brings to the Danube waters with higher concentrations of chlorophyll-a,
probably due to the higher algae growth in the reservoirs (e.g. Nové Mlýny).
Chlorophyll-a in the Danube section between Bratislava and Szob increased in 1998, in following
years situation improved (class II and I). Leftside tributary Váh contained more algae in the plankton
(class III - II). In the lower parts of this section (1560 1435 r.km) phytoplankton biomass increased
(class III), characteristic values ranged between 56 and 88 µg/l. Based on the results it can be stated,
that Sio is the most eutrophicated tributary in this part of the Danube (class III - IV). Better situation is
in Drava and Sajó (class I), while Tisza in Tiszasziget shows increase of the eutrophication during the
period 1997-2000.
Lower part of the Danube is represented only by some sporadic results from the Bulgarians section.
Characteristic values were between 6,8 and 54,4 µg/l, which results to the class I - III.
Tab.8.2.1.1: Characteristic values of the concentration of the chlorophyll-a of the TNMN stations
during period 1996-2000.
D - Danube site (rkm)
Chlorophyll-a (µg/l)
T, T/T Tributaries (site)
1996 1997 1998 1999 2000
D D01-Neu-Ulm (2581)
5,2
2,0
28,8
8,4
8,9
T/T D04-Salzach (Laufen)
T D03-Inn (Kirchdorf)
D D02-Jochenstein (2204)
27,8
3,6
30,0
21,4
21,5
D A01-Jochenstein (2204)
18,0
20,2
28,6
13,1
14,1
D A02-Abwinden-Asten (2120)
35,8
15,6
13,8
D A03-Wien-Nussdorf (1935)
42,8
19,7
12,3
D A04-Wolfsthal (1874)
18,0
43,4
50,8
18,7
11,7
CZ02-Dyije (Beclav) T/T
6,5
37,4
58,8
63,3
CZ01-Morava (Lanzhot) T
3,8
38,3
98,9
53,5
D SK01-Bratislava (1869)
7,1
45,9
27,9
21,3
D SK02-Medveov/Medve (1806)
8,2
54,6
33,8
18,4
D H01-Medveov/Medve (1806)
37,4
55,7
32,0
24,3
D SK03-Komárno/Komárom (1768)
10,0
55,5
39,7
24,6
D H02-Komárno/Komárom (1768)
49,7
83,1
52,7
26,8
SK04-Váh (Komárno) T
10,7
75,5
27,7
33,6
D H03-Szob (1708)
59,3
44,6
29,9
27,7
D H04-Dunafoldvar (1560)
72,5
88,0
58,4
56,0
T Sio (Szekszard-Palanka)
136,3
68,1
74,3
236,0
D H05-Hercegszanto (1435)
71,9
87,0
49,0
76,0
T H07-Drava (Dravaszabolcs)
19,0
15,5
14,4
12,3
D HR01-Batina (1429)
D HR02-Borovo (1337)
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 205
D - Danube site (rkm)
Chlorophyll-a (µg/l)
T, T/T Tributaries (site)
1996 1997 1998 1999 2000
T HR03-Drava (Varazdin)
H09-Sajo (Sajopuspeki) T/T
16,7
9,7
5,0
11,1
H08-Tisza (Tiszasziget) T
14,9
29,5
48,7
84,0
T SL01-Drava (Ormoz)
T HR04-Drava (Botovo)
T HR05-Drava (D.Miholjac)
T SL02-Sava (Jesenice)
T HR06-Sava (Jasenice)
T HR07-Sava (us.Una Jasenovac)
T BIH01-Sava (Jasenovac)
T/T BIH02-Una (Kozarska Dubica)
T/T BIH03-Vrbas (Razboj)
T/T BIH04-Bosna (Modrica)
T HR08-Sava (ds.Zupanja)
D RO01-Bazias (1071)
D RO02-Pristol/Novo Selo Harbour (834)
D BG01-Novo Selo/Pristol (834)
6,5
20,5
23,8
D BG02-us.Iskar-Bajkal (641)
T BG06-Iskar (Orechovitza)
D BG03-ds.Svishtov (554)
54,4
T BG07-Jantra (Karantzi)
46,0
D BG04 - us.Ruse (503)
15,4
T BG08-Russenski Lom (Basarbovo)
16,6
D RO03-us.Arges (432)
RO09-Arges T
D RO04-Chiciu/Silistra (375)
D BG05-Silistra/Chiciu (375)
17,7
13,8
RO10-Siret T
MD01-Prut (Lipcani) T
MD02-Prut (Leuseni) T
MD03-Prut (Giurgiulesti) T
RO11-Prut (Giurgiulesti) T
D RO05-Reni-Chilia/Kilia arm
D UA01-Reni-Chilia/Kilia arm
D RO06-Vilkova-Chilia arm/Kilia arm
D UA02-Vilkova-Chilia arm/Kilia arm
D RO07-Sulina-Sulina arm
D RO08-Sf.Gheorghe arm-Gheorghe arm
CLASSIFICATION SCALE
I.
II.
III.
IV.
V.
µg/l
25
50
100
250 >250
Conclusion
1. Spatial coverage of Danube River basin by data on chlorophyll-a in TNMN is not complete.
Only the upper part of the Danube and the main tributaries were monitored during period
1997-2000 in a way as it was proposed within TNMN. Only a few data were obtained from
Bulgarian section.
2. Statistical values correspond to class I - III according to the above mentioned classification
scale.
3. Only the Sio river (left side tributary) was in class IV during 1997 and 2000.
4. Results from the lower part of the Danube were in the class I III as well.
V 206
UNDP/GEF Danube Regional Project
Recommendation
1. It is stated that the Danube is eutrophicated river. More attention should be focused to the
monitoring of determinands characterizing eutrophication mainly in the lower part of the
river. This will enable to obtain coherent database along the River Danube and its main
tributaries.
2. The measurements of the chlorophyll-a content should by monitored at least 10-12 times per
year to obtain sufficient database for evaluation trends and changes.
8.2.2.
Saprobic index of macrozoobenthos
Interpretation of the results can be only based on data which are at disposal from the TNMN database.
Therefore only some parts of the Danube River and selected tributaries can be evaluated.
It should be said that database of the results of the measurements within TNMN is very heterogenious
during period 1997 2000 (Tab. 8.2.2.1). Data from 1996 were missing. As it was mentioned in case
of chlorophyll-a, data from the Danube River and its tributaries for mentioned period were very rare.
Upper part of the Danube up to Borovo was investigated from the point of macroinvertebtares only.
As for the tributaries, some of them were monitored up to Romanian stretch of the Danube.
Based on the results can be stated that the Danube and tributaries of the monitored TNMN station
belong to the class II II-III. Maximum values of Saprobic Indices ranged from 1,77 to the 2,7. This
means mesosaprobity. Only the Sava river (downstream Zupanja and Jasenice) belong to the
worse classes in the first two years (III III-IV) which means strong or very high pollution (up to
polysaprobity). However within next two years the situation improoved (II-III; mesosaprobity).
The differences show slight positive trend of pollution reduction within the investigated years.
Generaly, based on this results can be said that Danube and its some tributaries were moderatelly or
criticaly polluted.
Table 8.2.2.1: Saprobic Indices of macrozoobenthos of TNMN stations in the years 1997-2000.
D - Danube site (rkm)
Saprobic index of macrozoobenthos
T, T/T Tributaries (site)
1997 1998 1999 2000
D D01-Neu-Ulm (2581)
T/T D04-Salzach (Laufen)
2,12
2,03
2,25
T D03-Inn (Kirchdorf)
1,86
1,77
1,85
D D02-Jochenstein (2204)
2,26
2,27
2,19
D A01-Jochenstein (2204)
2,11
2,09
2,00
2,19
D A02-Abwinden-Asten (2120)
2,08
2,00
2,00
D A03-Wien-Nussdorf (1935)
1,93
2,19
2,00
2,20
D A04-Wolfsthal (1874)
2,14
2,15
2,10
2,20
CZ02-Dyje (Beclav) T/T
2,40
2,20
2,13
2,16
CZ01-Morava (Lanzhot) T
2,71
2,30
2,23
2,15
D SK01-Bratislava (1869)
2,08
2,04
2,54
1,98
D SK02-Medveov/Medve (1806)
2,12
2,09
2,18
1,99
D H01-Medveov/Medve (1806)
2,20
2,18
2,00
D SK03-Komárno/Komárom (1768)
2,11
2,12
2,27
2,11
D H02-Komárno/Komárom (1768)
2,25
2,27
2,10
SK04-Váh (Komárno) T
2,70
2,45
2,42
2,26
D H03-Szob (1708)
2,11
2,24
2,26
D H04-Dunafoldvar (1560)
H06-Sio (Szekszard-Palank) T
2,38
D H05-Hercegszanto (1435)
T H07-Drava (Dravaszabolcs)
D HR01-Batina (1429)
D HR02-Borovo (1337)
2,24
T HR03-Drava (Varazdin)
H09-Sajo (Sajopuspeki) T/T
H08-Tisza (Tiszasziget) T
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
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D - Danube site (rkm)
Saprobic index of macrozoobenthos
T, T/T Tributaries (site)
1997 1998 1999 2000
T SL01-Drava (Ormoz)
2,34
2,35
2,52
T HR04-Drava (Botovo)
T HR05-Drava (D.Miholjac)
T SL02-Sava (Jesenice)
2,57
2,32
2,36
T HR06-Sava (Jasenice)
2,60
2,80
2,50
2,24
T HR07-Sava (us.Una Jasenovac)
2,70
2,40
2,50
2,03
T BIH01-Sava (Jasenovac)
T/T BIH02-Una (Kozarska Dubica)
T/T BIH03-Vrbas (Razboj)
T/T BIH04-Bosna (Modrica)
T HR08-Sava (ds.Zupanja)
3,70
2,90
2,60
2,34
D RO01-Bazias (1071)
D RO02-Pristol/Novo Selo Harbour (834)
D BG01-Novo Selo/Pristol (834)
D BG02-us.Iskar-Bajkal (641)
T BG06-Iskar (Orechovitza)
D BG03-ds.Svishtov (554)
T BG07-Jantra (Karantzi)
D BG04 - us.Ruse (503)
T BG08-Russenski Lom (Basarbovo)
D RO03-us.Arges (432)
RO09-Arges T
D RO04-Chiciu/Silistra (375)
D BG05-Silistra/Chiciu (375)
RO10-Siret T
MD01-Prut (Lipcani) T
MD02-Prut (Leuseni) T
MD03-Prut (Giurgiulesti) T
RO11-Prut (Giurgiulesti) T
D RO05-Reni-Chilia/Kilia arm
D UA01-Reni-Chilia/Kilia arm
D RO06-Vilkova-Chilia arm/Kilia arm
D UA02-Vilkova-Chilia arm/Kilia arm
D RO07-Sulina-Sulina arm
D RO08-Sf.Gheorghe arm-Gheorghe arm
I.
I.-II.
II.
II.-III.
III.
III.-IV.
IV.
CLASSIFICATION
moderately criticaly strongly very high extensively
SCALE
unpolluted low
polluted
polluted
polluted polluted
polluted
polluted
1,25
1,75
2,25
2,75
3,25
3,75 >3,75
Conclusion
1. The TNMN data of the Saprobic Index of macrozoobenthos are not complete, only the upper
part of the Danube (up to 1337 r.km) and some tributaries were monitored during period 1997-
2000.
2. It is evident that some countries included saprobic index of bioseston into the database instead
of saprobic index of macrozoobenthos. Such results were excluded from the evaluation.
3. In the Danube and some tributaries the statistical characteristics correspond to the class II
II-III in accordance with used seven-class classification scale.
4. Only the Sava River (stations downstream Zupanja and Jasenice) belongs to the worse classes
in the first two years (III III-IV), however within next two years the situation improved (II-
III).
5. Based on the results can be said that the Danube and its some tributaries were moderately or
criticaly polluted, the slight positive trend appeared within the years.
6. Saprobic Indices in the Danube and its some tributaries were in the range of
mesosaprobity.
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Recommendation
1. In the future more characteristics of the macrozoobenthos is needed (e.g. number of taxa,
diversity or other indices, list of species) for the evaluation development and changes of the
invertebrates in the Danube.
2. The investigation of the macrozoobenthos should be monitored at least 2-3 times per year and
on the whole stretch of the Danube to obtain sufficient database for evaluation trends and
changes.
3. Connecting to the Water Framework Directive (2000/60/EC) more communities should be
monitored (e.g. phytobenthos).
8.2.3. Microbiological
determinands
Based on the obtained results (see Tab.8.2.3.1) it can be stated that some data from upper part of the
Danube, some data from lower part of the Danube and data from tributaries of the middle and lower
part of the Danube (Dava, Una, Vrbas, Bosna, Iskar, Jantra, Arges, Prut) are missing.
In the period 1996-2000 the faecal pollution represented by the Total Coliforms range predominantly
within class II-IV in the Danube and its tributaries. The worse situation was in Tisza (class V) in the
year 1998. Class I was obtained at some Danubian stations on the Romanian-Bulgarian stretch of the
river in the year 1996 only. In the next years there classes II-IV were observed. This evoke idea to
check the method used for investigation of the Total Coliforms in the laboratory.
Beside Tisza (Tiszasiget), there are other tributaries bringing faecal pollution to the Danube (Váh,
Siret). However, data of the tributary (Rusenski Lom and Arges), that were classified during Joint
Danube Survey as the worst ones, are almost missing.
Water quality of the Danube is influenced not only by the mentioned tributaies, but predominantly by
direct antropogenic impacts caused by the raw or treated sewages and diffuse impact from the
agriculture.
Looking to the TNMN border stations it is shown that the measurements between countries were not
harmonized. In some cases (Medve/Medveov, Komárno/Komárom, Novo Selo/Bristol,
Chiciu/Silistra, Sava) the differences are within two or three classes at the same stations in particular
year.
Below Cunovo (Gabcíkovo) Reservoir and Iron gate Reservoir the number of the Total Coliforms
decreased that in some years it resulted to the II (I) class. The reason is that due to the sedimentation
processes bacteria that are attached to solids particles are stored in the sediments of the reservoir.
Sedimentation can be also reason for the relatively possitive situation in the Danube Delta (I-II class).
Data of the Total Coliforms from the Danube shows that pollution ranged almost between moderate
and critical, in some cases strong pollution appeared. There is no trend in faecal pollution in the
longitudinal profile of the Danube river. Similarly, there are no significant changes comparing
individual years.
Based on the data of Faecal Coliforms faecal pollution of the Danube belong to the class I - IV during
period 1996-2000. The Danube in Komárom (1998) was in the class V only. The extensive pollution
was observed in Váh (2000), Tisza (1998) and Siret (1998).
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 209
In 1996 the low pollution is shown in the lower part of the Danube even though data from this stretch are
very rare. First class was also in Bazias (1997, 1999) and Pristol/Novo Selo (1999).
Decrease of the number of Faecal coliforms due to the sedimentation can be seen in Medveov/Medve
but not downstream of Iron Gates.
In the 1999 the Danube from Jochenstein (r.km 2204) to Hercegszanto (r.km 1435) was critically
polluted except Wolfsthal (r.km 1874) where was class IV.
Faecal pollution of the Danube Delta characterized by the Faecal Coliforms was slightly higher (I.-
III.class) than indicated by the Total Coliforms (class I-II).
Similarly as Total Coliforms, results on Faecal Coliform bacteria did not pointed out any significant
change or trend in the longitudinal profile of the
The methods of analyses were probably not fully harmonized between countries at TNMN border
stations as it was in case of Total Coloforms. In Medve/Medveov and Komárno/Komárom the
differences were in two classes. Big differences within numbers of Faecal Coliform bacteria were in
Siret in the individual years (64 920 000 CFU per 100 ml).
Tab. 8.2.3.1.: Statistical values of microbiological analyses of Total Coliforms and Faecal Coliforms
in TNMN stations in the period 1996-2000.
Total coliforms (CFU per 100ml)
D - Danube site (rkm)
Faecal coliforms (CFU per 100ml)
1996
1997
1998
1999
2000
T, T/T Tributaries (site)
1996
1997
1998
1999
2000
D D01-Neu-Ulm (2581)
T/T D04-Salzach (Laufen)
T D03-Inn (Kirchdorf)
19200
1920
16900
10760
22380
D D02-Jochenstein (2204)
1280
332
1325
1460
2230
12600
1460
11760
14900
18720
D A01-Jochenstein (2204)
1460
116
1430
1290
2840
D A02-Abwinden-Asten (2120)
4530
1750
17300
10900
10820
D A03-Wien-Nussdorf (1935)
721
316
1258
1820
2520
31000
11000
204000
127000
56600
D A04-Wolfsthal (1874)
12000
3070
14000
22000
6360
1056
8260
8200
10860
7160
CZ02-Dyje (Pohansko) T/T
552
2100
3560
3200
3280
578
1260
5500
4600
10800
CZ01-Morava (Lanzhot) T
220
430
2200
1390
3100
27600
4400
10630
13600
19000
D SK01-Bratislava (1869)
9600
1520
4210
5000
3680
7220
920
3420
3020
3950
D SK02-Medveov/Medve (1806)
2200
300
880
1100
500
160000
5400
4200
D H01-Medveov/Medve (1806)
17000
2400
1300
260000
24200
38100
21700
118000
D SK03-Komárno/Komárom (1768)
44800
4360
7520
6170
7900
540000
46400
92000
D H02-Komárno/Komárom (1768)
220000
3500
16000
214000
63000
135800
205000
390000
SK04-Váh (Komárno) T
72600
18900
34400
53500
158300
172000
13226
13510
D H03-Szob (1708)
36667
5100
5367
295000
24700
23800
D H04-Dunafoldvar (1560)
70000
6000
11667
50000
31000
20000
H06-Sio (Szekszard-Palank) T
662000
18000
28500
D H05-Hercegszanto (1435)
80000
1500
8000
170000
25500
24700 T H07-Drava (Dravaszabolcs)
22000
1300
2730
35500
22610
8890
D HR01-Batina (1429)
2290
7600
2230
D HR02-Borovo (1337)
350
13900
7500
23900
11000
11000
T HR03-Drava (Varazdin)
488000
50000
30000
H09-Sajo (Sajopuspeki) T/T
40000
6000
5600
1921000
251083
255167
H08-Tisza (Tiszasziget) T
145634
18974
23527
14000
27600
8630
15170
T SL01-Drava (Ormoz)
4450
4050
5470
7910
17700
12200
6520
T HR04-Drava (Botovo)
20980
49800
36010
9810
3060
T HR05-Drava (D.Miholjac)
22000
27800
29000
52200
T SL02-Sava (Jesenice)
7000
3520
43800
9300
39630
43800
35000
T HR06-Sava (Jasenice)
1800
24000
24000
24000
24000
24000
T HR07-Sava (us.Una Jasenovac)
4960
T BIH01-Sava (Jasenovac)
T/T BIH02-Una (Kozarska Dubica)
T/T BIH03-Vrbas (Razboj)
T/T BIH04-Bosna (Modrica)
23100
45700
42600
15000
19500
T HR08-Sava (ds.Zupanja)
2350
1178
8270
10634
5700
7667
D RO01-Bazias (1071)
96
677
47
922
303
4300
6667
777
7467
D RO02-Pristol/Novo Selo Harbour (834)
16
1334
250
45
1357
490334
146500
2504
D BG01-Novo Selo/Pristol (834)
D BG02-us.Iskar-Bajkal (641)
T BG06-Iskar (Orechovitza)
D BG03-ds.Svishtov (554)
T BG07-Jantra (Karantzi)
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UNDP/GEF Danube Regional Project
Total coliforms (CFU per 100ml)
D - Danube site (rkm)
Faecal coliforms (CFU per 100ml)
1996
1997
1998
1999
2000
T, T/T Tributaries (site)
1996
1997
1998
1999
2000
140000
D BG04 - us.Ruse (503)
40000
T BG08-Russenski Lom (Basarbovo)
4845
2452
2567
16000
D RO03-us.Arges (432)
310
190
758
6830
RO09-Arges T
204
13733
92133
19067
D RO04-Chiciu/Silistra (375)
10
8067
24100
1280
163334
32667
D BG05-Silistra/Chiciu (375)
350
16000
24000
920000
RO10-Siret T
64
810
920000
1300
MD01-Prut (Lipcani) T
35000
16000
16000
16000
MD02-Prut (Leuseni) T
16000
3600
2100
430
MD03-Prut (Giurgiulesti) T
9200
16000
9200
RO11-Prut (Giurgiulesti) T
2200
16000
220
193
7367
2867
7640
D RO05-Reni-Chilia/Kilia arm
16
3167
1527
1630
D UA01-Reni-Chilia/Kilia arm
63
6934
2434
3864
D RO06-Vilkova-Chilia arm/Kilia arm
11
2500
1664
4467
D UA02-Vilkova-Chilia arm/Kilia arm
110
7467
2300
6757
D RO07-Sulina-Sulina arm
7
2400
1860
490
9834
1811
3474
D RO08-Sf.Gheorghe arm-Gheorghe arm
507
1727
2700
I.
II.
III.
IV.
V.
CLASSIFICATION SCALE
I.
II.
III.
IV.
V.
500
10000 100000
1000000 >1000000
(CFU/100
ml)
100
1000
10000
100 000
>100000
Conclusion
1. Data on presence of bacteria (Total Coliforms and Faecal Coliforms) in TNMN databases are
not complete for the river basin.
2. Data from the upper part of the Danube (up to Borovo) and the main tributaries monitored
during period 1998-2000 are more homogenous than lower part of the Danube.
3. Characteristic values of the Total Coliforms result to the class I - IV in the Danube and the
tributaries except for Tisza in the year 1998 (class V).
4. Statistical values of the Faecal coliforms show similar situation to the Total Coliform bacteria.
The data ranged from class I to IV in the Danube and the tributaries except for Tisza (1998),
Váh (2000) and Danube in Komárno (1998) where the extensive pollution was observed.
Recomendation
The results from the Danube and its tributaries were evaluated according to the about mentioned
classification scheme. The EU Bathing Water Quality Directive (76/160/EEC) is now in the period
of the revision.
It is recomended to wait for the new version of the mentioned EU Directive and re-valuate data
from five years period (1996-2000).
For the TNMN the additional determinands should be included into the programme.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 211
9.
Conclusions and recommendations
The objective of this report was to assess water quality in Danube River basin, including classification
and identification of spatial and temporal changes. The basis for assessment are data on physico-
chemical and biological determinands collected in the frame of TNMN in five-years period 1996
2000.
The basis for assessment of spatial and temporal changes were 90 %-iles of yearly data sets, which is
able to express also unfavourable situations that occurred in particular year in the monitoring site. The
90 %-iles create also the basis for classification of water quality, but in case of frequency of
measurements lower than eleven the maximum value was used for comparison with limit values for
different water quality classes.
Results of classification are given in Annex I, assessment of water quality on the basis of physico-
chemical determinands is in chapter 8.1 and assessment based on biological determinands in chapter
8.2.
To supplement interpretation of heavy metals and micropollutants content in water of Danube River
basin, comparison of TNMN data had been done with Environmental Quality Standards (EQS) of EU
legislation. Existing EQS for List I substances together with proposed EQS for Priority Substances had
been used for the comparison. For this purpose, not 90 %-iles, but mean values calculated with ,,LOD-
method" and in selected cases also with ,,Zero-method" were used.
General characteristics
Suspended solids content increases slightly from upper to lower Danube section; as concerning its
tributaries, some of them show significantly higher concentrations of suspended solids than the
Danube River itself Tisza, Russenski Lom, Arges, Siret and Prut.
Values of pH show a slight alkaline medium; values exceeding 8.50 are present mainly in the middle
Danube, where, correlated with dissolved oxygen concentrations, show the influence of primary
productivity and organic matter load. This pH distribution along the Danube River is in accordance
also with results obtained from Joint Danube Survey.
Conductivity values do not present significant variations along the main course of the river. However,
after an intermediate decrease after confluence with Sava River, a slight increase is observed in the
lower Danube. From tributaries, Sio and Prut present relatively higher salts content.
Excluding only few values (at Danube-Batina, rkm 1429), alkalinity shows a constant spatial pattern in
the upper and in the middle Danube; slightly increasing values appear in the second part of the lower
Danube. As concerning the tributaries, higher alkalinity values are present on Sio and Russenski Lom.
Nutrients
From the different fractions analyzed within the TNMN Programme, ammonium-N, nitrite-N, nitrate-
N, ortho-phosphate-P and total phosphorous were chosen for assessment of nutrient content in waters.
Information on organic and total nitrogen are sparce and can not provide a good picture on situation in
the river basin.
Ammonium-N and nitrite-N present an increasing profile from upper to lower Danube, which is much
more significant in case of ammonium-N. From existing data along the Danube itself, 53.3 % of
ammonium-N and 37.2 % nitrite-N values are above the target limit for these determinands. For
tributaries, rather high values appear on the Morava, Dyje, Vah and Sio in the upper and middle
Danube and on Jantra, Arges, Siret and Prut in the lower Danube section. A special concern should be
V 212
UNDP/GEF Danube Regional Project
paid to the ammonium-N content recorded on the Arges tributary, where all five values of C90
characterising situation in different years in period from 1996-2000, are above the limit for Class V;
these extremely high values, correlated with BOD5 values, show the impact of untreated or
insufficiently treated waste waters from municipalities.
Unlike the ammonium-N and nitrites-N, the spatial distribution of nitrate-N concentrations show a
decrease from upper and middle to lower Danube. From data for the Danube itself, 27.1% are above
the target value, whereas 33.1% are above this limit in monitored tributaries. Tributaries with the
highest content of nitrates-N are Morava, Dyje, Sio in the upper/middle part, and Iskar, Russenski
Lom, Arges and Prut in the lower part of river basin.
Orthophosphate-P shows a similar spatial pattern with total phosphorous, both characterized by a
slight increasing profile from upper to lower Danube; concerning the exceeding of the target value,
17.6% of orthophosphate-P and 11.3% of total P values are above this limit along the Danube River,
while 45.2% of orthophosphate-P and 57.3% of total P values are above this limit in tributaries.
Heavy metals
Within the framework of TNMN in the Danube River Basin eleven heavy metals are regularly
analyzed in water both as total and dissolved forms (for dissolved forms data are available only from
1998 to 2000, and even not for the whole river basin). Excepting the conservative element aluminium,
ten of them were chosen to be discussed in the quality assessment of the Danube River water and its
tributaries; out of these, eight heavy metals are of a particular importance due to the fact that they are
considered as priority substances for the Danube River Basin - four of them are listed in the list of
Priority Substances included in Annex X of the Water Framework Directive (cadmium, lead, mercury
and nickel) and the other four belong between priority substances specific to the Danube River Basin
(arsenic, copper, chromium and zinc).
Except manganese, where a maximum spatial profile is present in the middle Danube, for most of the
discussed heavy metals the general pattern is increasing from upper and middle to the lower Danube.
Further, the heavy metals content in some tributaries mainly those located in the lower Danube - is
higher than the content in the Danube River itself.
According to the classification for the Danube River Basin and regarding the exceeding of the target
values, the assessed data for the total heavy metals forms led to the following conclusions:
· the contamination of the Danube River water is rather high in case of lead and copper, with
57.3% of values for lead and 56.7% values for copper above the target limit; in tributaries,
these percentages are 52.8% for lead and 21.6% for copper.
· the contamination pattern of the Danube itself for cadmium and mercury can be characterized
with 47.4% of values exceeding cadmium target level and 36.6% of values exceeding mercury
target level; however, it has to be mentioned the lack of data for mercury in the lower Danube
cannot provide a comprehensive picture in this respect. In tributaries, the situation is better for
cadmium, with 32.4% above the quality target but worse for mercury with 63.2% above this
limit.
· as regarding the contamination of the Danube river and its tributaries by arsenic, chromium,
nickel and zinc, it can be roughly said these watercourses are unpolluted from this point of
view; the percentages of exceeding the target values in the Danube and in selected tributaries
are the following: arsenic 8.7% in Danube River and 16.1% in tributaries, chromium 1.3%
in Danube River and 0% in tributaries, nickel 0% in Danube River and 2.1% in tributaries
and zinc 10.5% in Danube River and 12.9% in tributaries. However, the lack of data for
these heavy metals in the lower Danube section has to be mentioned again.
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
V 213
Because the analysis of heavy metals in water column only cannot provide a very good picture of this
kind of pollution, the assessment of the heavy metals content in both sediment and suspended solids
may be a better approach in this respect.
Oxygen regime
In order to assess the water quality of the Danube River and its tributaries from the point of view of
oxygen regime, four determinands were used - dissolved oxygen in terms of concentration,
biochemical oxygen demand (BOD) and chemical oxygen demand by KMnO4 and K2Cr2O7 (CODMn
and CODCr).
Dissolved oxygen concentrations generally show positive results, with only 7.4% of values below the
quality target in the Danube River and 8.6% in selected tributaries. Oxygen concentration decreases
from upper to lower part of the Danube River, lowest values reaching in the section from Danube-
Bazias to Danube-Novo Selo/Pristol. From tributaries, low oxygen content was also identified in those
located in the lower part of the river basin.
BOD values indicate that 13.3% of values are above the target value in the Danube River (mainly in
the middle and in the lower sections) and 35.9% in tributaries. Organic pollution expressed by BOD
increases along the Danube, reaching its maximum in the secion from Danube-Dunafoldvar (rkm
1560, H04) to Danube-Pristol/Novo Selo (rkm 834, RO02). Tributaries most polluted by degradable
organic matter are Morava, Dyje and Sio in the upper/middle part and Russenski Lom and Arges in the
lower part.
For CODCr, from all values 22.4% for the Danube itself and 39.7% for tributaries are above the quality
target; the picture is more positive in case of CODMn - no value above this limit for the Danube River
and 18.2% for tributaries. Measurements of CODCr and CODMn show the highest values in the lower
part of the Danube River.
In order to obtain a more complete pattern of oxygen regime, beside the 10 percentiles for dissolved
oxygen, both the minimum and maximum values were used in assessment, the results being in good
correlation with previous data (Joint Danube Survey - 2001). Also, the results confirm the critical
problems that occur in the tributaries which regularly serve as recipient of untreated or not adequately
treated waste water from industry and municipalities (the Arges tributary).
Organic micropollutants
Within the TNMN Programme, organic micropollutants that are regularly monitored are Lindan, pp'-
DDT, Atrazine, chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene. During
the five studied years, the content of these organic compounds presents very large limits of variation
due to the fact that there are big differences among the reported limits of detection.
The organochlorine compounds (Lindan and pp'-DDT) show almost the same spatial profile, with an
increasing pattern from upper and middle to lower Danube; concerning the exceeding of the target
value for Lindan, 23.8% from all values are above this limit in the Danube River water and 9.1% in
tributaries. These percentages are higher in case of pp'-DDT: 70.5% for the Danube itself and 54.2%
for tributaries.
The polar pesticide Atrazine is undetectable at most of the monitoring sites along the Danube River,
but 12.5% of the data are above the target limit (as far as the data are available). In tributaries, 30% of
values are above the quality target; the maximum values of Atrazine were found in rivers Sio and the
Sajo.
For the volatile organic compounds, data are available for upper and middle Danube only. Chloroform
and tetrachloroethylene present values above the target limits as it follows: 29.0% in the Danube and
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39.5% in tributaries for chloroform and 13.6% in the Danube and 7% in tributaries for
tetrachloroethylene. The situation is better in the case of tetrachloromethane and trichloroethylene - in
the Danube River water, no value is above the target limit for these compounds, while in tributaries
the same percentage of all data (2.3%) is above this value for both those determinands.
Biological determinands
In the group of biological determinands generally there were problems with unsufficient spatial
coverage of Danube River Basin, needed for meaningful interpretation of these data. From existing
results can be concluded that chlorophyll-a corresponds to class I III, only Sio River to class IV in
1997 and 2000.
Regarding saprobic index of macrozoobenthos, by using Austrian standard ÖNORM M6232 the
values in Danube River basin and some tributaries correspond to classes II II-III. Only Sava River
was characterized by worse quality class (III III-IV), however, within the years the situation had
been improved. Based on the results it can be concluded that Danube River and tributaries were
moderately or critically polluted.
Water quality from microbiological point of view corresponded to classes I IV in the Danube River.
Tributaries Vah, Tisza, Siret can be characterized as extensively polluted, however, data from many
important tributaries are missing. Sedimentation has positive effects to number of total coliforms
below Gabcíkovo Reservoir, Iron Gates and in Danube Delta as well.
An important part of the report is the evaluation of the water quality changes in time period from 1996
to 2000, main question being whether the water quality is improving or deteriorating. Water quality
changes in time depend on both natural characteristics like occurance of flood events, events of low
flows, periods of sunny warm weather and antropogenic activities like discharges of waste waters,
agricultural practises, accidental events. Taking into account great heterogeneity of the countries in
Danube River basin, their water management practices, and in majority of them their transforming
economics, both trends can be expected and should be detected.
Regarding indicators of organic pollution BOD, CODMn and CODCr, there is not their common trend
observed. The year-to-year fluctuation rises from CODMn to BOD and to CODCr.
Decreasing tendency of BOD from 1997/98 to 2000 was observed in section from Danube-Neu Ulm
(km 2581) to Danube-Abwindedn-Asten (km 2120), at the cross section Danube-Medvedov/Medve
(km 1806) and Danube Komarno/Komarom (km 1768); further from Danube-Borovo (km 1337) to
Danube-Bazias (km 1071), in Danube-Reni/Chilia arm/Kilia arm (km 132) and Danube Vilkov/Kilia
arm/Chilia arm (km 18). In evaluated period 1996-2000, BOD values in 2000 belonged to the lowest
in majority of monitoring sites located in Danube River. From tributaries, a decreasing trend of BOD
can be observed in Inn, Salzach, Dyje, Vah, Drava and Arges, whilst the sites at Tisza River and its
tributary Sajo show a reverse behaviour.
Comparing the 90%-iles of different years of determinands characterizing content of nitrogen in
waters, it appears that in general nitrate-N shows the less changes whereas ammonium N and nitrite-
N fluctuate to a great extent.
For nitrate-N concentrations the ratio of changes from year to year is apart from some exceptions low
for the Danube itself, but higher for tributaries. At River Arges (RO09) and Prut (RO11, MD03) it
amounts one to three. Despite the implications of seasonal affects this fluctuation seems to be very
high. For ammonium-N annual variations exceed 100 % at quite a number of monitoring sites and
even amount 300 %. This picture can be a result of natural variations but might be also an indicator for
accidentally detected impacts, e.g. when a specific yearly data set contains samples that were taken
just after an incident like flood event, effluence of manure or breakdown of a water treatment plant.
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In the Danube River, ammonium-N shows a decreasing tendency from 1996 to 2000 in the upper part
and in the middle section in Slovakian monitoring sites. In majority of tributaries located in the upper
and middle Danube, generally ammonium-N seems to decrease, excepting Croatian sites located on
Sava River.
Looking at nitrate-N, its content decreases in Morava and Dyje. A clear decreasing trend from 1996 to
1999 is visible on the Sio. An opposite temporal variation appears on the Sajo and Arges.
Phosphorus content was measured as a total P and ortho-phosphate P. From upper/middle part,
decreasing tendency is seen in the section from Danube-Bratislava (km 1869) down to Danube-Szob
(km 1708), an exception appears at Danube-Medvedov/Medve (km 1806). Further downstream,
variance between the years increases and specific problem arises with comparability of data in cross
sections measured by two neighbouring countries. From tributaries, decreasing tendency was observed
in Drava-Varazdin (HR03), but the rest of monitoring sites located on this tributary present a relative
stable state. No temporal changes were observed in Tisza River, even the variation is low there.
Concerning total P, the variance between years is much higher than that of ortho-phosphates.
Generally, total P temporal distribution in monitoring sites located on Danube River is rather scattered,
or tendency of development is opposite if data for the same cross section, but provided by two
countries, are taken into account (Danube-Novo Selo/Pristol). From tributaries the decrease of total P
is visible in Arges and Siret, especially taken into account high values reached in 1996 that did not
occur in the next period.
The heavy metals content is strongly dependent on quantity and nature of suspended solids, which is
the reason of natural variations and trends that might hide the effect of anthropogenic contaminations.
High values of heavy metals often reflect situations with high loads of suspended solids and flood
events and statistical parameter used also in this report (90%-ile) could be influenced by these
processes. For this five-years evaluation, data on total concentration of heavy metals in water samples
had been used, because data related to dissolved fraction are not available in sufficient extent.
Anyway, some restrictions related to the trend analysis of heavy metals has to be mentioned again
sparse data sets and detection limits, that had changed rapidly over the years. Besides it seems that
there are differences in analytical methods or extraction methods because in many cases data from
monitoring sites, which are shared by two countries, do not fit together.
As a result of above mentioned factors, rather big yearly variations were observed - up to three times
at most of the monitoring sites. Further, can be concluded, that there was practically no coincidence
between the developments of the different heavy metals along the Danube. In spite of these
uncertainties, it seems that development of heavy metals content in some tributaries is positive
decrease is indicated in Drava river (cadmium, chromium, copper, lead, nickel and zinc), in Arges
(cadmium, chromium, copper, lead), Prut (cadmium, chromium, lead), in Siret (chromium, copper,
lead).
From biological determinands, slight positive trend appeared within the evaluated years in case of
saprobic index of macrozoobenthos, but no significant trend in microbiological determinands has been
observed.
From comparison of TNMN data with EQS of EU legislation it can be concluded that:
atrazine concentrations at sampling sites seem to be no problem in comparison with proposed
EQS, even if the mean was calculated by using the worst case calculation
mean values of total cadmium in lower part of Danube lie very close or even above the List I
EQS stipulated by Directive 83/514/EEC. In the upper part of the river mean concentrations are
below the EQS with exceptions of few results in 1996/97.
for p,p-DDT in the upper part of the Danube practically all data are below LOD; downstream
Hungary the EQS laid down by Directive 86/280/EEC is exceeded in many cases. Change of
calculation method did not improve this situation.
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in case of lindane two EQS could be used existing EQS laid down by Direcitve 84/491/EEC
and proposed new EQS. Whilst the existing EQS is exceeded only by extreme values, with new
limit the situation will be worse.
for total mercury very limited data are available, and these existing results show only one
exceedance of the EQS. For Tetrachloroethane, Tetrachloromethane and Trichloroethylene the
results are below existing EQS. Trichloromethane exceeds the EQS in one case. This is the only
one of the four compounds which has been included in the list of Priority Substances. New
proposed EQS causes an increase the number of exceeding values to three in the five-year
period.
Recommendations
Assessment of water quality is very much dependent on availability and comparability of data
provided from countries in the river basin, if the purpose is to provide reliable information to decision
makers and public. This report used data from the first five years of joint monitoring programme of
Danubian countries in the River basin that have not yet fulfil all requirements on frequency and data
quality and comparability, although the situation is improving in the years. The gaps were discovered
during the process of data interpretation, mainly regarding data comparability it was revealed in
several cases that data from the same cross sections provided by two countries would result in
different final information, for example in trend assessment. Great problems were identified in case of
availability of data on biological determinands, data on heavy metals and organic micropollutants.
Even frequencies of measurements were such low in case of some determinands that prevent reliable
interpretation.
The main recommendations related to TNMN are the following:
Enhance TNMN in terms of keeping agreed set of physico-chemical and biological
determinands and their frequencies by countries participating in TNMN. Specifically
relevant in this respect is the group of organic micropollutants, biological determinands and
some heavy metals. In addition, "newly" recommended determinands like dissolved
phosphorus and heavy metals in dissolved phase should be improved in this way.
Exert an effort to further improvement of quality of data and to harmonize the methods to an
extent that will ensure data comparability between the countries. In addition, after finding
out of not satisfactory results repeatedly from proficiency testing organised for laboratories
involved in TNMN, the laboratories should analyse the reasons of this, propose and
implement the measures for improvement, which would be reported and discussed in the
MLIM-EG.
Laboratories involved in the TNMN should try to keep limits of detection agreed for
selected determinands for TNMN. It should be ensured that limits of detection of
determinands are at least on sufficiently low level enabling comparing the results of analysis
with target values set for the determinands.
In near future it should be clearly distinguished between the terms limit of detection (LOD)
and limit of quantification (LOQ) taking into account definitions used by the EU. TNMN
database should be adjusted in this sense, including both characteristics.
More attention should be paid in the future to determinands characterising eutrophication,
mainly in the lower part of the river basin. If the Danube River is generally considered as
eutrophicated river, on the basis of international monitoring it should be allowed to evaluate
this process, together with identification of the most critical areas.
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Much more attention should be paid to the microbiological analyses. As in the present time
would be rather difficult to ensure proficiency testing for microbiological determinands in
Danube River basin, it is recommended to focus mainly to methodological problems and to
enhance at least cooperation of neighbouring countries in DRB in this field.
In connection to the WFD, more biological communities should be monitored in the Danube
River basin, e.g. phytobenthos. In addition, discussion on inclusion of additional indices
should start.
It is recommended to report the dissolved oxygen in terms of both concentration and
saturation, the latter being more relevant in this respect.
Only very small fraction of specific organic micropollutants has been able to assess on the
basis of TNMN data. Taking into account new needs in the field of monitoring of priority
substances Tand other substances discharged in significant quantities in waters in Danube
River Basin, inclusion of new specific substances relevant for Danube River basin is
necessary. This process is recommended to do by utilisation of information from both JDS
and from national surveys performed.
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Abbreviations
c90 90
percentile
c10 10
percentile
DRB
Danube River Basin
DRPC
Danube River Protection Convention
EAF
Expert Advisory Forum Priority Substances
EC European
Commission
EQS
Environmental Quality Standard
FHI Fraunhofer-Institute
JAP
Joint Action Plan for the Danube River Basin
LOD
Limit of Detection
MAC
Maximum allowable concentration
PS Priority
Substances
SOP
Standard Operational Procedure
TNMN TransNational
Monitoring
Network
WFD
Water Framework Direcive
Five-years Report on Water Quality in the Danube River Basin Based on Trans-National Monitoring Network
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References
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Annex 1
Classification tables
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