130
Chapter 5
Temporal Variations in POP Levels
A critical component of the assessment of POPs in the
The high degree of variability normally observed in OC
Arctic is knowledge of the temporal trends of these
data in both air and biotic matrices therefore, requires
chemicals in the abiotic and biotic environment. The re-
that temporal-trend datasets cover a large number of
lationship between contaminant input into the Arctic
sampling years and have sufficient sample numbers for
and the levels and effects seen in wildlife and humans is
robust statistical analysis.
ultimately tied to the use and restriction of these chemi-
cals and any remedial action that is taken. It is, there-
5.1. Air and precipitation
fore, important to know if POPs are decreasing or in-
creasing in the Arctic, and whether this varies through-
5.1.1. Temporal trends in air
out the Arctic and between various media. Temporal-
Data on sub-decadal (3- 6 years) temporal trends of
trend datasets provide a tool to assess remedial actions,
POPs in Arctic air are available from air monitoring sta-
and also serve as an early warning system for potential
tions at Alert (Nunavut, Canada), Stórhöfi (Iceland),
changes in contaminant levels. Most of the Arctic na-
Ny-Ålesund (Svalbard, Norway) and Pallas (Finland).
tions have applied restrictions and bans on many of the
Shorter-term (1-3 years) results are also available from
major OCs for decades, resulting in significant declines
Dunai (eastern Russian Arctic) and Amderma (western
of these chemicals in temperate and Arctic regions in the
Russia). Comparisons of levels of major OCs and PAHs
1970s and 1980s. Continued use of chemicals such as
among these stations were made in Section 4.1. In this
PCBs, and emissions from areas where chemicals are
section, temporal trends in air concentrations of PCBs,
still in use, however, provides a continuing source of
PAH, and OC pesticides are evaluated and compared.
contamination. The signing of the Stockholm Conven-
Hung et al. (2001; 2002b) examined the temporal trends
tion on Persistent Organic Pollutants in May 2001
of PCBs and OC pesticides at Alert using both a temper-
(UNEP 2001), which calls for bans on a number of
ature-normalization method (where concentrations are
chlorinated pesticides, and reductions of use and emis-
expressed as partial pressures and adjusted to a standard
sions of POPs that are by-products, is likely to result in
temperature (288°K)), and a digital filter method (where
further declines. New concerns have arisen for current-
concentrations are expressed as partial pressures and
use chemicals such as brominated flame retardants.
short- and long-term variations are extracted using cut-
The use of these chemicals is increasing and, conse-
off filters). The estimated half-lives from their work are
quently, levels in the environment have been increasing
included in the discussion of each chemical group. Simi-
as well.
lar time trend analyses are not available for the Euro-
The first AMAP POPs assessment included a very
pean Arctic stations with long-term data.
limited number of good temporal-trend datasets with
which to assess long-term trends of OCs in the Arctic.
5.1.1.1. OC pesticides
Many of the datasets were confounded by changes in
analytical methodologies. For example, much of the
DDT
older data were generated using packed column gas
Time series for DDT-related compounds in Arctic air are
chromatography rather than current capillary column
available for Alert (1993-1998), Stórhöfi (1995-1999),
technology. The best temporal-trend datasets available
Ny-Ålesund (1993-2000), and Pallas (1996-1999). DDT
include the monitoring of OCs in Arctic marine biota
results are also available from Tagish (1993-94) and
dating back to the early 1970s, and the database avail-
Dunai (1993) and these full datasets have been discussed
able on OCs in fish from northern Scandinavia dating
previously (Halsall et al., 1998). Since these stations
back to the late 1960s. These datasets showed a de-
did not operate beyond 1994, no data were generated
creasing trend in OCs in the 1980s but a reduction in
in Phase II of AMAP. With the exception of Stórhöfi,
the rate of decline during the early 1990s.
where there was indication of local sources (Section
The assessment of temporal trends, however, is not a
4.1.1), the DDT transformation products p,p'- and
simple process and requires datasets from numerous lo-
o,p'-DDE were mainly found. Figure 5·1 presents the
cations and matrices. Regional differences in sources,
concentration distribution of p,p'-DDE over the period
changes in atmospheric and oceanic currents, and vari-
1993-2000. Concentrations at Ny-Ålesund and Stór-
ability associated with biota all can influence OC levels
höfi were generally higher than at Alert and tended to
and temporal trends. During the 1990s, weather pat-
be lower in 1999 than in earlier years. Indications of
terns changed in the northern hemisphere, with an in-
seasonal variation can be seen for all sites. The highest
crease in the number of deep storms, and these storms
concentrations were always found during winter (Janu-
penetrated deeper into the Arctic. The result has been a
ary/February) and the lowest values were found in
stronger connection between industrial areas of Europe
summer (August). The most extreme case is at Ny-Åle-
and North America and the Arctic (Macdonald et al.,
sund where p,p'-DDE concentrations increased 8 to 10
2003). This may mean that there has been increased
fold above prevailing concentrations in winter and
transport of contaminants to the Arctic during the past
early spring months, especially in 1996, 1997, and
decade, which would affect temporal-trend monitoring.
1999. This reflects the association of DDE with parti-
131
Concentration in air, pg / m3
12
Alert
p,p'-DDE
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
8
4
0
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
pg / m3
3.5
3.5
3.5
3.5
3.5
Alert
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
3.0
3.0
3.0
3.0
3.0
2.5
2.5
2.5
2.5
2.5
2.0
2.0
2.0
2.0
2.0
1.5
1.5
1.5
1.5
1.5
1.0
1.0
1.0
1.0
1.0
0.5
0.5
0.5
0.5
0.5
0
0
0
0
0
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'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
Figure 5·1. Temporal trends of p,p'-DDE in Arctic ambient air at five monitoring stations from 1993 to 2000.
cles under prevailing winter temperatures and higher
p,p'-DDE is decreasing slowly at Alert (estimated half-
particle concentrations during the winter associated
life of 19 years). Hung et al., (2002b) also found that
with Arctic haze (Halsall et al., 1998). p,p'-DDE is
o,p'-DDT actually increased, though not significantly,
strongly associated with soils and may be transported
in concentration at Alert over the period of 1993 to
with aeolian dusts that are advected into the Arctic
1998 (Table 5·1). The presence of o,p'-DDT implies a
(Welch et al., 1991; Hung et al., 2002b). Using tempera-
continued source of technical DDT entering the Arctic
ture-adjusted data, Hung et al. (2002b) concluded that
atmosphere.
Table 5·1. Half-lives (t1/2) of selected OC pesticides and PCBs at Alert (developed using the digital filtration
method; Hung et al., 2001) and comparison with the Great Lakes region and western Europe.
Great Lakes
Great Lakes
Alert,
(Eagle Harbor,
(Sleeping Bear Dunes,
Northern
Nunavut
Lake Superior)
Lake Michigan)
U.K.b
OC
t
a
a
a
a
1/2
(yr)
r2
t1/2 (yr) ±SE
t1/2 (yr) ±SE
t1/2 (yr)
-HCH 17
0.79
3.0
0.2
3.2
0.4
-HCH 4.9
0.88
4.4
0.6
3.4
0.6
trans-chlordane 8.3
0.48
6.9
2.9
5.2
1.7
cis-chlordane 4.1
0.71
23
25
9.7
4.9
trans-nonachlor 6.2
0.71
33
53
6.0
2.1
Dieldrin incr.
< 0.10
3.7
0.7
2.4
0.4
p,p'-DDE 19
< 0.10
o,p'-DDT incr.
0.29
PeCA 3.9
0.71
-endosulfan
incr.
0.25
Tetrachloroveratrole incr.
< 0.10
CB28 (Cl 3)
12
0.58
2.7
0.6
1.7-4.2
CB52 (Cl 4)
3
0.86
4.3
1.3
1.6-2.3
CB101 (Cl 5)
11
0.73
2.9
0.7
2.1-4.3
CB153 (Cl 6)
17
0.18
1.8
0.4
2.3-6.6
CB180 (Cl 7)
4
0.78
a t1/2 = half-life, calculated as ln 2/s where s = slope of the linear regression. For Alert s = slope of the time
trend developed using the digital filtration method. For other sites s = slope between ln P288 and t (where t =
time (years) and P288 = partial pressure of the chemical at 288 Kelvin). Data with increasing time trends are in-
dicated as `incr.'. r 2 values give an indication of the statistical significance of the relationship of ln P vs. time.
b Results from Sweetman and Jones (2000).
132
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in air, pg / m3
350
HCB
Alert
300
Stórhöfdi
Ny-Ålesund
Pallas
250
Amderma
200
150
100
50
0
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
pg / m3
140
140
140
140
140
Alert
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
120
120
120
120
120
100
100
100
100
100
80
80
80
80
80
60
60
60
60
60
40
40
40
40
40
20
20
20
20
20
0
0
0
0
0
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'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
Figure 5·2. Temporal trends of HCB in Arctic ambient air at five monitoring stations from 1993 to 2000.
HCB
evident for -HCH in spring-time samples (weeks 14-
No indication of major trends in concentrations of HCB
27) at Ny-Ålesund between 1993 and 1997 and Stór-
in the period of 1993 to 1999 were found in the data re-
höfi in 1995-96 (Figure 5·3). A spring increase in -
ported from the three stations with the longest time series
HCH was also observed at Alert; however, sharp in-
(Figure 5·2). HCB was relatively constant with occasion-
creases, like those found in springtime at Ny-Ålesund
ally elevated levels, especially at Ny-Ålesund and Alert.
and Stórhöfi were mainly observed in October-Decem-
The sources of these elevated HCB concentrations have
ber samples at Alert. The reason for this is not clear, al-
not been investigated. HCB concentrations show signifi-
though it could be due to agricultural practices in Can-
cant `break-through' of the polyurethane foam collection
ada (a major lindane user during the 1990s) where au-
material even at low temperatures (averaging 25.9%;
tumn plowing may release residual lindane that was
P. Blanchard, pers. comm.), and thus, the concentrations
used for seed treatment in oilseed crops. Decreases in -
might be underestimated. In 1997-1999, there were
HCH at Ny-Ålesund and Stórhöfi in 1999-2000 may
fewer short episodic increases in HCB concentrations at
reflect reductions and changing use patterns of lindane
Ny-Ålesund and Alert than in earlier years.
in Europe. In mid-1998, lindane use ceased in France,
the main user in western Europe.
HCH
Linear regression analysis of the `temperature-nor-
The time series for concentrations of - and -HCH
malized' or `digitally filtered' data revealed that -HCH
are presented in Figure 5·3. A discernible decrease
and -HCH concentrations are declining at Alert (Table
in concentration of -HCH from 1993 to 2000 at Ny-
5·1). The decline of -HCH was more rapid than that of
Ålesund and from 1995 to 1999 at Stórhöfi, is appar-
-HCH over the five-year period (1993-1998) (Hung et
ent from the raw data in Figure 5·3. -HCH concentra-
al., 2002b). Jantunen and Bidleman (1995) have shown
tions show no general tendencies. In all Arctic air sam-
-HCH to be outgassing from the Arctic Ocean, which
ples except those from Stórhöfi, -HCH represents
will buffer the concentrations in the overlying atmos-
about 15-20% of the total - and -HCH burden. Un-
phere, and may help to explain the long half-life found
like several other semivolatile OCs (dieldrin, endosulfan,
in this study. On the other hand, -HCH in Arctic air
cis-chlordane), - and -HCH concentrations at Alert
has a half-life comparable to that found at temperate
were not correlated with air temperature (Halsall et al.,
sites (Table 5·1). Haugen et al. (1998) reported no trend
1998; Hung et al., 2002b). This lack of correlation re-
for -HCH in air from southern Norway (Lista air sta-
flects the importance of long-range transport events that
tion) between 1991 and 1995. This probably reflects the
bring higher concentrations to each site. This is most
effect of a strong European signal at that site.
Chapter 5 · Temporal Variations in POP Levels
133
Concentration in air, pg / m3
300
-HCH
250
Alert
Stórhöfdi
Ny-Ålesund
Pallas
200
Amderma
150
100
50
0
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
pg / m3
120
120
120
120
120
Alert
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
100
100
100
100
100
80
80
80
80
80
60
60
60
60
60
40
40
40
40
40
20
20
20
20
20
0
0
0
0
0
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'93 '94 '95 '96 '97 '98 '99 '00
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'93 '94 '95 '96 '97 '98 '99 '00
Concentration in air, pg / m3
120
-HCH
100
Alert
Stórhöfdi
Ny-Ålesund
Pallas
80
Amderma
60
40
20
0
± 59.27
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
pg / m3
30
30
30
30
30
Alert
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
25
25
25
25
25
20
20
20
20
20
15
15
15
15
15
10
10
10
10
10
5
5
5
5
5
0
0
0
0
0
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'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
Figure 5·3. Temporal trends of - and -HCH in Arctic ambient air at five monitoring stations from 1993 to 2000.
134
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in air, pg / m3
15.0
Alert
CHLs
Stórhöfdi
12.5
Ny-Ålesund
Pallas
Amderma
10.0
7.5
5.0
2.5
0
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
pg / m3
6
6
6
6
6
Alert
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
5
5
5
5
5
4
4
4
4
4
3
3
3
3
3
2
2
2
2
2
1
1
1
1
1
0
0
0
0
0
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
Figure 5·4. Temporal trends of total chlordanes (sum of cis/trans-chlordane, cis/trans-nonachlor) in Arctic ambient air from 1993 to 2000.
Cyclodiene pesticides including chlordanes
ter months as well as a general rise in concentrations
Time trends for CHLs and dieldrin are presented in Fig-
during summer. This trend was not apparent in northern
ures 5·4 and 5·5. For purposes of comparison, CHLs
Finland. These weekly episodes might be due to fresh
was restricted to cis/trans-chlordane and cis/trans-
use of chlordane-based pesticides (Hung et al., 2002b).
nonachlor. Alert shows relatively high average values of
Previous episodes of elevated trans-chlordane at Ny-Åle-
CHLs from 1993-1994 and a subsequent continuous
sund were traced to North American sources (Oehme et
decrease in average concentrations until 1998. The time
al., 1995b), which might explain why the seasonal trend
series of CHLs at Alert, Ny-Ålesund, and Stórhöfi are
is not as apparent at Pallas or Amderma. Cis/trans-non-
characterized by sharp weekly episodes during the win-
achlor and cis-chlordane were significantly correlated
Concentration in air, pg / m3
5
Dieldrin
Alert
Stórhöfdi
4
Amderma
3
2
1
0
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
2.5
2.5
2.5
Alert
Stórhöfdi
Amderma
2.0
2.0
2.0
1.5
1.5
1.5
1.0
1.0
1.0
0.5
0.5
0.5
0
0
0
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'93 '94 '95 '96 '97 '98 '99 '00
Figure 5·5. Temporal trends of dieldrin in Arctic ambient air from 1993 to 2000.
Chapter 5 · Temporal Variations in POP Levels
135
-HCH air concentration, pg/m3
-HCH emissions, kt/ yr
1000
200
Global emissions
Air concentration
800
160
Figure 5·6. Global emissions of -HCH
600
120
and mean concentrations of -HCH in
Arctic air from 1979 to 1996. Air con-
centration data for -HCH in the Arctic
have been measured at different stations
400
80
by several research groups (i.e. Tanabe
and Tatsukawa, 1980; Oehme and
Ottar, 1984; Hargrave et al., 1988; Pat-
ton et al., 1989; 1991; Hinckley et al.,
200
40
1991; Oehme, 1991; Iwata et al., 1993;
Bidleman et al., 1995; Falconer et al.,
1995; Jantunen and Bidleman, 1995;
1996; Oehme et al., 1995c; Pacyna and
0
0
Oehme, 1998).
1979
1985
1990
1995
1998
with air temperature at Alert (Hung et al., 2002b). Con-
another one in 1990. Figure 5·6 shows the long-term
centrations of CHLs also declined at Stórhöfi until
trends in global emissions of -HCH and its mean air
1997 and then increased in 1999. Using digitally filtered
concentrations in the Arctic regions from 1979 to 1998.
data, Hung et al. (2002b) concluded that cis-/trans-chlor-
The trends shown here are similar to those shown by Li et
dane and trans-nonachlor concentrations declined signi-
al. (1998a), who reported technical HCH emissions. By
ficantly at Alert with half-lives of 4.1, 8.3 and 6.2 years,
comparing these two figures, it was found that concentra-
respectively (Table 5·1). These half-lives were compar-
tions of -HCH in the Arctic air are more highly corre-
able (within a factor of 2) to half-lives calculated for
lated with global -HCH emissions than with global tech-
these pesticides at rural sites in the Great Lakes (Table
nical HCH usage (Li et al., 2000; Li and Bidleman, 2003).
5·1) (Simcik et al., 1999).
Li et al., (2001b) also examined the emissions of toxa-
Hung et al. (2002b) concluded that dieldrin concen-
phene in the U.S. and their influence on levels in Arctic
trations did not change significantly from 1993 to 1998
air. Figure 5·7 shows the temporal trends in concentra-
at Alert. Dieldrin concentrations appeared to increase at
tions of toxaphene in Canadian Arctic air and the esti-
Stórhöfi from 1995 to 1999 (Figure 5·5). Dieldrin was
mated emissions of toxaphene from the U.S. from 1985
not reported at the Ny-Ålesund or Pallas stations. Diel-
to 1995. The estimated emissions of toxaphene are, in
drin concentrations were significantly correlated with air
general, consistent with the concentrations of toxaphene
temperature at Alert and typically showed higher con-
in Canadian Arctic air in the summer. The consistency
centrations during summer at both Alert and Stórhöfi.
between toxaphene emissions from agricultural soils in
Concentrations of -endosulfan at Alert increased
over the period of 1993 to 1998 (Hung et al., 2002b).
Toxaphene concentration in air, pg/m3
Unlike the more persistent, now banned, OC pesticides
Toxaphene emissions, tonnes/ yr
discussed above, this is explained by continued use of en-
50
2000
US emissions
Canadian Arctic air concentration
dosulfan in southern Canada and throughout the U.S.
Summer
(NCFAP, 2001).
Winter
;
40
1600
Other OC compounds
Tetrachloroveratrole, a by-product of wastewater and
;
30
1200
wood pulp chlorination also increased in concentration
at Alert (Hung et al., 2002b). PeCA declined in concen-
trations at Alert over the same time period. Time trends
20
800
of other by-products and current-use pesticides meas-
ured at Alert (Section 4.1.1) have not been reported,
mainly due to their low atmospheric concentrations, nor
;;
10
400
have they been studied at other monitoring stations.
Other time series for HCH, toxaphene, and chlordane
0
0
;;
;;
;;
1985
1987
1989
1991
1993
1995
Li et al. (1998a) studied the relationship between the
global trends in use of technical-HCH and air concen-
Figure 5·7. Temporal trends in concentrations of toxaphene in Can-
trations in the Arctic atmosphere by combining data
adian Arctic air and the calculated emissions of toxaphene from the
mainly from short-term measurement campaigns in the
United States from 1985 to 1995. (Sources of air concentration
5.1.1.1.7
data: data for 1986 and 1987, Patton et al. (1989); data for 1988,
Bering Sea, western Canadian Arctic and Svalbard from
Patton et al. (1991); Hinckley et al. (1991); data for 1992, Bidleman
the 1980s and 1990s. Two significant drops in global
et al. (1995); Fellin et al. (1996); data for 1993, de March et al.
technical HCH usage were identified, one in 1983 and
(1998); Macdonald et al. (2000)).
136
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in air, pg/m3
10
Winterspring
Summerautumn
5
cis-chlordane
cis-chlordane
trans-chlordane
trans-chlordane
2
1
0.5
0.2
1984
1986
1988
1990
1992
1994
1996
1998
1984
1986
1988
1990
1992
1994
1996
1998
Figure 5·8. Long-term time trends of trans- and cis-chlordane concentrations in Arctic air during winterspring and summerautumn (from
Bidleman et al., 2002a).
the U.S. and air concentrations of toxaphene in Canadian
trans-nonachlor were combined from literature reports
Arctic regions illustrates that toxaphene residues in the
from numerous monitoring programs beginning with
United States, the southeastern part in particular, could be
measurements in Canada (Alert and Mould Bay) and
the major sources of toxaphene in the Canadian Arctic
Norway (Ny-Ålesund and Jergul) in 1984. Winter spring
atmosphere. Other sources of toxaphene could include
and summerautumn results were grouped and sepa-
countries in other regions, since toxaphene was still in use
rated since previous reports had shown changing ratios
in Russia and eastern Europe during the 1980s (HEL-
of trans- to cis- compounds between these seasons. Sig-
COM, 2001). For example, Bidleman et al. (1987) found
nificant declines for cis- and trans-chlordane were found
that toxaphene reached southern Sweden during 1984/
(Figure 5·8) as well as for trans-nonachlor (not shown).
1985 from eastern Europe and western Russia.
Half-lives in Arctic air for cis- and trans-chlordane, and
Bidleman et al., (2002a) examined temporal trends
trans-nonachlor, were estimated to be 6.4, 9.7 and 6.3
of chlordane compounds in Arctic air over a 14-year pe-
years, respectively, in agreement with estimates of Hung
riod 1984-1998. Results for cis-/trans-chlordane and
et al. (2002b).
Concentration in air, pg / m3
120
PCB
Alert
10
Stórhöfdi
Ny-Ålesund
Pallas
90
Amderma
60
30
0
1993
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
pg / m3
40
40
40
40
40
Alert
Stórhöfdi
Ny-Ålesund
Pallas
Amderma
30
30
30
30
30
20
20
20
20
20
10
10
10
10
10
0
0
0
0
0
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'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
'93 '94 '95 '96 '97 '98 '99 '00
Figure 5·9. Temporal trends of PCB (sum of ten congeners) in Arctic ambient air at five monitoring stations (1993-2000).
Chapter 5 · Temporal Variations in POP Levels
137
Concentration in air (gas phase and particles), pg / m3
5000
PAH 11
Alert
Ny-Ålesund
4000
Pallas
Amderma
3000
2000
1000
0
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
1500
1500
1500
1500
Alert
Ny-Ålesund
Pallas
Amderma
1000
1000
1000
1000
500
500
500
500
0
0
0
0
'94 '95 '96 '97 '98 '99 '00
'94 '95 '96 '97 '98 '99 '00
'94 '95 '96 '97 '98 '99 '00
'94 '95 '96 '97 '98 '99 '00
Figure 5·10. Temporal trends of PAHs (11 compounds) in air (gas phase and particles) at Alert, Amderma, Ny-Ålesund, and Pallas.
showed a clear downward trend, with a calculated half-
5.1.1.2. PCBs
life of only four years (compared to 15 years for CB153).
The time series for PCBs at five air-monitoring stations
It is therefore possible that heavier congeners might be
is shown in Figure 5·9. A sum of ten PCB congeners was
subjected to different removal processes than the lighter
used to represent the time series because the total num-
ones, including scavenging by precipitation.
ber of congeners measured at each station varied (see
Section 4.1.1). The 1992 data from Alert, as well as data
5.1.1.3. PAHs
from Ny-Ålesund (1994 -97), may reflect some on-site
contamination and were therefore not used here or in
Data for two or more years were available only for the
previous studies of the datasets (Stern et al., 1997; Hung
Alert (1994-1998), Ny-Ålesund (1994-1999), and Pallas
et al., 2001). PCB concentrations tend to be elevated in
(1996-1999) stations and, with missing sampling times,
summer at all stations and, like OC pesticides, show
from Amderma (1999-2000). The three longer-term sta-
sharp concentration `episodes' in both winter and sum-
tions determined from 11 to 25 PAH compounds of
mer months. No clear downward trend is evident, ex-
which anthracene, benzo[a]anthracene, benzo[a]pyrene,
cept for Alert, where a distinct reduction in PCB levels
benzo[b,j,k]fluoranthenes, benzo[g,h,i]perylene, chry-
from 1993 to 1998 is apparent. At Alert, penta- and
sene, dibenz[a,h]anthracene, fluoranthene, indeno[c,d]-
hexachlorobiphenyls were significantly correlated with
pyrene, phenanthrene, and pyrene were common to all
air temperature, while di- and trichlorobiphenyls were
measurement programs. Trends for PAH11 at the four
not. The lack of temperature dependence of the less
stations are shown in Figure 5·10. All sites show an
chlorinated congeners suggests that regional/local re-
annual cycle of higher concentrations in the winter
volatilization does not have a marked effect on atmos-
months, especially during November to February, coin-
pheric levels of the predominant PCBs in the Arctic at-
ciding with the dark period at these latitudes and with
mosphere, and emphasizes the importance of long-range
the Arctic haze season. The air sampled at the Ny-Åle-
transport to the Arctic (Hung et al., 2001).
sund and Pallas stations is distinguished from Alert by
Hung et al. (2001) found declining trends for several
significantly higher PAH concentrations in all seasons,
of the lower chlorinated congeners in the High Arctic at-
particularly in winter months, over the period of 1996/7
mosphere at Alert (Table 5·1). The half-lives observed
to 1999. Unlike some OCs, no consistent trends can be
for most of the PCBs at Alert were longer than those ob-
derived from the PAH data at Ny-Ålesund or Alert.
served at a rural site in northern England (Sweetman
Maximum concentrations generally increased from 1994
and Jones, 2000) and at background/rural sites in the
to 1997, but were lower in 1998-1999 than in previous
Great Lakes (Table 5·1) (Simcik et al., 1999). Haugen et
years. Ny-Ålesund also had consistently higher ratios of
al. (1999) did not find an obvious decrease in atmos-
B[a]P : B[e]P, an indicator of reactive versus stable atmos-
pheric levels of PCBs (1992-1995) from Lista in south-
pheric PAH, indicating fresher sources than at Alert.
ern Norway. However, longer time series combined with
B[a]P : B[e]P averaged 2.9 (range < 0.1-10) compared
temperature adjustment would probably be needed to
with an average of 0.4 (range < 0.1-1.7) at Alert. B[a]P
see any such trend. At Alert, CB180 (heptachlorinated)
concentrations at Ny-Ålesund were highest in 1994 and
138
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in air (gas phase and particles), pg / m3
250
B[a]P
Alert
Ny-Ålesund
200
Pallas
Amderma
150
100
50
0
1994
1995
1996
1997
1998
1999
2000
pg / m3
pg / m3
pg / m3
pg / m3
±73.24
45
45
45
45
Alert
Ny-Ålesund
Pallas
Amderma
40
40
40
40
30
30
30
30
20
20
20
20
10
10
10
10
0
0
0
0
'94 '95 '96 '97 '98 '99 '00
'94 '95 '96 '97 '98 '99 '00
'94 '95 '96 '97 '98 '99 '00
'94 '95 '96 '97 '98 '99 '00
Figure 5·11. Temporal trends of B[a]P in air (gas phase and particles) at Alert (Nunavut), Ny-Ålesund (Svalbard) and Pallas (Northern Fin-
land), and Amderma from 1994 to 2000. B[a]P is predominantly found on particles.
declined during the 1990s. During the summer months,
the maximum concentrations of all measured contami-
B[a]P concentrations at Ny-Ålesund and Pallas were
nants occur below the snow surface, indicating that in-
similar to those seen at Alert. However, much higher
puts have declined in recent years (Figure 5·12). The
winter maxima were observed (Figure 5·11). No investi-
contaminant with the highest concentration at any depth
gations of PAH trends similar to those carried out for
is -HCH (12 600 pg/L) followed by -HCH (2780
PCB and OC pesticide data have been made to date.
pg/L), and p,p'-DDT (2710 pg/L) (Matthews, 2001).
These results provide the first detailed picture of deposi-
tion of persistent chlorinated organics in the European
5.1.2. Temporal trends in wet deposition
Arctic. In the only other comparable study, from the
The time series of bulk deposition of PAHs, PCBs, and
Canadian Arctic, Franz et al. (1997) reported OC pesti-
HCHs at Oulanka and Pallas in northern Finland during
cides in snow layers dating from the late 1980s and early
the summers (June to September/October each year)
1990s from the snow core on the Agassiz Ice Cap. The
from 1993 to 2001 (Korhonen et al., 1998; 2002) is
same layers were also analyzed for PCBs (Gregor et al.,
shown in Figure 4·9. Highest deposition values for
1995). Concentrations of all major OC pesticides in sub-
PAHs were observed in 1993. Elevated PCB concentra-
surface layers were about 10 fold lower than in the
tions were found in mid-summer 1994, autumn 1995,
Lomonosovfonna core. Comparison of samples col-
and mid-summer 1998. Highest HCH concentrations
lected on the surface of the Agassiz Ice Cap with subsur-
were observed in mid-summer 1998. Total PCBs in pre-
face layers collected one to two years later and dating to
cipitation at Pallas appear to have declined significantly
the time of original collection at the surface, however,
over the period of 1993 to 2001, while no trend was ev-
showed a 40% to more than 100% decrease following
ident for PAHs or HCHs.
deposition. The greatest decrease was seen for the more
volatile OCs, such as -HCH and -endosulfan. The
loss is thought to be due to changes in surface area as the
5.1.3. Temporal trends in snow cores
deposited snow undergoes metamorphosis, which revol-
5.1.3.1. OC pesticides
atilizes the POPs (Wania, 1997).
Snow and ice samples were collected from the Lomo-
The DDT results in the Svalbard study are unusual,
nosovfonna Ice Cap, Svalbard, to identify the historic in-
both qualitatively and quantitatively. DDT, when manu-
puts of organic industrial contaminants and pesticides in
factured, is 65%-85% p,p'-DDT, and the remainder is
the European Arctic (Matthews, 2001). The upper 38 m
mainly o,p'-DDT with small amounts of other com-
of an ice core, representing approximately the past 70 -
pounds, including p,p'-DDE and p,p'-DDD. In the envi-
80 years, were analyzed for OC pesticides, while shorter
ronment, DDT normally degrades to either DDE (most
cores and pit samples were also analyzed for PCBs. Dat-
common) or DDD. The amount of p,p'-DDT present
ing results are not complete, so only depth is available
relative to total DDT ranges from 62 to 90%, with an
for trend evaluation so far. The ice core results show that
average of 76%. These numbers are very similar to those
Chapter 5 · Temporal Variations in POP Levels
139
Depth, m
0
10
20
30
p,p'-DDE
trans-chlordane
Dieldrin
40 0
5
10
15
20
0
20
40
60
80
100
120
140
0
100
200
300
400
500
Concentration in snow layer, pg/L
Concentration in snow layer, pg/L
Concentration in snow layer, pg/L
0
10
20
30
p,p'-DDT
cis-chlordane
-HCH
-HCH
40 0
1000
2000
3000
4000 0
20
40
60
80 10
100
1000
10 000
100 000
Concentration in snow layer, pg/L
Concentration in snow layer, pg/L
Concentration in snow layer, pg/L
Figure 5·12. OC concentrations in snow cores collected on the Lomonosovfonna glacier in Svalbard (1999). Note: logarithmic scale on HCH graph.
found in the undecomposed technical product (Mat-
most contaminated Arctic rivers (de March et al., 1998).
thews, 2001). The high concentration and proportion of
Overall, these HCH trends are consistent with what has
p,p'-DDT in the Lomonosovfonna ice core relative to
been observed elsewhere in the Arctic in air, where
both degradation products indicate that DDT was trans-
higher concentrations of -HCH were seen in the 1980s
ported from its source to Svalbard without degrading, or
(Li et al., 1998a).
that the much more volatile DDE and DDD evaporated
Dieldrin concentrations are much lower than - and
from the snow surface following deposition. DDT use
-HCH or DDT (Figure 5·12), the subsurface maxima
peaked before or during the 1970s in areas that are the
coinciding with that of p,p'-DDT. The results suggest a
closest source regions to Svalbard such as northwest
steady decline in deposition of dieldrin at Svalbard, prob-
Russia and Scandinavia (HELCOM, 2001). The proxi-
ably since the mid-1970s.
mity of Lomonosovfonna to population centers on Sval-
Total chlordane was present at similar concentra-
bard makes it more susceptible to accumulation of local
tions to dieldrin, but did not show clear subsurface max-
contaminants. Evidence that sediments from an isolated
ima. Chlordane has two major isomers, cis-chlordane
lake near the coal-mining towns of Barentsburg and
and trans-chlordane. The latter is less stable, being sub-
Longyearbyen had high PCBs and PAHs (Rose et al.,
ject to photolysis in the atmosphere and decomposition
2003; Section 4.3.2) lends support to this hypothesis.
in sunlight. The depth profile of the cis- : trans-chlordane
Subsurface maxima of - and -HCH were found at
ratio was consistently less than 1, and thus did not indi-
Lomonosovfonna, although the maxima were in more
cate large-scale degradation of trans-chlordane.
recent deposits than maxima for DDT isomers, cis-chlor-
dane, and dieldrin. - : -HCH ratios in deeper samples
5.1.3.2. PAHs
from Lomonosovfonna suggest some losses of -HCH,
but in more recent samples, the pattern is characteristic
Masclet et al. (2000) reported a high-resolution histori-
of observations in other parts of the world. Samples cov-
cal profile of PAHs on particulate filtered from snow/ice
ering the last 20 years show that the ratio has been de-
cores collected in 1993 at Summit, Greenland. A strong
creasing, which corresponds to the phasing-out of -
seasonal variation was observed, with the highest PAH
HCH-containing technical products and increasing use
concentrations in winter, except for retene (Figure 5·13,
of lindane. Technical HCH, consisting of about 80% -
next page). Retene deposits in snow dated to spring/
HCH and about 15% -HCH was the major form of
summer 1991, corresponded to intense fires in the bo-
HCH released into the environment prior to 1980 (Li et
real forests of Canada and Siberia. PAH deposition cor-
al., 1998a). The HCH isomers were the predominant
related strongly with black carbon showing the same
OCs measured in snow at Svalbard, which is somewhat
seasonal variation. Black carbon has the same source as
unusual because they are also the most volatile. Their
PAHs, from anthropogenic and natural combustion, and
high volatility has led other snow investigators to sus-
its high correlation with PAH suggests a common source
pect high amounts of evaporation of HCH isomers fol-
region. Total PAHs in the snow particulate were not
lowing deposition to the snow surface (Wania et al.,
strongly correlated with sulfate, another indicator of
1999d). If true, the original concentrations of these com-
combustion (e.g., coal burning). However, maxima of
pounds at Svalbard would have been even greater. Lo-
fluoranthene and pyrene concentrations coincided with
monosovfonna concentrations near the surface are simi-
elevated sulfate in four strata indicating common sources.
lar to lake and river water concentrations throughout
Since only the insoluble phase of the snow was analyzed
much of the Arctic. The highest concentrations are simi-
for PAH, the lack of complete correspondence with sul-
lar to the Yenisey River in Russia in 1993, one of the
fate is not surprising. Jaffrezo et al. (1994) found good
140
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Depth, cm
5
Spring
20
1993
35
50
65
Spring
1992
80
95
110
125
Spring
140
1991
155
170
185
200
215
Spring
230
1990
PAHs
Carbon
Retene
245
0
4
8
12
0
2
4
6
8
0
1
2
3
4
5
Concentration in snow, ng/g
Concentration in snow, ng/g
Concentration in snow, ng/g dw
Figure 5·13. PAH concentrations in a snow core from Summit, Greenland, showing the relationship to black carbon and retene (an alkylated
PAH generated in forest fires). Spring time each year is inferred from maximum deposits of calcium. Results adapted from Masclet et al. (2000).
correspondence between sulfate and PAHs in a snow
from rural Great Lakes locations. This might be due to
core from Summit that included the analysis of dissolved
lower temperatures encountered in the Arctic, coupled
and particulate phases. These authors also noted post-
with winter darkness, which will slow both biotic and
depositional declines in concentrations of phenanthrene,
abiotic degradation relative to temperate regions. In the-
fluoranthene, and B[a]P in the snow pack over a four-
ory, global fractionation (Wania and Mackay, 1995), a
year period. In the case of B[a]P, possible degradation by
process whereby chemicals may be latitudinally fraction-
OH radicals produced on the ice and snow surfaces was
ated according to ambient temperature and physical-
suggested as the main loss pathway. In the case of
chemical properties, will have the effect of maintaining
phenanthrene and fluoranthene, volatilization from snow
Arctic air concentrations, while levels in temperate re-
as it undergoes metamorphosis may also occur (Jaffrezo
gions are showing apparent reductions. In support of this,
et al., 1994).
in northwest England at a site much closer to major ur-
ban sources in the U.K., a suite of tri- to heptachloro-
biphenyl congeners have half-lives of 2- 6 years, which is
5.1.4. Conclusions on temporal trends
shorter than those at Alert. The high week-to-week vari-
in air and precipitation
ation of air concentrations at Alert, Ny-Ålesund, and
A sufficiently large dataset now exists to examine tem-
other sites, and the lack of a strong relationship with
poral trends for a number of POPs in Arctic air. Unfor-
temperature indicates that, for the Arctic in general,
tunately, the detailed analysis of the data, which requires
long-range transport is having a marked influence on at-
adjustment for temperature for comparison among sites
mospheric levels, accounting for the large degree of scat-
and with temperate latitude, has been conducted only
ter in the temporal database. This uncertainty will prob-
for data from Alert. The trends appear to be similar at
ably be reduced with longer-term datasets.
Ny-Ålesund, but further study is required.
The unique, long-term datasets for -HCH, toxa-
Comparisons of trends in the Arctic with temporal
phene, and chlordane demonstrate that the atmosphere
trends at rural sites in the Great Lakes show that, after
plays a significant role in the global distribution of both
temperature adjustment, half-lives of most OC pesti-
compounds and responds rapidly to changes in emis-
cides and PCBs are similar overall, considering the as-
sions. Atmospheric long-range transport provides rapid
sociated margin of error, although interesting differ-
dispersion of these OC pesticides from their areas of
ences have been observed. For example, the half-life of
emission (primarily China in the case of HCH, and
-HCH at Alert is five times longer than at two sites in
southern U.S. in the case of toxaphene and chlordane)
the Great Lakes. Outgassing of -HCH from the Arctic
into the Arctic. The results further imply that a reason-
Ocean will buffer the concentrations in the overlying
able estimate of historical air concentrations of HCH
atmosphere at Alert. This process could also explain
isomers and toxaphene in the western Canadian Arctic,
the apparent lack of decline of other OCs with similar
and possibly in the Arctic as a whole, can be inferred
airwater fugacity ratios (e.g., HCB, lower chlorinated
from the global emission data, or emission data for the
PCBs, endosulfan).
major-use area.
The estimated half-lives of tri- to heptachlorobi-
The historical trends of OC pesticides in a snow core
phenyl congeners at Alert were typically longer than those
from Svalbard provide the first insights into the histori-
Chapter 5 · Temporal Variations in POP Levels
141
cal inputs to the European Arctic. Unfortunately, direct
5.3. Freshwater environment
comparisons with previous snow core work on the
Agassiz Ice Cap on Ellesmere Island (de March et al.,
5.3.1. Water and sediments
1998; Macdonald et al., 2000) are not possible because
Russian river water and sediment
that core was analyzed only for PCBs (Gregor et al.,
Monitoring data on OC pesticides in river water from
1995) and PAHs (Peters et al., 1995). The results for
the 1980s and early to mid-1990s have recently been
DDT at Svalbard suggest a local source, possibly the
published (Gordeev and Tsirkunov, 1998; Petrosyan et
mining towns within 50 km of the glacier. The dates of
al., 1998; Alexeeva et al., 2001; Zhulidov et al., 2002).
deposition are also unknown at present. However, max-
This permits a historical perspective of pesticide load-
imum deposition of DDT around 1970 suggests that
ings to Russian northern seas. Gordeev and Tsirkunov
maximum deposition of HCH isomers and dieldrin was
(1998) summarized the estimated fluxes of HCHs and
reached post-1970 (Matthews, 2001). For HCH, this is
DDTs for 32 rivers in Russia including 11 flowing to
consistent with use in the northern hemisphere which
the Arctic Ocean. To obtain fluxes, they used annual
peaked in the 1980s based on concentrations in Arctic
arithmetic mean concentrations, summarized by Petro-
air (Macdonald et al., 2000) and global use patterns (Li
syan et al. (1998), and river discharges taking into ac-
et al., 1998a; Li, 1999b). In the case of PAHs in snow
count seasonal variability in flows. Alexeeva et al.
cores at Summit, Greenland, and the Agassiz Ice Cap,
(2001) used a similar approach to estimate fluxes for the
there is a clear linkage to combustion sources in the mid-
same pesticides for the period of 1990 to 1996. They
latitudes of North America and Eurasia.
used monitoring data from the regional laboratories of
Overall, the results for the depositional profiles of
ROSHYDROMET and thus, used data from the same
the OC pesticides and PAHs in glacial cores appear to
pesticides monitoring program that Gordeev and Tsirku-
have better temporal resolution than Arctic sediment
nov's (1998) study used. The combined results (Figure
cores, reflecting high annual deposition rates compared
5·14) show a general decline in loadings of HCH and
to most Arctic lakes or marine sediments. The post-de-
DDT isomers over the period of 1981 to 1996, coincid-
positional volatilization of semi-volatile organics such
ing with the reduction in use of HCH in Russia follow-
as HCH, HCB, and phenanthrene from snow as its
ing conversion to use of lindane, and the complete cessa-
density increases and its surface area decreases, may,
tion of agricultural use of DDT in the 1970s.
however, confound the interpretation of temporal
Zhulidov et al. (2002) reported temporal trends of
trends. Further study is needed to understand the basic
DDTs (p,p'-DDT, DDE, and DDD) and HCHs ( -
processes governing the fate of semi-volatile organics in
and -isomers) in water and sediments from eight Rus-
snow.
sian Arctic rivers for the period of 1988 to 1994. OC
levels in burbot liver were also determined from the
same rivers (Section 5.3.4). DDT was not detected in
5.2. Terrestrial environment
any sediment, and DDE and DDD were only detected in
A number of temporal-trend datasets for the terrestrial
sediments of three rivers. DDD was not detected in river
Arctic were reported in the previous AMAP POPs as-
water, and DDT and DDE were only present in North
sessment (de March et al., 1998), but none of these pro-
Dvina and Pechora River water. However, the detection
grams have been continued. This is likely due to the low
limits for the methods used were relatively high in both
levels found in this environment. Consistent with studies
in the freshwater and marine systems, levels of OCs
Flux, tonnes/ yr
100
were found to be decreasing in the terrestrial environ-
1981-85
DDTs
ment prior to 1996.
;
;;
1986-90
10
One temporal-trend dataset that was not reported in
1990-96
the previous AMAP assessment examined OCs in Alas-
1 ;;
;;;
;
;
;;
kan peregrine falcons from 1979 to 1995 (Ambrose et
al., 2000). Dieldrin, p,p'-DDE, heptachlor epoxide, oxy-
0.1
chlordane, and total Aroclor PCBs were consistently de-
;
;;
;
;;
;;
;
;;
;;
tected and measured, and were tested statistically for re-
0.01
lationships with time and productivity. Mirex was only
100
measured from 1988 to 1995, but was detected in all
;
;;
;
;;
;;
;
;;
;;
1981-85
HCHs
samples. HCB, p,p'-DDD, p,p'-DDT,
-HCH, and
1986-90
10
1990-96
trans-nonachlor were detected in >50% of samples, but
;;;
;
;;
;;
;;
;;
;
were not tested for relationships with time or productiv-
1
ity because they were not consistently analyzed. -HCH,
-HCH, cis-chlordane, trans-chlordane, o,p'-DDD, o,p'-
0.1 ;;;
;;
;;;
;;
;;
;;
;;;;
;;;
DDE, o,p'-DDT, endosulfan II, and endrin were detected
in < 50% of samples, and because of the large propor-
0.01
Ob
tion of data below detection limits, none were tested for
;;;
;;
;;;
;;
;;
;;
;;;;
;;;
Lena
Onega
Mezen
Kolyma
time or productivity relationships. The five persistent
Pechora
Yenisey Olenek
OC contaminants that were consistently measured (diel-
drin, p,p'-DDE, heptachlor epoxide, oxychlordane, total
Severnaya Dvina
Figure 5·14. Temporal trends in fluxes of DDTs and HCHs in
PCBs) declined significantly from 1979 to 1995, but the
major rivers flowing in the Russian northern seas for the periods
trend was weaker for total Aroclor PCBs than other con-
1981-1985, 1986-1990, and 1990-1996 (from Gordeev and Tsir-
taminants.
kunov (1998) and Alexeeva et al. (2001)).
142
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration, ng/g dw
Concentration, ng/L
8
20
Sev. Dvina
DDTs, bottom sediments
DDTs, water
Mezen
18
7
Pechora
Sev. Dvina
16
6
14
Pechora
5
12
4
10
8
3
6
2
Ob
4
Yenisey
Ob
Pyasina
1
Lena
Yenisey
2
Pyasina
Lena
0
0
Concentration, ng/g dw
Concentration, ng/ L
6
Sev. Dvina
12
HCHs, bottom sediments
Pechora
HCHs, water
Mezen
5
10
Pechora
Sev. Dvina
4
8
Ob
Ob
3
6
Yenisey
Yenisey
Lena
Lena
2
4
Pyasina
Pyasina
1
2
0
0
1988
1989
1990
1991
1992
1993
1994
1988
1989
1990
1991
1992
1993
1994
Figure 5·15. Temporal trends in concentrations of DDT and HCH isomers in water and sediments from major rivers flowing into the Russian
northern seas for the periods 1988 to 1994 (Zhulidov et al., 2002).
sediment and water. Both HCH isomers ( - and -) were
`direct' input from non-atmospheric sources, and dyna-
detected in all river sediments except Kolyma River and
mic lake processes including bioturbation, sediment fo-
in water from all rivers. Concentrations of both DDT
cusing, and re-suspension. Factors unique to Arctic lakes,
and HCH declined significantly over the period of 1988
such as long periods of ice cover and low sedimentation
to 1992 and were near detection limits for all chemicals
rates, may limit inputs to bottom sediments and make
in most rivers by 1992 (Figure 5·15).
them a less significant reservoir for hydrophobic organ-
ics than temperate lakes (Macdonald et al., 2000).
Dated sediment cores from Canadian Arctic lakes
Additional sediment cores collected in the Canadian
Outside of the Arctic, analysis of dated sediment cores
Arctic in the mid- to late 1990s have been analyzed for
has been used to infer the depositional history of POPs
POPs since the previous AMAP assessment (Lockhart,
in the Great Lakes region (Jeremiason et al., 1994; Wong
1997; Lockhart et al., 1997; Macdonald et al., 2000;
et al., 1995; Pearson et al., 1998) and in European
Stern and Evans 2003; Muir et al., 2002b; Rose et al.,
alpine lakes (Fernandez et al., 1999; 2000; Grimalt et
2000). Undated cores were also analyzed from Bjørnøya
al., 2001). The previous AMAP POPs assessment in-
(Kallenborn, 2002b). However, there were no cores re-
cluded results for PCBs and PCDD/Fs in Arctic sediment
ported from other circumpolar countries.
cores from Alaska, Canada, and Finland. These cores all
A series of cores in the Yukon (western Canadian
showed a later onset of PCB deposition than that ob-
Arctic) were analyzed for PCBs and OC pesticides (Rawn
served in most lakes closer to sources, as well as maxi-
et al., 2001). DDT was found to be the most prominent
mum inputs near or at the surface, indicating continuing
OC in the sediment profiles of most of the lakes. Maxi-
inputs from atmospheric deposition. Further analysis of
mum DDT levels (0.86 ng/g dw to 21.4 ng/g dw) were
the data from Canadian lakes showed that lower chlori-
observed in sediment slices dated to the 1950s from
nated PCBs predominated in High Arctic cores, while
lakes (Lake Laberge and Fox Lake) near populated areas,
sediments from temperate lakes had higher proportions
(Figure 5·16), as well as in Watson Lake (not shown). In
of Hx-, Hp- and OcCBs (Muir et al., 1996a). The sedi-
contrast, in more remote lakes (Hanson and Lindeman
ment records from Arctic lakes, therefore, can provide
Lakes), maximum DDT concentrations were observed
information on temporal trends of deposition of these
in sediments dated to the 1980s and 1990s, similar to
hydrophobic contaminants in the Arctic. However, in-
other Arctic lakes (Muir et al., 1995a). The sediment
terpretation of sediment records can be complicated by
profiles from lakes situated near populated areas and
Chapter 5 · Temporal Variations in POP Levels
143
Fox Lake
Hanson Lake
Lake Laberge
Lindeman Lake
Median age
of slice
;;;;
;;
1990
;;;;;;;;;
;;;
;;
;;
;;;;;
;;
;;;
;;
;;
;;
;;;
;;;
;;;;;;;
;;;;;
1980
;;;
;;
;;;;;
;;;;;;
;
;;;;;
;;;
not analyzed
;;
;;;;;;
;;;;;;
;
1970
not analyzed
;;
;;;
;;;;;;
;;;
;;;;
;;;
;;;
;;
;;;;;
1960
not analyzed
;;;
;;
;;
;;;;;
;;
;
;;
;;;;;
1950;;
;
;;
;;;
;;
;;
not analyzed
;;
;;;
;;
;;
;;
;;;
;;
;;
;;
1940
;;;
;;
;;
;;;
;;
;;
1930
;;;
;;
;;
;;;
;;
;;
;;
1920;;
;;
;;
<1900
;;
;;
;;
0
10
20
30
40 0
10
20
30
40
0
10
20 0
10
Concentration in sediment, ng/g dw
Fox Lake
Hanson Lake
Lake Laberge
Lindeman Lake
1990
1980
not analyzed
1970
not analyzed
1960
not analyzed
1950
not analyzed
1940
1930
1920
<1900
0
5
10 0
5
10
0
5
10
15
20
0
0.5
1.0
Concentration in sediment, ng/g dw
;;;;;;
;;;;;;
TriCBs
Penta-hexaCBs
Other
PCB homologues
p,p'-DDE
p,p'-DDD
p,p'-DDT
Figure 5·16. Historical profiles of PCBs and DDT-related compounds in four lakes within the Yukon River watershed (Rawn et al., 2001),
5.3.1.3
two remote lakes (Hanson, Lindeman) and two lakes nearer to populated areas (Fox, Laberge).
144
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
along the Alaska Highway in the Yukon indicate PCB
lakes located in Alberta, Canada (Miskimmin et al.,
and DDT contamination has occurred mainly from lo-
1995; Stern et al., 1996), but not in remote lakes ex-
cal usage and waste disposal, rather than long-range
posed only to atmospheric sources (Muir et al., 1999a;
transport and deposition. The onset of appearance and
Rose et al., 2001). B6-923 and B7-1001 are formed via
maximum concentrations and fluxes of PCBs and
anaerobic reductive dechlorination of other, less stable,
DDTs are similar to cores from southern Canada, and
chlorobornanes present in the technical mixture but not
coincide well with the use profile of these chemicals
generally in air (Vetter et al., 1999). The toxaphene
in North America in general, and with the known his-
profile in Watson Lake (Figure 5·17) is not entirely con-
tory of use in the Yukon as well. The historical profile
sistent with what would be expected based solely on at-
of PCBs and DDTs in most of these Yukon sediments
mospheric deposition (i.e. peak levels occurring in the
is quite different from sediments in the High Arctic,
early to mid-1970s). The higher subsurface levels of
where delayed onset has been found (Muir et al.,
toxaphene congeners B6-923 and B7-1001 (Stern and
1996a). Even in the remote, glacier-fed Lindeman Lake,
Evans, 2003) and the overlap of the toxaphene and
the lower chlorinated PCB congeners made relatively
DDT historical concentration profiles, suggest that
small contributions to PCBs. This may be due to
toxaphene usage in the Watson Lake area occurred
volatilization losses of the lower chlorinated congeners
prior to the banning of DDT, possibly for use as a fish
from melting snow and flowing glacial streams (Mac-
toxin or as an additional active ingredient in the insecti-
donald et al., 1999; Blais et al., 2001). The results sug-
cidal DDT mixtures.
gest that glacial runoff is a significant source of OCs to
A laminated core from a lake on Devon Island (Nu-
small high-elevation lakes (Lindeman Lake) but not to
navut) has been analyzed for a wide array of OC com-
larger lakes within the Yukon River drainage basin
pounds (Figure 5·18). The laminations are due to annual
which are also affected by glacial sources (Lake La-
layers of sediment, with differing color or texture. These
berge, Kusawa Lake).
form detectable laminations that can be counted. This is
Historical deposition of toxaphene in five Yukon
the first laminated core analyzed for POPs in the Arctic
lakes is shown in Figure 5·17. Elevated toxaphene lev-
and provides an unusual degree of temporal resolution
els had been found in fish tissues from several of the
compared to most other cores from the High Arctic.
large lakes in the Yukon River Basin system (Kidd et al.,
DDT concentrations peaked between the mid-1950s
1993; 1995), and thus, the source of toxaphene was of
and early 1970s. An increase in toxaphene was first ob-
interest. Sediment core results confirm that the source is
served in the early 1970s, reaching a maximum in the
mainly atmospheric rather than local. The exception is
1980s. These results are consistent with the known his-
Hanson Lake which was treated with toxaphene in
torical usage of DDT and toxaphene in North America
1963 (Walker et al., 1973). The toxaphene congeners in
(Voldner and Li, 1995; Li et al., 2001b).
this lake consist almost entirely of a hexa- (B6-923) and
Concentration profiles for total PCDD/Fs in a sec-
heptachlorobornane (B7-1001) (these have no Parlar
ond sediment core from Lake DV09 on Devon Island,
numbers). These same two congeners were also pre-
normalized to organic carbon, are also shown in Figure
dominant in the sediment of two toxaphene-treated
5·18 (Stern and Evans, 2003). PCDF levels start to in-
Lake Laberge
Fox Lake
Lake Kusawa
Hanson Lake
Watson Lake
Median
age of
slice
1990
1980
1970
1960
1950
1940
1930
1864
1890
0
0.2
0.4
0.6
0.8 1.0 0
1
2
3
4
5 0
0.2 0 0.4 0 0.6 0 0 020000400006000080000 0 1 2 3 4 5 6 7 8 9
Toxaphene concentration in sediment, ng/g dw
Figure 5·17. Concentration profiles of toxaphene in sediment cores from five Yukon lakes. Elevated concentrations in Hanson Lake are the
result of application of toxaphene to this lake in 1963. The curves correspond to the atmospheric input functions for toxaphene derived by
Rapaport and Eisenreich (1988) from peat cores.
Chapter 5 · Temporal Variations in POP Levels
145
Core slice
Core slice
0
0
1997
1997
2
1992
2
1992
1987
1987
1980
4
4
1980
1970
1970
6
1961
6
1961
1956
1956
1953
8
8
1953
1943
1949
1949
10
10
1937
1937
12
1931
12
1931
14
1918
14
16
DDTs
Toxaphene
1900
16
18
18
0
2
4
6
8
10
12
14
0
20
40
60
80
100
120
0
0
1997
1997
1997
1992
2
1992
2
1986
1992
1987
1986
4
1980
4
1978
1978
1970
1970
1961
1963
1970
6
6
1963
1956
1956
1956
8
8
1950
1949
1953
1950
Furans
1945
1943
1945
1938
10
10
1938
1937
1930
12
1931
12
1923
Dioxins
1917
14
SCCPs
14
1909
16
16
18
18
0
200
400
600
800
1000
0
0.050
0.100
0.150
0.200
0.250
0.300
Concentration in sediment, ng/g organic carbon
Concentration in sediment, ng/g organic carbon
Figure 5·18. Concentration profiles of DDT, toxaphene, SCCPs, and PCDD/Fs in dated, laminated cores from Lake DV09 on Devon Island,
Nunavut, Canada. Concentrations are in ng/g organic carbon.
crease in the early 1950s, peak at 0.27 ng/g organic
Sediment cores from lakes on Bjørnøya
carbon in 1978, and are dominated by the TCDF ho-
Sediment cores were taken from two small lakes (El-
mologue group, in particular the 1,2,4,8-TCDF con-
lasjøen and Øyangen) on Bjørnøya, approximately half
gener. PCDD levels start to increase about ten years
way between Norway and Svalbard, in 1996 for OC
earlier but also peak in 1978. Between 1938 and 1963,
analysis as part of a larger study (see Section 4.3.5).
sediment core slices were dominated by octachlori-
PCB7 concentrations decreased downward in the sedi-
nated dibenzo-p-dioxin (OCDD) (64 ± 9 %). This ho-
ment to 0.5 and 0.4 ng/g dw at 13 -15 cm in Ellasjøen
mologue profile is consistent with a signature resulting
and Øyangen, respectively (Figure 5·19). In Ellasjøen,
from usage of pentachlorophenol as a wood preserva-
DDTs was 6.9 ng/g dw in surface sediment, of which
tive. OCDD is the major impurity in the PCP technical
p,p'-DDE comprised about 90%. In Øyangen, the corre-
mixtures and can also be formed by photolytic degra-
dation of PCP (Crosby et al., 1981). From 1970 to
Depth in sediment core, cm
1992, the PCDD/F profiles are indicative of signatures
Ellasjøen
arising from combustion of coal and wood (Kjeller et
0-1
al., 1996).
Øyangen
The DV09 core was also analyzed for SCCPs (Figure
1-2
5·18). Maximum concentrations occur in the surface
sediment and in the core slice dated to 1956. Maximum
2-3
usage of SCCPs occurred much later, probably between
1978 and 1985 (Muir et al., 2000a), and thus, the his-
torical profile in this core is not consistent with histori-
cal usage or historical profiles in other lakes (Tomy et
PCB
13 -15
7
al., 1999). Shorter carbon chain length and lower chlori-
nated C10 and C11 formula groups become more pre-
0
10
20
30
40
50
60
dominant downward in the core, suggesting microbial
Concentration in sediment, ng/g dw
degradation of the longer chain, more highly chlorinated
Figure 5·19. PCB7 concentrations in sediment cores sampled from
compounds, over time, and/or that the earlier emissions
the lakes Ellasjøen and Øyangen on Bjørnøya in July, 1996 (Even-
had higher proportions of more volatile SCCPs.
set et al., 2002).
146
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
PCBs in muscle, µg/g lw
DDTs in muscle, µg/g lw
6.0
0.6
3.0
Storvindeln, pike
Abiskojaure, char
Storvindeln, pike
Abiskojaure, char
5.0
0.5
2.5
4.0
0.4
2.0
0.20
3.0
0.3
1.5
0.15
2.0
0.2
1.0
0.10
1.0
0.1
0.5
0.05
0
0
0
0
1970
1980
1990
1900
1980
1990
2000
1970
1980
1990
2000
1980
1990
2000
0.23
-HCHs in muscle, µg/g lw
Lindane in muscle, µg/g lw
Storvindeln, pike
Abiskojaure, char
Storvindeln, pike
Abiskojaure, char
0.10
0.12
0.08
0.10
0.08
0.06
0.06
0.06
0.06
0.04
0.04
0.04
0.04
0.02
0.02
0.02
0.02
0
0
0
0
1970
1980
1990
2000
1980
1990
2000
1970
1980
1990
2000
1980
1990
2000
HCB in muscle, µg/g lw
0.10
Storvindeln, pike
Abiskojaure, char
Figure 5·20. Temporal trends in levels of PCB, DDT, -HCH, -
HCH (lindane), and HCB in muscle from pike and char from the
0.08
Swedish lakes Storvindeln and Abiskojaure, respectively. Symbols
and vertical bars represent geometric mean concentrations and as-
0.06
sociated 95% confidence intervals. Symbols without vertical bars
represent single pooled samples. Dashed horizontal lines represent
the overall geometric mean level. The trend, over the entire period
0.04
0.04
of sampling and in some cases the period 1990-2000, is shown by a
log-linear regression line (black lines, plotted if p < 0.10, two-sided
0.02
0.02
regression analysis). Red lines show a three-point running smoother
applied to test for non-linear trend components if p < 0.10. Source:
0
0
A. Bignert, 2001, pers. comm.).
'70
'80
'90
2000
'80
'90
2000
sponding numbers were 0.8 ng/g dw and 63%, respec-
freshwater fish have declined significantly since the late
tively. The concentrations at 13-15 cm were 0.05 ng/g
1960s into the 1990s (Figure 5·20 and Table 5·2). How-
dw in Ellasjøen and 0.2 ng/g dw in Øyangen. These re-
ever, the rates of decline have slowed in the 1990s, and
sults imply that loadings of PCBs and DDT have been
no significant decline has been observed for the past ten
increasing in these systems, which is not consistent with
years. The concentrations of PCBs and DDTs have
other temporal trends in the Arctic. The sediment slices
been decreasing at a rate of approximately 3 -7% and
were not dated, however, and therefore, caution is
10% per year, respectively, in all investigated time series
needed regarding these trends.
(i.e. both southern and northern Sweden and in both
species of fish). Since the monitoring began in 1967/68
for pike and 1981 for Arctic char, the temporal trend is
5.3.2. Temporal trends in fish
long enough to be able to detect a change of this magni-
in northern Scandinavia
tude. For the last ten years, the decreasing trends in
In 1967, a Swedish program was initiated to monitor
PCBs seem to have slowed in the northern parts of Swe-
PCB, DDT, HCB, and HCH levels in fish from areas that
den, as no significant decreasing trends are found for
had little or no known point sources of pollution (Ols-
these years (Table 5·2). For DDT, over the past ten years,
son and Reutergårdh, 1986; Olsson and Bignert, 1997).
the decreasing trends have leveled off in the southern
Muscle samples from 20 northern pike have been col-
parts of Sweden, but continued at approximately the
lected every year since 1967 from Lake Storvindeln, a
same annual rate (8 -14%, significant decrease) in the
forest lake near the Swedish Alps occupying an area of
northern parts.
55 km2. Beginning in 1980, muscle samples from 20
HCH levels have decreased rapidly during the stud-
Arctic char have been collected from the the lake Abis-
ied time period, more than 10% annually, following the
kojaure (Àbeskojávre), 200 km north of the Arctic Cir-
bans and restricted use of technical HCH and lindane in
cle. Efforts have been made to collect specimens that are
countries neighboring Sweden. The concentrations in
of similar sex, age, size, and in the same sampling sea-
Swedish freshwater biota are now below or close to the
son. This program has yielded an unparalleled temporal-
detection limit (during recent years all samples have
trend dataset for OCs in the Arctic and subarctic.
been below). A significant decreasing trend is also found
As was reported in the previous AMAP POPs assess-
for the last ten years in the northern part of Sweden. The
ment (de March et al., 1998), levels of OCs in Swedish
high peak for lindane in pike from Lake Storvindeln dur-
Chapter 5 · Temporal Variations in POP Levels
147
ing 1977-1978 is, as yet, unexplained. HCB concentra-
Fort Good Hope burbot
tions have decreased at a rate of approximately 5% per
POPs were measured in the livers of burbot collected at
year, but northern pike have shown a nearly significant
Fort Good Hope, NWT, in 1988 and 1999 to examine
(p < 0.1) increasing trend over the past ten years.
temporal trends of OCs (Stern et al., 2001a). Significant
The comprehensive nature of this dataset, comprised
declines, 2.0- and 3.1-fold, were observed for both -
of many samples and time points covering a long time
and -HCH over this 11-year time period. -HCH con-
period, provides an invaluable tool in assessing the time
centrations were below the detection limit in all samples.
trends of OCs in the European Arctic. Olsson and Big-
Interestingly, the - : -HCH ratio has increased from
nert (1997) found that the annual rate and the onset of
4.5 to 6.9, which is opposite to what one might have ex-
the decline (1971-1972) in concentrations of DDT com-
pected based on the decreased usage of the technical
pounds did not differ between the Arctic and other re-
mixture ( -HCH (60 -70%), -HCH (5-12%), and -
mote areas of northern Sweden, or between the southern
HCH (10 -15%)) and the corresponding increase in the
parts of the Baltic Sea and lakes in the southern part of
usage of lindane in western Canada since the early
the Swedish mainland. The results of this program have
1990s (Waite et al., 2001; Li and Bidleman, 2003). This
demonstrated that the banning and reduction of use of
is likely due to the ability of the burbot to more effi-
ciently degrade the - compared with the -isomer. The
Table 5·2. Mean annual rate of change (%) in concentrations in
-isomer is generally found to be the most easily de-
pike and Arctic char in two lakes in northern Sweden.
graded in biota (Moisey et al., 2001). DDT concentra-
Species: Pike
Arctic
char
tions did not change over this 11-year time interval;
Location:
Storvindeln Abiskojaure
however, a 1.8-fold decline and a 2.2-fold increase in the
concentration of p,p'-DDT and its metabolite, p,p'-DDE
Annual change (%)
Annual change (%)
(not age adjusted), respectively, was observed. These
OC
1967-1999 1990-1999
1980-1999 1990-1999
changes translated into a significant increase in the p,p'-
DDE :
DDT
10
8.3
9.9
14
DDT ratio from 0.39 to 0.60 and suggests `old'
PCB
4.1
4.1
6.7
6.0
rather than recent DDT inputs. Overall, a 1.7-fold
-HCH
11
10
17
decline in the lipid-adjusted mean concentrations of
-HCH
3.4
15
CHLs was observed. Oxychlordane, the principal me-
HCB
4.8
5.4
5.0
5.5
tabolite of cis- and trans-chlordane, and second only to
trans-nonachlor as the most abundant chlordane-related
OCs in much of the world has resulted in significant de-
residue in the Fort Good Hope burbot liver, did not
clines in Arctic biota. However, in recent years this re-
change significantly over this 11-year period. The de-
duction has slowed, suggesting that residual sources of
creasing trans- : cis-CHL ratio suggests `old' rather than
OCs are likely to continue to contaminate Arctic biota
recent chlordane inputs. TrCB concentrations have in-
for some time to come.
creased 2.9 fold, while all other PCB homologue groups
have either declined in concentration or did not change
significantly. PCB levels declined 1.3 fold. No signifi-
5.3.3. Temporal trends in freshwater fish
cant differences were observed in levels of nPCBs 77, 81
in the North American Arctic
or 169. CB126 levels decreased 1.8 fold. Toxaphene and
A number of temporal-trend datasets for OC pesticides
dieldrin concentrations decreased by 1.7 and 1.5 fold,
and PCBs are now available for North American Arctic
respectively.
freshwater fish. These datasets are of much shorter
Combining the OC data generated for burbot by Stern
length, and comprise fewer sample collections compared
et al. (2001a) with previously published data for burbot
to the monitoring studies currently being carried out in
at Fort Good Hope (Muir et al., 1990a; Muir and Lock-
Sweden (Section 5.3.2). Therefore, they lack the statisti-
hart, 1996), which includes the years 1986, 1988, and
cal power to make conclusive statements about temporal
1994, provides a longer-term dataset (Figure 5·21). The
trends of OCs, but they do provide some insights. Most
results from 1988 reported by Stern et al. (2001a) are
of these studies do not include data prior to 1990. A
much lower than those reported previously (Muir et al.,
number of studies can be combined to provide better in-
1990a) and are excluded. Slow declines in all of the
sight into temporal trends. No definitive pattern emerges,
major OC groups and toxaphene are observed in the
but in general, OC concentrations appear to be decreas-
Fort Good Hope burbot, although the rate of change
ing in freshwater fish.
varies with the chemical and the period concerned.
Concentration in burbot liver, ng/g ww
200
Fort Good Hope, NWT
CBz
HCHs
CHLs
150
DDTs
PCBs
Toxaphene
100
50
Figure 5·21. Trends in concentrations
of major OC groups in liver of bur-
bot at Fort Good Hope, NWT, Can-
0
ada (1986-1999).
1986
1988
1994
1999
148
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration, ng/g ww
Lake Laberge
5.3.4. Temporal trends in fish in the Russian Arctic
DDT
Burbot, liver
PCB
4000
Zhulidov et al. (2002) studied temporal trends of
Toxaphene
DDTs and HCHs in burbot livers collected from eight
3000
Russian north-flowing rivers from 1988 to 1994. Three
DDT isomers (p,p'-DDT, DDE, and DDD) and two
HCH isomers ( and ) were measured. Levels in sedi-
2000
ment and water were also assessed from the same rivers
(Section 5.3.1). DDTs (up to 70 ng/g ww) and HCHs
1000
(up to 18 ng/g ww) both declined significantly in burbot
liver between 1988 and 1994 (Figure 5·23) in parallel
0
1990
1993
1996
1999 2000 2001
with declines in river water. The magnitude of the de-
clines for DDTs in burbot was up to 10 fold depending
600
on the river system, and much more rapid than observed
Lake trout, muscle
in burbot from the Mackenzie River (Canada) over the
same period. This may reflect the response to the rela-
400
tively recent cessation of DDT use within some of the
watersheds, and in Russia in general (see Section 2.3.1).
A 3- to 4-fold decline was seen for HCHs in burbot
from the eight Russian rivers, which is similar to the de-
200
cline in HCHs in burbot in the Canadian Arctic.
0
5.4. Marine environment
1993
1996
2000 2001 2002
5.4.1. Temporal trends of TBT effects
Figure 5·22. Concentrations (mean ± 1 SD) of DDT, PCBs, and
in invertebrates
toxaphene in liver of burbot and muscle of lake trout from Lake
Laberge, Yukon, Canada (1990-1999).
There is only a limited amount of information concern-
ing temporal trends in TBT and its effects on subarctic
Lake Laberge lake trout and burbot
and Arctic biota. The only available information on ef-
Combining data from a number of studies on OCs for
fects within the AMAP area is for imposex (i.e. the de-
burbot and lake trout from Lake Laberge also allows an
velopment of a penis and vas deferens in female marine
examination of temporal trends spanning almost twelve
snails). This occurs only within neogastropods (Mollusca)
years (Muir and Lockhart, 1992; Kidd et al., 1998; Stern
and has been examined in dogwhelks.
et al., 2000; Palmer and Roach, 2001; Ryan et al., 2003).
Svavarsson (2000) studied imposex in dogwhelks in
Levels of DDT and toxaphene in lake trout from Lake
southwestern, western, and northwestern Iceland in 1998,
Laberge declined between 1993 and 2002 by approxi-
and compared the imposex levels to those reported from
mately 86% and 55%, respectively (Figure 5·22). Al-
Iceland in 1992-1993 by Svavarsson and Skarphéins-
though PCB levels also appear to have declined consid-
dóttir (1995). There has been a substantial decline in the
erably (approx. 85%) since 1993, the high variability in
level of imposex in dogwhelks in Icelandic waters since
the samples over this period has resulted in a marginally
1992/1993. At 24 of the 31 studied localities in Iceland,
insignificant statistical result (p = 0.06). Lipid levels in
the Vas Deferens Sequence Index (VDSI) was lower in
lake trout also show a significant decrease since 1993,
1998 than in 1992-1993 (Svavarsson, 2000). At one site,
which may account for some of the decrease in contami-
the species was extinct, at five sites the index was higher
nants. This decline is in contrast to that observed in bur-
in 1998 than previously, and at one site, no change had
bot collected in Lake Laberge, which showed no decline
occurred. The most pronounced changes occurred near
in DDT and PCB concentrations in liver between 1990
large harbors, such as Reykjavík and Hafnarfjörur
and 1999 (Figure 5·22). However, a significant decline
harbors, where effects had been previously most pro-
in toxaphene concentrations in burbot (approx. 57%)
nounced. Changes were also evident in the Relative Pe-
was observed between 1993 and 2001 (Figure 5·22). Lake
nis Size Index (RPSI) at both small and large harbors.
Laberge burbot liver displayed only a marginal decrease
Similar imposex declines have been seen in dog-
in fat content, which may be attributed to sampling
whelks in Norway just south of the AMAP area (Følsvik
variation (spring and summer fish). Studies on the Lake
et al., 1999). No evident improvements have, however,
Laberge system continue (Stern et al., 2001b).
occurred in northern Norway (Green et al., 2002) and in
the Faroe Islands (FEA, 2002). Among eight studied
Great Slave Lake burbot and lake trout
sites in northern Norway, the VDSI levels were high
OC data spanning six years (1993-1999) in burbot and
(greater than 3) at six of these stations. Some improve-
lake trout are also available for Great Slave Lake (Evans
ment may have occurred at two stations, but the situa-
and Muir, 2000; 2001). No clear trend emerges for
tion was worse at one station (Green et al., 2002). In the
PCBs in either species using lipid-normalized data, but
Faroe Islands, no improvements were seen at the studied
CHLs, DDTs, and toxaphene do appear to be de-
sites, apart from possibly one site (Kirkjutangi) (FEA,
clining slowly (see Annex Table 7). These conclusions
2002). The study sites were few, and most had been ob-
should be used with caution, because no effort has been
served previously to have both high VDSI and RPSI in
made to correct for biological variables such as size or
dogwhelk. The latter is high only where tissue levels of
growth rate.
TBT are very high.
Chapter 5 · Temporal Variations in POP Levels
149
Concentration in burbot liver, ng/g ww
Concentration in burbot liver, ng/g lw
400
70
DDTs, whole liver
DDTs, total lipid
60
Pechora
Pechora
300
50
40
200
Ob
30
Sev. Dvina
Ob
Sev. Dvina
Mezen
20
100
Mezen
Yenisey
Lena
Yenisey
Kolyma
Lena
10
Kolyma
Pyasina
Pyasina
0
0
Concentration in burbot liver, ng/g ww
Concentration in burbot liver, ng/g lw
20
80
HCHs, whole liver
Sev. Dvina
HCHs, total lipid
Pechora
Pechora
15
60
Mezen
Sev. Dvina
Mezen
Kolyma
Yenisey
10
Yenisey
40
Kolyma
Lena
Lena
Pyasina
Pyasina
Ob
5
20
Ob
0
0
1988
1989
1990
1991
1992
1993
1994
1988
1989
1990
1991
1992
1993
1994
Figure 5·23. Temporal trends in concentrations of DDTs and HCHs in liver of burbot from major rivers flowing into the Russian northern
seas for the periods 1988 to 1994 (Zhulidov et al., 2002). Results are reported on a wet weight and lipid weight basis.
The declines in imposex seen in Iceland and southern
(FEA, 2002). Although the results do not indicate any
Norway have been related to restrictions implemented in
major changes over the five years from the first to the
Iceland and Norway on the use of TBT on vessels
second sampling period, and the occurrence of imposex
smaller than 25 m (Følsvik et al., 1999; Svavarsson,
in the Faroe Islands is still widespread, there are sites
2000). Svavarsson (2000) also related these changes to a
where the phenomenon is hardly seen.
change in marketing of paint in 1993 in Iceland. At that
time, large Icelandic producers of anti-fouling paints
5.4.2. Temporal trends in marine fish
started encouraging their customers to use non-TBT-
based paints. Additionally, these improvements may
Temporal-trend data for marine fish were not available
partly be explained by developments in paint technology
for the previous AMAP POPs assessment (de March et
(see Bennett, 1996). The earlier paints were `free associ-
al., 1998). Two studies have however been reported for
ation' paints, while later paints were copolymer paints
the current AMAP assessment.
with uniformly chemically bonded TBT with a constant,
The first of these is a temporal-trend study on the
but minimal, release of TBT (Bennett, 1996; Svavarsson,
OC levels in liver of Altantic cod and dab in the coastal
2000).
waters of Iceland (Yngvadóttir and Halldórsdóttir, 2002).
Studies of the occurrence of imposex in dogwhelks in
This study covers the period 1991 through 2000, with
the Faroe Islands were conducted in 1996 and in 2001
data missing only from 1993, and includes the major
150
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in Atlantic cod liver, ng/g ww
90
DDTs
80
NW
NE
;
70
60
;;
;;
;;
;;
;;
;;
50
;;
;;
I C E L A N D
E
;
;
;
;
;;
;;
;;
;
;;
;;
;
;;
;;
40
;;
;;
30
;;
;;
;;
;;
20
;;
;;
SW
SE
;
;
;
;
;;
;;
;;
;;
;
;
;;
;;
;
;;
;;
10
;;
;;
;;
;
;;
;;
;;
;;
;;
0
NE NW SE SW
NE NW SE
NE NW SW
NE NW SE SW
NE NW SE SW
NE NW E
NW E SW
NE NW SE
NE NW
45
;
;
;
;
;;
;;
;;
;;
;
;
;;
;;
;
;;
HCB
NE
40
NW
35
SE
;;
;;
;;
;
;;
30
;;
E
;
;
;;
;
;;
;;
;;
;;
;;
25
;;
SW
;;
;;
;;
20
;;
;;
;;
;;
15
;;
;
;
;
;
;;
;;
;;
;;
;
;
;;
;;
;
;;
;;
;;
10
;;
;;
;;
;;
;
;;
;
;;
5
;;
;;
0
;
;
;
;
;;
;;
;;
;;
;
;
;;
;;
;
NE NW SE SW
NE NW SE
NE NW SW
NE NW SE SW
NE NW SE SW
NE NW E
NW E SW
NE NW SE
NE NW
;;
250
PCB7
;;
;;
;;
;
;;
200
150
;
100
;;
;;
;;
;;
;
;;
;;
;;
;;
;;
50
;;
;;
;
;
;
;
;;
;;
;;
;;
;
;
;;
;;
;
;;
;;
;;
;;
0
NE NW SE SW
NE NW SE
NE NW SW
NE NW SE SW
NE NW SE SW
NE NW E
NW E SW
NE NW SE
NE NW
;;
;;
70
;
;
;
;
;;
;;
;;
;;
;
;
;;
;;
;
;;
;;
;;
;
;;
HCHs
60
50
40
30
;;
;;
;;
;;
;;
20
10
;;
;;
;;
;;
0
;;
;;
;;
;;
;;
;;
;
;
;;
;;
;
NE NW SW
NE NW SE SW
NE NW SE SW
NE NW E
NW E SW
NE NW SE
NE NW
;;
;;
;
;;
60
trans-nonachlor
50
40
;;
;;
;;
30
;;
;
;;
;;
;
;;
;;
;;
;;
20
Figure 5·24. Average concentra-
;;
;;
;;
;;
tions of OCs in the livers of At-
;;
;;
10
lantic cod (length = 30 - 45 cm) in
;;;;
;
;;
;;
;
;;
;;
;;
;;
Icelandic waters, 1991-2000.
0
;;
;;
NE NW SW
NE NW SE SW
NE NW E
NW E SW
NE NW SE
NE NW
;;
;;
;;
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
;;
;;
;;
;
;;
;;
;
OC groups and toxaphene. The study involves collection
5.4.3. Temporal trends in seabirds
of similar sized fish at a number of locations around the
coast of Iceland. No significant temporal trends were
The previous AMAP POPs assessment detailed a number
found for any of the OC groups in either Atlantic cod or
of studies on temporal trends of OCs in Arctic seabirds.
dab (Figures 5·24 and 5·25).
These studies showed a downward trend in all `legacy'
OCs have also been measured in cod (Gadus mor-
OCs in seabirds around the circumpolar Arctic (de
hua callarias) liver from the Vestertana Fjord (N. Nor-
March et al., 1998). There have been a number of new
way) from 1987 to 1998 (Sinkkonen and Paasivirta,
studies on OCs in Arctic seabirds, but few were designed
2000). Significant decreases in DDD, -HCH, and -
to address temporal trends, and insufficient new data
HCH were observed, but no trends were found for
have been added to warrant reexamination of these time
DDE, TCDF, PCBs, chlordanes, PCNs, HCB or poly-
series in this report. Further, studies that were designed
chlorinated diphenyl ethers (PCDEs). Hepta- and oc-
specifically to evaluate temporal trends however do pro-
taCDFs were found to increase from 1987 to 1994, and
vide results that yield firmer and more convincing con-
to increase steeply from 1994 to 1998, probably due
clusions about temporal trends.
to the use of a chlorophenol product as a wood preser-
One such study has monitored temporal trends of
vative.
OCs in Arctic seabird eggs in the eastern Canadian Arc-
Chapter 5 · Temporal Variations in POP Levels
151
Concentration in dab liver, ng/g ww
Concentration in eggs, µg/g lw
500
18
PCB7
400
16
DDTs
300
14
Black-legged kittiwake
Northern fulmar
200
Thick-billed murre
12
PCBs
100
Black-legged kittiwake
10
Northern fulmar
0
Thick-billed murre
8
160
DDE
140
6
120
4
100
80
2
60
0
40
1975
1980
1985
1990
1995
2000
20
Figure 5·26. Concentrations of DDTs and PCBs in seabird eggs
0
collected between 1975 and 1998 on Prince Leopold Island (Braune
5.4.3.1
40
et al., 2001a; 2001b).
HCB
35
concentrations of
30
PCBs and DDTs in this study have
also been observed in seabirds from other areas in-
25
cluding the Baltic Sea (Olsson and Reutergårdh, 1986;
20
Andersson et al., 1988; Bignert et al., 1995), the Bar-
15
ents Sea (Barrett et al., 1996), and the Great Lakes
10
(Hebert et al., 1997). The only OC compound in this
5
study for which a significant increase in concentrations
0
was seen, was for HCHs, particularly for -HCH in
3.5
murres (Figure 5·27) and fulmars. Stable-nitrogen iso-
-HCH
3.0
tope analyses ( 15N) indicated that the temporal trends
2.5
HCH isomer : HCH ratio, %
2.0
100
1.5
80
1.0
-HCH
0.5
60
0
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
40
Figure 5·25. Average concentrations of OCs in the livers of dab in
Icelandic waters, 1991-2000.
-HCH
20
tic at Prince Leopold Island (Braune et al., 2001a; 2001b).
This study encompasses three species of seabirds and
0 '75'76'77
'87'88
'93
'98
covers a long time period, 1975-1998 (Braune et al.,
2001a; 2001b). At the time of egg formation, OC com-
Concentration in thick-billed murre eggs, ng/g lw
pounds are transferred along with lipids to the eggs (Mi-
neau et al., 1984). Contaminant burden in the egg re-
1000
flects residues assimilated over a long time period by the
HCHs
female and, particularly in migratory species, may inte-
800
grate exposure from a number of different locations
(Hebert, 1998; Monteiro et al., 1999).
600
-HCH
With the exception of HCHs, OC compounds
showed declines or, in some cases, no significant change
400
-HCH
in levels between 1975 and 1998. Levels of PCBs and
DDTs (Figure 5·26) as well as CBz decreased signifi-
200
cantly in eggs of all three species, while CHLs, diel-
drin and mirex levels decreased in kittiwake eggs only.
0
Kittiwakes, whose migration pattern would have his-
'75'76'77
'87'88
'93
'98
torically brought them into closer contact with indus-
Figure 5·27. Temporal trends in relative proportions and concentra-
trial sources of contaminants, such as PCBs, in the
tions of HCH isomers in thick-billed murre eggs. -HCH shows a
more temperate latitudes, showed the most dramatic
significant increase vs - and -HCH (Braune et al., 2001c). -HCH
declines through to 1998. The significant declines in
is < 5% of HCH.
152
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
observed in OC and trace metal concentrations in
analyzed for PCDD/F (Mikkelsen, 2002). The results
seabird eggs were not the result of shifts in trophic
indicate a decrease in concentrations of PCDD/Fs, as
level over time (Braune et al., 2001b). More likely, the
TEQ decreased from 160 pg/g lw in 1989 to 66 pg/g lw
trends reflect changes in contaminant deposition into
in 2000.
the various marine environments that these birds oc-
cupy throughout the year, as well as the toxicokinetics
5.4.4. Temporal trends in pinnipeds and cetaceans
of each contaminant as it is transported through the
food chain.
The previous AMAP POPs assessment noted that there
Data from the late 1970s for two seabird colonies
were relatively few long-term (multi-decade) studies of
in the Bering Sea (common guillemot at St. George Is-
POPs in Arctic marine mammals (de March et al. 1998).
land and thick-billed murres from Bogoslof Island) are
This is still the case. However, additional studies con-
available (Ohlendorf et al., 1982) for comparison with
ducted using archived samples or analysis of new sam-
data generated for 1999 and 2000 (Vander Pol et al.,
ples from previously studied sampling locations have
2002). There were significant (p < 0.05) declines in mean
significantly increased the information available.
concentrations of p,p'-DDE, oxychlordane and hepta-
chlor epoxide in the common guillemot eggs, and p,p'-
5.4.4.1. Pinnipeds
DDE and cis-nonachlor in the thick-billed murre eggs.
HCB and dieldrin did not appear to have declined over
Ringed seals
the 20-year period. PCB concentrations were not com-
Temporal trends of PCBs, DDTs, -HCH, and -HCH
pared due to analytical differences between the two
have been studied in ringed seals from the Canadian
studies. These temporal trends are consistent with what
Arctic, sampled at the communities of Ausuittuq (Grise
has been seen in guillemot eggs in the Baltic Sea (Bignert
Fiord), Ikpiarjuk (Arctic Bay), and Holman (Addison
et al., 1995) and in murres from Prince Leopold Island
and Smith, 1998; Muir et al., 2001c). In the case of Hol-
(Braune et al., 2001b).
man, the results are part of a long-term study (Addison
PCDD/Fs and toxaphene have also been measured
and Smith, 1998). Elsewhere, sampling locations were
in Canadian Arctic seabirds over a period of almost 20
selected based on whether previous results were avail-
years (Braune et al., 2000), providing a time-series
able (Muir et al., 1988; Weis and Muir, 1997). At all
dataset. Liver samples of thick-billed murres, northern
three locations, results were available from the early
fulmars and black-legged kittiwakes collected in 1975
1970s to the late 1990s and 2000.
and 1993 from Prince Leopold Island, as well as egg
At all locations, only samples from female seals were
samples from 1993, were analyzed for PCDDs, PCDFs
selected for analysis in order to minimize age-related ef-
and non-ortho PCBs (nPCBs) (Annex Table 16). In the
fects on OC levels (Addison and Smith, 1974). Mean
kittiwake liver samples, concentrations of total PCDDs,
concentrations (± 95% confidence limits; ng/g lw) in
PCDFs and nPCBs decreased from 1975 to 1993. In ful-
ringed seals for DDTs, PCBs, HCHs and CHLs,
mar liver samples, concentrations of total PCDDs and
along with ratios of recalcitrant members of each class
PCDFs decreased, and nPCBs increased from 1975 to
for each location, are shown in Figure 5·28 a- c. PCB10
1993. In murre liver samples, concentrations of total
(sum of CBs 28, 31, 52, 101, 105, 118, 138, 153, 156,
PCDDs and PCDFs increased and nPCBs decreased from
and 180) in seals from Ikpiarjuk declined significantly
1975 to 1993. CB126 was the predominant nPCB con-
(2.4 fold) from 1975 to 2000 (Figure 5·28 a) and 1.5
gener in all years and in all Arctic seabird samples ana-
fold at Ausuittuq, based on the comparison of arith-
lyzed. The nPCB fraction of the TEQ decreased, and the
metic means. PCB10 was used for comparison with ear-
PCDF fraction increased from 1975 to 1993 in kitti-
lier data rather than all congeners. All previous results,
wake and murre livers. In fulmars, the PCDFs consti-
including the samples from 1972-1975, were based on
tuted the dominant fraction in both 1975 and 1993 liv-
capillary gas chromatography with quantitation using
ers. Calculated TEQ values were highest in northern ful-
authentic standards (Muir et al., 1988; 1999b; Muir,
mars both in 1975 and 1993 (Annex Table 16). The
1996; Weis and Muir, 1997; Muir et al., 1999b).
highest estimated level of toxaphene was found in the
At Holman, PCBs (based on conversion of Aroclor
pool of kittiwake eggs from 1993 (64 ng/g ww), and
1254 to a PCB value consisting of 20 major congeners)
the second highest level was found in the 1993 pool of
was significantly higher in 1972 than in 1981 and de-
fulmar eggs (53 ng/g ww), suggesting increasing concen-
clined significantly over the ten-year period from 1991
trations.
(510 ±133 ng/g lw) to 2001 (335 ±18 ng/g lw). The over-
PBDEs were also analyzed in kittiwake, northern ful-
all decline for PCBs is 5.5 fold. Ratios of CB153 :
mar, and thick-billed murre liver samples from 1975 and
PCBs increased over the 25-year period at Ikpiarjuk
1993 from Prince Leopold Island (Braune et al., 2001a).
and Ausuittuq and between 1991 and 2001 at Holman,
PBDEs were below detection limits in samples from
reflecting the slower elimination of CB153 over time by
1975 while low ng/g concentrations were found in those
the seals, compared to other PCBs.
from 1993. These preliminary data indicate that PBDEs
DDTs declined significantly in female ringed seals
are increasing in concentration in seabirds as they are in
from all three sites, between the early/mid-1970s and
other marine biota in the Canadian Arctic.
late 1990s/2000. DDTs exhibited the largest decline of
PCDDs and PCDFs, including the nPCBs (CBs 77,
any `legacy' OC: 2.5 fold at Ausuittuq, 3.3 fold at Ikpi-
126, and 169), were analyzed in guillemot eggs sam-
arjuk and 3.3 fold at Holman over the 25-30-year pe-
pled in 1989 in Greenland, Iceland, and in the Faroe Is-
riod. Significant increases in p,p'-DDE : DDT ratios were
lands (Cederberg et al., 1991). Guillemot eggs were
also found at all three locations, reflecting the shift from
collected from the Faroe Islands in 2000 (n =10) and
fresh DDT to `weathered' or degraded older sources.
Chapter 5 · Temporal Variations in POP Levels
153
a Ikpiarjuk (Arctic Bay)
b Ausuittuq (Grise Fiord)
c Holman
Concentration in ringed seal blubber,
Concentration in ringed seal blubber,
Concentration in ringed seal blubber,
ng/g lw
Ratio
ng/g lw
Ratio ng/g lw
Ratio
500
0.35
800
0.35 2000
0.30
CB153 : PCB10 ratio
PCB10
PCB10
PCB
CB153 : PCB ratio
0.25
400
CB153 : PCB10 ratio
0.30
0.30
600
1500
0.20
300
0.25
0.25
400
1000
0.15
200
0.20
0.20
0.10
200
500
100
0.15
0.15
0.05
0
0.10
0
0.10
0
0.00
400
0.20
200
0.25
400
-HCH : HCH ratio
-HCH : HCH ratio
HCHs
HCHs
HCHs
0.20
300
0.15
150
300
0.15
200
0.10
100
200
0.10
100
0.05
50
100
0.05
0
0
0
0
800
0.80 1500
0.80
800
0.80
DDTs
p,p'-DDE : DDT ratio
DDTs
p,p'-DDE : DDT ratio
DDTs
p,p'-DDE : DDT ratio
0.70
1200
600
0.70
600
0.60
0.60
900
400
0.60
0.50
400
0.40
600
0.40
200
0.50
200
0.20
300
0.30
0
0.40
0
0.20
0
0.00
500
0.60
500
0.45
500
0.40
CHLs
CHLs
CHLs
Oxychlordane: CHL ratio
0.50
400
400
0.43
400
Oxychlordane: CHL ratio
0.30
0.40
Oxychlordane: CHL ratio
300
300
0.41
300
0.30
0.20
200
200
0.39
200
0.20
0.10
100
100
0.37
100
0.10
0
0.00
0
0.35
0
0.00
1975
1983
1993
2000
1972
1993 1998
1972
1981
'89'91
2001
n = 5
n =16
n = 7
n = 7
n = 3
n = 4 n =10
Figure 5·28. Temporal trends in concentrations and proportions of major OC components in blubber of female ringed seals from three sites
in the Canadian Arctic Archipelago. Bars are arithmetic means and vertical lines are 95% confidence intervals. a) Ikpiarjuk (Arctic Bay); sig-
nificant differences between 1975 and 1993 were found in the case of PCB10 and DDTs. b) Ausuittuq (Grise Fiord); no significant differ-
ences over time were found because of small sample sizes from 1972 and 1993. Nevertheless, the results suggest similar trends to those ob-
served at Ikpiarjuk for concentrations and proportions of major components. c) Holman, NWT, in the western Canadian Arctic Archipelago.
At Holman, PCB includes all congeners analyzed.
HCH concentrations showed no significant changes
CHLs showed quite a different trend from DDTs,
in concentrations from the 1970s (1981 in the case of Hol-
with increasing concentrations at Holman and Ausuittuq,
man) to 2001. However, -HCH : HCH ratios increased
and a slow decline (2.1 fold over 25 years) at Ikpiarjuk.
(3 fold at Ikpiarjuk). This shift in the composition of HCH,
Proportions of oxychlordane, a recalcitrant metabolite of
with higher proportions of -HCH, has also been reported
chlordane in mammals, increased at all three locations.
in seawater in the western Canadian Arctic during the
Ikonomou et al. (2002) examined temporal trends of
1980s and 1990s (Li et al., 2002) (see Section 4.4.1.2).
non- and mono-ortho PCB and PCDD/F concentrations
154
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in ringed seal blubber, ng/g ww
Muir et al. (2000e) examined temporal trends in lev-
500
els of a wide range of OC compounds in archived (1978)
Mono-ortho- + non-ortho PCBs
samples of northwestern Greenland walrus as well as
Males 0-15 yr
400
Females 0-15 yr
more recently collected samples (1988) (Annex Table
Males 16-35 yr
12). They did not detect any significant differences in
;
Females 16-35 yr
mean concentrations of any OCs in male walrus from
300
the two time periods, but for females, they found signif-
;
;
icantly higher levels of di- and trichlorobiphenyls, diel-
200
drin, toxaphene, -HCH, and HCHs in the 1988 mate-
;
rial, but no differences for PCBs or DDT compounds.
100
;
5.4.4.2. Cetaceans
0
Belugas
Concentration in ringed seal blubber, pg/g ww
PCDD/ Fs
;
Stern (1999) and Stern and Addison (1999) examined
20
temporal trends of `legacy' OCs in blubber of beluga
from Cumberland Sound (southeast Baffin Island) be-
15
tween 1982 and 1997 (Annex Table 13). They reported
a significant decline in -HCH concentrations over the
10
15-year interval from 1982 to 1997, while no significant
5
differences were observed for the - and -HCH isomers
(Figure 5·30). In this regard, belugas differ from sea-
;
0
birds, ringed seals and polar bear, which all show in-
1981
1991
1996
2000
creasing proportions of -HCH. DDT concentrations
Figure 5·29. Concentrations of mono-ortho- and non-ortho-PCBs
;
did not change over this 15-year interval. However, a
and PCDD/Fs in ringed seals from Holman, NWT, in the Canadian
2.2-fold decline and a 1.3-fold increase in the (age-ad-
Arctic Archipelago (Ikonomou et al., 2002).
justed) concentration of p,p'-DDT and its metabolite
in male ringed seals from Holman. Concentrations of
p,p'-DDE, respectively, was observed (Figure 5·31).
non- and mono-ortho PCBs (149-174 ng/g ww) and
These changes translated into a significant increase in
PCDD/Fs (8.6 -14.6 pg/g ww) in ringed seals aged 0 -15
the p,p'-DDE : DDT ratio from 0.37 to 0.48 and sug-
years remained approximately constant from 1981 to
gests `old' rather than recent DDT sources. Two of the
2000 (Ikonomou et al., 2002) (Figure 5·29). Total PCB
most abundant congeners in technical chlordane, cis-
concentrations did not decline significantly in males
and trans-nonachlor, increased in concentration by 1.4
or females over the period of 1981 to 1991 (Addison
and 1.7 fold, respectively, from 1982 to 1997, while
and Smith, 1998). Older male seals (16 -35 yr) from
only cis-chlordane showed any significant decline. Over-
the 2000 sampling group have higher levels of non-
all, a 1.2-fold increase in the concentrations of CHLs
and mono-ortho PCBs than their younger counterparts
Concentration in beluga blubber, ng/g lw
(0 -15 yr; 302 vs. 150 ng/g ww). In female seals from
350
1996 and 2000, non- and mono-ortho PCB levels are
much lower in the 16 -35-year age group from 2000
(43 ng/g ww) than the 0 -15-year age group from 1996
300
(105 ng/g ww).
No other temporal-trend studies of OCs in Arctic
ringed seals have been reported. At Svalbard and north-
ern Norway, where results are available since the mid-
250
1990s, it is likely that this will be accomplished in the
near future. In the White Sea, mean levels of PCBs,
HCHs
DDTs, chlordanes, HCHs, and HCB declined between 2
200
and 3 fold in blubber samples taken from harp seal pups
between 1992 and 1998 (Muir et al., 2002c). Mirex lev-
els in 1998 samples were about one quarter of their
150
1992 levels, in the same study. These declines should be
viewed with caution since there could be regional differ-
-HCH
ences in exposure of adult harp seals to PCBs and DDT
100
within the White Sea area depending on their proximity
to urban areas.
No significant temporal trend in butyltin concentra-
50
-HCH
tions was observed in Steller sea lions sampled from
Alaska between 1976 and 1985 (Kim et al., 1996a). This
-HCH
was despite the fact that the annual consumption of
0
organotin compounds doubled in the U.S. during the
1982
1986
1992
1996/97
same period. The authors suggest that the butyltin com-
Figure 5·30. Temporal trends of age-adjusted concentrations of
pounds are degraded faster than the intake from diet in
HCHs, -HCH, -HCH, and -HCH in male beluga blubber sam-
Steller sea lions.
ples from Pangnirtung, Nunavut.
Chapter 5 · Temporal Variations in POP Levels
155
Concentration in beluga blubber, ng/g lw
Concentration in beluga blubber, ng/g lw
7000
14 000
6000
12 000
DDTs
5000
10 000
Total toxaphene
4000
8000
3000
6000
Parlar 50
p,p'-DDE
2000
4000
p,p'-DDT
Parlar 26
1000
2000
0
0
1982
1986
1992
1996/97
1982
1986
1992
1996/97
Figure 5·31. Temporal trends of age-adjusted concentrations of
Figure 5·32. Temporal trends of age-adjusted concentrations of
DDTs, p,p'-DDE and p,p'-DDT in male beluga blubber samples
total toxaphene and Parlars 50 and 26 in male beluga blubber sam-
from Pangnirtung, Nunavut.
ples from Pangnirtung, Nunavut.
was observed. Levels of oxychlordane, the principal
declines, ranging from 1.7 fold for CB81 to 2.8 fold for
metabolite of cis- and trans-chlordane, second only to
CB126, were observed (Figure 5·33). Non-ortho PCB
trans-nonachlor as the most abundant chlordane-related
TEQs (CBs 77, 126, and 169) declined from 16 to 6.1
residue in the southeast Baffin beluga blubber, did not
pg/g lw (2.6 fold) from 1982 to 1997. Age-adjusted
change significantly over this 15-year period. For total
concentrations of major PCB homologue groups (hexa-,
toxaphene and Parlars 26 and 50, no clear trends were
heptachlorobiphenyls) did not show a consistent de-
evident (Figure 5·32). For PCB congeners, significant
cline over the 15-year period (Stern and Addison, 1999).
Concentration in beluga blubber, pg/g lw
Concentration in beluga blubber, pg/g lw
450
40
400
35
350
30
300
25
250
CB 81
20
200
CB 80
15
150
CB 169
10
100
CB 77
5
50
CB 79
CB 126
0
0
1982
1986
1992
1996/97
1982
1986
1992
1996/97
Figure 5·33. Temporal trends of age-adjusted concentrations of PCB congeners 77, 79, 80, 81, 126, and 169 in male beluga blubber samples
from Pangnirtung, Nunavut.
156
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in beluga blubber, ng/g lw
ment with findings outlined in the previous AMAP as-
Endosulfan
HCB, CBz, Dieldrin
1,2,3,4-CBz
sessment report (de March et al., 1998), male narwhal
Endosulfan, 1,2,3,4-CBz
HCB
from Pond Inlet showed no discernible changes in con-
CBz
Dieldrin
centrations of PCBs, DDTs, CHLs or toxaphene.
HCHs and CBz also showed no statistically signifi-
800
16
cant trends over this time period. This lack of change in
DDTs, CHLs, PCBs, and toxaphene concentrations
700
14
in narwhal is consistent with results for beluga in south-
eastern Baffin Island. One difference however between
600
12
these two odontocetes was the decline in HCHs in bel-
uga, while no such decline was found in narwhal.
500
10
400
8
5.4.5. Temporal trends in polar bear
5.4.5.1. Canadian Arctic polar bears
300
6
Temporal trends of the major OC groups in polar bears
from the Churchill area of western Hudson Bay (Can-
200
4
ada) are presented in Figure 5·33. Biopsy samples from
adult female polar bears were chosen to study temporal
100
2
trends because there is no significant effect of age on OC
levels, whereas there is a significant effect (increase with
0
0
1982
1986
1992
1996/97
age) of highly chlorinated PCBs in male polar bears
(n = 8)
(n =17)
(n =11)
(n =17)
(Bernhoft et al., 1997; Norstrom et al., 1998). Bears less
Figure 5·34. Temporal trends of age-adjusted concentrations of en-
than five years old were also excluded because levels of
dosulfan, 1,2,3,4-chlorobenzenes, HCB, sum of tetra-, penta- and
some OCs are higher due to high exposure in milk the
hexachlorobenzene (CBz), and dieldrin in blubber of male belugas
first two years of life. The trends observed in adult fe-
from Cumberland Sound, Nunavut, in the eastern Canadian Arctic
male polar bears are therefore more likely to represent
(Stern and Addison, 1999).
the actual changes in OC levels in the polar bear food
A 2.1-fold increase in age-adjusted mean concentrations
chain. Biopsy samples were collected opportunistically
of endosulfan sulfate and a 1.4-fold decline in dieldrin
nearly every year throughout the 1990s (Norstrom,
were also observed over the 15-year period (Stern and
2001). Archived adipose tissue samples from 1968, 1984,
Addison, 1999) (Figure 5·34).
and 1989 were included to extend the time period for
comparison. There were no consistent upward or down-
Pilot whales
ward trends over the period 1968 to 1989 for most OCs;
In 1997, a large number of pilot whale blubber samples
therefore, only trends in the 1990s were analyzed statis-
were taken in the Faroe Islands to study levels of OCs
tically. There were no statistically significant (p < 0.05)
(Dam and Bloch, 2000). Samples were analyzed in pools
increasing trends in female bears over the entire nine-
sorted according to sexual maturity and sex. Temporal
year period. There were however statistically significant
trends were examined by comparing results from a sub-
(p < 0.05) downward trends for total chlorobenzenes, -
set of individual 1997 pilot whale samples (Dam, 2001)
HCH, and PCBs between 1991 and 1999. There were
with a previous study of pilot whales collected in the
no significant (p < 0.05) changes in chlordanes, DDTs
Faroes in 1987 (Borrell, 1993). Statistical analysis of the
(mostly p,p'-DDE), dieldrin, -HCH, and HCHs.
data for the adult females and adult males from 1987 and
There was a consistent (and significant) decrease in
1997 showed a significant decrease during the ten-year
DDTs throughout the entire 1968 to 1990s time pe-
interval for both PCB and DDT concentrations (Mikkel-
riod. Such strong trends are unusual in Arctic biota, sug-
sen, 2002). There are some weaknesses in the statistical
gesting that the phenomenon may be related to local
analysis since the total PCB concentration in the subset
conditions around Hudson Bay. Spraying of DDT for
of adult females analyzed individually was slightly lower
biting-insect control in communities and military bases
than in the entire 1997 bulk of adult females. The level
in the Hudson Bay area in the 1950s and 1960s may
was quite similar in the adult males, however, and this
have contributed a significant load to Hudson Bay dur-
indicates that the observed decrease is real.
ing this period. This likely declined after the DDT ban
and closing of the large military base at Churchill, and
Narwhal
may not have contaminated other nearby areas. In sup-
Results for OCs in blubber of narwhal from the Baffin
port of this hypothesis, it can be seen in Annex Table 14
Bay-Lancaster Sound region (Pond Inlet) of the Cana-
that DDT levels were 2-3 times higher in polar bear fat
dian Arctic were available from previous work (Muir et
from western Hudson Bay than in other areas of the
al., 1992a), and more recent data for the same region are
Canadian Arctic in 1984.
available (Stern, 2001). Using this information, it was
The overall trend for CBz appears to be an in-
possible to make a qualitative assessment of temporal
crease between 1968 and 1984, followed by a consis-
changes in `legacy' OCs in narwhal from this region over
tent downward trend since that time. Most of the de-
a 12-16-year period (1982-83 to 1999). Male narwhal
cline in CBz was due to HCB, which decreased with a
were selected for temporal-trend comparisons because,
half-life of approximately nine years during the 1990s.
unlike seals, they show little relationship between PCB
HCB and 1,2,4,5-TeCBz were each roughly half of the
concentrations and age (Muir et al., 1992a,b). In agree-
total, with a minor contribution from PeCBz. The pro-
Chapter 5 · Temporal Variations in POP Levels
157
Concentration in polar bear adipose tissue, ng/g lw
The apparent half-life of -HCH in the 1990s was ap-
160
proximately ten years, very similar to that of HCB. The
-HCH
decrease in the 1990s appears to be part of a general
120
trend. Levels of -HCH were approximately two to
three times higher in 1968 and 1984 than the average in
80
the 1990s. By contrast, -HCH concentrations were
40
lower in 1968 than in any subsequent year, and the over-
all trend in the 1980s and 1990s is rather flat. As a con-
0
sequence, a significantly higher proportion (approxi-
300
-HCH
mately 50%) of present day HCHs in polar bears from
Hudson Bay is -HCH compared to 1984 (25%) and
200
1968 (17%). A parallel trend is observed in ringed seals,
the major prey of the polar bears (Section 5.4.4.1).
100
PCBs decreased fairly steadily throughout the 1990s,
but with a long half-life of approximately 18 years. The
shift in composition of the PCBs was subtle over the
0
decade, but there was a clear tendency for the propor-
400
CBz
tion of less chlorinated congeners to increase, and the
300
highly chlorinated congeners to decrease. Thus, CB99
increased from approximately 10% to 12% of PCBs,
200
CB153 was relatively stable at approximately 35%, and
CB180 decreased from 17% to 14%. The trends in these
300
three congeners indicate that the half-life of CB153 (19
years) was similar to that of
0
PCBs. The half-life of
5000
CB180 (13 years) was shorter, and the half-life of CB99
CHLs
(>50 years, not significant) was longer than PCBs.
4000
Thus, the decreasing trend in PCBs is driven by loss of
3000
the highly chlorinated congeners. There is less than a
factor-2 difference in
2000
PCB levels through the 1968-
1999 period, and no long-term trend is apparent. Con-
1000
centrations in the early 1990s in Hudson Bay were simi-
0
lar to those in the late 1960s, in sharp contrast to areas
1400
such as the Great Lakes or the North Atlantic, where
DDTs
1200
PCB concentrations in herring gull eggs were on the
1000
order of ten times higher in the late 1960s and early
800
1970s than at present (Hebert et al., 2000).
600
Shorter-term temporal trends in polar bears from
400
Queen Maud Gulf (I) in the western Canadian Arctic
200
Archipelago, Barrow Strait (II) in the central archipel-
0
ago, and northern Baffin Bay (III) and Davis Strait (IV)
7000
PCBs
in the eastern archipelago, and also one area in western
6000
Hudson Bay (V) were reported by Muir and Norstrom
5000
(2000) (Annex Table 14). In that comparison, samples
4000
were taken from eight to ten individual adult male polar
3000
bears per area in each of 1984 and 1989/1990. PCDD/
2000
PCDF concentration changes were also determined in
1000
pooled samples. There were significantly lower concen-
0
1970
1980
1990
2000
trations of HCHs, DDTs, and dieldrin in (I), a signifi-
cant decrease in dieldrin in (II), no changes in (III), a sig-
Figure 5·35. Trends of major OC compounds in female polar bear
nificant increase in CHLs in (IV), and a significant de-
adipose tissue from the Churchill area of western Hudson Bay
crease in CBz, DDTs, and PCBs in (V), between
(Canada) from 1968 to 1999. Samples from 1991 to 1999 are fat
1984 and 1989.
biopsies, but earlier samples are adipose tissue.
Results for PCDD concentrations in pooled sam-
portion of 1,2,4,5-TeCBz peaked at 53% between 1995
ples of polar bear adipose tissue from polar bear areas
and 1997, and then decreased to values similar to the
(I), (II), (III), and (IV) in the Canadian Arctic Archipel-
pre-1995 period of 40 - 45%.
ago in 1984 and 1990 (Norstrom, 1997) are given in
The downward trend of HCHs in Hudson Bay po-
Annex Table 16. PCDDs consisted almost entirely of
lar bears in the 1990s was not significant (Norstrom,
2,3,7,8-TCDD and 1,2,3,7,8-PeCDD. Other PCDDs and
2001), but it was significant if 1984 and 1989 were con-
all PCDFs were at sub-pg/g lw concentrations. Concen-
sidered (Figure 5·35). However, comparing HCH trends
trations of TCDD were low and tended to be more
is complicated by differences in temporal trends of -
evenly distributed in 1990 (0.8-3.1 pg/g lw) than in 1984
HCH and -HCH ( -HCH declines and -HCH in-
(2.0-15 g/g lw), as was the case for the other OCs. Be-
creases). -HCH was less than 2% of HCHs and could
cause pooled samples were analyzed, the significance of
not be reliably quantified in the majority of samples.
the differences cannot be established. Nevertheless, con-
158
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
centrations of TCDD in (I) and (II) were a factor of 4-5
Concentration in polar bear plasma, ng/g ww
lower in 1990 than 1984. The results are consistent with
100
the findings of Norstrom et al. (1990) in which ringed
seal, beluga, and polar bears were analyzed. It is appar-
CB 153
ent that PCDD/Fs are at very low concentrations in the
polar bear food chain and are unlikely to be of toxico-
10
logical significance.
5.4.5.2. East Greenland polar bears
-HCH
1
Dietz et al. (2004) compared concentrations of PCBs
and OC pesticides in polar bear from central East
Greenland collected in 1999-2001 with results for 1990
0.1
reported by Norstrom et al. (1998). Overall a significant
1990
1992
1994
1996
1998
decrease was observed in OC contaminants in all age
Figure 5·36. Temporal trends of two major OCs ( -HCH and
and sex groups studied over the period from 1990 to
CB 153) in polar bear plasma from Svalbard (means ± 95% C.I.) for
1999-2001. Using the same congeners to calculate PCB
the period 1990-1998. CB153 concentrations are adjusted for covar-
for both groups, PCB showed a reduction of 78%. PCB
iates (extractable lipids, condition index and sampling site longitude).
congener proportion also changed over the ten-year pe-
riod. A less chlorinated PCB congener like CB99 com-
5.4.5.3. Svalbard polar bears
prised 7.3% of the 1999-2001 bears from East Green-
land, a slight decrease compared to the 8.3% that Nor-
Henriksen et al. (2001) studied the trend in CB153 con-
strom et al. (1998) reported from the trans-Arctic survey
centrations in blood from polar bears at Svalbard that
of polar bears from 1989 to 1992. The decreases in
was collected annually between 1990 and 1998. De-
DDT and p,p'-DDE in East Greenland since 1990 (34%
creases of approximately 40% occurred in the early
and 29%, respectively) were also significant, although
1990s, and stabilized thereafter (Figure 5·36). This is a
less pronounced than for other OCs, and the estimated
somewhat steeper trend than was found in Hudson Bay
half-life for p,p'-DDE was the longest of all OCs meas-
during the same time period. However, Svalbard bears
ured (17.5 years). Total chlordane-related compounds
had significantly higher levels of PCBs in 1990 than
and dieldrin were both found to decrease (between
those in Hudson Bay, probably due to the proximity of
about 31% to 75% dependent of the sex and age group
Svalbard to European sources. Svalbard PCB levels may
studied). HCH concentrations declined about 60%
have approached steady state with global distribution of
over the ten-year period. -HCH increased in western
PCBs later than in Hudson Bay because of this proxim-
Hudson Bay polar bears during the 1990s (Norstrom,
ity. It is well established that trends of POPs in environ-
2001) and a similar pattern was expected in East Green-
ments close to sources tend to follow production and use
land. However, this was not the case, as -HCH showed
of the chemical rather closely, whereas those in environ-
an increase from 18% to 25% and -HCH showed a de-
ments remote from sources are significantly dampened.
crease from 82% to 75%. The high percentage of -
That is, peak concentrations are lower, took longer to be
HCH is consistent with findings from the Svalbard re-
reached, and take longer to decrease than those near
gion where Bernhoft et al. (1997) reported -HCH to
sources. Present results indicate that further decreases in
constitute 81% of HCH. In general, the decrease in
PCB contamination of the Arctic may be slight.
PCB and OC concentrations in East Greenland polar
-HCH also declined in plasma of polar bears from
bear is faster than that observed over the same period in
Svalbard between 1991 and 1999 (Lie and Skaare, 2002).
Canada, but similar to the decrease found in polar bears
Concentrations were similar from 1991 to 1993 and de-
from Svalbard.
clined about 3 fold between 1993 and 1996 (Figure 5·36).
Relative change in concentration in polar bear plasma from 1967-1993/94
10
Svalbard
9
Males
Females
8
7
6
Figure 5·37. Relative change in
5
major PCB congeners and OC
pesticides from 1967 to 1993-
4
94 for adult female and male
polar bear samples at Svalbard,
3
Norway (from Derocher et al.,
2003). Results for 1993-94 are
2
from Skaare et al. (2001d) and
1
Bernhoft et al. (1997). Values <1
imply a decrease in concentra-
0
tion.
99
138
153
156
157
170
180
194
p,p'-DDE CHLs HCHs
PCB congener
OC pesticide
Chapter 5 · Temporal Variations in POP Levels
159
The trend for -HCH in Svalbard polar bears differs
Concentration in beluga blubber, ng/g lw (age adjusted)
from that in the Hudson Bay bears, where concentra-
16
tions appeared to increase during the same time period.
PBDEs
Derocher et al., (2003) compared PCBs and OC pes-
ticides in blood plasma collected in 1967 from 32 polar
12
bears in eastern Svalbard with results from 1993 and
1994. Most major, persistent, PCB congeners in polar
BDE 47
bears (CBs 99, 138, 153, 180, 194) showed significant
8
increases from 1967 to 1993-94 in both males and fe-
males (Figure 5·37). Chlordane compounds also increased
while p,p'-DDE and HCH isomers declined. These in-
4
creases for chlordanes, PCBs and decline in p,p'-DDE
over the 26-27-year period were similar to trends in the
BDE 154
eastern Canadian Arctic polar bears over the period
0
1980
1985
1990
1995
2000
1969 to 1984 (Muir and Norstrom, 2000) (Figure 5·35).
Figure 5·39. Temporal trends of PBDEs in blubber of beluga whales
from southeast Baffin Island in the eastern Canadian Arctic, 1982-
5.4.6. Temporal trends of `new' POPs
1997 (Stern and Ikonomou, 2000; 2001).
in marine mammals
(PCDEs) in beluga blubber samples from southeast Baf-
5.4.6.1. PBDEs
fin Island in the eastern Canadian Arctic. Levels of the
Ikonomou et al. (2002) reported exponential increases
total PBDEs (Di- to HpBDEs) and major congeners in-
in PBDEs (di- to heptabromodiphenyl ethers) in male
creased significantly in the southeast Baffin Bay beluga
ringed seals aged 0-15 years from Holman in the west-
over the period of 1982 to 1997. Age-adjusted concen-
ern Canadian Arctic over the period of 1981 to 2000
trations of BDE47, the most predominant PBDE con-
(Figure 5·38). PBDEs increased 9 fold over this period.
gener, increased 6.5 fold over this 15-year period, while
Pe- and HxBDEs were found to be increasing at approx-
BDE154 increased 30 fold (Figure 5·39). Over the 15-
imately the same rate (t2 = 4.7 yr and 4.3 yr, respectively)
year time span, contributions of the TrBDE homologue
and more rapidly than TeBDEs (t2 = 8.6 yr), while
group and BDE47 to total PBDEs declined by 7% and
TrBDEs showed no increase in this age/sex group. The
3%, respectively. Conversely, PeBDE and HxBDE con-
tributions have increased by 20% and 80%, respec-
PBDE concentration in ringed seal blubber, ng/g lw
tively. This change in the beluga could be related to the
7
shift in composition of commercial PBDEs to more
Males 0 -15 yr
Females 0 -15 yr
highly brominated mixtures (de Boer et al., 2000).
6
Males 16 - 35 yr
Females 16 - 35 yr
5
;;
;
5.4.6.2. PCDEs
4
PCDE concentrations declined in the same beluga sam-
;;
ples that were analyzed for PBDEs (Stern and Ikono-
3
mou, 2000). Maximum concentrations were found in
samples from 1982 (Figure 5·40). The two most abun-
;;
2
dant congeners were CDE99 (2,2',4,4',5-CDE) and
CDE154 (2,2',4,4',5,6'-CDE), which declined 2.5 fold
1
;;
;
and 1.8 fold, respectively, over the 15-year period. These
congeners are prominent contaminants in pentachloro-
0
1981
1991
1996
2000
phenol-based wood preservatives, and the decline most
;;
;
likely reflects the ban on PCP use in Canada and use re-
Figure 5·38. Temporal trends of PBDEs in blubber of ringed seals
from Holman, NWT, in the western Canadian Arctic, 1981-2000
strictions in the U.S.
(Ikonomou et al., 2002).
Concentration in beluga blubber, ng/g lw (age adjusted)
35
three most prevalent PBDE congeners: BDEs 47, 99, and
100, all increased over the 19-year period. However,
30
only BDEs 47 and 100 increased in parallel with PB-
25
DEs. BDE99 increased exponentially in a similar manner
to PBDEs and BDEs 47 and 100 from 1981 to 1996.
20
However, the 2000 samples show that the levels of
PCDEs
BDE99 are stabilizing. This suggests a shift in sources or
15
change in composition of PBDE products. No difference
10
in PBDE levels (both total and of individual congeners),
were observed between younger (0 -15 yr) and older (16-
5
35 yr) male seals in 2000 (p = 0.98 for PBDEs), sug-
CDE99
0
gesting that, for the older seals, recent PBDE accumula-
1980
1985
1990
1995
2000
tion dominates potential historic accumulation.
Figure 5·40. Temporal trends of PCDEs in blubber of beluga from
Stern and Ikonomou (2000; 2001) studied temporal
southeast Baffin Island in the eastern Canadian Arctic, 1982-1997
trends of PBDEs and polychlorinated diphenyl ethers
(Stern and Ikonomou, 2000; 2001).
160
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
Concentration in ringed seal blubber, µg/g lw
5.4.7. Modeling temporal trends
10
of PCBs and DDT in pinnipeds
Observed
Aroclor
Evaluating temporal trends of OCs in marine mammal
Predicted
PCBs
populations, and linking them to trends in other biota or
environmental media can be confounded by factors that
affect tissue concentrations such as age, life span, sex, re-
productive activity, and blubber thickness. OC concen-
1
trations in marine mammals also reflect their exposure
history over many years, which could result in a signifi-
cant lag in response to changes in their exposure levels.
These factors can be accounted for quantitatively using
species-specific dynamic bioaccumulation models as has
been shown in an examination of the history of PCB
contamination in the St. Lawrence beluga whale popu-
0.1
lation (Hickie et al., 2000). Similar individual- and popu-
10
lation-based models developed for ringed seals (Kingsley
and Hickie, 1993) are used here to reconstruct the his-
DDTs
tory of accumulation of selected POPs (PCBs, DDTs,
Observed
CHLs, -HCH, and -HCH), and to predict their po-
Predicted
tential future trends in Arctic populations. In Figure
5·41, some results for males are compared to temporal-
trend data for ringed seals from Holman Island, NWT
1
from 1972 to 1991 (Addison and Smith, 1998) and from
2001 (Hoekstra et al., 2003a).
For these simulations, the entire diet of ringed seals
was assumed to consist of Arctic cod. Average POP con-
centrations reported for Arctic cod from several locations
in the Canadian Arctic in the 1990s (Hargrave et al., 1992;
0.1
Muir et al., 1999b) were used to calculate baseline average
concentrations (ca. 1996) for use in simulations that ex-
tended over the period 1970 to 2010. Resulting baseline
0.04
1970
1980
1990
2000
2010
concentrations were 4.7 ng/g ww for PCBs, 3.8 ng/g ww
for DDTs, 4.5 ng/g ww for CHLs, 2.1 ng/g ww for -
Figure 5·41. Modeled temporal trends of PCBs and DDTs in
HCH, and 0.32 ng/g ww for -HCH. Since temporal-
blubber of male ringed seals from 1972-2001 with projection into
the near future.
trend data are lacking for Arctic cod in the Canadian Arc-
tic, trends back to the early 1970s were estimated using
ecosystem. The results also suggest that contaminant lev-
temporal trends derived from the Lancaster Sound sea-
els in ringed seal populations do not show any apprecia-
bird egg monitoring program (Braune et al., 2001a) using
ble lag in response when contaminant exposure concen-
loge-linear regressions. Where discrepancies in temporal
trations change gradually over time, as appears to be the
trends were noted between the three bird species exam-
case in the Arctic. The lack of a lag in response can be at-
ined, trends from thick-billed murres were used owing
tributed to the relatively rapid elimination rates for the
to their year-round Arctic residence. Significant declines
chemicals examined, combined with the effect of popula-
were noted for PCBs (5.4%/yr) and DDTs (5.6%/yr)
tion turnover. The good agreement between the simula-
over the period of 1975 to 1998, while -HCH levels in-
tions and monitoring data serves to validate the model,
creased over time (4.2%/yr). Although trends for CHLs
and indicates that it can be used with some confidence in
and -HCH were not statistically significant, resulting
forecasting responses to potential future loading scenar-
slopes (1.1%/yr and 0.4%/yr, respectively) were used
ios. Concentrations of PCBs and DDTs in blubber are
in model simulations. These trends were assumed to re-
predicted to decline by about 40% between 2000 and
main in effect in simulations to predict possible future con-
2010, to ranges of 150-500 ng/g ww PCBs and 60-300
centrations up to the year 2010. Chemical elimination
ng/g ww DDTs for the scenarios presented here.
half-lives for seals used in these simulations were 4.1 years
for PCBs, 6.9 years for DDTs, 3.3 years for CHLs,
5.5. Summary and conclusions
2.4 years for -HCH and 1.8 years for -HCH. These
temporal trends
were derived from model calibration exercises using inde-
pendent datasets (Hickie, 2002). The half-life estimate of
A critical question in the assessment of POPs in the Arc-
PCBs was based on the weighted sum of half-life esti-
tic is whether concentrations are increasing or decreas-
mates for the 20 most abundant PCB congeners.
ing. The previous POPs assessment found a general lack
Overall, the simulations showed good agreement with
of information on temporal trends of POPs in biota
observed temporal trends in the Holman ringed seal
within the circumpolar Arctic, particularly for the High
population for all five chemicals examined, and demon-
Arctic. While results for fish in northern Sweden demon-
strated that the temporal trends evident in ringed seals
strated declines over the period of 1968 to 1996, there
are consistent with those in seabirds, and likely reflect
were only a few long-term datasets from other circum-
changes throughout lower trophic levels in the marine
polar countries. In the abiotic environment, temporal-
Chapter 5 · Temporal Variations in POP Levels
161
trend information was limited to sediment cores, which
Concentration, ng/g lw
;;
had relatively poor temporal resolution in most loca-
Ringed seal blubber
400
Polar bear adipose tissue
tions and measurements of HCH in seawater from the
300
Bering Sea and the western Canadian Arctic. For the
;;
current assessment, considerably more data on temporal
200
trends was available. Previous studies have been ex-
100
;;
;;
;;
;;
tended so that a 25 to 30-year perspective is now avail-
0
able for polar bears, seabirds, and ringed seals in the
1975
1980
1985
1990
1995
2000
Canadian Arctic, as well as for fish in the Swedish Arc-
;;
;;
;;
;;
-HCH concentration in air, pg/m3
tic. Studies covering a 10 to 15-year period are available
-HCH emissions, kt/yr
for polar bear at Svalbard, peregrine falcons in Alaska,
1000
200
Air concentrations
Atlantic cod in Iceland, glaucous gulls in Svalbard, bur-
bot, lake trout and beluga whales in Canada and walrus
800
160
Global emissions
in northwestern Greenland. Continuous air monitoring
of POPs extends from 1992-93 to 2001 at Alert, Ny-Åle-
600
120
sund, and Pallas, although results were only available to
400
80
1998 for Alert and 1999 for Pallas. `New' chemicals such
as PBDEs have been added to the list of chemicals for
200
40
which temporal trends are available in marine biota.
PCBs, the major OC contaminants in the Arctic, ap-
0
0
1980
1985
1990
1995
2000
pear to be declining in most media. In air, half-lives of
tri- to heptachlorobiphenyl congeners, based on digitally
Figure 5·42. Comparison of temporal trends of HCHs in ringed
filtered results at Alert, ranged from 3 to 17 years. These
seals and polar bears and trends of -HCH in Arctic air (mainly
from sites in the Bering/Chukchi/Beaufort Seas), as well as estimated
are much longer than in temperate locations (Great Lakes
emissions of -HCH (Li et al., 2002) over the same time period.
and the U.K.), but they do indicate a slow, downward
trend. Downward trends in air were also found for HCH
the same time period (Figure 5·42). The observed trends
and chlordane isomers; however, their half-lives were
in biota agree better with the much smaller estimated re-
also generally longer at Alert than in the Great Lakes.
duction (3% / yr) of HCHs in surface seawater (Bidle-
In the case of p,p'-DDE, o,p'-DDT, dieldrin, and en-
man et al., 1995; Jantunen and Bidleman, 1995). Unfor-
dosulfan, slight increases in air at Alert were found dur-
tunately, no time-trend data are available for any other
ing the 1990s. This is unexpected in the case of DDE and
persistent OC compound concentrations for air (or sea-
dieldrin because the use of their precursors (DDT and al-
water) over this long period. The comparison of air and
drin/dieldrin) has been restricted for more than ten years,
biota indicates the long times needed to affect a change
and in some cases, up to 30 years in circumpolar and most
in concentration in long-lived marine biota following re-
northern-hemisphere countries. It does not parallel ob-
ductions in emissions of a chemical with multiple sources
servations for marine or freshwater biota. The increases
(e.g., a re-emitted chemical that is recycled globally) and
may be unique to the particular five-year dataset exam-
long half-lives for some components (e.g., -HCH),
ined by Hung et al. (2002b) for Alert. At Ny-Ålesund, in
which assume increasing importance in seals and polar
the Norwegian Arctic, a pronounced decline in DDTs
bears over time.
in air was observed at least from 1997 to 2000. The great
While declines of major OC concentrations in biota
variation in concentrations of most OCs in air, particu-
are slow because of global cycling and long half-lives,
larly DDT at Ny-Ålesund, makes evaluation of temporal
the increasing concentrations of PBDEs in ringed seals
trends in air difficult. Long-range transport events ap-
and beluga (Figure 5·43) demonstrate that newly emit-
pear to be very important for delivering DDT, PCBs and
other OCs to these sampling sites and this may have
Worldwide PeBDE production,
kt/yr
been affected by changes in weather patterns during the
PBDE concentration, ng/g lw
1990s (Macdonald et al., 2003). Digital filtering and tem-
10
20
perature normalization (Hung et al., 2001; 2002b) have
Production
Beluga
proved useful in interpretation of air data. Unfortunately,
Ringed seal
this detailed analysis has only been applied to data from
8
16
Alert. The trends appear to be generally similar at Alert
and Ny-Ålesund, but further study is required.
6
12
Temporal trends of POP concentrations in air and
biota in the Arctic are not expected to parallel each
other given the strong influence of the inventories of
4
8
chemicals in the Arctic Ocean. This is illustrated in the
case of HCHs in ringed seals and polar bears. Air con-
centration data for -HCH, collected since 1979 by var-
2
4
ious groups at different Arctic locations, have been col-
lated into a time series up to 1996 (Li and Bidleman,
0
0
2003; Li et al., 2002). HCH levels decreased more than
1980
1985
1990
1995
2000
20 fold in air from 1979 to 1996. However, there has
Figure 5·43. Comparison of temporal trends of PBDE (Br2-Br7) in
been only a modest change in concentrations in ringed
ringed seals and beluga in the Canadian Arctic to the estimated an-
seals and polar bears in the eastern Canadian Arctic over
nual global production of PeBDE for the same time period.
162
AMAP Assessment 2002: Persistent Organic Pollutants in the Arctic
ted persistent semi-volatile chemicals can increase in cir-
of major OCs from the 1960s / early 1970s to late 1990s /
cumpolar countries in parallel with emissions. The dou-
early 2000s or from late1980s / early1990s to late1990s /
bling time for PBDE concentrations in beluga during
early 2000s, reported for selected species from remote
the early 1990s (t2 = 3.0 yr) was faster than in Holman
locations. In general, declines are more rapid if calcu-
ringed seals (t2 = 4.5 yr). By comparison, in the Great
lated for the 25-30-year period than the more recent pe-
Lakes region, PBDE concentrations in herring gull eggs
riod, as seen in the pike and char from northern Sweden.
and lake trout are increasing at approximately the same
The annual declines are best examined within species.
rate as in beluga (t2 approximately 3 yr) (Norstrom et
A statistical comparison of temporal trends of HCB,
al., 2002; Luross et al., 2003). If the same rate of in-
HCHs, and PCBs among seabirds, ringed seal, and
crease of PBDEs and declines in PCBs were to continue,
polar bear in the Canadian Arctic showed significant
PBDEs will reach parity with PCBs in Canadian Arctic
differences in rates of decline among species (Braune et
ringed seals sometime between 2015 and 2025.
al., 2001c). This reflects different biological half-lives of
No temporal trends of PBDEs are available from the
the contaminants in each species as well as migratory be-
European Arctic to compare to the somewhat different
havior in the case of Arctic seabirds, and illustrates the
temporal trends being seen in the Baltic Sea and north-
need to have multi-species data when evaluating tempo-
ern Europe (exponential increases in the 1980s, with de-
ral trends.
clines or no change occurring in some time series from
One of the most rapid declines of POPs was observed
the mid- or late 1990s) (Kierkegaard et al., 1999; 2004;
by Zhulidov et al. (2002) who found that DDTs and
Sellström, 1999; Sellström et al., 2003; Norén and
HCHs declined 15 and 13% respectively in burbot
Meironyté, 2000). The changing (and in some cases, de-
over a six-year period in the Pechora River and at a sim-
clining) temporal trends of lower brominated congeners
ilar rate in the Yenisey River. These rates are comparable
in Europe after voluntary withdrawal of the PeBDE
to those for DDT and HCH isomers in char and pike in
product show the close relationship between discontin-
northern Sweden but much higher than in burbot in the
ued use/production, reduced emissions, and decreased
Mackenzie River in Canada over the same period. This
concentrations in the environment. The European Union
rapid decline may be related to reductions in the use of
(EU) will ban the PeBDE technical product in 2004,
DDT and technical HCH during the 1980s in Russia,
which should continue the reduction in emissions in Eu-
whereas this decline occurred earlier in Canada and
rope in the long term. However, it is not clear what ef-
Sweden due to usage bans in the early 1970s. Annual de-
fect this will have on PBDE concentrations in the Arctic,
clines of PCB and -HCH in polar bear from Svalbard
since no reductions in PeBDE use are presently in force
and Hudson Bay during the 1990s differ. PCBs declined
in North America, and no temporal trends for PBDEs
more rapidly, while -HCH actually increased in Hud-
have been performed in the European Arctic.
son Bay bears and declined in Svalbard. These temporal-
A major unanswered question is the extent to which
trend results illustrate the need for information from
the temporal trends observed for various POPs to date
multiple sites within the Arctic in assessing temporal
apply throughout the circumpolar Arctic. This is partly
trends of `legacy' OCs, taking into account the history of
addressed in Table 5·3 using the annual percent declines
POPs use within a given region.
Table 5·3. Annual percent declines for major OCs calculated from long-term temporal-trend data.
Species
Location
Time period
DDTs
PCBs
-HCH a
-HCH
HCB b
Freshwater fish
Pike
Northern Sweden
1967-1999
10
4.1
11
3.4
4.8
Pike
Northern Sweden
1990-1999
8.3
4.1
10
5.4
Char
Northern Sweden
1980-1999
9.9
6.7
17
15
5.0
Char
Northern Sweden
1990-1999
14
6.0
5.5
Burbot
Mackenzie River
1986-1999
1.8
3.2
5.2
2.5
Burbot
Pechora River
1988-1994
15
13
Burbot
Yenisey River
1988-1994
16
15
Marine mammals
Ringed seals
Eastern Canadian Arctic
1975-2000
2.8
1.8
2.2
0.8
2.1
Ringed seals
Eastern Canadian Arctic
1983-2000
2.6
0.5
2.2
0.2
1.5
Ringed seals
Western Canadian Arctic
1972-2001
2.4
2.8
3.3
Ringed seals
Western Canadian Arctic
1991-2001
3.7
4.4
Beluga
Eastern Canadian Arctic
1982-1997
0.3
0.5
1.2
3.5
Polar bear
Eastern Canadian Arctic
1968-1999
4.1
0.3
1.1
1.4
Polar bear
Eastern Canadian Arctic
1989-1999
2.7
2.7
11.7
18.3
Polar bear
Svalbard
1990-1998
6.1
7.2a
Seabirds
Black-legged kittiwake
Central Canadian Arctic Archipelago 1975-1998
3.6
3.9
0.5
3.0
Black-legged kittiwake
Central Canadian Arctic Archipelago 1975-1998
7.3
7.5
1.8
2.2
Northern fulmar
Central Canadian Arctic Archipelago 1975-1998
3.2
3.1
0.9
2.1
Northern fulmar
Central Canadian Arctic Archipelago 1975-1998
0.4
2.4
3.0
0.5
Thick-billed murre
Central Canadian Arctic Archipelago 1975-1998
2.4
2.5
2.8
2.6
Thick-billed murre
Central Canadian Arctic Archipelago 1975-1998
5.1
5.6
1.1
5.5
a HCH except for pike, char and ringed seals; -HCH for polar bears at Svalbard.
b Total Te-HxCBz except for pike, char, and ringed seals.