Executive Summary

Inter-calibration Summary Workshop for UNDP/GEF Yellow Sea Project:

Nutrients – Round 1 and Round 2

Metals and Organics – Round 1

8^th to 10^th October 2007

Jeju Island, Republic of Korea

A. Background

The UNDP/GEF Yellow Sea Project’s experts working with the Pollution Component identified “inter-calibration exercises to analyse nutrients, metals and organic compounds” as a high priority activity to be implemented in the region. It was expected that these exercises would enhance the region’s capacity in analytical methods, and also attempt to identify labs that would analyse samples from joint survey activities, in order to ensure standardisation of analytical methods and results.

From 2005 to 2006, two rounds of nutrients in seawater inter-calibration exercises were carried out by 4 labs in China and 3 labs in Republic of Korea. The Queensland Health Scientific Services, Australia, co-ordinated the activity on behalf of the Yellow Sea Project, by supplying the reference materials to each lab, collecting and analysing the results, and preparing the final reports containing the summary results and recommendations for future improvement.

The members of the 3^rd Regional Working Group Meeting for the Pollution Component (4 to 7 Sept. 2006, Dandong, China) decided that a “Summary Workshop” for the nutrients exercises should be organised for the labs to assess their degree of comparability of the results, to exchange their experiences, and to learn from each other how to improve their analytical skills.

The first inter-calibration exercise for metals and organics in sediment and biota was carried out in 2007. The International Atomic Energy Agency’s Marine Environment Laboratory (IAEA-MEL) in Monaco co-ordinated the activity on behalf of the Yellow Sea Project. Some of the labs implementing this activity also participated in the “Summary Workshop.” At the time the workshop was convened, the metals and organics exercises were near completion, with the majority of labs already submitted their results. Thus, the summary includes results only from labs that had submitted results.

The “Summary Workshop” consisted of two parts to include sessions for both sets of exercises. The co-ordinators for both exercises participated in the workshop to make recommendations to participants on improving analytical skills, and obtain information from participants on technical and capacity gaps in their laboratories. The objectives of the workshop are listed below.

B. Objectives

• Review and summarise the two nutrient inter-calibration exercises organised by YSLME and QHSS

• Review results for metals & organics inter-calibration exercise

• Assess the degree of comparability of the results obtained by the participating labs

• Exchange experiences on and lessons learned from problems related to analytical chemistry, and to apply lessons learned to future work

C. Expected Outcomes

The expected outcomes for the workshop are listed below:

• Each participating lab will describe its standard operating procedures for analytical methods used in the two nutrient, metals, and/or organics inter-calibration exercises¹, QC methods used in analysis², the difficulties encountered during the exercise, solutions taken, and reactions to the results.

• The workshop is expected to allow the labs to exchange experiences on analytical methods, learn skills from each other, and share knowledge on how to improve analytical methods and skills.

• It is expected that, upon return home, each lab will re-examine its current aptitude in analytical methods and improve where necessary.

D. Results and Discussion

Although not all labs were able to attend the workshop, the ones that did, presented their results, operating procedures, and problems encountered during the analysis. All participants shared their experiences, suggestions, advice, and ideas on how to improve future results. The activity co-ordinators reported that, in general, the results illustrated a very good level of performance.

The workshop produced a summary table of sampling materials, methods, and storage described in Table 1.

Table 1. Results of discussion on materials and methods for sampling and storage.

The nutrients section of the workshop also discussed and provided a summary of some of the major issues and problems faced during the exercise. Some tips are listed below.

Nutrients in Seawater

Nutrients QA/QC – during Analyses

Nutrients:

• calibration standards – in-house reference materials reflect concentration and matrix

• spiking actual samples

• produce control chart, acceptance criteria

• repeat samples between every 1 and 10 samples

• instrument check

• internal standards – 4 to 5 deuterated PAHs

• CRMs

Ammonia (NH₃) problems in the lab

Lab contamination: - isolate the lab

• cover sample tubes with Al foil

Cross contamination with other reagents: NOx, NH₄Cl, FRP, ammonium molybdate

- Need to be careful with glassware and apparatus used for preparing reagents

- Need dedicated glassware

- good DI water

Contaminated reagents from manufacturer: record batch numbers each time

Getting low results: may be due to samples thawed for too long

• small amount of microbial activity in sample – do not leave at ambient temperature > 24 hours

• calibration standard might be compromised

• complexing reagents are not adequate for saline waters

• in-house reference material should be < 0.001mg/L as N or P

• Need depleted sea water to set up everyday

Phenol problem

Bad smell, carcinogenic

Draw waste line from instrument into sink’s drain with S-bend. Smell will go directly down the drain.

FRP

Overall results were good

Nitrate

2^nd round results not as good as first round.

Beware that buffer solution contains phosphoric acid

Cd-reduction column can be contaminated with sulfides & high metals, and result in low recovery. Add 5ml of 2% CuSO4 in 2L buffer solution.

Check column efficiency - run standards, run nitrate standard. Run check standard every 20 samples to see if instrument is drifting. Can increase temperature (ambient or 35C or 45C).

Si

Use hydrated standard.

Store in plastic container. Don’t freeze samples. Otherwise keep at room temperature for 3 days.

Si can interfere with P. Measure P ASAP.

TN and TP

Kjeldahl digest – high temperature, strong acid – sulfuric acid at 360C. High solids.

Persulfate oxidation at 121C

• base

• acid

base/acid – x2 digestion & shaking in between. 30 mins.

Metals in Sediment and Biota

Some salient summary points are listed below:

• In general, a very good level of performance was indicated, with only 2 of 7 labs that had submitted results thus far, having problems with accuracy for metals in sediment analyses with the chosen level of sigma.

• For metals in biota, only 1 lab had outliers in its results, while another lab had some problems only with Cr and Hg analysis.

• Two labs had low results for Zn and As, probably due to differences in acid strength between the test solution and the calibrating standards.

• The analytical performance for QC samples appeared to be significantly better than that for contemporaneously analysed, similar matrix unknown samples in several cases.

• It was suggested to use closed vessel microwave digestion to speed up sample digestion (better throughput), minimise contamination, and gain greater control of the digestion process.

Organics in Sediment and Biota

The summary points for this exercise are listed below:

• Similar to the metals exercise, the overall results were quite good, with only 1 lab that should review its analytical methods.

• Extraction method for sediment and biota should not be the same, as lipids in biota need to be accounted for.

• Acid treatment can be used for chlorinated pesticides. This can affect only aldrin and diedrin. Sulphuric acid extraction will destroy aldrin and diedrin.

PAH analysis:

Extract samples, allow Cu to sit overnight in the extract. If still black over night, then there is still sulphur present. Add more Cu to limit interference. Then analyse samples. If Cu added directly to samples, then cannot determine if sulphur is present.

Using Hg is old method, and not as reliable. Hg may have health problems, and can destroy PAHs.

Samples can degrade if stored long time. Radiation can help keep samples, but can still destroy sample a bit. Keep in cool and dark place.

Approximately 260°C for naphthalene analysis is sufficient.

E. Workshop Programme

NUTRIENTS

METALS

ORGANICS

6. Presentation files

All presentation and reference files of the workshop are available on this CD under the “Presentations” folder.