Report of the Working Group on the Statistical Aspects of Environmental Monitoring (WGSAEM)

) WGSAEM agreed on the need for data flow quality assurance (QA). This was addressed in several presentations:

• An assessment of Swedish nutrient monitoring data, where apparent trends might have been caused by changes in laboratory practices (see Chapter 4.1 and Chapter 8 Recommendations);

• Presentation of several tools for testing the plausibility of measured metals and PAH’s in suspended matter of fresh water rivers, which takes into account the correlations between compounds (see Chapter 4.2);

• An investigation of systematic changes in observed levels of persistent organic pollutants (POP) in stored samples at -20°C (see Chapter 4.3).

• Review of the proposed HELCOM Combine Manual; request by the ICES Working Group STGAQB.