OSPAR request on spatial design of a regional monitoring programme for contaminants in sediments

This is an update of the advice given in 2012 on spatial design of a regional monitoring programme for contaminants in sediments. Advice is provided on preferred types of sediment, sampling depths, ship time considerations, and the selection of areas where monitoring will be most effective.

The following approach for sediment monitoring designs on a regional scale is advised:

1. Identify areas of sediment with ≥20% fines1.

2. Create sampling strata containing only areas with ≥20% fines.

3. Use existing data to estimate mean concentrations and variability in the sampling strata.

4. Undertake a power analysis to determine the number of samples required in each stratum.

5. Aggregate individual stratum assessments to the regional scale by using the weighted mean of the individual stratum means, using stratum area as the weighting factor.

6. Refine the design in the light of the additional data obtained above (e.g. the location of strata, and the number of samples required per strata).

7. Statistically compare the aggregated values with the assessment criteria to determine compliance with good environmental status (GES) as expressed in the Marine Strategy Framework Directive (MSFD).

ICES advises that OSPAR coordinates regional sampling programmes based on the approach outlined. ICES is of the opinion that this sampling design allows assessment of compliance with the MSFD GES for the European regional seas.