Scottish Marine and Freshwater Science Volume 5 Number 15: Development of a Sampling Programme and Measurement of Contaminants in Food for Marine Strategy Framework Directive Descriptor 9

Conclusions

1. The Marine Strategy Framework Directive's Descriptor 9 states that 'contaminants in fish and other sea food for human consumption do not exceed levels established by Community legislation or other relevant standards '. Therefore, for Descriptor 9 assessment, contaminant concentrations in fish and seafood should be compared against the EC regulatory levels.
2. European regulatory levels are available for trace metals (Cd, Hg and Pb), dioxins, DL-PCBs and non DL-PCBs ( ICES6, CB28, 52, 101, 138, 153 and 180) in fish muscle, crustacea and bivalve molluscs, for PAHs (benzo[ a]pyrene), in crustacean and bivalves and for dioxins (including DL-PCBs) and non DL-PCBs in fish liver ( EC/1881/2006 and EC/1259/2011).
3. Current Scottish monitoring programmes for contaminants in shellfish undertaken by SEPA and FSAS will be of use for Descriptor 9 assessments. SEPA monitor 56 shellfish sites around Scotland for metals (including Cd, Hg and Pb), PCBs ( ICES7, CB28, 52, 101, 118, 138, 153 and 180) and PAHs (including benzo[ a]pyrene], this data is submitted to the MERMAN database. As part of statutory monitoring, FSAS conducts annual monitoring of chemical contaminants (metals, PAHs, PCBs, dioxins and organochlorine pesticides) in newly classified shellfish areas and/or shellfish areas which were subject to sanitary surveys. These data are not currently submitted to the MERMAN database, but may be in future, and could be of use for Descriptor 9 assessments. This may require amendments to MERMAN which will require additional resource.
4. MSS monitor contaminants (including Cd, Hg, Pb and ICES6 PCBs) in fish at sites around Scotland for programmes such as the UK Clean Seas Environment Monitoring Programme ( CSEMP) and Clyde trend monitoring programme. Most of these data will be of little use for Descriptor 9 assessments as commercially exploited fish species/size-ranges are not targeted and, with the exception of metals, contaminants are measured in fish liver rather than in the edible flesh.
5. Dioxins and DL-PCBs in fish muscle or liver are not an OSPAR CEMP requirement and, therefore, are not routinely monitored for UK CSEMP. Due to the very low concentrations of dioxins found in the environment, the chemical analysis requires high-resolution mass spectrometry. MSS and SEPA do not have the capability to measure dioxins, so this analysis would have to be contracted out at significant cost. However, dioxin TEQs may be estimated from the PCB concentrations using published models and could be used to demonstrate if dioxin TEQs are likely to exceed the MPC. Therefore, no additional monitoring of dioxins and DL-PCBs is proposed for Descriptor 9.
6. Available data obtained from FSAS and from the MERMAN database indicates that GES is likely to be achieved for Descriptor 9. Shellfish data in the MERMAN database (trace metals, PCBs and PAHs) and from FSAS (trace metals, PAHs, PCBs and dioxins) shows that concentrations are below the available maximum permitted concentrations ( MPCs) in nearly all samples. Although there is very little data on the concentration of dioxins, particularly for fish, the available data indicates that concentrations are not of concern. The FSAS has carried out a number of surveys on dioxins in fish and fishery products. Concentrations were generally below MPCs.
7. Recent data are not available on the concentrations of contaminants in Nephrops, although this is the most fished crustacean species. Nephrops burrow in fine sediment, which will contain higher concentrations of contaminants than coarse sediments. A statistical sampling design has not been undertaken, but samples will be taken from commercially important fishing grounds (the Clyde and the Moray Firth) close to potential sources of contaminants.
8. Although there are monitoring programmes in place for the analysis of contaminants in biota (such as FSAS surveys and the UK CSEMP), they do not fully meet the requirements of MSFD Descriptor 9, particularly for fish. Therefore, a fish sampling programme for Descriptor 9 was designed. Haddock, monkfish and herring were selected based on their importance to the human diet (based on landings data) and their ability to accumulate contaminants. Sampling was based around existing research vessel surveys for obtaining indices of abundance for use in fish stock assessments. Fish were sampled on these surveys from haul locations with probabilities proportional to landings.