Evaluation du descripteur 8 « Contaminants dans le milieu » en France Métropolitaine.

Good Environmental Status (GES) for descriptor 8 of MSFD is reached when concentrations of contaminants are at levels not giving rise to pollution effects. According to the decision 2017/848/CE, descriptor 8 is defined by four criteria: concentration in the relevant matrices (sediment, biota) (D8C1), effects of chronic contamination to the marine organisms (D8C2), duration and spatial extent of acute pollution events (D8C3), effects of acute contamination to the marine organisms (D8C4). The GES for descriptor 8 is assessed at the level of four marine subregions (SRM), including: Channel – North Sea (MMN), Celtics Seas (MC), Bay of Biscay (GdG) and the Occidental Mediterranean Sea (MO). In order to achieve GES, each indicator of descriptor 8 should respect the environmental thresholds (OSPAR, MED POL, EPA, DCE) or, alternatively, the sanitary thresholds (EC) and should not increase over time. Regarding D8C1, the assessed matrices include sediment, bivalves and fishes. The associated indicator is the couple of matrix/taxon*substance. For sediment and bivalves, this indicator is assessed at the station level for the marine reporting unit “coastal waters”. For fishes, indicator is assessed at the scale of the sea-campaign area for the marine reporting unit “territorial/offshore waters”. For D8C2, the assessed matrices include gastropods, bivalves and fish. The associated indicator is the couple of biomarker*species. For gastropods, Imposex is reported at the station level for the marine unit reporting “coastal waters”. Biomarkers are reported at the scale of the study area (Seine Bay) for the marine unit reporting “coastal waters” for bivalves and “territorial/offshore waters” for fishes. For D8C3, the pollution-reporting datas (POLREP) have not been collected, this criteria is therefore not assessed. For D8C4, assessed matrices are oiled birds corresponding to the EcoQO “oiled guillemot”. This indicator is assessed at the MMN scale for marine unit reporting “coastal waters”. GES assessment showed that the contamination was more important, but not limited to, the Bay of Seine and Mediterranea, wich are an epicontinental area and an enclosed sea, respectively, consequently, seas more subject to anthropic pressure than GdG and MC. GES assessment also pointed out the need to develop monitoring tools and knowledge to reach more firm interpretation of the monitoring data, e.g. 1) a better harmonization of the monitoring programs over the 4 SRM, 2) development of environmental thresholds for D8C1 and D8C2, 3) assessment of contaminants biogeochemistry for a better understanding of the contamination fate into the different matrices and also their associated effects to marine ecosystems.