| Summary: | The report summarises the monitoring activities within the National Swedish Contaminant Programme inmarine biota.Few trends are found for the biological variables of the biota included in the programme (age, weight,length, and fulton´s condition factor). This is expected, as samples are selectively selected to avoidtrends. However, all variables for Holmöarna in the Bothnian Bay and the fish age at the West Coastsites (Kullen, Fladen and Väderöarna) stands out for herring, cod and perch as having upward trendsover the last 10 years. Since many of the contaminants presented in this report bioaccumulate, this islikely to affect the trends presented below.For the aggregated herring data (on sub-basin scale) on chlorinated pesticides, PCBs, dioxins andfurans, brominated flame retardants and perfluorinated substances (PFAS) a general downward trendfor the last 10 years (2010-2019) is seen for all sub-basins (Southern and Northern Baltic Proper andBothnian Sea and Bay) except the West Coast. On the West Coast, changes are small and often nonsignificant. The contaminant concentrations are in general lowest on the West Coast but theconcentration difference between the West Coast and the other sub-basins has shrunken over the last10 years as the concentrations in the other sub-basins are decreasing towards West Coast levels. Theperfluorinated compound FOSA is an exception to this picture, with 2-4 times higher concentrations onthe West Coast compared to the Baltic Sea. For the metals, no common patterns are seen for theaggregated herring data across the metals or for each specific metal between sub-basins.
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