Contaminants in coastal waters 2024: Miljøgifter i kystområdene 2024

Abstract

The Norwegian environmental monitoring programme “Contaminants in coastal waters” (Miljøgifter i kystområdene - MILKYS) examines the levels, trends, and effects of contaminants annually in biota along the Norwegian fjords and coastline including Svalbard. The 2024 investigation included analyses of more than 180 different contaminants or biological effect methods (BEM) in five species (blue mussel, cod, dogwhelk, common periwinkle, and common eider). The contaminants measured include metals, TBT, PCBs, PAHs, PBDEs, PFAS, HBCDs, chlorinated paraffins, siloxanes, and pesticides. BEM includes imposex (VDSI) and intersex (ISI), PAH-metabolites, ALA-D, and EROD. The 2024 optional monitoring also included sediment cores (Oslo, Bergen, and Tromsø) and alternative species (whiting, pollack, and haddock) for cod in the Inner Oslofjord. In this report, 37 contaminants and in addition, BEM were chosen for in-depth presentations. EQSs (Environmental Quality Standards) were exceeded in blue mussel (16%), cod (37%), and common eider (22%) expressed as datapoints (contaminants x stations). Contaminants above EQSs were mercury (Hg), sumPCB7, and sumBDE6. PROREFs (Norwegian provisional high reference contaminant concentrations) were exceeded in blue mussel (35%) and cod (11%) expressed as datapoints (contaminants x stations), and exceedances were higher in mussel (10-20x PROREF) than for cod (5-10x PROREF). Significant downward time trends for specific contaminants/effects dominated both recent (≤10 years) and whole period (>10 years) where trends could be statistically detected. The OSPAR method for time trends, HARSAT was used. The highest occurrences of upward whole and recent trends were found for blue mussel in the Inner Oslofjord, and for cod at Lista and Sandnessjøen. Biological effect parameters showed no effects of TBT in snail, but confirmed exposure to PAH and lead in cod. The additional monitoring showed that sediments from the Inner Oslofjord had higher frequency of exceedances of EQS than close to Bergen and Tromsø. Whiting seems to be the most appropriate species for monitoring as an alternative to cod, compared to pollack and haddock, based on biology and comparisons of contaminant levels in the Inner Oslofjord.