Contaminants in coastal waters of Norway 2020

Sammendrag

The monitoring programme “Contaminants in coastal waters of Norway” (Miljøgifter i norske kystområder - MILKYS) examines levels, trends and effects of contaminants in biota. The 2020-investigation included analyses of more than 176 different contaminants or biological effect parameters in six species (blue mussel, cod, dogwhelk, common periwinkle, flounder and common eider). The contaminants measured includes metals (Hg, Cd, Pb, Cu, Zn, Ag, As, Ni, Cr and Co), tributyltin (TBT), organochlorines (e.g. PCBs (PCB-7), DDT, HCB, OCS and QCB), PAHs, polybrominated diphenyl ethers (PBDEs), perfluorinated alkylated substances (PFAS), hexabromocyclododecane (α-, γ- and β HBCD), chlorinated paraffins (SCCP, MCCP) and siloxanes (D4, D5 and D6). Biological effects parameters includes imposex (VDSI) and intersex (ISI), OH-pyrene metabolites as a marker of PAH-exposure, ALA-D as a marker of exposure to lead, and EROD as a marker to exposure to planar PCBs, PAHs and dioxines. In this report, 30 contaminants or biological effects parameters were chosen for statistical analyses of 739 time series (short-term trends for the last 10 years). Of these, there were statistically significant trends in 96 cases: 67 (9.1 %) were downwards and 29 (3.9 %) upwards. The dominance of downward trends indicated that contamination was decreasing. The downward trends were primarily accociated with metals, α-HBCD and PBDEs, and the upward trends with metals. Of the 2020-medians for all 739 time series, 380 cases could be classified against EQS, of which 264 (35.7 %) were below the EQS and 116 (15.7 %) were above. Of the 739 time series, 644 cases could be classified using Norwegian provisional high reference contaminant concentrations (PROREF). Of these, 447 (69.4 %) were below PROREF. The remaining 197 (30.6 %) cases exceeded PROREF: 105 (16.3 %) by a factor of less than two, 57 (8.9 %) by a factor between two and five, 30 (4.7 %) by a factor between five and 10, three (0.5 %) by a factor between 10 and 20, and two (0.3 %) by a factor greater than 20. Some cases warrant special concern, such as high concentrations of several organic contaminants in cod liver from the Inner Oslofjord.