Hazardous substances in fjords and coastal waters – 2008. Levels, trends and effects. Long-term monitoring of environmental quality in Norwegian coastal waters

Sammendrag

This report is part of the Norwegian contribution to OSPAR’s Coordinated Environmental Monitoring Programme (CEMP). CEMP 2008 included the monitoring of contaminants in blue mussel (51 stations), dogwhelk (8 stations), cod (11 stations), tusk (1 station), ling (3 stations), prawn (5 stations), flatfish (10 stations) and sediments (5 stations) along the coast of Norway from the Oslofjord to the Varangerfjord. Of the 890 time series in this project, 256 were statistically significant trends, 228 (89 %) of these were downward trends and 28 were upwards. In 142 cases concentrations were above what is expected in only diffusely contaminated areas (collectively termed overconcentrations). The results showed elevated levels of contaminants, in a few cases up to extremely polluted, in blue mussel in the Frierfjord (dioxins/TCDDN), in the Ranfjord (B[a]P) and in the Sørfjord (ppDDE). Blue mussel in the Kristiansandsfjord and the Ranfjord were up to severely polluted with B[a]P. Cod liver from Inner Oslofjord was markedly polluted, and the fillet was moderately polluted with PCBs. There was a significant downward trend for PCBs in blue mussel from Gressholmen in the Inner Oslofjord. Fillet of cod from the Inner Oslofjord was moderately polluted with mercury, a significant upward trend was detected for the period 1984-2008. A significant downward trend was found for lead, cadmium and mercury in blue mussel from Sørfjord/ Hardangerfjord. Fillet of cod from the Inner Sørfjord was moderately polluted with mercury, and cod liver was insignificantly polluted with ppDDE and PCBs. Fillet of ling from the Inner Sørfjord had a median concentration of mercury of 0.48 mg/kg, which is close to the lower limit of Class IV (severely polluted). Fillet of both tusk and ling from the Høyanger area were moderately contaminated with mercury. Contamination of organotin in blue mussel and imposex in dogwhelk were still apparent, however, most of the trends were downwards indicating that regulatory action has lead to an improvement in the investigated areas. The results from studies using biological effects methods in cod, indicated reduced exposure to planar organic contaminants in the Oslofjord. In the Grenlandsfjord area there was a significant downward trend for HCB in blue mussel. No overconcentrations of contaminants were found in prawns. A reduction since 1990-1999 was found for mercury in sediment at Mølen-Moss and Steilene, and for PCBs (50 %) at Steilene. A decrease of PCBs, PAH and sum KPAH in sediment was found at all stations since 1990-1999. The sediment at Steilene was moderately polluted with TBT. No overconcentrations were found in sediment for cadmium (Cd), dichlorodiphenyldichloroethylene (ppDDE), lindane (g-HCH) and hexachlorobenzene (HCB).