Diffuse kilder til PCB og effektstudier i torsk og blåskjell ved Haakonsvern orlogsstasjon

Abstract

Studies of diffuse sources of PCB in addition to studies of toxicological and physiological effects in cod and blue mussel has been carried out at Haakonsvern Naval Base in connection with a clean up of PCB contaminated sediments. A risk evaluation concerning human health and marine life is also carried out. These studies show that there are some local sources of PCB on land which may contaminate the sediments. The total transport of PCB7 from land has been calculated to 10 g/year. The concentration of PCB in rain is also quantified. The concentration of PCB in rain in June was much higher than in November, which can be explained by temperature differences. It is calculated that the deposition of PCB7 at the sea surface is 14 g/year. These two sources can cause a minimum concentration of PCB in the sediments of 65 μg/kg. The mean concentration of PCB7 in sediments collected in sediment traps was 280 μg/kg. This will probably reduce the effects of the clean up effort. No physiological and only signs of toxicological effects were observed in caged cod at the naval base. A significant accumulation of PCB in mussels was observed and the accumulation has not changed since 1998. Results from the health risk evaluation shows that the concentration of PCB7 in the sediments should be below 10 μg/kg. There is no risk associated with the PCB contamination in sediments to the marine life at the study site.