Levels of organochlorine compounds in an inland seal population in eastern Finland

Abstract

Fourteen Saimaa ringed seals ( Phoca hispida saimensis) were studied for PCB, DDT, chlordane and chlorophenol compounds in blubber, liver, muscle, heart and kidney in Lake Saimaa, eastern Finland, in 1977–1981. Both PCBs and total DDT increased on average from a good 5 mg kg −1 in extractable fat of blubber in a new-born to a good 65 mg kg −1 in sexually mature specimens, the maximum being 93 and 104 mg kg −1 respectively. Concentrations of PCBs and tDDT in blubber and liver were most clearly dependent on the age and weight of the seal. Chlordanes were found in all 14 specimens (mean 0.59 mg kg −1 in blubber), trichlorophenol in one, tetrachlorophenol in two and pentachlorophenol in all three specimens studied. Although some of the Saimaa seals had reached quite high levels of both PCBs and tDDT, the present results do not indicate that the steady decrease of the Saimaa seal population during the last two decades would have been caused by these toxins, at least not in isolation.