Seasonal fluctuations of organochlorine levels in the common elder (Somateria mollissima) in Iceland

Breast muscle of 55 common elders (Somateria mollissima) and liver samples of 12 birds, caught at Skerjafjorour in SW-Iceland in February, May, June a nd November 1993 were analysed for organochlorine contamination (10-30 diff erent congeners of PCBs, pp'-DDT, -DDE, -DDD, HCB, alpha-, beta-, and gamma -HCH). The levels of the contaminants were similar in both tissues and were at their lowest in February. A substantial increase (up to 10-fold) in the levels of all substances was observed in June, in the females, which at th at point had lost about one-third of their late winter body weight. The inc rease may be due to relocation to other tissues of organochlorines stored i n the shrinking bodyfat. During this period the birds must be vulnerable to the toxic effects of these chemicals as they can transiently reach high co ncentrations in the blood. The levels found were similar or higher than tho se recently reported for elders from Spitsbergen, the NWT of Canada and Fra ns Josefs Land of Russia, especially the levels of PCBs. (C) 1998 Elsevier Science Ltd. All rights reserved.