Organochlorine pesticides, polychlorinated biphenyls, and butyltin compounds in blubber and livers of stranded California sea lions, elephant seals, and harbor seals from coastal California, USA

Concentrations of polychlorinated biphenyls (PCBs), DDTs (p,p ' -DDE, p,p ' -DDD, p,p ' -DDT), chlordanes (CHLs; cis-chlordane, cis-nonachlor, trans-n onachlor, and oxychlordane), hexachlorocyclohexane isomers (HCHs), hexachlo robenzene (HCB), tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)m ethanol (TCPMOH), and mono- (MBT), di-(DBT), and tri-butyltin (TBT) were de termined in blubber and livers of 15 California sea lions (Zalophus califor nianus), 6 northern elephant seals (Mirounga augustirostris), and 10 harbor seals (Phoca vitulina) found stranded along the coasts of California, USA, during 1991-1997. Among the organochlorines analyzed, DDTs were predominan t, followed in decreasing order by PCBs, CHLs, TCPMe, TCPMOH, HCHs, and HCB . The greatest concentrations of organochlorines were found in California s ea lions. The highest DDT and PCB concentrations found in the blubber of Ca lifornia sea lions were 2,900 and 1,300 mug/g, lipid weight, respectively. Concentrations of TCPMe and TCPMOH in California sea lions were correlated significantly with DDT concentrations. Concentration ratios of various orga nochlorines in harbor seal livers were different from those in California s ea lions and elephant seals, which suggested that the sources of exposure o f harbor seals to organochlorines were different from those in the other tw o species. Concentrations of butyltin compounds in livers of pinniped speci es ranged from 2 to 99 ng/g, wet weight, which were less than those observe d in cetaceans and in California sea otters.