H. Nakata | Geology Reports

USGS2004

Profiles of polychlorinated biphenyl congeners, organochlorine pesticides and butlyns in southern sea otters and their prey

Concentrations of organochlorine pesticides, polychlorinated biphenyl (PCB)congeners, and butyltins were measured in sea otters and selected prey species (invertebrates) collected from the California (USA) coast. Polychlorinated biphenyls, DDTs (sum of p,p ′-dichlorodiphenyldichloroethylene [ p,p -DDE], p,p ′-dichlorodiphenyldichloroethane [ p,p -DDD], and p,p ′-DDT), and butyltins were the major contaminants found in sea otters and their prey. Lipid-normalized concentrations of PCBs and DDT in sea otter livers were 60- and 240-fold greater than those found in the prey. Great biomagnification of PCBs and DDT in sea otters is suggested to result from their high per-capita intake of diet compared with those of other marine mammals. Profiles of PCB congeners in sea otters and prey species suggest a great capacity of sea otters to biotransform lower-chlorinated congeners. Sea otters seem to possess a greater ability than cetaceans to metabolize PCBs. The 2,3,7,8-tetrachlorodibenzo- p -dioxin equivalents of non- and mono- ortho PCBs in sea otters and certain prey species were at or above the theoretical threshold for toxic effects.

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USGS1998

Accumulation pattern of organochlorine pesticides and polychlorinated biphenyls in southern sea otters (Enhydra lutris nereis) found stranded along coastal California, USA

Concentrations of PCBs, DDTs ( p,p' -DDE, p,p' -DDD and p,p' -DDT), HCHs (α-, β-, γ-isomers), chlordanes ( trans -chlordane, cis -chlordane, trans -nonachlor, cis -nonachlor and oxychlordane) and HCB (hexachlorobenzene were measured in liver, kidney and brain tissues of adult southern sea otters ( Enhydra lutris nereis ) found stranded along coastal California, USA, during 1992–96. The contamination pattern of organochlorines in sea otters from several locations was in the order of DDTs>PCBs>>CHLs>HCHs>>HCB, whereas those from Monterey Harbor contained greater concentrations of PCBs than of DDTs. Hepatic concentrations of PCBs and DDTs were in the ranges of 58–8700 and 280–5900 ng/g, wet weight, respectively, which varied depending on the geographic location. Sea otters collected from Monterey Harbor contained the greatest concentrations of PCBs and DDTs. In general, accumulation of DDTs, CHLs and PCBs was greater in kidney than in liver, whereas that of HCHs was similar in both the tissues. The gender difference in organochlorine concentrations was less than those reported in cetaceans. The composition of DDTs, HCHs and CHLs compounds in sea otter tissues indicated no recent inputs of these compounds in coastal California. Sea otters that died from infectious diseases, neoplasia and emaciation contained higher concentrations of DDTs than those that died from trauma.

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