Organochlorine and butyltin residues in deep-sea organisms collected from the western North Pacific, off-Tohoku, Japan.

Organochlorine (OCs) and butyltin (BTs) residues were determined in deep-sea organisms collected from the western North Pacific, off-Tohoku, Japan. Among OCs, concentrations of polychlorinated biphenyls (PCBs) and DDTs (DDTs and its metabolites) were the highest in deep-sea organisms (maximum concentrations of 6,700 and 13,000 ng/g lipid wt, respectively). Chlordane compounds (CHLs) were the next most abundant OCs, and hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were the lowest. BTs were also detected at maximum concentrations of 570 ng/g wet wt. Concentrations of PCBs, CHLs and BTs in deep-sea organisms collected from the western North Pacific, off-Tohoku, were generally lower than those in deep-sea and shallow water organisms from Japanese coastal waters. On the other hand, considerable variations in the concentrations of OCs were found among deep-sea organisms analyzed. Several carnivorous fishes such as snubnosed eel, lanternshark and grenadiers accumulated some OCs such as PCBs, DDTs and CHLs at high concentrations of up to a few microg/g levels. In addition, the residue pattern of OCs and BTs in fishes showed a specific trend according to the sampling depth; higher concentrations of PCBs, DDTs and CHLs and lower concentrations of HCHs, HCB and BTs were found in fishes collected from greater depth (approximately 1,000 m) compared to those from shallower waters. This trend is consistent with the results of our earlier study on mesopelagic myctophid fishes. Results of this study suggest vertical transport of hydrophobic OCs such as PCBs, DDTs and CHLs and its accumulation in benthic deep-sea organisms.

Organochlorine and butyltin residues in walleye pollock (Theragra chalcogramma) from Bering Sea, Gulf of Alaska and Japan Sea.

Persistent organochlorine (OC) and toxic butyltin compounds (BTs) were determined in walleye pollock (Theragra chalcogramma) collected from Gulf of Alaska, Bering Sea and Japan Sea, during 1991 and 1992. Polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDTs) and its metabolites were the most abundant compounds ranging up to 3200 and 2500 ng/g on lipid weight, respectively, followed by chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs) and hexachlorobenzene (HCB) in the liver of walleye pollock. Concentrations of HCHs and HCB in walleye pollock from these remote areas were higher than those in fishes from the western North Pacific and Japanese coastal waters, indicating atmospheric transport of these compounds to higher latitude regions such as Bering Sea and Gulf of Alaska and/or local input around northern Japan Sea. The concentrations of other OCs were generally comparable to those in fishes from North Pacific Ocean and Japanese waters but significantly lower than in cod-like fishes from North Atlantic and European countries. Among sampling locations, walleye pollock from Japan Sea showed higher concentrations of DDTs and HCHs compared to fishes from Bering Sea and Gulf of Alaska, suggesting greater input of these compounds around Japan Sea. Slower declining trend of DDTs and CHLs and an increasing pattern of PCBs concentrations were found in walleye pollock from Bering Sea during 1982-1992. This may imply a continuous input of these compounds by long-range transport and/or long-term persistency in these cold regions. Compared to the fishes from Japan Sea, walleye pollock from Bering Sea and Gulf of Alaska showed higher proportions of alpha-HCH and p,p'-DDE in the composition of HCH isomers and DDT compounds, respectively. This suggests selective transportability of these compounds during long-range transport to higher latitude remote areas. Concentrations of tributyltin (TBT) in the muscle of walleye pollock ranged from 1.1 to 5.5 ng/g on wet weight. Concentrations of TBT in deep-sea walleye pollock from Gulf of Alaska and Bering Sea were lower than those in Japan Sea.