Contamination Status of Organohalogen Compounds in Deep-Sea Fishes in Northwest Pacific Ocean, Off-Tohoku, Japan

Twelve species of deep-sea fishes collected in 2005 from the western North Pacific, off-Tohoku, Japan were analyzed for persistent organochlorine compounds (OCs) and brominated flame retardants (BFRs). PCBs and DDTs were the predominant contaminants, followed by CHLs > HCB ≈ HCHs ≈ HBCDs > PBDEs. Concentrations of DDTs and CHLs were lower than those reported in 1994–95 from the same area. PCBs, however, did not show a decreasing trend, suggesting its recent input from the nearby land areas. BFRs were detected in all the specimens, evidencing that the contamination by these compounds reached even the deep-sea environment. Significant positive correlations between δ15N and concentrations of PCBs, DDTs and PBDEs were observed indicating that these compounds are biomagnified in higher trophic level fish. On the other hand, correlations between δ15N and concentrations of HCHs and HCB were not significant. As PCBs, DDTs and PBDEs have higher logKow values than those of HCHs and HCB, our findings confirm the fact that lipophilic compounds are bioaccumulated and biomagnified more easily.