Polychlorinated-dibenzo-p-dioxins, -dibenzofurans and -dioxin-like polychlorinated biphenyls in aquatic organisms from lake Kasumigaura, Japan

Abstract

Polychlorinated-dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs) and -dioxin-like polychlorinated biphenyls (DLPCBs) were determined in aquatic wildlife of Kasumigaura Lake (KUL), Japan from 1978 to 2001. Two plankton species elucidated several fold greater concentrations (2400-7800) than small tiger fish (310-6500), shrimp (160-1100), and three large fish namely, black bass (120-240), carp (94-120) and mullet (54) on pg/g fat. PCDD homologues were predominant accumulants with >68-<95% contribution and remaining was shared by PCDFs. Accumulation, non-ortho DLPCBs in plankton (3500-9200), shrimp (1600-8600) and small fish (2000-8800) and large fish (1300-3900) on ng/g fat basis were several orders magnitude greater than PCDD/DFs. The mono-ortho DLPCBs in large fish species were 23 000-83 000 ng/ g fat and which it is accounted 94.3-95.9% the total dioxin-like PCBs accumulation. Temporal trends of PCDDs, PCDFs, non-ortho PCBs and TEQ in shrimp and small tiger fish were varied. The mullet had minimum toxic equivalency ''TEQ'' (14 pg TEQ/g) followed by plankton Neomysis intermedia (25 pg TEQ/g), small tiger fish (mean: 33, ranges 14-66 pg TEQ/g), plankton Cyclopus vicinus (34 pg TEQ/g), carp (mean: 35, ranges 32-38 pg TEQ/g), shrimp (mean: 38, ranges 11-68 pg TEQ/g) and black bass (mean: 59, ranges 38-79 pg TEQ/g) on fat basis. In all the samples, PCDD was predominant TEQ contributor followed by PCDFs and DLPCBs. The contribution of mono-ortho DLPCBs to the total TEQ was 0.52-0.92 in large fish.