CONCENTRATIONS OF HEAVY-METALS, ORGANOCHLORINES, AND ORGANOTINS IN HORSESHOE-CRAB, TACHYPLEUS-TRIDENTATUS, FROM JAPANESE COASTAL WATERS

Concentrations of heavy metals, organochlorine pesticides, polychlorinated biphenyls and organotins were determined in horseshoe crabs, Tachypleus tridentatus, collected from Japanese coastal waters. Heavy metal concentrations were high in the hepatopancreas, gill and egg. Residue levels of heavy metals were comparable to those recorded in most benthic organisms from Japanese coastal waters. Organochlorine concentrations were detected at a few ng/g acid the residue pattern followed the order of polychlorinated biphenyls (PCBs) > chlordane compounds (CHLs) > hexachlorocyclohexanes (HCHs) > dichlorodiphenyltrichloroethane (DDTs) > hexachlorobenzene (HCB). Butyltin concentrations were high in the hepatopancreas, ranging from 350-2,270 ng/g in Hakata Bay and 570-5,000 ng/g (on a wet wt basis) in Habu Bay. Elevated concentrations of butyltins were also detected in the eggs of horseshoe crabs. High accumulations of butyltins in horseshoe crabs may pose a serious threat to their survival and therefore needs immediate attention to prevent their extinction.