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

Concentrations of heavy metals, organochlorine pesticides, polychlorin ated biphenyls and organotins were determined in horseshoe crabs, Tach ypleus tridentatus, collected from Japanese coastal waters. Heavy meta l concentrations were high in the hepatopancreas, gill and egg. Residu e levels of heavy metals were comparable to those recorded in most ben thic organisms from Japanese coastal waters. Organochlorine concentrat ions were detected at a few ng/g acid the residue pattern followed the order of polychlorinated biphenyls (PCBs) > chlordane compounds (CHLs ) > hexachlorocyclohexanes (HCHs) > dichlorodiphenyltrichloroethane (D DTs) > hexachlorobenzene (HCB). Butyltin concentrations were high in t he 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 accu mulations of butyltins in horseshoe crabs may pose a serious threat to their survival and therefore needs immediate attention to prevent the ir extinction.