Determination of butyltins and phenyltins in oysters and fishes from Taiwan coastal waters

Along the western coast of Taiwan, high concentrations of butyltin compounds (BTCs), such as tributyl- (TBT), dibutyl- (DBT) and monobutyl- (MBT) (91–1658 ng/g, dry wt) with relatively high percentages (85–100%) were found in oysters (Crassostrea gigas) collected in winter compared with those concentrations (99–763 ng/g) with relatively low percentages (as low as 23%) in summer. However, in contrast to BTCs, higher contents (102–590 ng/g) with low percentages (as high as 77%) of phenyltins (PTCs), such as triphenyl- (TPT), diphenyl- (DPT) and monophenyl- (MPT), were found in summer compared with those values (nd–147 ng/g) with low percentage (0–15%) in winter. For the fish (Pahrus major, Cephalopholis argus, Lates calacriter, Scarus cedema) samples, collected near Kaohsiung offshore area, the contents (dry wt) of MPT (<8.7 ng/g), DPT (<7.2 ng/g) and TPT (<15.7 ng/g) as well as TBT (<9.1 ng/g) were under the detection limits. The contents of DBT (18.5±3.0 to 46.5±4.0 ng/g), and MBT (<8.1 to 9.6±2.0 ng/g) in muscle tissue of fish varied with species. High values were found in Lates calacriter and low values in Pahrus major. Higher contents of OTCs in oysters and lower values in muscle of fish might indicate that the organotin pollution problem in Taiwan is more serious in estuary mariculture sites compared with the offshore coast, where the fish live.