Current Status of Antifouling Biocides Contamination in the Seto Inland Sea, Japan

Abstract A monitoring survey of antifouling biocides was conducted in Harima Nada Sea and Osaka Bay of the Seto Inland Sea, Japan, in order to assess contamination by organotin (OT) compounds and alternative biocides. The concentrations of tributyltin (TBT) compounds in surface water ranged from 1.0–2.8 ng/L and the detected TBT concentrations in the bottom water layer were higher than those in the surface water, The concentrations of TBTs in sediment samples ranged from 2.0–28 ng/g dry weight (dw) respectively. The concentrations in the water and sediment were lower than those before the banning of TBT by the IMO. Although TPT compounds were not detected in water samples, triphenyltin (TPT) compounds were detected in the range of < 0.1–2,700 ng/g dw in sediment samples. The concentrations of diuron, Sea-Nine 211, Irgarol 1051, dichlofluanid and chlorothalonil in water samples ranged from < 1–53 ng/L, < 1–1.8 ng/L, < 1–4.0 ng/L, < 1–343 ng/L and < 1–1 ng/L, respectively and these alternative compounds in sediment samples ranged from 32–488 ng/g dw, 47–591 ng/g dw, 33–128 ng/g dw, 67–8,038 ng/g dw and 31 − 2,975 ng/g dw, respectively. The partition coefficients of the alternative biocides between water and sediment were similar to those in BT compounds. Thus, the OTs and alternative biocides have still been detected in water and sediment samples from closed sea areas.