Monitoring of Tributyltin Contamination of Demersal Fish in Coastal Water in East China Sea

Tributyltin (TBT) has been widely used as an antifouling agent in marine environments since the early 1960s (Huggett et al., 1992), having been applied to boat hulls and to marine aquaculture equipment. Because of its high toxicity of TBT to aquatic organisms (Clark et al., 1988), the use of TBT has been regulated worldwide since the 1980s. The International Maritime Organization (IMO) imposed a worldwide ban on TBT in 2003 (Champ, 2000). However, TBT is still detected in coastal sediments in the world (Antizar–Ladislao, 2008). In around northern Kyushu, Japan, the concentrations of TBT have been found to range from 0.005 to 0.094 μg/L and 0.007 to 1.1 μg/g dry weight (dw) in seawater and sediments, respectively (Inoue et al., 2002), high TBT concentrations were also detected in sediments from next to the shipyard in Hakata port (0.63 μg/g wet weight), Fukuoka, Japan (Undap et al., 2013a) and from 0.0014 to 0.19 μg/mL in blood from marine fish (Miki et al., 2011). Contamination of sediment and aquatic organism by TBT still occurred in coastal areas around northern Kyushu. These results suggest TBT has been detected not only in water and sediments, but also in fish in coastal areas. Many studies have monitored TBT in coastal fish species. In the coastal area of northern Kyushu, Japan, contamination of fish such as Pagrus major (in blood: 0.0082 μg/mL), Lateolabrax japonicus (in blood: 0.190 μg/mL; liver: 0.14 μg/g), and the common Japanese conger, Conger myriaster (in blood: 0.0014 μg/mL; liver: 0.015 μg/g) by TBT was found (Miki et al., 2011). TBT pollution of pelagic coastal fish was also reported by Kannan et al. (1995): <0.1–0.013 μg/g in muscle of rubberlip morwong, shovelnose ray, blue groper, long–spined snapper, sea mullet, spiny–tailed leatherjacket, Australian herring, striped sea perch, black bream, rainbow trout, Atlantic salmon, stripey, and seabass collected from Australia; and 0.0002–0.001 μg/g in muscle, and 0.0065– 0.02 μg/g ww in liver of green–spotted kingfish, Indian mackerel, and paddletail snapper collected from the Solomon Islands. In pelagic fish, TBT levels of 0.0049– 0.002 μg/g ww have been reported in skipjack tuna (Ueno et al., 2004). A few studies have monitored TBT in marine demersal fish species; for example, in walleye pollock (Theragra chalcogramma) from the Bering Sea, Gulf of Alaska, and Japan Sea, the TBT concentrations ranged from 0.0011 to 0.0055 μg/g ww (de Brito et al., 2002). However, pollution by TBT of demersal fish from the East China Sea is not clear. High levels of human activity and discharge of pollutants might occur in the countries surrounded by the East China Sea. Thus TBT input into the marine environment, and accumulation of TBT in demersal fish, is suspected. The common Japanese conger is a possible biomonitoring species among demersal fish. The common Japanese conger is an important commercial fish species Monitoring of Tributyltin Contamination of Demersal Fish in Coastal Water in East China Sea