The concentrations of butylitn and phenyltin compounds in water, sediment, plankton, mussel and fish samples in the Port of Osaka were monitored for a long time. The characteristics of contamination of organotin compounds in the Port of Osaka were clarified by cluster analysis using the concentrations of butyltin or phenyltin compounds before regulation in Japan. These stations in the Port of Osaka were clarified three groups of 1) marina, 2) the area where many small vessels are sailed and moored with poor flushing, 3) the area where many vessels are sailed. Tributyltin concentrations in most groups are decreasing during monitoring period and especially the trend was drastically in marina. Triphenyltin was not detected in water samples after regulation. The concentrations of TBT and TPT in fish samples were decreasing slowly after regulations and the concentrations of these compounds in fish in 1999 were lower than those acceptable concentration which were calculated from acceptable daily intake (ADI).
Although butyltin concentrations in water samples collected in 2016 from Tanabe Bay were similar to in 2004~2006, TPT concentrations in 2016 were lower than those in 2004~2006. TBT and TPT in sediment samples in 2016 were lower than those in 2004~2006.