Measurement of butyltin contamination of water and sediment in Osaka Bay, Japan

The concentration of tributyltin (TBT) in surface water from Osaka Bay rang ed from 0.023 to 0.061 mu g l(-1) in 1989 and from not detected (ND) to 0.0 59 mu g l(-1) in 1990 while the proportion of TBT as a percentage of the to tal butyltins (BTs) was more than 40%. The concentration of TBT was also su rveyed in the Port of Osaka and the Yodo River basin. TBT levels were highe st in the estuary (the Port of Osaka), followed by sea areas (Osaka Bay) an d rivers (Yodo River basin). A fairly high correlation coefficient between TBT concentration and salinity in water from the estuary and the sea areas was observed. This result shows that the TBT in the estuary water is dilute d by seawater. Generally, the TBT concentrations in the water columns were distributed uniformly and the composition of the BTs was also constant. TBT was detected in sediment from Osaka Bay in the range from ND to 0.023 mg k g-l dry weight with a high ratio of monobutyltin (MBT) to the total BTs, TB T in sediment core was also measured; its concentration decreased with core depth. It was estimated from these measurements that the release of TBT in to Osaka Bay began in the 1960s. (C) 1998 John Wiley & Sons, Ltd.