Increasing levels of tributyltin-induced imposex in muricid gastropods at Phuket Island, Thailand

Abstract

Tributyltin (TBT)-induced imposex, or the masculinization of female gastropods, was used in an investigation of TBT contamination around the major harbours at Phuket Island, Thailand. From 21 stations along the south-east coast of Phuket Island a minimum of 50 specimens of the muricid Thais distinguenda were collected and examined for the presence of imposex in February–April 1996 and in January –April 1998. The results showed clearly that both the incidence and the distribution of imposex increased dramatically from 1996 to 1998. In 1996, imposex was recorded at 10 stations within 3.5 km of the nearest port, but in 1998 imposex was present at 18 stations up to 7.5 km from the nearest port. A similar tendency to increase in the incidence and distribution of imposex was found using Thais bitubercularis and Morula musiva as indicators. Copyright ­© 1999 John Wiley & Sons, Ltd.