Imposex in thais clavigera used for biomonitoring butyltins pollution along the coastal waters of Zhejiang, China

We assessed the contamination status of butyltins (BTs) in the waters and the imposex status of Thais clavigera, i.e. relative penis size index and vas deferens sequence index (VDSI) along the coastal waters of Zhejiang, China. The snail samples were collected from 10 different sites from July to August in 2007 and July to October in 2010. The results showed that wide existences of BTs were found in these samples with detection rates up to 100%, and the concentrations of the total BTs ranged from 19.1 to 122.2 ng/L (mean 66.8 ng/L) along Zhejiang (including Wenzhou, Taizhou, Ninbo and Zhoushan). The results will serve as an important reference for long-term monitoring of BTs contamination in these areas. Meanwhile, the S-curve fitting to tributyltin (TBT) concentrations and VDSI in T. clavigera indicated TBT pollution was the key driving force to imposex, and VDSI was useful and practical for biomonitoring of BTs pollution. Meanwhile, this study could build the biomonitoring system of marine BTs pollution in the Zhejiang coast. Marine gastropods have strong enrichment ability for BTs. Therefore, the wide occurrence and serious pollution of BTs in the seafood indicated potential dangers for people's health.