Tributyltin exposure in early life stages induces the development of male sexual characteristics in the common whelk, Buccinum undatum

Common whelks ( Buccinum undatum) from the open North Sea show imposex; the development of male sexual characteristics in female prosobranch gastropods. A correlation with shipping intensities has been established (Ten Hallers-Tjabbes et al., 1994) and tributyltin (TBT), the active biocide in anti-fouling paints, was expected to be the cause. To study the supposed cause—effect relationship, adult whelks were experimentally exposed to TBT. Juvenile B. undatum, produced by the experimental specimens, were also exposed in ovo or just after hatching during this experiment and developed male sexual characteristics (a penis and/or a vas deferens) in a dose-dependent manner already after 10 months more than 80% of the young B. Undatum exposed to nominal TBT concentrations 100 ng TBT/litre developed these male sexual organs. Adult females, however, showed no signs of imposex, although they were exposed for 9 months to the same TBT concentrations as their offspring. In adult females exposed to a dose of 1 μg TBT/litre, a TBT body burden of > 300 ng Sn/g dry weight was measured.