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 establish ed (Ten Hallers-Tjabbes et al., 1994) and tributyltin (TBT), the activ e biocide in anti-fouling paints, was expected to be the cause. To stu dy the supposed cause-effect relationship, adult whelks were experimen tally exposed to TBT. Juvenile B. undatum, produced by the experimenta l specimens, were also exposed in ovo or just after hatching during th is experiment and developed male sexual characteristics (a penis and/o r a vas deferens) in a dose-dependent manner already after 10 months m ore than 80% of the young B. undatum exposed to nominal TBT concentrat ions 100 ng TBT/litre developed these male sexual organs. Adult female s, 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 mu g TBT/litre, a TBT body burden of >3 00 ng Sn/g dry weight was measured. Copyright (C) 1996 Elsevier Scienc e Ltd