Tributyltin (TBT) pollution in the coastal waters of west Brittany as indicated by imposex in Nucella lapillus

Tributyltin (TBT) pollution in west Brittany coastal waters was assessed in 1992, 1993 and 1994 using the bioindicator of imposex (superimposition of male sexual characters on females) in the neogastropod Nucella lapillus. Imposex was detected at all 75 stations sampled, from Kerfissien on the north coast to Ile de Sein in the south-west, indicating widespread pollution even at sites having full exposure to the Atlantic. Imposex levels in the Bay of Brest were found to be high; female sterilization was prevalent and certain populations appeared to have been exterminated, notably in the northern part of the Bay. The evidence suggests that the 1982 legislation, banning the use of TBT-based antifouling-paints on vessels less than 25 m, is being ignored in certain areas; some small ports, like those of the islands, are contaminated despite the fact there are few vessels eligible to use this paint.