Butyltin pollution in surface sediments of arcachon bay after ten years of restricted use of TBT ‐ based paints

Arcachon Bay is a site where TBT levels have been high from 1975 to 1981, but have fallen since then. It is therefore a convenient site for studies on the long term fate of butyltin pollution. Surface sediments throughout the Bay still contain all butyltin species. TBT concentration reaches up to 158 ng.g‐1 (as Sn) in marinas, but is only a few ng.g‐1 in remote areas. Amongst Butyltins, TBT predominates in marinas or mooring areas but MBT is the most abundant away from pollution sources. A general scheme of the pathways of butyltin compounds is proposed, the degradation of TBT in sediments beingmuch slower than in overlying waters.