Tributyltin pollution: A diminishing problem following legislation limiting the use of TBT-based anti-fouling paints

There is substantial evidence that tributyltin (TBT) contamination has decreased following the introduction of legislation prohibiting the use of TBT-based paints on vessels less than 25 m in length. Ambient levels of TBT have decreased in the water column, sediments and tissues of molluscs, and there has been recovery of dogwhelks and oysters from imposex and shell deformation, respectively. Severe pollution is now restricted primarily to hotspots of boating activity, such as ports. There is no evidence that it is a major problem in open seas and oceanic waters. There are now indications that imposex is less specific than has been supposed. While the response will still be useful in monitoring recovery of populations of Nucella lapillus from the effects of TBT pollution, its general use as a bioindicator of TBT is questionable.