Tributyltin in the environment - sources, fate and determination an assessment of present status and research needs

Abstract

The aim of this report is to assess the present status and the need for further research on toxicity, sources, fate and determination of tributyltin (TBT) in the environment. Emphasis has been on information which may have an impact on the regulation concerning the use of TBT. The evaluation of available data shows that the toxicity of TBT towards aquatic organisms, which tend to be the most exposed and sensitive, is well documented. The main release of TBT progresses into the aquatic environment. No significant reduction of TBT levels in the technosphere (e.g. sewage treatment plants) is supposed to occur. Degradation of TBT in the aquatic environment is a slow process. Half-lives range from 1 to 3 weeks under optimal conditions to several years under anaerobic conditions. TBT accumulates in sewage sludges, sediments and biota. High residue levels in sewage sludge indicate sources other than antifouling paints. The present situation of TBT pollution in the aquatic environment is reflected in several recent publications. Levels of TBT determined in surface water are often higher than the no observed effect levels for sensitive stages of aquatic organisms. There is still a lack of knowledge of TBT levels in most compartments of the environment. Analytical methods are available for the determination of TBT and its degradation products at trace levels. A preferred method is gas chromatography combined with a highly specific and sensitive detector. In this respect, interlaboratory comparisons and quality assurance programmes are recommended. Areas of future research which have been identified include: • - Assessment of sources other than antifouling paints • - Fate of TBT in sewage treatment plants • - Database improvement on residue levels of TBT in different compartments • - Impact of TBT released from sewage sludge and dredged sediments.