Survey of butyltin contamination in Portuguese coastal environments

Butyltin compounds (MBT, DBT and TBT) in intertidal sediments collected in four different Portuguese coastal environments have been measured in order to evaluate the extent of contamination. The sites chosen were the Rias of Aveiro and Faro, and the Sado and Tejo estuaries. These zones were traditional areas for shellfish production in the recent past, but the effects of industrial development have caused a deterioration of the environment. Specific contaminations were derived from the harbour (commercial and/or fisheries) and shipyard activities, resulting in a release of TBT and causing the oyster populations of the above mentioned estuaries to almost disappear. Results presented in this study give a survey of TBT contamination levels found in the four areas. The paper discusses the importance of the pollution in comparison with other European coastal areas.