Tributyltin contamination of marine sediments of Hong Kong

A study was conducted to assess the degree of tributyltin (TBT) contamination of sediments in local marinas and shipyards. An experimental design was formulated to address specific hypotheses concerning TBT distribution in relation to the size and type of the boats serviced. Transect and random sampling were selectively applied on different site geometries. Surface sediment samples were collected from eight shipyard sites and six marina/mooring sites in July 1994. Sediment samples close to shipyards and marinas showed very high contamination with TBT and corresponding decay products. The spatial variation of TBT was quite large. A decreasing trend of TBT level with distance was found for shipyards located in shallow and calm water. Sediments at shipyard and marina sites were not significantly different in TBT levels, suggesting that small boats might still be a source of TBT.