Contamination of outdoor settled dust by butyltins in Malta

Abstract

AbstractThe presence of compounds of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) was determined in outdoor settled dust collected from several sites on the island of Malta, mainly from flat rooftops of school buildings. The dust was separated into three size fractions with diameters (µm) > 250, 125–250 and < 125, and the two finer fractions were analysed for butyltins using extraction with glacial acetic acid followed by derivatization/solvent extraction with sodium tetraethylborate in the presence of iso‐octane and quantitation by gas chromatography with flame photometric detection. The presence of TBT, DBT and MBT was established in most of the samples and TBT concentrations varied from non‐detectable (<5 ng Sn g−1) to highs of 15.5 and 18.7 µg Sn g−1 in Senglea and Marsaxlokk. TBT was generally found at concentrations significantly higher than reported hitherto in house dust collected from European homes. The geographical distribution of total organotins in both dust fractions suggests that TBT originates mainly from antifouling marine paint residues which contaminate the urban environment when ships' hulls are sand‐ or hydro‐blasted during maintenance and repair at the drydocks facility in Grand Harbour. Other significant sources of TBT are located at Marsaxlokk fishing port and Wied iż‐Żurrieq creek, both hosting sizeable communities of fishermen and leisure boating. The data also suggest that the municipal solid waste landfill at Maghtab is an inland source of butyltins. We suggest that dust containing harmful butyltins could possibly be ingested to expose humans to a risk which is probably of concern especially for young children living close to the hotspots of contamination. Copyright © 2007 John Wiley & Sons, Ltd.