Problems associated with an environmental assessment of organotins: Application to the organic polluted saladillo harbor (southern Spain)

Abstract

AbstractProblems associated with assessing the environmental effects of organotin (OT) include extraction efficiency, whether to filter the water samples, effect of grain size of sediments, and mobility characteristics of OT species from sediments. This study considered these effects on the six OT species tributyltin, dibutyltin, monobutyltin, triphenyltin, diphenyltin, and monophenyltin in seawater and sediments collected from Saladillo Harbor, a representative enclosed area in southern Spain that receives inputs of both OTs and organic matter. Yields of organotin extracted from sediments with a high organic content by using dichloromethane were higher than those obtained by using pentane. Concentrations of butyltins were higher than those of phenyltins. A gradient was observed of decreasing butyltin concentrations in sediments from 280 ng Sn/g in the inner stations to 0.5 ng/g in the outer stations of the harbor. No dissolved organotin compounds were detected in the overlying seawater. Because OTs are related to the presence of organic matter, iron oxyhydroxides, and phylosilicates, they were strongly adsorbed onto particulate matter in both sediment and suspended matter. Low percentages of butyltins, ranging from undetectable to 0.54%, were released by extracting in unpolluted seawater at pH 8 and 5. Higher concentrations were found in finer sediments.