Sources and Accumulation of Butyltin Compounds in Ganges River Dolphin,Platanista gangetica

Abstract

Concentrations of butyltin compounds (mono-, di-, and tri-butyltin) were determined in dolphin (Platanista gangetica), fish, invertebrates and sediment collected from the River Ganges, India, in order to understand the contamination levels, sources, and potential for biomagnification in freshwater food chains. Total butyltin concentration in dolphin tissues was up to 2000 ng g 2 1 wet wt, which was about 5‐10 times higher than in their diet. The concentrations in fish and benthic invertebrates, including polychaetes, were 3‐10 times greater than in sediment. The biomagnification factor for butyltins in river dolphin from its food was in the range 0.2‐7.5. Butyltin concentrations in Ganges river organisms were higher than those reported for several persistent organochlorine compounds. Discharge of untreated domestic sewage was one of the major sources of butyltin residues in Ganges river biota. High concentrations of butyltin compounds in freshwater food chains suggest the need to assess their toxic effects in aquatic organisms and to regulate their use. © 1997 by John Wiley & Sons, Ltd.