Occurrence of Organotin Compounds in Water, Sediments and Mollusca in Estuarine Systems in the Southwest of Spain

Abstract

Six organotin species – tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT) andmonophenyltin (MPT) – have been determined in seawater (255 samples), sediments (85 samples) and bivalves (558 samples) collected at seventeen locations in the southwest of Spain in five occasions between May 1992 and August 1994. No phenyltinspecies were found but butyltin species were present in all the stations. The TBT concentrations ranged between 23 and 1500 ng g-1 Sn in biota, from less than 0.6 to 160 ng g-1 Sn in sediments and from less than 0.5 to 31 ng L-1 Sn in water, with the highest values closely related with boating activity and decreasing according to the distance from the potential sources. For biota and water, a consistent seasonal pattern of fluctuation of TBT concentrations was evident, with the highest values found in spring and summer except for a fishing harbour. A slow decreaseof TBT concentration was observed between 1992 and 1994. Percentages of DBT and MBT in biota (22±7 and 13±6,respectively) were lower than those in water (33±10 and 31±15, respectively) and sediments (48±16 and 25±16, respectively). Sediment-water partition coefficients for TBT were 240–65 000 and bioconcentration factors 17 000–350 000. This article discusses the significance of the pollution in our study area in comparison with other world coastal areas.