Kinetic monitoring of trisubstituted organotins in soil after sewage sludge application

Organotin compounds (OTC) are widely used for their biocidal effects in various agricultural or industrial activities, leading to their environmental presence. Among the organotin species, tributyltin (TBT) and triphenyltin (TPhT) are the most used and are generally considered the most toxic. So it is important to understand their behaviour in soils and obtain data about their persistence and phytoavailability. Many works deal with OTC speciation in various matrices, but few are concerned with OTC degradation in soil. The present study focuses on kinetic monitoring of TBT and TPhT in an agricultural soil. These compounds were introduced into the soil by the way of spiked sewage sludge, simulating agricultural practice and cliff use contamination. The influence of time and initial OTC concentration on the species preservation was evaluated. TBT concentration was shown to have a positive effect on TBT preservation. Corresponding half-lives were calculated. They were 61 days and over 39 days for TPhT and TBT, respectively. Degradation compounds, mono- and dibutyltin, and mono- and diphenyltin, were produced by both direct and successive dealkyl and dearylation processes. Copyright (C) 2008 John Wiley & Sons, Ltd.