TBT and TPhT persistence in a sludged soil

C. Marcic (1) , Isabelle Le Hécho (1) , L. Denaix , Gaetane Lespes (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

The persistence of tributyltin (TBT) and triphenyltin (TPhT) in soils was studied, taking into consideration the quantity of sewage sludge, TBT and TPhT concentrations in soil as well as the soil pH. The organotin compounds (OTC) were introduced into the soil via a spiked urban sludge, simulating agricultural practise. OTC speciation was achieved after acidic extraction of soil samples followed by gas chromatography-pulsed flame photometric analysis (GC-PFPD). Leaching tests conducted on a spiked sludge showed that more than 98% of TBT are sorbed on the sludge. TBT persistence in soil appeared to depend on its initial concentration in sludge. Thus, it was more important when concentration is over 1000 μg(Sn) kg-1 of sludge. More than 50% of the initial TBT added into the soil were still present after 2 months, whatever the experimental conditions. The main degradation product appeared to be dibutyltin. About 90% of TPhT were initially sorbed on sludge, whatever the spiking concentration in sludge was. However, TPhT seemed to be quantitatively exchangeable at the solid/liquid interface, according to the leaching tests. It was also significantly degraded in sludged soil as only about 20% of TPhT remain present after 2 months, the monophenyltin being the main degradation product. pH had a significant positive effect on TBT and particularly TPhT persistence, according to the initial amounts introduced into the soil. Thus, at pH over 7 and triorganotin concentration over 100 μg(Sn) kg-1, less than 10% of TBT but about 60% of TPhT were degraded. When the sludge was moderately contaminated by triorganotins (typically ≤50 μg(Sn) kg-1 in our conditions) the pH had no effect on TBT and TPhT persistence. © 2006 Elsevier Ltd. All rights reserved.

Mots clés: quantitative analysis; Contamination; pH effects; Persistence; Sewage sludge; Photometric analysis; Sewage; acid soil; organotin compound; Soil surveys; degradation; extraction method; soil chemistry; gas chromatography; sludge; soil type; soil quality; testing method; flame photometry; degradation kinetics; leaching; concentration (parameters); soil analysis; Reference Standards; Organotin Compounds; soil pollution; Soil Pollutants; Trialkyltin Compounds; agriculture

Domaines: Chimie analytique; Sciences de l'environnement

C. Marcic, Isabelle Le Hécho, L. Denaix, Gaetane Lespes. TBT and TPhT persistence in a sludged soil. Chemosphere, 2006, 65 (11), pp.2322-2332. ⟨10.1016/j.chemosphere.2006.05.007⟩. ⟨hal-01505734⟩