Marcic Christophe, Le Hecho Isabelle, Denaix Laurence, Lespes Gaëtane
Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, UMR CNRS 5034, CURS, Avenue de l'Université, F-64013 Pau cedex, France.
Chemosphere. 2006 Dec;65(11):2322-32. doi: 10.1016/j.chemosphere.2006.05.007. Epub 2006 Jul 3.
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 microg(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 microg(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 microg(Sn) kg(-1) in our conditions) the pH had no effect on TBT and TPhT persistence.
研究了三丁基锡（TBT）和三苯基锡（TPhT）在土壤中的持久性，同时考虑了污水污泥的数量、土壤中TBT和TPhT的浓度以及土壤pH值。通过添加城市污泥将有机锡化合物（OTC）引入土壤，模拟农业实践。对土壤样品进行酸性萃取后，采用气相色谱-脉冲火焰光度分析（GC-PFPD）实现OTC形态分析。对添加污泥进行的淋溶试验表明，超过98%的TBT吸附在污泥上。TBT在土壤中的持久性似乎取决于其在污泥中的初始浓度。因此，当浓度超过1000μg（Sn）kg⁻¹污泥时更为重要。无论实验条件如何，添加到土壤中的初始TBT在2个月后仍有超过50%存在。主要降解产物似乎是二丁基锡。无论污泥中的加标浓度如何，约90%的TPhT最初吸附在污泥上。然而，根据淋溶试验，TPhT在固/液界面似乎可定量交换。在污泥土壤中它也显著降解，2个月后仅约20%的TPhT仍存在，单苯基锡是主要降解产物。根据引入土壤中的初始量，pH对TBT尤其是TPhT的持久性有显著的正向影响。因此，在pH超过7且三有机锡浓度超过100μg（Sn）kg⁻¹时，不到10%的TBT但约60%的TPhT被降解。当污泥受到三有机锡的中度污染（在我们的条件下通常为50μg（Sn）kg⁻¹）时，pH对TBT和TPhT的持久性没有影响。
