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Predicting the Migration Rate of Dialkyl Organotins from PVC Pipe into Water
Citation:
Adams, W. A., Y. Xu, J. C. Little, A. F. Fristachi, G. E. RICE, AND C. A. IMPELLITTERI. Predicting the Migration Rate of Dialkyl Organotins from PVC Pipe into Water. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 45(16):6902-6907, (2011).
Impact/Purpose:
To inform the public.
Description:
Organotins (OTs) are additives widely used as thermal and light stabilizers in polyvinyl chloride (PVC) plastics. OTs can leach into water flowing through PVC pipes. This work examines the leaching rates of two neurotoxic OTs, dimethyl tin (DMT) and dibutyl tin (DBT), from PVC pipe. Water was circulated in a closed loop laboratory PVC pipe system. Using a gas chromatograph pulsed flame photometric detector (GC PFPD), the change in concentrations of DMT and DBT in the water in the system was monitored over time and allowed to reach equilibrium. OT concentration as a function of time was analyzed using a mechanistic leaching rate model. The diffusion coefficient for OT in the PVC pipe material, the only unknown model parameter, was found to be 9×10−18 m2/s. This value is consistent with the range of values estimated from the literature (1.6×10−18 and 2.4×10−17 m2/s) increasing confidence in the leaching rate model.
