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SPECIATION OF ORGANOTINS IN POLY VINYL PIPE VIA X-RAY ABSORPTION SPECTROSCOPY AND IN LEACHATES BY ELTHYLATION/DERIVITIZATION
Citation:
IMPELLITTERI, CHRISTOPHER, O. M. EVANS, AND B. RAVEL. SPECIATION OF ORGANOTINS IN POLY VINYL PIPE VIA X-RAY ABSORPTION SPECTROSCOPY AND IN LEACHATES BY ELTHYLATION/DERIVITIZATION. JOURNAL OF ENVIRONMENTAL MONITORING. Royal Society of Chemistry, Cambridge, Uk, 9(4):358-365, (2007).
Impact/Purpose:
The goal of this research effort is development of analytical methods for the determination of compounds selected for the 1998 Contaminant Candidate List (CCL) [Note: chemicals on the CCL are denoted below with a single asterisk, *. Chemicals with a double asterisk, **, are used as Internal Standards (Recovery and Quantitative).]. These may include selected non-pesticidal* , pesticidal, and other types of organotin compounds: monomethyltin trichloride*, dimethlytin dichloride*, trimethyltin trichloride, monobutyltin trichloride*, dibutyltin dichloride*, tributyltin chloride, phenyltin trichloride, diphenyltin dichloride, triphenyltin chloride, tricyclohexyltin, tripropyltin chloride**, tetrapentyltin**, tetrabutyltin**, etc.. The method(s) should be adequate for gathering occurrence data under the Unregulated Contaminant Monitoring Rule (UCMR) and should be applicable to / for compliance monitoring in the event selected non-pesticidal and / or pesticidal organotins become regulated contaminants under the Safe Drinking Water Act (SDWA).
Description:
Three different polyvinyl chloride (PVC) pipe types were subjected to de-ionized water exposures over the course of at least 180 days. Water exposed to the pipe was analyzed for organotin speciation and concentration. Organotin concentrations were the highest during the first 1-5 days. The species and concentrations of organotins leached varied by pipe type. Data were normalized by surface area in order to compare laboratory results with results from a residential pipe system. For one pipe type, the lowest non-zero concentrations from the laboratory tests overestimated organotin concentrations in solution when compared with water samples from the same pipe type in a residence. For organotin exposure estimates, a range of 0.1 ng mµ 2 to 10 ng mµ 2 could be used for mature pipes (e.g. in use for 1 year). These estimates should be refined with more field study, however, due to the high variation in organotin species and concentrations leached as a function of pipe type, accuracy within an order of magnitude may be optimal as, in many instances, the type of pipe installed or buried may be unknown. X-ray absorption spectroscopy (XAS) was used to identify organic and inorganic tin species in reference materials and the PVC samples. Monobutyl tin was identified as the primary organotin species in the pipes. Results from the XAS analyses also indicate that the technique shows promise for distinguishing between inorganic tin and organotins. Furthermore, organotins may be distinguished between mono-, di-, and tri-ligand species using XAS.