R5 AM Perflourochemical Biodegradation, Fate, and Transport
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in 321-323

(MAB-1117-777215) Fate of FTOHs in the Environment.

Mabury, Scott¹, ¹ University of Toronto, Toronto, ON, Canada

ABSTRACT- The chemical architecture of the alkyl fluorine bond imparts unique and useful properties such that it is now widely utilized in both consumer and industrial applications. Some of these properties result in fugitive emissions of fluorinated alkyl compounds that are subsequently widely dispersed in the environment, bioaccumulative, and yield highly persistent and potentially toxic degradation products. Of particular interest are the fluorotelomer alcohols (FTOHs) that are widely incorporated into polymers for the paper, carpet, and textile markets. Residual FTOHs are present in significant quantities in fluorinated polymers and data suggests they may be the dominant source of these perfluorinated alkyl acid (PFCAs) precursors in the atmosphere. FTOHs are widely observed across North America in the 10 to 100 pg/m3 range. They react primarily with OH leading to a lifetime on the order of 20 days, sufficient for significant long-range transport. The sole degradation product is the FTOH aldehyde, also long-lived, which proceeds through successive OH initiated reactions to ultimately yield the FTOH acids, perfluorinated aldehydes, PFCAs (1 to 10%), and carbonyl fluoride as the dominant product. PFCAs appear in the majority of biological samples tested and are particularly high in remote Arctic regions in species at the top of the food chain. The PFCA isomer signature suggests a linear alkyl source thereby ruling out an electrochemical process. Metabolism studies, in both microbes and rats, show analogous transformation pathways leading to PFCAs, as well as highly reactive intermediates. Substantial evidence now supports an overall theory that FTOHs are the primary source of PFCAs in the remote environment and may be important in human exposures.

Key words: PFCAs, FTOHs