Polyfluorinated telomer alcohols and sulfonamides are classes of compounds recently identified as precursor molecules to the perfluorinated acids detected in the environment. Despite the detection and quantification of these volatile compounds in the atmosphere, their sources remain unknown. Both classes of compounds are used in the synthesis of various fluorosurfactants and incorporated in polymeric materials used extensively in the carpet, textile, and paper industries. This study has identified the presence of residual unbound fluoro telomer alcohols (FTOHs) in varying chain lengths (C6-C14) in several commercially available and industrially applied polymeric and surfactant materials. NMeFOSE, a perfluoroalkyl sulfonamido alcohol, was also detected in a commercially available carpet protector product. A method was developed to remove these residual compounds from polymeric and surfactant materials by dispersion in water and stripping of the volatiles using a constant flow of air and trapping on XAD resin. Using gas chromatography mass spectrometry analysis, it was determined that the fluorinated materials examined consist of 0.04-3.8% residual alcohols on a fluoro alcohol to dry mass basis. These values indicate that residual alcohols, left unreacted and unbound from the manufacturing process of fluorinated polymers and surfactants, could be a significant source of the polyfluorinated telomer alcohols and sulfonamides released into the environment. This study suggests that elimination or reduction of these residual alcohols from all marketed fluorinated polymers and fluorosurfactants is key in reducing the prevalence of perfluorinated acids formed in the environment.

Saturated and unsaturated fluorotelomer carboxylic acids have been identified as intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (PFCAs). Although surface waters are the likely environmental sink for telomer acids, no fate or toxicity data exist for this matrix. We assessed the acute toxicity of the 4:2, 6:2, 8:2, and 10:2 saturated (FTCA) and unsaturated (FTUCA) fluorotelomer carboxylic acids to Daphnia magna, Chironomus tentans, and Lemna gibba. In general, toxicity increased with increasing fluorocarbon (FC) chain length, particularly for telomer acids of g8 FCs. In addition, the FTCAs were generally more toxic than the corresponding FTUCAs. Acute EC50s ranged from 0.025 mg/L (0.04 µmol/L) for D. magna (10:2 FTCA, immobility) to 63 mg/L (167 µmol/L) for C. tentans (6:2 FTCA, growth). While chain-length trends observed in the current study agree with those previously reported for PFCAs, the toxicity thresholds generated here are up to 10 000 times smaller. Our data provide the first evidence that PFCA precursors are more toxic than the PFCAs themselves.

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1,2-Dichloroethane (1,2-DCA), a chlorinated aliphatic hydrocarbon, is a well-known groundwater contaminant. In this study, fractionation of stable carbon isotope values of 1,2-DCA during biodegradation was used as a novel reaction probe to provide information about the mechanism of 1,2-DCA biodegradation under both aerobic (O2-reducing) and anaerobic (NO3-reducing) conditions. Under O2-reducing conditions, an isotopic enrichment value (epsilon) of -25.8 +/- 1.1 per thousand (+/-95% confidence intervals) was measured for the enrichment culture. Under NO3-reducing conditions, an epsilon-value of -25.8 +/- 3.5 per thousand was measured. The microbial culture produced isotopic enrichment values (epsilon) that are not only large and reproducible, but also are the same whether O2 or NO3 was used as an electron acceptor. Combining data measured under both O2- and NO3-reducing conditions, an isotopic enrichment value (epsilon) of -25.8 +/- 1.6 per thousand is measured for the microbial culture during 1,2-DCA degradation. The epsilon-value can be converted into a kinetic isotope effect (KIE) value to relate the observed isotopic fractionation to the mechanism of degradation. This KIE value (1.05) is consistent with degradation via hydrolytic dehalogenation under both electron-accepting conditions. This study demonstrates the added value of compound-specific isotope analysis not only as a technique to verify the occurrence and extent of biodegradation in the field, but also as a natural reaction probe to provide insight into the enzymatic mechanism of contaminant degradation.