Investigation of the biodegradation potential of a fluoroacrylate polymer product in aerobic soils.
ABSTRACT Biodegradation of fluorinated polymers is of interest to assess them as a potential source of perfluorocarboxylates (PFCAs) in the environment. A fluoroacrylate polymer product test substance was studied in four aerobic soils over two years to assess whether the fluorotelomer alcohol (FTOH) side chains covalently bonded to the polymer backbone may be transformed to form PFCAs. The test substance itself was not directly measured; instead, nine analytes were determined to evaluate biodegradation. Terminal biotransformation products measured included perfluorooctanoate (PFO), perfluorononanoate (PFN), perfluorodecanoate (PFD), perfluoroundecanoate (PFU), and pentadecafluorodecanoate (7-3 acid). The molar concentration of 8-2 fluorotelomer alcohol (8-2 FTOH) in the test substance, fluoroacrylate polymer and residual unreacted raw materials and impurities ("residuals") were compared with the molar concentrations of the terminal biotransformation products for mass balance and kinetic assessments. Over the two year time frame of the experimental study, the fluoroacrylate polymer showed a slight extent of potential biodegradation under the experimental conditions of the study. A biodegradation half-life of 1200-1700 years was calculated for the fluoroacrylate polymer based on the rate of formation of PFO in aerobic soils. When the degradation rates of the fluoroacrylate polymer and residuals were applied to estimated total historic fluoroacrylate polymer production, use and disposal, the biodegradation of fluoroacrylate polymer and residuals is calculated to contribute less than 5 tonnes of PFO per year globally to PFCAs present in the environment.
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ABSTRACT: The aim of this study was to measure perfluoroalkyl substances in a selection of imported consumer products (n = 45) and estimate population normalized emission rates during the use phase. 6:2 and 8:2 fluorotelomer alcohol (FTOH) were found in the highest concentrations ranging from <MDL to 374 and 163 μg m−2 respectively. Concentrations of FTOHs were approximately 2–3 orders of magnitude higher than those of perfluoroalkyl carboxylic acids (PFCAs). Although perfluorooctane sulfonate (PFOS) was detected in one carpet sample at 1.7 μg m−2, the majority of samples complied with regulatory limits for PFOS in the EU. Population normalized emission rates of perfluorooctanoic acid, 6:2 FTOH and 8:2 FTOH from imported consumer products were estimated to be 6.6, 2130 and 197 μg year−1 capita−1 respectively for the “intermediate” emission scenario. The results from this study suggest that emissions from imported products would have a small impact on the environmental concentrations of perfluoroalkyl acids on a regional scale.Environmental Pollution 03/2015; 198:223-230. · 3.90 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the aquatic toxicity of a C4–C6 chemistry based fluoroalkylated polymer and the perfluoroalkyl carboxylic acids, PFBA, PFHxA and PFOA to Daphnia magna. The acute toxicity decreased with decreasing carbon chain length, but the polymer did not show a dose related effect. In a chronic toxicity test performed with PFHxA, mortality was observed at similar concentrations as in the acute toxicity test, indicating that toxicity did not increase with increasing exposure time. Effects on mortality, reproduction and population growth rate occurred at similar concentrations, indicating no specific effect of PFHxA on sublethal endpoints. C4–C6 chemistry is thus less hazardous to daphnids than C7–C8 chemistry. Yet, these compounds are persistent, hard to remove from the environment and production volumes are increasing.Environmental Pollution 03/2015; 198. · 3.90 Impact Factor
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ABSTRACT: Fluorotelomer-based acrylate polymers (FTACPs) are a class of side-chain fluorinated polymers used for a variety of commercial applications. The degradation of FTACPs through ester hydrolysis and/or cleavage of the polymer backbone could serve as a significant source of perfluoroalkyl carboxylates (PFCAs). The biodegradation of FTACPs was evaluated in a soil-plant microcosm over 5.5 months in the absence/presence of wastewater treatment plant (WWTP) biosolids, using a unique FTACP determined to be a homopolymer of 8:2 fluorotelomer acrylate (8:2 FTAC). Though structurally different from commercial FTACPs, the unique FTACP possesses 8:2 fluorotelomer side chain appendages bound to the polymer backbone via ester moieties. Liberation and subsequent biodegradation of the 8:2 fluorotelomer appendages was indirectly determined by monitoring for PFCAs of varying chain lengths (C6-C9) and known fluorotelomer intermediates by liquid chromatography tandem mass spectrometry (LC-MS/MS). A FTACP biodegradation half-life range of 8-111 years was inferred from the 8:2 fluorotelomer alcohol (8:2 FTOH) equivalent of the unique FTACP and the increase of degradation products. The progress of FTACP biodegradation was also directly monitored qualitatively using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The combination of indirect and direct analysis indicated that the model FTACP biodegraded predominantly to perfluorooctanoate (PFOA) in soils, and at a significantly higher rate in the presence of a plant and WWTP biosolids.Environmental Science and Technology 10/2014; · 5.48 Impact Factor