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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 periluorooctanoate (PFO), perfluorononanoate (PFN), perfluorodecanoate (PFD), pertluoroundecanoate (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. [ABSTRACT FROM AUTHOR]

Sex-, species-, and chain length-dependent renal elimination is the hallmark of mammalian elimination of perfluorocarboxylates (PFCAs) and has been extensively studied for almost 30 years. In this review, toxicokinetic data of PFCAs (chain lengths ranging from 4 to 10) in different species are compared with an emphasis on their relevance to renal elimination. PFCAs vary in their affinities to bind to serum albumins in plasma, which is an important factor in determining the renal clearance of PFCAs. PFCA-albumin binding has been well characterized and is summarized in this review. The mechanism of the sex-, species-, and chain length-dependent renal PFCA elimination is a research area that has gained continuous interest since the beginning of toxicological studies of PFCAs. It is now recognized that organic anion transport proteins play a key role in PFCA renal tubular reabsorption, a process that is sex-, species-, and chain length-dependent. Recent studies on the identification of PFCA renal transport proteins and characterization of their transport kinetics have greatly improved our understanding of the PFCA renal transport mechanism at the molecular level. A mathematical representation of this renal tubular reabsorption mechanism has been incorporated in physiologically based pharmacokinetic (PBPK) modeling of perfluorooctanoate (PFOA). Improvement of PBPK models in the future will require more accurate and quantitative characterization of renal transport pathways of PFCAs. To that end, a basolateral membrane efflux pathway for the reabsorption of PFCAs in the kidney is discussed in this review, which could provide a future research direction toward a better understanding of the mechanisms of PFCA renal elimination.