Investigation of the biodegradation potential of a fluoroacrylate polymer product in aerobic soils.

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.