Aerobic biotransformation of fluorotelomer compounds in landfill leachate-sediment

摘要

Consumer products containing fluorotelomer polymers are a source of fluorotelomer compounds to the environment following their disposal at landfills. The fate and transformation of fluorotelomer compounds are unknown in landfill leachates. This study investigates the aerobic biotransformation of 8:2 fluorotelomer alcohol (FTOH) and 6:2 fluorotelomer sulfonate (FTS) in landfill leachate-sediment microcosms using batch tests. Spiked 8:2 FTOH, 6:2 FTS and their known biotransformation products were quantified in sediment-leachate and headspace over 90 days under aerobic conditions. 8:2 FTOH and 6:2 FTS biotransformation was slow (half-life »30 d) in landfill leachate-sediment microcosm, suggesting persistence of fluorotelomer compounds under the conditions investigated. Significant volatilization (>20%) of 8:2 FTOH was observed in the microcosm headspace after 90 days. C6 -C8 and C4 - C6 perfluorocarboxylic acids (PFCAs) were the most abundant products for 8:2 FTOH and 6:2 FTS, respectively. PFCAs accounted for 4-9 mol% of the initially spiked parent compounds at 90 days. Perfluorooctanoic acid (PFOA) was the single most abundant product of 8:2 FTOH (>2.8 mol% at 90 days). The unaccounted mass (20 to 35 mol%) of the initially spiked parent compounds indicated formation of fluorotelomer intermediates and sediment-bound residue. Overall the findings suggest that aerobic biotransformation of fluorotelomer compounds acts as a secondary source of long- and short-chain (