Anaerobic biotransformation of N‐methyl perfluorobutanesulfonamido ethanol and N‐ethyl perfluorooctanesulfonamido ethanol

Abstract

Some fluorochemical products are manufactured using N-methyl perfluorobutanesulfonamido ethanol (MeFBSE), a short-chain replacement for perfluorooctyl-based chemistries N-methyl and N-ethyl perfluorooctanesulfonamido ethanols (EtFOSE). The present study shows for the first time the anaerobic biodegradation of MeFBSE and EtFOSE in municipal digester sludge under methanogenic conditions. Both MeFBSE and EtFOSE were incubated for 108 d with anaerobic digester sludge. Although sterile controls did not remove MeFBSE, it was degraded in live sludge. The loss of MeFBSE coincided with production of N-methyl perfluorobutanesulfonamido acetate (MeFBSAA) and perfluorobutane sulfinate (PFBSI). The biodegradation appeared biphasic, with pseudo first-order loss between days 0 and 70, resulting in approximately 75% removal but no further depletion of MeFBSE between days 70 and 108. By day 108 MeFBSAA and PFBSI accounted for 57 and 40 mol% of initial dose, respectively. Mass balance values in live cultures on days 0, 10, 21, 29, 70, and 108 were 103, 92, 94, 100, 93, and 122%, respectively. The apparent first-order biodegradation rate constant for MeFBSE over the first 70 d was 0.0194 d , and the apparent half-life was 35.8 d. Incubation of EtFOSE with live digester sludge resulted in low-level formation of N-ethyl perfluorooctane-sulfonamido acetate and perfluorooctane sulfinate, which did not form in sterile controls. Although it was not measurably lost, 2 to 3% loss of EtFOSE was calculated based on product concentrations. The total product formation rate constant was determined by first-order kinetic evaluation over the first 72 d to estimate a first-order biodegradation rate constant for EtFOSE at 0.000374 d , and the apparent half-life time was 1860 d. Environ Toxicol Chem 2018;37:768-779. © 2017 SETAC.

Biotransformation of AFFF Component 6:2 Fluorotelomer Thioether Amido Sulfonate Generates 6:2 Fluorotelomer Thioether Carboxylate under Sulfate-Reducing Conditions

“…Previous studies have demonstrated that anaerobic microbial activities play important roles in the transformation of some classes of PFASs, but not all of them. − In cultures inoculated with anaerobic digester sludge, n :2 fluorotelomer alcohols (FtOHs) ( n = 6 or 8) were mainly transformed into n :2 and ( n –1):3 FtCAs and n :2 fluorotelomer unsaturated carboxylates (FtUCA) ( n = 6 or 8) . Similar biotransformations have also been observed in laboratory anaerobic bioreactors treating municipal solid waste containing disubstituted polyfluorinated phosphate esters (DiPAPs) .…”

“…(18) Additionally, methanogenic cultures were demonstrated to convert N -methyl perfluorobutane sulfonamido ethanol (MeFBSE) and Nethyl perfluorooctane sulfonamido ethanol (EtFOSE) into their respective perfluoroalkyl sulfonamide acetates and perfluoroalkyl sulfinates. (19) In contrast, perfluoroalkyl sulfonamide acetates were recalcitrant to biotransformation in methanogenic culture, and FtSs were persistent in both methanogenic or sulfate-reducing cultures. (18,20) The lack of information about the anaerobic biotransformation of fluorotelomer thioethers highlights the importance of further studies of PFAS biotransformation at AFFF-impacted groundwater sites.…”

Neutral Per- and Polyfluoroalkyl Substances, Butyl Carbitol, and Organic Corrosion Inhibitors in Aqueous Film-Forming Foams: Implications for Vapor Intrusion and the Environment

“…104,115 The anaerobic degradation of neutral ECF-based PFAS was found to be minimal by Yin et al, 114 while Lange found perfluoroalkyl sulfonamide acetic acids and perfluoroalkyl sulfonates as the transformation products, with half-life between 36 and 1860 days. 116 Accordingly, biotransformation of neutral PFAS would result in their reduced VI potential. Prior laboratory-based studies involving FTOHs and sludge, sediment, and soil indicated half-life anywhere from <1 to >365 days.…”

Degradation of Perfluorooctane Sulfonamide by Acinetobacter Sp. M and Its Extracellular Enzymes

“…Representative microbial degradation technologies in recent years include marine sediments, aerobic soils, activated sludge, aquatic oligochaetes and mammals that can degrade and convert PFOS′s precursors . It is reported that 1 H, 1 H, 2 H, 2H‐perfluorooctane sulfonate (6:2 FTSA) can be degraded by a Pseudomonas strain D2, and 8:2 fluoroalcohol (8:2) FTOH) can be degraded by Pseudomonas strain OCY4 and OCW4, and PFOS can be used as the sole carbon source for their growth . Kwon et al.…”