Per- and poly-fluoroalkyl substances (PFASs) are synthetic chemicals commonly used in manufacturing of fluoropolymers and fluorinated surfactants, which have a wide range of applications in surface protection products and aqueous film-forming foams (AFFFs). Since the phase-out of long chain PFASs, shorter chain length polyfluroroalkyl substance like 6:2 fluorotelomer alcohol (6:2 FTOH) have been used as alternative compounds. New AFFFs formula contains fluorotelomer-based surfactants manufactured from 6:2 FTOH or its derivative, 6:2 fluorotelomer sulfonate 6:2 FtS. The occurrence prevalence of 6:2 FtS in humans, biota, and the environment are increasing. In AFFFs-impacted subsurface, 6:2 FtS was commonly detected at high levels, ranging from ug/L to mg/L, in soils and groundwater which serves as drinking water source. Recent reports indicated that 6:2 FtS induced liver weight increase, inflammation, and necrosis of mice. 6:2 Fts is considered as a persistent substance due to its extremely slow and incomplete biodegradation. For example, no 6:2 FtS biotransformation was observed in anaerobic sediment over 100 days or in activated sludge over 90 days under aerobic conditions.  In this study, we have successfully isolated a number of 6:2 FtS-degrading bacteria from soils collected from soils contaminated with detergent at car wash facilities as well as sediments. The isolates have shown active growth in sulfur(S)-free media with 6:2 FtS, suggesting these isolates are capable of using 6:2 FtS as sole sulfur source. Fluoride release was detected after one-day incubation, indicating that 6:2 FtS biotransformation occurred. On-going research efforts are placed at determination of enzyme responsible for desulfonation, and to identify and characterize the isolates. Our results suggest that 6:2 FtS can be biotransformed within one day under S-limiting conditions.

Biotransformation of 6:2 fluorotelomer sulfonate (6:2 FtS) under sulfur-limiting condition

256th National Meeting (2018)

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