6-2 Fluorotelomer alcohol aerobic biodegradation in soil and mixed bacterial culture

Aerobic Soil Biotransformation of 6:2 Fluorotelomer Iodide

“…PFHpA identity was confirmed by high-resolution mass spectrometry analysis along with other transformation products (see Figure SI-2 of the Supporting Information). It is worth noting that PFHpA was not detected in soil, sediment, and activated sludge dosed with 6:2 FTOH or 6:2 FTSA [F(CF 2 )CH 2 CH 2 SO 3 ], [19][20][21]24 further confirming that PFHpA did not come from 6:2 FTOH biotransformation. Even-number PFBA was not observed, and PFHxA accounted for 3.8 mol % by day 91 ( Figure 3B and Table 1), less than half of that in soil dosed with 6:2 FTOH.…”

“…20,35 Transient polyfluoroalkyl acids, such as 6:2 FTCA, 6:2 FTUCA, and 5:3 Uacid, were detected at low concentrations during 6:2 FTI biotransformation in soil ( Figure 3C), likely because of their fast further degradation to downstream biotransformation products, as was observed in 6:2 FTOHdosed soil. 19 Low levels of 6:2 FTOH (<1 mol %) were observed from days 1 to 58 in soil dosed with 6:2 FTI because of 6:2 FTOH subsequent rapid biotransformation. More volatile downstream biotransformation products, 5:2 ketone and 5:2 sFTOH (direct precursors of PFPeA and PFHxA), 19 peaked between 9 and 14 days with 7.8 and 8.2 mol %, respectively, and then decreased gradually thereafter to 3.7 and 2.4 mol % by day 91, with the majority of them detected in the headspace.…”

“…6:2 FTOH was rapidly biotransformed to downstream major products, such as PFPeA, PFHxA, and x:3 acids, as also occurred in soil dosed with 6:2 FTOH as the starting material. 19 6:2 FTOH soil biotransformation pathways were described in detail 19 and were later confirmed by pure Pseudomonas bacterial culture. 41 In this study, PFPeA and 5:3 acid were observed as two abundant products, consistent with a previous soil biotransformation study with 6:2 FTOH 19 and further confirming that the 6:2 FTOH route was operational in soil dosed with 6:2 FTI.…”

“…Even-number PFBA was not observed, and PFHxA accounted for 3.8 mol % by day 91 ( Figure 3B and Table 1), less than half of that in soil dosed with 6:2 FTOH. 19 On the basis of the current literature, 6:2 FTI seems to be a fluorotelomer substance that can be biotransformed to PFHpA with significant molar yields by microbes in the environment. Other analogues, including 6:2 FTOH itself, were either not converted to PFHpA or with low conversion yields (Table 2 and references therein).…”

“…Chemical names, acronyms, and molecular structures of the poly-and perfluoroalkyl substances described in this paper are shown in Experimental System. The Sassafras soil (Ultisol) used to study 6:2 and 8:2 FTOH aerobic biotransformation 19,34,35 was also selected as the microcosm to study 6:2 FTI aerobic biodegradation. The soil was collected from the same site in an undisturbed forested area for more than 40 years in Newark, DE in March, 2012, was sieved immediately upon collection via a 2 mm sieve, and was stored at 4°C until use.…”