Organic fluorine content in aqueous film forming foams (AFFFs) and biodegradation of the foam component 6 : 2 fluorotelomermercaptoalkylamido sulfonate (6 : 2 FTSAS)

Abstract

Environmental context Total organofluorine and known fluorosurfactants were quantified in 11 aqueous film forming foams (AFFFs) used to extinguish fires in Ontario, Canada, and one commercial AFFF product. By comparing the concentrations of known fluorosurfactants with the total organofluorine, less than 10% of the fluorosurfactants were identified in half of the samples. Our biodegradation experiment with one of the fluorosurfactants using waste-water treatment plant sludge showed that it was a potential source of perfluoroalkyl carboxylates, which are persistent in the environment. Abstract Eleven aqueous film forming foam (AFFF) samples that were used to extinguish fires in Ontario, Canada, and one commercial product, were analysed using a variety of analytical techniques to obtain structural information and quantities of organofluorine and known perfluoroalkyl and polyfluoroalkyl substances (PFASs). The NMR spectra of the foams distinguished the fluorosurfactants that were synthesised by either electrochemical fluorination or telomerisation. Total organofluorine content was quantified using total organofluorine–combustion ion chromatography (TOF-CIC), which revealed that the samples contained from 475 to 18 000µgFmL–1. The common AFFF component 6 : 2 fluorotelomermercaptoalkylamido sulfonate (FTSAS) was quantified by liquid chromatography tandem mass spectrometry (LC-MS/MS) together with perfluoroalkane sulfonates (PFSAs), perfluoroalkyl carboxylates (PFCAs) and fluorotelomer sulfonates (FTSAs); in five samples, 6 : 2 FTSAS was present in concentrations greater than 1000µgmL–1. By comparing the concentrations of these quantifiable fluorochemicals with the total organofluorine content, it was evident that in half of the AFFF samples, less than 10% of the fluorochemicals were identified; in two of the samples, perfluorooctane sulfonate (PFOS) accounted for ~50% of the total organofluorine content. Our degradation experiment with 6 : 2 FTSAS using waste-water treatment plant sludge showed that 6 : 2 FTSAS was a potential source of FTSAs, fluorotelomer alcohols and PFCAs in the environment.

Identification of Novel Polyfluorinated Ether Sulfonates as PFOS Alternatives in Municipal Sewage Sludge in China

“…36 FTSA was found to be present in some AFFF formulations, and significant release levels (up to 14 600 ng/L) of 4:2, 6:2, and 8:2 FTSA were detected in groundwater where fire-training activities were conducted. 36 Degradation of fluorotelomer precursors is the primary FTSA source, 37 and the elevated abundance of 8:2 FTSA on surfacial AFFF-impacted soil further suggest contributions of the C8 FTSA-based compounds in the environment. 38 Correlations between Fluorinated Sulfonates and Influencing Factors.…”

Elevated levels of PFOS and PFHxS in firefighters exposed to aqueous film forming foam (AFFF)

“…The relatively high PFOS and PFHxS serum levels are likely attributable to exposure to 3M AFFF as perfluorinated sulfonates (PFSAs) have been identified as major components in 3M foam concentrates (Backe et al, 2013;Weiner et al, 2013), as well as in groundwater Table 3 Results of ANOVA for possible associations between PFAA levels and biochemical outcomes. Models for cholesterol, HDL, LDL, and triglycerides (mmol/L) based on participants with measured BMI, confirmed fasting before blood sample, and those not taking cholesterol-lowering medications (n = 17).…”

Biodegradability of fluorinated fire-fighting foams in water

“…As a reference, the 6:2 fluorotelomer thioether amido sulfonate (C 15 H 17 O 4 NS 2 F 13 À1 ) which has been identified in some AFFF formulations is 42% fluorine by weight. A 0.15-3% estimate of organic fluorine in foam concentrates is somewhat less than 5% found by Weiner et al (2013). With these assumptions, 100 mg foam concentrate/L solutions used in this study represent a minimum of 150 lg L À1 fluorine which would be within IC detection limits.…”

“…Identities of surfactants in foam formulations are proprietary, however some components and degradation products have been identified (Schultz et al, 2004;Place and Field, 2012;Backe et al, 2013;D'Agostino and Mabury, 2014). Biotransformation studies of some fluorotelomers including a fluorotelomer sulfonate specifically identified in AFFFs demonstrate that one or more CF 2 groups may be sequentially removed by wastewater treatment plant microbes (Wang et al, 2005;Weiner et al, 2013). In another study, biodegradation of the perfluorinated portion of a fire fighting foam fluorotelomer did not occur (Moe et al, 2012).…”