Observation of a Novel PFOS-Precursor, the Perfluorooctane Sulfonamido Ethanol-Based Phosphate (SAmPAP) Diester, in Marine Sediments

Abstract

The environmental occurrence of perfluorooctane sulfonate (PFOS) can arise from its direct use as well as from transformation of precursors ((N-alkyl substituted) perfluorooctane sulfonamides; FOSAMs). Perfluorooctane sulfonamidoethanol-based phosphate (SAmPAP) esters are among numerous potential PFOS-precursors which have not been previously detected in the environment and for which little is known about their stability. Based on their high production volume during the 1970s-2002 and widespread use in food contact paper and packaging, SAmPAP esters may be potentially significant sources of PFOS. Here we report for the first time on the environmental occurrence of SAmPAP diester in marine sediments from an urbanized marine harbor in Vancouver, Canada. SAmPAP diester concentrations in sediment (40-200 pg/g dry weight) were similar to those of PFOS (71-180 pg/g). A significant (p < 0.05) correlation was observed between SAmPAP diester and N-ethyl perfluorooctane sulfonamido acetate (an anticipated degradation product of SAmPAP diester). ∑PFOS-precursor (FOSAM) concentrations in sediment (120-1100 pg/g) were 1.6-24 times greater than those of PFOS in sediment. Although SAmPAP diester was not detected in water, PFOS was observed at concentrations up to 710 pg/L. Among the per- and polyfluoroalkyl substances monitored in the present work, mean log-transformed sediment/water distribution coefficients ranged from 2.3 to 4.3 and increased with number of CF(2) units and N-alkyl substitution (in the case of FOSAMs). Overall, these results highlight the importance of FOSAMs as potentially significant sources of PFOS, in particular for urban marine environments.

PFAS in Paper and Board for Food Contact

“…PFAAs can, however, also stem from indirect sources, being PFAA precursors. These are typically polyfluorinated compounds, which have been shown to degrade to perfluorinated compounds, both abiotically and biotically, in the environment (Benskin et al 2012), during processing and upon intake (D'eon and Mabury 2007, Lee et al 2010Butt et al, 2014). Polyfluorinated substances that are taken up from food and transformed in the body into PFAAs (Danish EPA, 2015) are examples of indirect sources.…”

“…In paper and board, examples are the polyfluorinated alkyl phosphate esters (PAPs), fluorotelomer mercaptoalkyl phosphate diesters (FTMAPs) (Begley et al, 2005) and fluorotelomer acrylates, as shown in Figure 6. Examples of polyfluorinated PFOS derivatives used in paper and board (P&B) are the alkyl-FOSEs and FOSAs, and SN-diPAPs (Begley et al, 2005) also called SAmPAPs (Benskin et al, 2012).…”

Selected physicochemical aspects of poly- and perfluoroalkylated substances relevant to performance, environment and sustainability—Part one

“…Electrochemical fluorination of octanoyl fluoride C 7 H 17 COF leads to C 7 F 17 COF from which C 7 F 17-COOH (PFOA 20) and its salts can be derived. The electrochemical process is harsh, non selective and actually leads to complex, usually poorly-defined mixtures of linear chain, branched chain and cyclic perfluorinated molecules of various chain lengths and isomeric forms, thus providing a product signature that can help track the source of a contaminant (Benskin et al, 2012). Products labelled as PFOS typically contain 70-80% of the linear molecule, and up to eleven identified isomers (Fig.…”

Methodology for studying biotransformation of polyfluoroalkyl precursors in the environment

“…Soil is the primary deposit medium of volatile precursors through atmospheric deposition, while sewage sludge and river sediment are important sinks of PFASs in aqueous systems from household and industry emissions [15][16][17]. To obtain knowledge on the specific microorganisms responsible for the polyfluoroalkyl precursor biotransformation processes, microbial consortium or pure bacterial cultures from soil and sewage sludge were isolated and used [30][31][32].…”

“…Both fluorotelomer-based (FT) precursors (e.g., FTOHs and FTIs) and perfluoroalkane sulfonamido derivatives, including N-ethyl perfluorooctane sulfonamide (N-EtFOSA) and N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE), were found in ambient air particles [13][14][15]. Fluorotelomer alcohols, monosubstituted and disubstituted PAPs, and perfluorooctane sulfonamidoacetic acid (FOSAA) analogues have frequently been detected in wastewater-treatment plant (WWTP) effluent, activated sludge and marine sediments [15][16][17]. Elevated PFAS concentrations found in effluents compared with those in influents may further indicate contributions of polyfluorinated-precursor biodegradation in the WWTPs [18].…”