Detection of ultra-short chain perfluoroalkyl substances in Swedish environmental waters

• The ubiquitous distribution of perfluoroalkyl substances (PFASs) has been documented worldwide in different environmental samples including humans. In Sweden, severe PFAS contamination in drinking water has resulted in elevated blood PFAS concentrations in residents living in contaminated areas. In many cases, the use of aqueous film forming-foams (AFFFs) at both civil and military airports has resulted in this contamination, as PFASs are one of the active ingredients in AFFFs. According to a nationwide survey, it was estimated that 30 % of the Swedish population has their closest drinking water source contaminated with these substances. A guideline value for safe use of drinking water set by the Swedish Food Agencyis the sum of eleven PFASs including perfluoroalkylated sulfonates (PFSAs; C4, C6, C8), perfluoroalkylated carboxylates (PFCAs; C4-C10) and 6:2 fluorotelomer sulfonate.This is set to 90 ng/L, while the health based limit, based on the tolerable daily intake,is set to 900 ng/L. In the US, Barzen-Hansen et al.showed the presence of ultra-short chain PFASs, perfluoropropanesulfonate (PFPrS) and perfluoroethanesulfonate (PFEtS), in five AFFFs. In ground water samples from eleven US military bases, PFEtS was detected in eight out of eleven samples ranging from 11-7500 ng/L, while PFPrS was detected in all samples, ranging from 19-63000 ng/L). Conventional reversed-phase LC using C18 column is not suitable to chromatograph these ultra-short chain PFAS, because they are highly polar; ion-exchange column has been demonstrated useful for separating these ultra-short chain PFAS. In this study a new analytical approach employing supercritical fluid chromatography (SFC) was developed for chromatographic separation of these ultra-short chain PFASs. Environmental water samples (surface water, ground water, rain water, snow and sediment) from various locations with suspected PFAS contamination were analyzed to investigate the potential occurrence of these ultra-short chain compounds in the Swedish environment. Solid phase extraction according to ISO method was used to concentrate water samples prior to instrumental analyses using both UPLC-MS/MS and UPC2-MS/MS.Results show that both PFPrS and PFEtS could be detected in environmental samples from Sweden using SFC separation coupled to triple quadrupole detection. Out of the 26 samples analysed,the ultra-short-chain PFPrS could be detected and quantified in 22 samples. The concentrations for PFPrS in all the samples ranged between 0.93 ng/l to 390 μg/l. The ultra-short-chain PFPEtS could be quantified in 24 out of the 26 samples, with a concentration range between 0.07-5 680 ng/l. The highest concentrations represents highly contaminated ground water samples collected from a military airport.

Ämnesord

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

Nyckelord

Supercritical fluid chromatography

ultra-short chain PFAS

Analytical Chemistry

Analytisk kemi

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