Till Örebro universitet

Per- and polyfluoroalkyl substances (PFASs) are now widely detected in drinking water globally as a result of decades of production and use. Although recent regulations aim to address this issue, including the recast EU Drinking Water Directive (DWD), which introduces a PFAS Total parametric value, no standardized analytical method has yet been established for their determination. Here, extractable organofluorine (EOF) analysis of drinking water using combustion ion chromatography (CIC) was evaluated as a proxy for assessing PFAS Total under the EU DWD. Due to the low recovery of trifluoroacetic acid (TFA) in the EOF extraction, a workflow was presented that separated TFA from the PFAS Total reporting. The impact of different fluorine mass fractions on the conversion factor used to translate EOF concentrations into a PFAS Total parametric value was evaluated. Based on this discussion, PFOA (67% F) was selected as a representative reference compound. Due to the broad, non-specific coverage of the EOF method, contributions from non-PFAS organofluorine compounds or inorganic fluorinated species may occur, potentially inflating the PFAS Total parametric value. Therefore, a structured follow-up protocol for investigation of PFAS Total parametric value exceedance was presented to support the use of EOF-CIC as a screening and compliance-support tool.

Comprehensive quantification of per- and polyfluoroalkyl substances (PFAS) and extractable organofluorine (EOF) for assessing PFAS total in complex environmental matrices requires extraction methods capable of retaining chemically diverse fluorinated compounds. In this study, the performance of three solid-phase extraction (SPE) sorbents (weak anion exchange (WAX), weak cation exchange (WCX), and hydrophilic-lipophilic balance (HLB)) was comprehensively evaluated for the extraction of selected targeted PFAS and inorganic anions and determination of extractable fluorine from landfill leachate. Recovery experiments covering multiple PFAS classes, including PFCA, PFSA, zwitterionic PFAS, and bis-FASI, together with inorganic fluorinated anions, showed clear sorbent-dependent selectivity. WAX provided the most consistent recoveries across compound classes and yielded comparable concentrations of Σ33PFAS + BF4- and EOF, indicating retention of a broad fraction of fluorinated compounds and a closed fluorine mass balance. In contrast, WCX resulted in lower EOF concentration and a negative fluorine mass balance, attributed to matrix composition that emerged as a critical factor controlling EOF recovery, with divalent cations (Ca2+ and Mg2+) causing significant EOF suppression. HLB also yielded lower EOF concentrations, primarily due to poor retention of ultra-short-chain PFAS that contributed significantly to the overall fluorine balance, and similar behavior was observed for WCX. In addition, retention of inorganic fluorinated anions indicates that EOF concentrations included both organic and inorganic fluorinated compounds. The findings reveal that both sorbent chemistry and matrix chemistry critically influence EOF quantification, thereby affecting fluorine mass balance.

Previous studies on per- and polyfluoroalkyl substances (PFAS) have indicated large amounts of unidentified organofluorine in municipal wastewater, raising concerns about their environmental impact. Here, a novel multisorbent solid phase extraction method was applied to municipal wastewater samples, followed by liquid chromatography-high-resolution mass spectrometry-based screening and a quantification workflow combining targeted analysis and combustion ion chromatography for fluorine mass balance analysis. Twenty-three highly fluorinated compounds (i.e., perfluoroalkyl acids and precursors) were identified and, apart from trifluoroacetic acid, quantified in the low- to sub-ppt range. In contrast, 30 low-fluorinated substances (i.e., active pharmaceutical ingredients, pesticides, and transformation products, including some previously unreported metabolites) were identified and quantified at concentrations up to 3 orders of magnitude higher. Despite their lower fluorine content (<30% by mass), these pharmaceuticals accounted for 28-42% of the extractable (organo)fluorine (EOF), with sitagliptin, bicalutamide, and celecoxib carboxylic acid being important drivers of the EOF. The inorganic fluoroanions hexafluorophosphate and tetrafluoroborate were coextracted and contributed 7-19% of the EOF. The multisorbent approach also captured polar cationic pharmaceuticals, substantially influencing the EOF composition. These findings highlight the complexity of fluorine mass balance in municipal wastewater and the need for advanced methods to uncover unidentified organofluorine.

This study investigated the amount and proportion of unidentified organofluorine (UOF) in human serum and assessed short-term variability in exposure using extractable organofluorine (EOF) analysis and a fluorine mass balance approach. Serum samples were obtained from the well-characterized EuroMix cohort, comprising residents living in and around Oslo, Norway, collected between September 2016 and November 2017. Short-term intra-individual variability was evaluated using 72 paired serum samples collected 2-3 weeks apart. An extended target list of 64 PFAS, including trifluoroacetic acid (TFA), was applied to quantify identified and unidentified EOF. UOF accounted for up to 81% of EOF (median: 38%) in EuroMix samples. In 36% of paired samples, EOF concentrations varied by more than 25% over the 2-3-week interval, indicating the presence of compounds with relatively short biological half-lives. TFA was the most abundant individual PFAS detected, with median concentrations approximately twice those of PFOS. In a separate case study, serum samples from individuals using the fluorinated pharmaceutical Fluoxetine showed substantially elevated EOF and TFA concentrations (EOF: median 140 ng F/mL; TFA: median 27.7 ng/mL) compared with samples from individuals not using Fluoxetine (EOF: median < 8 ng F/mL; TFA: median 6.22 ng/mL). These findings indicate that fluorinated pharmaceuticals may contribute significantly to circulating EOF and TFA in humans. The large fraction of UOF and the widespread occurrence of TFA highlight the need to identify their sources relevant to human exposure. Together, these findings indicate that current PFAS including TFA biomonitoring approaches capture only a fraction (estimated to be 50%) of total human exposure to fluorinated substances and highlight the need to complement target analysis with fluorine mass balance approaches in future exposure assessment.

Per and polyfluoroalkyl substances (PFAS) have emerged as ubiquitous contaminants in municipal solid waste (MSW) landfill leachates due to their widespread industrial applications, environmental persistence, and the disposal of PFAS-containing waste in landfill. This study presents a multi-regional investigation of PFAS occurrence, influencing factors, and treatment performance in 17 landfill leachates and 9 corresponding effluents across China. Sum PFAS concentrations in raw leachates ranged from 634 to 46,400 ng/L, with short-chain perfluoroalkyl acids (PFAAs) dominating the compositional profile (65.4 to 97.2%). Landfill age exhibited a significant positive correlation with PFAS levels (p ≤ 0.05). Moreover, physicochemical parameters of leachate such as electrical conductivity and ammonia nitrogen exhibited strong positive correlations with PFAS concentrations (p ≤ 0.05), while meteorological variables showed compound-specific (perfluorobutanoic acid, PFBA and perfluorodecanesulfonic acid, PFDS) associations. PFAS concentrations in the treated effluents ranged from 6.29 to 7390 ng/L, with short-chain PFAAs dominating. Among the evaluated technologies, two-stage (TS) membrane bioreactor (MBR) combined with membrane separation systems achieved the lowest effluent concentrations (<10 ng/L) and the highest apparent removal efficiencies (up to ∼99.9%) in this dataset. However, removal effectiveness varied considerably across compounds, especially for short-chain PFAAs and PFAA-precursors. Overall, this study provides an assessment of PFAS occurrence and treatment performance in landfill leachate systems, highlights key environmental and operational factors, and provides insights for improving PFAS management in landfill leachate treatment.

Per- and polyfluoroalkyl substances (PFAS) are persistent pollutants that raise food safety concerns, especially near contamination hotspots. This study measured 9 PFAS in milk and 15 PFAS in water from 22 Swedish dairy farms <10 km from contamination hotspots and 49 PFAS in milk from 20 regional production facilities. PFOA, PFOS, and PFNA were quantified in 5-77% of milk from dairy farms, with maximum levels of 18, 17, and 10 pg/g milk ww, respectively; the remaining PFAS were below method detection limits (MDL). All PFAS were < MDL at production facilities. One dairy farm milk sample exceeded EU's indicative level for PFOA (10 pg/g), but levels in production facilities suggest limited consumer exposure. No correlation was found between PFAS in farm water and milk, implying other exposure routes may dominate when water contamination is low. While results indicate limited health risks, contamination in other milk-producing regions cannot be ruled out, supporting the need for continued PFAS monitoring in dairy production.

In this study, the levels of per- and polyfluoroalkyl substances (PFAS) in food available on the Swedish market were measured, to estimate dietary exposure in different population groups and to compare with the tolerable weekly intake (TWI) established by the European Food Safety Authority (EFSA). In total, 14 PFAS were analysed in food group samples representative for the Swedish market (n = 51) and additional samples (n = 107) of specific foods, including fish and shellfish, meat, eggs, fruits, and vegetables. Dietary exposure was calculated with all detectable PFAS and consumption data from three national dietary surveys of young children, adolescents, and adults. PFAS were observed in 3 of the 17 food groups: eggs, fatty fish, and lean fish. Additional analyses revealed PFAS in all fish and shellfish samples, as well as in wild boar, reindeer, liver pâté, and organic eggs. No quantifiable PFAS were found in fruit, vegetables, conventional eggs, or other meat samples. The intake estimations showed that the median PFAS exposure was below the TWI across all age groups, but up to 19 % of young children, 18 % of adolescents, and 5 % of adults exceeded the TWI. Scenario calculations demonstrated that most of the population, except young children, could safely consume drinking water at the Swedish maximum limit (4 ng Σ4PFAS/L) and fish according to the recommendation (2-3 servings per week) without exceeding the TWI. Approximately 60 % of sum PFAS exposure from food came from Σ4PFAS, emphasizing the need for further risk assessments of other PFAS.

Short-chain (C4-C6) per- and polyfluoroalkyl substances (PFAS) have become the dominant PFAS fraction in the environment following the phase-out of long-chain analogues. Their exceptional chemical stability, amphiphilic character and resistance to degradation have led to ubiquitous occurrence of short-chain PFAS across the global hydrological cycle. At the same time, their enhanced aqueous solubility, mobility and persistence resulted in poor removal by conventional water treatment leading to widespread detection in drinking water. By first providing the general classification of PFAS, this Review summarises the physicochemical properties of short-chain PFAS and their interactions to elucidate their removal challenges. While heterogeneous photocatalysis has long been the vanguard technology for the abatement of aqueous-phase micropollutants, it now finds itself in uncharted territory. Previously, photocatalysts that efficiently generate hydroxyl radicals generally exhibit strong activity toward hydrocarbon-based micropollutants; however, in the absence (or lacking) of C-H bonds in PFAS, this paradigm may no longer apply. Hence, this Review presents an up-to-date understanding of short-chain PFAS and their abatement through heterogeneous photocatalysis. As the field remains in its infancy, critical knowledge gaps must be addressed before the rational design of PFAS-targeted photocatalysts and treatment processes can be realized.

Per- and polyfluoroalkyl substances (PFAS) are organofluorine chemicals with widespread global occurrence. Despite over 4,700 known compounds, only a small fraction is regularly monitored, leading to potential underestimation of PFAS pollution, particularly perfluoroalkyl acid (PFAA) precursors. To address this analytical challenge, this study employed a comprehensive analytical approach, combining target analysis, oxidative conversion of PFAS precursors, and extractable organofluorine (EOF) mass balance analysis on surface sediment samples collected from the coastal South China Sea (n = 18) and eight major Pearl River outlets (n = 8) in 2021 and 2020, respectively, to investigate unidentified PFAA precursors and EOF levels for the first time. Target analysis revealed a ten-fold increase of mean PFAS concentrations in the estuary compared to a previous study on samples collected in 2018. PFAA precursors, including N-ethyl perfluorooctane sulfonamide phosphate diesters, perfluorooctane sulfonamidoacetic acids, and polyfluoroalkyl phosphate diesters, were more frequently detected at estuarine outlets. C4-C6 short-chain perfluoroalkyl carboxylic acids and perfluorooctanoic acid emerged as the predominant oxidation products, with a different composition between estuarine outlet and coastal sediment samples. Multiple regions with occurrence of C6 electrochemical fluorination precursors were identified, and 6:2 fluorotelomer sulfonic acid was detected as an unexpected oxidation product near an airport, suggesting the potential contribution from aqueous film-forming foams. A substantial fraction of extractable organofluorine was not explained by targeted PFAS analysis, indicating the presence of unidentified fluorinated compounds in the investigated coastal sediments.

Per- and polyfluoroalkyl substances (PFAS) are an extensive group of anthropogenic compounds with a large diversity of classes. Relying only on target analysis may underestimate the level of PFAS contamination in the environment. The extractable organofluorine (EOF) mass balance is a widely applied method to estimate the fraction of organofluorine not captured by target analysis. This study aimed to conduct a comprehensive EOF mass balance analysis on sludge and evaluate the impact of three different sample treatments on target PFAS and EOF, as well as their respective mass balance. Two complementary sample treatments were applied to 26 Swedish sludge samples: ion-pair extraction (IPE) for anionic and neutral PFAS, and hexane:acetone extraction (Hx:Ac) for nonpolar PFAS. The results demonstrated that the EOF concentrations were highly influenced by the sample treatment. The IPE method observed up to 40 times higher EOF concentrations than the Hx:Ac method, indicating a high proportion of polar organofluorine. Unidentified EOF increased between 2004 and 2017 for both sample treatments. These findings demonstrate that both polar and nonpolar organofluorine contribute to the EOF and that no single method captures them. In the present study, only two side-chain fluorinated copolymers were monitored, and other fluorinated polymers may be contributors to the unknown EOF.