Uptake of per- and polyfluoroalkyl substances by plants

The extensive use of per- and polyfluoroalkyl substances (PFASs) as surfactants in, for example textiles,cookware and aqueous firefighting foams (AFFFs) during the last decades has resulted in widespread environmental contamination. Due to the persistent and bioaccumulative characteristics of PFASs, they are ubiquitously found in the environment, wildlife and humans. Currently, the knowledge of remediation techniques for environments contaminated with PFASs is limited. Therefore, this study aims at evaluating the potential of plant uptake of 26 different PFASs from contaminated soils and groundwater. Arlanda airport, Sweden’s biggest airport, has a fire training facility that is suffering from severe PFAS contamination due to former regular practices with PFAS-containing AFFFs for safety purposes. Samples from different plant species, namely silver birch (Betula pendula), Norway spruce (Picea abies), bird cherry (Prunus padus), mountain ash (Sorbus aucuparia), ground elder (Aegopodium podagraria), long beechfern (Phegopteris connectilis) and wild strawberry (Fragaria vesca), surface soil and groundwater were taken near the fire training site to assess the accumulation potential and eligibility of selected plants for phytoremediation. In comparison to typical background levels, elevated ΣPFAS levels were detected in soil and groundwater ranging from 16-156 ng g⁻¹ dry weight (dw) and 1,200 and 34,000 ng L⁻¹, respectively. The plants showed a high variability of concentrations with highest ΣPFAS concentrations in vegetative compartments, particularly the foliage. Birch leaves exceeded all other sampled tissues and species with a maximum of ΣPFAS 327 ng g⁻¹ dw, followed by spruce needles with 222 ng g⁻¹ dw. The leaves and twigs of mountain ash were generally the least contaminated (<10 ng g⁻¹ dw, while the other twigs had concentrations of up to 76 ng g⁻¹ dw (birch). Interestingly, the annual ground cover plants were highly contaminated and accumulated high amounts of PFASs. The bioconcentration factors (BCFs; plant/soil ratios) were found to be as high as 143,700 for 6:2 FTSA (birch leaves), which turned out to have the highest accumulation potential in plants. Moreover, the BCFs were highest for short-chained C3-C5 perfluoroalkyl carboxylic acids (PFCAs; median ~0.9) and decreased for the longer chained C7-C9 PFCAs (~0.4), while being lowest for the long-chained C6-C8 perfluoroalkane sulfonic acids (PFSAs; ~0.2). In conclusion, silver birch, Norway spruce, bird cherry and long beechfern seem promising candidates for phytoremediation of PFASs

Mass flow of per- and polyfluoroalkyl substances (PFAS) in a Swedish municipal wastewater network and wastewater treatment plant

Per: and polyfluoroalkyl substances (PFAS) are ubiquitously distributed in wastewater, due to their numerous uses in industry and consumer products, but little is known of PFAS mass flows in municipal wastewater network systems and within wastewater treatment plants (WWTPs). This study assessed mass flows of 26 PFAS in a wastewater network and WWTP, to provide new insights into their sources, transport, and fate in different treatment steps. Wastewater and sludge samples were collected from pumping stations and the main WWTP in Uppsala, Sweden. PFAS composition profiles and mass flows were used to identify sources within the sewage network. Wastewater from one pumping station showed elevated concentrations of C3–C8 PFCA, likely caused by an industrial source, and two stations had elevated concentrations of 6:2 FTSA, probably originating from a nearby firefighter training facility. Within the WWTP, short-chain PFAS dominated in wastewater, whereas longchain PFAS dominated in sludge. The ratio of perfluoroalkyl sulfonates (PFSA) and ethylperfluorooctanesulfonamidoacetic acid (EtFOSAA) to ∑26PFAS decreased during the WWTP process, likely due to sorption to sludge, but also transformation (EtFOSAA). Overall, PFAS were not efficiently removed in the WWTP, with mean removal efficiency of 10 ± 68% for individual PFAS, resulting in discharge of 7000 mg d− 1 ∑26PFAS into the recipient. This shows that conventional WWTPs are inefficient in removing PFAS from wastewater and sludge, so advanced treatment techniques are needed

A critical review on passive sampling in air and water for per- and polyfluoroalkyl substances (PFASs)

Passive sampling methods have been widely used for monitoring pollutants in different environments due to their advantages including simplicity to use and time-integrated sampling. Despite the advantages, challenges still exist and are associated with the calibration and implementation of passive sampling, in particular for per- and polyfluoroalkyl substances (PFASs) due to their unique physicochemical properties. In the current review, we focus on the calibration and use of passive samplers for PFASs in air and water. The comparison of the sampling rates generally showed a higher variability for the aqueous passive samplers compared to the passive air samplers. A better standardization for calibration methods for PFASs in air and water is needed. Nevertheless, passive samplers are an ideal tool for monitoring PFASs in air and water and can identify spatial or temporal trends and pollution sources, variations in water quality and ultimately improve our understanding of the global distribution of PFASs

Plant Uptake of Per- and Polyfluoroalkyl Substances at a Contaminated Fire Training Facility to Evaluate the Phytoremediation Potential of Various Plant Species

Fire training facilities and other areas suffer from serious per- and polyfluoroalkyl substance (PFAS) contamination in soil, surface water, and groundwater due to regular practices with PFAS-containing aqueous firefighting foams (AFFFs). Therefore, the uptake of 26 PFASs in plants and the contamination of soil and groundwater has been investigated at a fire training site at Stockholm Arlanda airport, Stockholm (Sweden) in 2016. Elevated ∑₂₆PFAS levels were detected in soil and groundwater ranging from 16 to 160 ng g^–1 dry weight (dw) and 1200–34 000 ng L^–1, respectively. Samples from different plant species and tissues (i.e., roots, trunk/cores, twigs, leaves/needles) of the local plant community were taken, namely silver birch (<i>Betula pendula</i>), Norway spruce (<i>Picea abies</i>), bird cherry (<i>Prunus padus</i>), mountain ash (<i>Sorbus aucuparia</i>), ground elder (<i>Aegopodium podagraria</i>), long beechfern (<i>Phegopteris connectilis</i>), and wild strawberry (<i>Fragaria vesca</i>). The plants showed a high variability of concentrations with highest ∑₂₆PFAS concentrations in vegetative compartments with up to 97 ng g^–1 wet weight (ww) and 94 ng g^–1 ww in birch leaves and spruce needles, respectively. Annual ground cover plants such as long beechfern and ground elder, and bushes like bird cherry showed concentrations up to 6.9, 23, and 21 ng g^–1 ww, respectively. The bioconcentration factors (BCFs; plant/soil ratios) were highest in foliage, while the total tree burden of ∑₂₆PFASs per tree was up to 11 mg for birch and 1.8 mg for spruce. Considering a shelterwood system with mixed stands of silver birch and spruce in combination with regular harvest of leaves and birch sap and an understory of ground elder, it is potentially feasible to remove 1.4 g of ∑₂₆PFASs per year and hectare from (heavily) contaminated sites. An alternative approach is the coppicing of birch trees in combination with an understory of ground elder, potentially removing 0.65 g yr^–1 ha^–1 of ∑₂₆PFASs, while a simple meadow with ground elder can remove 0.55 g yr^–1 ha^–1 ∑₂₆PFASs

PFAS in waste residuals from Swedish incineration plants : A systematic investigation

Incineration is the dominant treatment for residual waste in Sweden. It is desirable to reach complete thermal oxidation of chemical substances in the incineration process to destroy toxic substances contained in waste. Otherwise, there is a risk of toxic substances being released into the environment through incineration residuals. This project has investigated to which extent Swedish waste incineration plants emit PFAS (per- and polyfluoroalkyl substances) via bottom ash, fly ash and condensate water.  Of 38 incineration plants in Sweden, 27 (in total 31 furnaces) joined the project, answered questionnaires about operating parameters, and sampled incineration residuals. Five samples from each matrix, fly ash, bottom ash, or condensate water, were collected during a two-week period to compensate for the variation over time.  The collected samples of bottom ash, fly ash and condensate were analysed for 27 different PFAS according to a methodology developed by IVL Swedish Environmental Research Institute, based on LC-MS / MS. Out of the 27 incineration plants in this project, five plants had no samples with PFAS-27 concentrations above the analytical limit of detection in any of the matrices. Generally, the results show low concentrations in the sampled matrices from most plants, with a few exceptions. No apparent relationships were found between the analysed concentrations of PFAS in the sampling matrices and the operational data.Avfallsförbränning är den vanligaste behandlingen av restavfall i Sverige. Vid förbränningen är ambitionen att nå fullständig oxidation av kemiska ämnen, så att giftiga ämnen i avfallet förstörs. Om så inte sker finns det risk att giftiga ämnen släpps ut i miljön via restprodukter. Detta projekt har undersökt i vilken utsträckning svenska avfallsförbränningsanläggningar släpper ut PFAS till miljön via bottenaska, flygaska och kondensatvatten.  Av de totalt 38 förbränningsanläggningarna som finns i Sverige anslöt sig 27 till projektet, besvarade enkäter från projektet om driftsparametrar och provtog material för analyser. Fem prover samlades in under en tvåveckorsperiod från varje matris, för att kompensera för variationen över tid.  De insamlade proverna av bottenaska, flygaska och kondensat analyserades med avseende på 27 olika PFAS-ämnen enligt en metod som utvecklats av IVL, baserad på LC-MS / MS. Av de 27 förbränningsanläggningarna i detta projekt hade fem anläggningar inga prover med PFAS-27-koncentrationer över detektionsgränsen. I allmänhet visar resultaten på låga koncentrationer i de provtagna matriserna från de flesta anläggningar, med några utstickande värden. Inga uppenbara samband hittades mellan de analyserade koncentrationerna av PFAS i provtagningsmatriserna och driftsuppgifterna

Per- and Polyfluoroalkyl Substances in Swedish Groundwater and Surface Water: Implications for Environmental Quality Standards and Drinking Water Guidelines

The aim of this study was to assess per- and polyfluoroalkyl substances (PFASs) in the Swedish aquatic environment, identify emission sources, and compare measured concentrations with environmental quality standards (EQS) and (drinking) water guideline values. In total, 493 samples were analyzed in 2015 for 26 PFASs (∑₂₆PFASs) in surface water, groundwater, landfill leachate, sewage treatment plant effluents and reference lakes, focusing on hot spots and drinking water sources. Highest ∑₂₆PFAS concentrations were detected in surface water (13 000 ng L^–1) and groundwater (6400 ng L^–1). The dominating fraction of PFASs in surface water were perfluoroalkyl carboxylates (PFCAs; 64% of ∑₂₆PFASs), with high contributions from C₄–C₈ PFCAs (94% of ∑PFCAs), indicating high mobility of shorter chain PFCAs. In inland surface water, the annual average (AA)-EQS of the EU Water Framework Directive of 0.65 ng L^–1 for ∑PFOS (linear and branched isomers) was exceeded in 46% of the samples. The drinking water guideline value of 90 ng L^–1 for ∑₁₁PFASs recommended by the Swedish EPA was exceeded in 3% of the water samples from drinking water sources (<i>n</i> = 169). The branched isomers had a noticeable fraction in surface– and groundwater for perfluorooctanesulfonamide, perfluorohexanesulfonate, and perfluorooctanesulfonate, highlighting the need to include branched isomers in future guidelines