Epsilon Archive for Student Projects

Abstract

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.