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In this study, 6:2 and 8:2 polyfluoroalkyl phosphate diester (diPAP) were individually investigated in lysimeters under near-natural conditions. Leachate was sampled for 2 years, as was the soil after the experiment. In the leachate of the diPAP spiked soils, perfluorocarboxylic acids (PFCAs) of different chain lengths were detected [23.2% (6:2 diPAP variant) and 20.8% (8:2 diPAP variant) of the initially applied molar amount]. After 2 years, the soils still contained 36-37% 6:2 diPAP and 41-45% 8:2 diPAP, respectively, in addition to smaller amounts of PFCAs (1.5 and 10.6%, respectively). Amounts of PFCAs found in the grass were low (

Vor dem Hintergrund des Schadensfalls mit per- und polyfluorierten Alkylsubstanzen (PFAS) in Baden-Württemberg, bei dem landwirtschaftliche Nutzflächen durch PFAS-haltige Papierschlämme kontaminiert wurden, erfolgten im Rahmen des BWPLUS-Verbundvorhabens PROSPeCT Untersuchungen zum Sorptions- und Transportverhalten von PFAS im Boden sowie zum Transfer in die einzelnen Kompartimente der Maispflanze. Unter Labor- und Feldbedingungen wurde das Abbauverhalten der polyfluorierten Alkylphosphatdiester 6:2 diPAP und 8:2 diPAP in perfluorierte Carbonsäuren (PFCAs) im Pfad Boden-Sickerwasser sowie Boden-Pflanze erforscht und wichtige Einflussfaktoren bestimmt.

Fluorotelomer precursors in soil constitute a reservoir for perfluoroalkyl acids (PFAAs) in the environment. In the present study, precursor degradation and transfer rates of seven fluorotelomer precursors and F-53B (chlorinated polyfluoroalkyl ether sulfonates) were investigated in pot experiments with maize plants (

Per- and polyfluoroalkyl substances (PFAS) are environmentally ubiquitous, anthropogenic substances with adverse effects on organisms, which shows the need to study their environmental fate and leaching behavior. In the present soil columns study, the leaching behavior and fate of nontransformable and transformable (precursors) were investigated. Ten nontransformable PFAS in two different soils, two precursors and two field soils, which were already contaminated with a mixture of PFAS, and two uncontaminated controls, were set up for a time span of 2 years. At the end of the study, the molecular balance could not be closed for nontransformable PFAS. This effect was positively correlated to the fluorinated carbon chain length. The precursors, which were both polyfluoroalkyl phosphate diesters (diPAP), had different transformation products and transformation rates, with a higher rate for 6:2 diPAP than 8:2 diPAP. After 2 years, amounts of diPAP were still found in the soil with no significant vertical movement, showing high adsorption to soils. Transformation products were estimated to be simultaneously formed. They were predominantly found in the percolation water; the amounts left in soil were negligible. Up to half of the initial precursor amounts could not be balanced and were considered missing amounts. The results of contaminated field soil experiments showed the challenge to estimate PFAS leaching without knowing all occurring precursors and complex transformation dynamics. For this purpose, it was shown that a broad examination of contaminated soil with different analytical methods can help with qualitative estimations of leaching risks. For a better quantitative estimation, analytical determination of more PFAS and a quantification of the missing amounts are needed. Environ Toxicol Chem 2022;41:2065-2077. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Per- and polyfluoroalkyl substances (PFASs) are fluorinated anthropogenic compounds of which numerous have a high thermal stability, high surface tension, water and oil repellence. PFASs are used e.g. as surfactants, in agrochemical products and in fire extinguishing foams. Due to negative effects to the environment and human health some compounds are already declared as Persistent Organic Pollutants (POPs) or Substances of Very High Concern (SVHC). The behaviour of PFASs in environmental matrices can differ dependent on the molecular structure and environmental conditions. Sorption, for example, depends on soil characteristics, compound properties such as the carbon chain length and the functional group. When PFASs are found in soils, the knowledge of factors affecting the leaching behaviour in soil can be helpful to assess plant availability and risk of groundwater contamination.In some contamination cases, e.g. Rastatt/Baden-Baden, Germany, PFASs precursors such as polyfluoroalkyl phosphate diesters (diPAPs) are present in soil and are transformed into PFAAs (perfluoroalkyl acids), a sub-group of PFASs, which are stable in the environment. To study the behaviour of diPAPs in soil, 8:2 diPAP and 6:2 diPAP were applied to 50 cm soil-filled columns with a concentration of 1 mg per kg soil. For two years, the columns are watered on 3-5 days per week with an average weekly natural rainfall of Baden-Württemberg. The leaching water is collected and analysed every two weeks. After the first year, there was no detection of precursors in the leaching water. The main products were, in accordance with literature, PFPeA (Perfluoropentanoic acid) and PFHxA (Perfluorohexanoic acid) for the precursor 6:2 diPAP and PFHpA (Perfluoroheptanoic acid) and PFOA (Perfluorooctanoic acid) for the precursor 8:2 diPAP. The breakthrough peak of PFPeA (864 µg/l) and PFHxA (487 µg/l) was found in week nine after the start of the experiment, the major peak of PFHpA (124 µg/l) in week 15 and the peak of PFOA (303 µg/l) in week 25. Even though the major breakthrough of PFAAs was over after the first year, all of them are still found in leaching water in relatively constant concentrations: ~40 µg PFPeA/l, ~20 µg PFHxA/l (6:2 diPAP) and ~5 µg PFHpA/l, ~50 µg PFOA/l (8:2 diPAP). Thus, as a preliminary result after the first year, there is a higher mass of PFPeA and PFHxA in the leachate compared to PFHpA and PFOA, which can be led back to higher transformation rates of 6:2 diPAP than 8:2 diPAP.After two years, the soil columns will be cut horizontally in sections, and the soil will be analysed for precursors and PFAAs in order to calculate a mass balance. This will provide more insight into the transformation and mobilisation behaviour of investigated diPAPs and PFAAs.