Effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) on soil structure and function

Highlights

● PFAS significantly increased litter decomposition and soil pH.

● Soil respiration was significantly inhibited by PFAS.

● Perfluorooctanesulfonic acid suppressed soil water-stable aggregates.

● Three PFAS exerted varying degrees of impact on soil health.

Abstract

Soils are impacted globally by several anthropogenic factors, including chemical pollutants. Among those, perfluoroalkyl and polyfluoroalkyl substances (PFAS) are of concern due to their high environmental persistence, and as they might affect soil structure and function. However, data on impacts of PFAS on soil structure and microbially-driven processes are currently lacking. This study explored the effects of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutanesulfonic acid (PFBS) at environmental-relevant concentrations on soil health, using a 6-week microcosm experiment. PFAS (even at 0.5 ng g^–1 for PFBS) significantly increased litter decomposition, associated with positive effects on β-glucosidase activities. This effect increased with PFAS concentrations. Soil pH was significantly increased, likely as a direct consequence of increased litter decomposition affected by PFAS. Soil respiration was significantly inhibited by PFAS in week 3, while this effect was more variable in week 6. Water-stable aggregates were negatively affected by PFOS, possibly related to microbial shifts. PFAS affected soil bacterial and fungal abundance, but not microbial and certain enzyme activities. Our work highlights the potential effects of PFAS on soil health, and we argue that this substance class could be a factor of environmental change of potentially broad relevance in terrestrial ecosystem functioning.

Graphical abstract

Keywords

Litter decomposition / Soil respiration / Water-stable aggregates / Soil microbial abundance / Perfluorobutanesulfonic acid (PFBS) / Perfluorooctanesulfonic acid (PFOS)

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Acknowledgements

B.X. thanks the China Scholarship Council and Deutscher Akademischer Austauschdienst (CSC-DAAD) for a postdoctoral scholarship. M.C.R. acknowledges support from an ERC Advanced Grant (694368). We thank Daniel Lammel, Yun Liang, Tingting Zhao, and Lili Rong for their help with experimental measurements. We thank Rosolino Ingraffia for providing soil samples. Open Access funding enabled and organized by Projekt DEAL.

Conflicts of interest

We declare that there is no conflict of interest.

Availability of data and material

All data used for analyses and plotting are available online and can be accessed at https://doi.org/10.6084/m9.figshare.19772860.v1.

Electronic supplementary material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s42832-022-0143-5 and is accessible for authorized users.

Author contributions

B.X. and M.C.R. conceived the idea and designed experiments; B.X. conducted experiment and drafted the manuscript; G.Y assisted in measurements of soil function; A.L. assisted in data analysis and presentation; S.R. assisted in the determination of PFAS concentrations; All authors contributed to the final version of this manuscript.

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2022 The Author(s) 2022, corrected publication 2022. This article is published with open access at link.springer.com and journal.hep.com.cn