Predictions of anthropogenic background PFAS concentrations in soil and relation to bedrock lithology and groundwater quality

Environmental Science & Technology
By: , and 

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Abstract

Detectable concentrations of per- and polyfluoroalkyl substances (PFAS) have been observed in soils in remote areas and presumably originate from atmospheric deposition. These anthropogenic background concentrations may enable some PFAS to leach to groundwater at levels that exceed regulatory criteria for drinking water. However, anthropogenic background soil concentrations and their connection to groundwater are not well characterized. We developed a boosted regression tree model to predict perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) concentrations in shallow soils across northern New England. Low soil pH was the most important predictor of elevated anthropogenic PFOS and PFOA concentrations in background soils, rather than potential PFAS sources, land use, or population density. Total organic carbon (TOC) was also an important predictor for PFOS soil concentrations. Model predictions indicate that 73% of the shallow soils within Maine, Vermont, and New Hampshire exceed New Hampshire’s Soil Remediation Standard for PFOS (0.5 ng/g) and 41% exceed the PFOA standard (0.4 ng/g). Analysis of soil model results and groundwater data suggests that areas with high soil pH are associated with higher groundwater detection frequencies, illustrating how areas with less retention in soil are, conversely, also areas with potentially greater groundwater vulnerability. Further analysis indicates that groundwater may be more vulnerable in calcareous lithologies.

Suggested Citation

Tokranov, A.K., Santangelo, L.M., Ayotte, J.D., Welch, S.M., Schlosser, K.E., Marts, J.M., Drouin, A.F., and Roakes, H., 2026, Predictions of anthropogenic background PFAS concentrations in soil and relation to bedrock lithology and groundwater quality: Environmental Science & Technology, v. 60, no. 23, p. 16792-16804, https://doi.org/10.1021/acs.est.5c16810.

ISSN: 1520-5851 (online)

Study Area

Publication type Article
Publication Subtype Journal Article
Title Predictions of anthropogenic background PFAS concentrations in soil and relation to bedrock lithology and groundwater quality
Series title Environmental Science & Technology
DOI 10.1021/acs.est.5c16810
Volume 60
Issue 23
Publication Date June 01, 2026
Year Published 2026
Language English
Publisher ACS Publications
Contributing office(s) New England Water Science Center
Description 13 p.
First page 16792
Last page 16804
Country United States
State Maine, New Hampshire, Vermont
Additional publication details