Data and model archive for shallow soil PFAS predictions in Maine, New Hampshire, and Vermont, 2026

Anthropogenic background concentrations of per- and polyfluoroalkyl substances (PFAS) in shallow soils (zero to six inches in depth) across Maine, New Hampshire, and Vermont are compiled in this data release, together with a summary table of soil PFAS method detection limits. New Hampshire samples were collected in 2021 (Santangelo and others, 2022), Vermont samples were collected in 2018 (Zhu and others, 2019; Zhu and others, 2022), and Maine samples were collected in 2021 (Sanborn, Head & Associates, Inc., 2022). A boosted regression tree model was developed using these soil concentrations as training data to predict where perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) concentrations may exceed New Hampshire's Soil Remediation Standards (SRS) of 0.5 nanograms per gram and 0.4 nanograms per gram in shallow soil, respectively, across the states of Maine, New Hampshire, and Vermont. The concentrations used for training data were converted to binary variables depending on whether each sample exceeded the SRS for PFOS and PFOA. The model output provides a map of probability of SRS exceedance for each 1x1 kilometer grid cell in the study area of northern New England along with maps of 95% confidence intervals. A model archive is provided, which provides the R code, all input files, and model predictions.

Santangelo, L.M., Tokranov, A.K., Welch, S.M., Schlosser, K.E.A., Marts, J.M., Drouin, A.F., Ayotte, J.D., Rousseau, A.E., and Harfmann, J.L., 2022, Statewide survey of shallow soil concentrations of per- and polyfluoroalkyl substances (PFAS) and related chemical and physical data across New Hampshire, 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P9KG38B5.

Sanborn, Head & Associates, Inc., 2022, Background levels of PFAS and PAHs in Maine shallow soils: Maine Department of Environmental Protection, https://www.maine.gov/dep/spills/topics/pfas/Maine_Background_PFAS_Stud….

Zhu, W., Roakes, H., Zemba, S. G., and Badireddy, A. R., 2019, PFAS Background in Vermont Shallow Soils: https://anrweb.vt.gov/PubDocs/DEC/PFOA/Soil-Background/PFAS-Background-….

Zhu, W., Khan, K., Roakes, H., Maker, E., Underwood, K.L., Zemba, S., and Badireddy, A.R., 2022, Vermont-wide assessment of anthropogenic background concentrations of perfluoroalkyl substances in surface soils: Journal of Hazardous Materials, v. 438, p. 129479, https://doi.org/https://doi.org/10.1016/j.jhazmat.2022.129479.