Soils Study Sheds Light on Background PFAS Concentrations

Woodard & Curran’s environmental experts advanced the science of PFAS by conducting a self-funded study of background concentrations of PFAS in Massachusetts surface soils. The resulting data solidify the background occurrence of PFAS in soil, helping stakeholders distinguish regulated PFAS releases that may warrant response actions.

Putting contamination into context

Understanding background concentrations of contaminants in the environment allows us to more effectively determine whether a regulated release to the environment has occurred. When it has, this important contextual information helps us to more accurately assess the nature, extent, and associated risks associated with release-related constituents.

Regulatory limits for PFAS in soil and groundwater are among the most stringent ever promulgated in Massachusetts and other states throughout the U.S. However, background levels of PFAS are not well understood. In addition to broadening our understanding of the levels and distribution of PFAS in Massachusetts soils and elsewhere, the results of this study may be considered as part of a reassessment of soil standards in the Bay State.

Distributed, double-blind data collection

Designed to quantify typical background levels of 36 PFAS in soils and identify regional trends, the study involved collection of 100 surface soil samples from 25 undeveloped properties across the state. We intentionally selected and solicited landowner permission for testing locations that were not in proximity to known PFAS releases or potential source locations.

Sample procedure

  • Collected from upland areas
    > off any trails/walkways
    > mainly mature forest
  • Shallow samples
    > collected from top 0-6” of soil
    > following PFAS sampling protocols
  • Four samples collected per property
  • Analysis of 36 PFAS via isotope dilution


compounds tested were detected


of samples tested positive for PFOS


samples were non-detect

The study team collected four shallow samples from each of the 25 properties selected for testing, with at least two properties sampled per day. In consideration of potential Massachusetts Contingency Plan (MCP) reporting requirements for the property owners, we designed a double-blind study where we intentionally did not record specific location-identifying information for samples other than region of the state (western, central, northeast, and southeast). Analytical results therefore could not be associated with any one specific location or property.

The results are in

Results indicate the presence of measurable concentrations of nine PFAS compounds in soil across all regions of the state, and in many instances at levels exceeding the most stringent of the Massachusetts Method 1 soil standards. PFOS and PFOA were detected most frequently and at the highest concentrations. For each property, at least one sample tested positive for PFAS; only 12 samples of the 100 were entirely non-detect. The greatest number of PFAS compounds and highest concentrations were detected in the central region, but the overall variability among PFAS concentrations was relatively low. None of the samples tested at high enough concentrations to present immediate human or ecological risk.

Putting PFAS background data to work

Current MCP standards for PFAS in soil are in part based on Vermont PFAS concentrations as established in a background study published in 2019. New Hampshire, Maine, and Connecticut are actively conducting studies of PFAS in surface soils as well. Woodard & Curran’s study results are generally slightly higher than those found in the Vermont study. We are providing our dataset to MassDEP with the goal of revising these standards using Massachusetts-specific concentrations.

Once data from these other states are made available, Woodard & Curran will incorporate the study results into a regional dataset. Collating this valuable information on PFAS concentrations across New England allows stakeholders and environmental professionals to reference a more complete picture of background levels in the Northeast.

Study Team

Lisa Campe MPH, LSP Senior Technical Manager Health, Risk, and Toxicology
Lisa McIntosh MS, DABT Senior Technical Manager Health, Risk, and Toxicology
Sam Olney PG Technical Manager Environmental Remediation
Duff Collins PG, LSP Innovation Leader Environment
Cathy Rockwell PE Senior Technical Manager Environmental Remediation
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