Understanding PFAS and Potential Soil Contamination
Per- and polyfluoroalkyl substances, known as PFAS, are a large group of manufactured chemicals used since the 1940s because of properties such as resistance to heat, water, oil, and stains. Many PFAS persist in the environment for long periods, which is why they are often called "forever chemicals."
PFAS have been used in some stain-resistant and water-repellent products, food packaging, firefighting foams, and industrial applications. Research indicates that exposure to certain PFAS may be associated with health effects including changes in cholesterol, reduced immune response, reproductive and developmental effects, and increased risk of some cancers. However, health effects vary by the specific PFAS, exposure level, duration, and individual circumstances.
PFAS in Soil
PFAS can enter soil through sources such as firefighting foam releases, industrial activity, contaminated water, disposal practices, and the application of contaminated biosolids.
If you suspect PFAS contamination, particularly after firefighting activity, an industrial release, or a known local contamination event, contact your state environmental agency, local health department, or a qualified environmental professional.
PFAS testing and interpretation can be complex. There is no single nationwide soil standard that applies to every PFAS and every land use. Avoid digging, moving, or disposing of potentially contaminated soil without appropriate professional guidance because disturbing soil can spread contamination or increase exposure.
Soil Remediation
The appropriate cleanup method depends on the PFAS present, contamination levels, soil characteristics, groundwater conditions, land use, and applicable regulations.
Current field-implemented approaches include:
Sorption and stabilization: Materials such as activated carbon can be added to soil to reduce PFAS mobility and limit movement toward groundwater. This approach generally contains or immobilizes PFAS rather than destroying it.
Soil washing: Soil washing uses physical separation and extraction processes to concentrate PFAS into a smaller waste stream. It is generally considered a transfer technology rather than a destruction method.
Excavation and disposal: Contaminated soil can be removed and transported to an authorized facility. This can reduce contamination at the original site but does not destroy the PFAS.
Thermal treatment: Thermal technologies are being studied and used in some applications to treat PFAS-contaminated materials. Their effectiveness depends on the specific technology, PFAS compounds, temperature, treatment time, emissions controls, and verification methods. Thermal treatment should be evaluated and managed by qualified professionals.
No single approach is appropriate for every site. EPA and ITRC emphasize the importance of site-specific evaluation and continued research into PFAS treatment and destruction technologies.
Gardening Near Potential PFAS Contamination
PFAS can enter gardens through contaminated soil, irrigation water, compost or other amendments, and environmental sources. Some PFAS can be taken up by plants, although the amount varies depending on the chemical, crop, soil conditions, and water source.
If PFAS contamination is suspected:
Consider growing food in raised beds or containers using soil from a reliable, uncontaminated source.
Avoid using potentially contaminated well water for irrigation until it has been tested.
Avoid using questionable compost, biosolids, or soil amendments.
Follow guidance from local environmental and public-health authorities.
A layer of clean soil alone may not eliminate a contamination concern. PFAS can move through soil and water, so the appropriate response depends on site-specific conditions.
The Bigger Picture
PFAS contamination is difficult to address because these chemicals can persist in the environment and move between soil, water, plants, and other parts of the ecosystem.
At the same time, research into detection, treatment, destruction, and safer alternatives continues to advance. EPA is supporting research into new approaches for treating PFAS in soil, water, and other environmental media.
For communities concerned about PFAS, the most important steps are informed testing, professional assessment, careful soil management, protection of drinking-water sources, and adherence to applicable state and federal requirements.
PFAS contamination can be complex, but understanding the potential sources and pathways can help communities make informed decisions.
When contamination is suspected, professional testing and site-specific assessment should come before attempting cleanup or growing food in affected soil. Meanwhile, continued research, transparent monitoring, improved treatment technologies, and safer chemical practices can help reduce PFAS exposure and protect communities and ecosystems.
Sources
3M, "3M Settlement with Public Water Suppliers to Address PFAS in Drinking Water Receives Final Court Approval"
U.S. Environmental Protection Agency, "Our Current Understanding of the Human Health and Environmental Risks of PFAS"
https://www.epa.gov/pfas/our-current-understanding-human-health-and-environmental-risks-pfas
U.S. Environmental Protection Agency, "Interim Guidance on the Destruction and Disposal of PFAS and Materials Containing PFAS"
U.S. Environmental Protection Agency, "PFAS Innovative Treatment Team"
https://www.epa.gov/chemical-research/pfas-innovative-treatment-team-pitt
U.S. Environmental Protection Agency, "PFAS Thermal Treatment Database"
https://www.epa.gov/chemical-research/pfas-thermal-treatment-database-pfastt
Interstate Technology and Regulatory Council, "PFAS Treatment Technologies"
https://pfas-1.itrcweb.org/12-treatment-technologies/
U.S. Environmental Protection Agency, "Research Grants for Understanding PFAS Uptake and Bioaccumulation in Plants and Animals"
U.S. Environmental Protection Agency, "Uptake of Perfluoroalkyl Acids Into Edible Crops Via Land Applied Biosolids"
https://www.epa.gov/sites/default/files/2019-11/documents/508_pfascropuptake.pdf
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