Identification and Mitigation of Per- and Polyfluoroalkyl Substance Contamination in Highway Construction: Current and Future Practices

Per- and polyfluoroalkyl substances (PFAS) are persistent contaminants that pose risks to human health and the environment. PFASs can spread far from their sources, which include, but are not limited to, fire training areas, manufacturing sites, and landfills. PFAS regulation includes recently adopted federal mandates and a patchwork of state-level measures. This study analyzes state department of transportation (DOT) practices for identifying and mitigating PFAS contamination in highway construction and maintenance. We captured the state of the practice through a practitioner survey and case interviews. While 39% of responding states have formal or informal PFAS-related policies within state agencies, only 23% have such measures within their DOTs. In addition, 27% of responding states have PFAS action plans, but fewer than half of those were developed with DOT involvement. Most interviewees articulated concern about the cost of disposing PFAS-contaminated soil in landfills. Landfill restrictions would add transportation and disposal costs to many projects with unclear benefits for the environment. This study highlights the need for comprehensive guidance to aid DOTs in developing policies for PFAS impact mitigation. It identified states that have already adopted standard practices that could serve as models for such guidance. The results also highlight the need for interagency collaboration to address challenges in identifying and mitigating PFAS contamination. With recent (April 2024) designation of PFASs as hazardous substances, this paper uses state of the practice data and findings to inform concerns with respect to the potential impacts of this designation to DOT construction and maintenance operations.