The National Academies

NCHRP Synthesis 20-05/Topic 54-01 [Active (Synthesis)]

Practices to Identify and Mitigate PFAS Impacts on Highway Construction Projects and Maintenance Operations
[ NCHRP 20-05 (Synthesis of Information Related to Highway Practices) ]

  Project Data
Funds: $55,000
Authorization to Begin Work: 4/29/2022 -- estimated
Staff Responsibility: Jo Allen Gause
Research Agency: Iowa State University
Principal Investigator: Joe Charbonnet
Fiscal Year: 2023

Final Scope

Per- and polyfluoroalkyl substances (PFAS) are a group of manmade fluorinated chemicals that have been manufactured and used in a variety of industries since the 1940’s. They are persistent in the environment and the human body, and there is evidence that exposure to PFAS can lead to adverse health effects and ecological risks. There are no federal maximum contaminant level standards for PFAS compounds. However, states have regulated various PFAS compounds at varying standards and in varying media.


Some state departments of transportation (DOTs), such as New Hampshire DOT, Michigan DOT, and Minnesota DOT, are navigating PFAS-related issues, at significant expense, due to situations such as: DOT-owned legacy sites with PFAS impact; road construction and improvement through PFAS-contaminated soil and groundwater due to aerial deposition, stormwater runoff and

groundwater migration; increased assessment and analytical cost for soils to be graded, cut, or excavated; storage and disposal of spoil materials from road way maintenance in areas with PFAS aerial deposition; PFAS impact in dewatered construction groundwater; and, landfill testing requirements and restrictions leading to increased transportation and disposal costs.


A number of states directly address PFAS in their action plans with the focus on biosolids and wastewater treatment, sources that impact drinking water, air quality, landfills, and food safety, or airports where firefighting foams containing PFAS were known to have been used. With these focus areas in mind, several states have formed interagency groups to address minimizing human exposure to PFAS within their state. These groups are charged with developing PFAS management strategies, such as locating likely contaminated areas, sample collection and analysis, remediation/removal strategies, surveying inventory and improving storage practices of unused supplies of products containing PFAS, etc. However, none of the identified state action plans explicitly address the impact of PFAS contamination on state DOT construction and maintenance sites.


The objective of this synthesis is to document state DOT current practice for identifying locations of potential PFAS contamination and for mitigating the impacts of PFAS related to highway construction and maintenance operations.  The synthesis will look at PFAS impact and mitigation efforts in all phases of highway project development (planning, design, right-of-way acquisition), construction, and maintenance activities.  The synthesis will consider impacts to soil, groundwater, surface water, and storm water.


Information to be gathered includes (but is not limited to):

  • Written DOT policies and guidance for identifying and mitigating locations of PFAS contamination;
  • Methodologies for identifying and mitigating PFAS impacts related to highway construction and maintenance operations (e.g., site screening, sampling, geo tracker, new and existing approved product lists, management and disposal considerations, pollutant source assessments, regulatory restrictions, liability considerations, addressing legacy DOT right-of-way acquisitions with PFAS impact);
  • Timing and approaches used to screen for PFAS contamination in construction sites; and
  • Identification of materials used currently or in the past by state DOTs on construction sites that may contain PFAS or that are cross-contaminated (e.g., containers with PFAS).

 Information will be gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected agencies for the development of case examples. Information gaps and suggestions for research to address those gaps will be identified.

TRB Staff
Jo Allen Gause
Phone: 202-334-3826
Email: jagause@nas.edu
Meeting Dates
First Panel: September 13, 2022, Virtual
Teleconference with Consultant: October 3, 2022, 11 am Eastern
Second Panel: June 13, 2023, Washington, DC

Topic Panel
Stephanie Bolyard, North Carolina Department of Transportation
Bhaskar Joshi, California Department of Transportation
Harrison Roakes, Sanborn Head & Associates
Shawn Schmelzer, Maryland State Highway Administration
David Wilson, Virginia Department of Transportation
Harold Zweng, Michigan Department of Transportation
Susan Jones, Federal Highway Administration
Christine Gerencher, Transportation Research Board

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