NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
NCHRP SYNTHESIS 630
Practices to Identify and Mitigate PFAS Impacts on Highway Construction Projects and Maintenance Operations
A Synthesis of Highway Practice
Joseph A. Charbonnet
Roy E. Sturgill, Jr.
DEPARTMENT OF CIVIL, CONSTRUCTION, AND ENVIRONMENTAL ENGINEERING
IOWA STATE UNIVERSITY
Ames, IA
Subscriber Categories
Construction • Environment • Maintenance and Preservation
Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM
Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research.
Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 initiated an objective national highway research program using modern scientific techniques—the National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration (FHWA), United States Department of Transportation, under Agreement No. 693JJ31950003.
The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRB’s recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, universities, and industry; TRB’s relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of specialists in highway transportation matters to bring the findings of research directly to those in a position to use them.
The program is developed on the basis of research needs identified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the FHWA. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&I’s recommendations are proposed to the AASHTO Board of Directors and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Academies and TRB.
The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs.
NCHRP SYNTHESIS 630
Project 20-05, Topic 54-01
ISSN 0547-5570
ISBN 978-0-309-70976-7
Library of Congress Control Number 2024937259
© 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved.
COPYRIGHT INFORMATION
Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein.
Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP.
NOTICE
The report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine.
The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; the FHWA; or the program sponsors.
The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.
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The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president.
The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president.
The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president.
The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine.
Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org.
The Transportation Research Board is one of seven major program divisions of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to mobilize expertise, experience, and knowledge to anticipate and solve complex transportation-related challenges. The Board’s varied activities annually engage about 8,500 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation.
Learn more about the Transportation Research Board at www.TRB.org.
COOPERATIVE RESEARCH PROGRAMS
CRP STAFF FOR NCHRP SYNTHESIS 630
Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program
Jo Allen Gause, Senior Program Officer
Emi Carbray, Program Coordinator
Natalie Barnes, Director of Publications
Heather DiAngelis, Associate Director of Publications
NCHRP PROJECT 20-05 PANEL
Joyce N. Taylor, Maine Department of Transportation, Augusta, ME (Chair)
Anita K. Bush, Nevada Department of Transportation, Carson City, NV
Joseph D. Crabtree, Kentucky Transportation Center (retired), Lexington, KY
Mostafa Jamshidi, Nebraska Department of Transportation, Lincoln, NE
Jessie X. Jones, Arkansas Department of Transportation, Little Rock, AR
Raymond J. Khoury, Virginia Department of Transportation, Richmond, VA
Brenda Moore, North Carolina Department of Transportation (retired), Cary, NC
Jesus Alberto Sandoval-Gil, Arizona Department of Transportation, Phoenix, AZ
Cynthia J. Smith, Mississippi Department of Transportation, Jackson, MS
Jack D. Jernigan, FHWA Liaison
Jim T. McDonnell, AASHTO Liaison
Stephen F. Maher, TRB Liaison
TOPIC 54-01 PANEL
Stephanie Carbone Bolyard, North Carolina Department of Environmental Quality, Raleigh, NC
Bhaskar Joshi, California Department of Transportation, Sacramento, CA
Harrison Roakes, Sanborn Head & Associates, Concord, NH
Shawn D. Schmelzer, Maryland State Highway Administration, Hanover, MD
David L. Wilson, Virginia Department of Transportation, Richmond, VA
Harold Zweng, Michigan Department of Transportation, Lansing, MI
Susan Cheung Jones, FHWA Liaison
Christine L. Gerencher, TRB Liaison
ABOUT THE NCHRP SYNTHESIS PROGRAM
Highway administrators, engineers, and researchers often face problems for which information already exists, either in documented form or as undocumented experience and practice. This information may be fragmented, scattered, and unevaluated. As a consequence, full knowledge of what has been learned about a problem may not be brought to bear on its solution. Costly research findings may go unused, valuable experience may be overlooked, and due consideration may not be given to recommended practices for solving or alleviating the problem.
There is information on nearly every subject of concern to highway administrators and engineers. Much of it derives from research or from the work of practitioners faced with problems in their day-to-day work. To provide a systematic means for assembling and evaluating such useful information and to make it available to the entire highway community, the American Association of State Highway and Transportation Officials—through the mechanism of the National Cooperative Highway Research Program—authorized the Transportation Research Board to undertake a continuing study. This study, NCHRP Project 20-05, “Synthesis of Information Related to Highway Practices,” searches out and synthesizes useful knowledge from all available sources and prepares concise, documented reports on specific topics. Reports from this endeavor constitute an NCHRP report series, Synthesis of Highway Practice.
This synthesis series reports on current knowledge and practice, in a compact format, without the detailed directions usually found in handbooks or design manuals. Each report in the series provides a compendium of the best knowledge available on those measures found to be the most successful in resolving specific problems.
FOREWORD
By Jo Allen Gause
Staff Officer
Transportation Research Board
Per- and polyfluoroalkyl substances (PFAS) are a class of contaminants of emerging concern that can harm both ecosystems and human health. These anthropogenic compounds contain carbon-fluorine bonds, which make them stable and persistent in the environment, earning them the nickname “forever chemicals.” PFAS regularly migrate from sources of contamination, including fire training areas at military sites and airports, PFAS manufacturing sites, land-applied wastewater biosolids, and landfills. PFAS can be found at low levels in soils and water far from any likely source.
There are currently no binding federal regulations for PFAS. However, the EPA has begun the process of designating several PFAS as hazardous substances. This designation would likely restrict the ways in which state departments of transportation (DOTs) handle and dispose of impacted materials. The objective of this synthesis was to document current state DOT practices for identifying locations of potential PFAS contamination and for mitigating the impacts of PFAS related to highway construction and maintenance operations.
Information for this study was gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected DOTs. Case examples of eight state DOTs provide additional information on identifying and mitigating PFAS impacts on highway construction projects and maintenance operations.
Joseph A. Charbonnet and Roy E. Sturgill, Jr., of the Department of Civil, Construction, and Environmental Engineering at Iowa State University, collected and synthesized the information and wrote the report. The members of the topic panel are acknowledged on page iv. This synthesis is an immediately useful document that records practices that were acceptable within the limitations of the knowledge available at the time of its preparation. As progress in research and practice continues, new knowledge will be added to that now at hand.
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CONTENTS
Typical Sites of PFAS Contamination
Chapter 3 State of the Practice
PFAS Policy, Guidance, and Action Plans
PFAS Remediation and Mitigation
Inventorying and Monitoring PFAS Substances
PFAS Contamination Identification and Mitigation
Sampling, Testing, and Screening Approaches
Knowledge Gaps and Further Suggested Study
Appendix A Survey Questionnaire
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