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Guest Comment: Perfluoroalkyl Acid Focus Issue ’ GUEST COMMENT Over the past decade, a great deal has been learned about the perfluoroalkyl acids (PFAAs), a new class of environmental contaminants that includes the now well-known perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and many other related compounds. These materials quickly gained worldwide attention when they were found to be globally distributed in the environment and present in most of the human blood samples that were tested. Additional interest and concern has come from the fact that some compounds in this class have been found to be persistent in the environment, bioaccumulative in food chains, and toxic to various species. Moreover, the half-lives of many of these compounds in humans are on the order of several years, making potential human toxicity a particular concern. In aggregate, the human health studies conducted to date have yielded inconclusive results, but recent investigations are beginning to indicate a number of possible effects in human populations. As awareness of these compounds has increased, research has grown to include a broader range of polyfluorinated compounds (PFCs), including the telomer alcohols, polyfluoroalkyl phosphate esters (PAPs), perfluorinated phosphonic acids (PFPAs), fluoropolymers, and a growing number of new compounds that have recently been introduced by commercial manufacturers. Some governmental entities have taken steps to limit or restrict the production of some PFCs, with the greatest emphasis being the discontinuation of perfluoroalkyl chemistries with eight or more carbons, as this size range is the most likely to bioaccumulate in living organisms. Perhaps most notably, PFOS, its salts, and perfluorooctane sulfonyl fluoride (POSF) have recently been listed in Annex B of the Stockholm Convention on Persistent Organic Pollutants, indicating a growing worldwide consensus on this issue. It is now a critical time for the PFC research community, government regulators, and industrial manufacturers. We have learned much about the toxicity of PFOS and PFOA (and some related compounds) in animal models. We are coming to a better understanding of the environmental occurrence of some of the PFCs, including their various sources, modes of transport, and concentrations in important media. We have started to understand how animals and humans are exposed, and are beginning to develop an understanding of what the long-term environmental and health consequences might be. But as the studies highlighted in this focus issue help to make clear, we are only just beginning to understand the magnitude of the long-term challenge ahead of us. In the first place, because of their utility and economic value, it is important to realize that the production and use of PFCs is likely to increase for the foreseeable future. While there has been some progress in reducing emissions of some PFCs in some parts of the world, this has largely come about through voluntary agreements between governments and some of the major chemical producers. Mounting global economic pressures make it questionable as to whether these agreements will be maintained. Furthermore, the new alternative compounds that have been produced to replace the legacy materials (e.g., PFOS, PFOA) are r 2011 American Chemical Society
based on the same carbon fluorine chemistry, making it logical to hypothesize that they may also have the same undesirable characteristics as the materials they are meant to replace. Finally, the large quantity of PFCs that have already been produced and emitted into the environment will not degrade, making it important to maintain research to effectively monitor their transport and fate in the environment and their potential toxicity toward humans and wildlife. With all of these new developments and significant existing concerns, it is certain that this research will continue for some time to come. As part of the U.S. Environmental Protection Agency’s (EPA) effort in this area, we have held a biennial conference since 2006 at the Research Triangle Park, NC campus called “PFAA Days” which has been dedicated this research. Dr. Christopher Lau from the EPA has coordinated this conference with the help of a growing number of government, academic, and industrial researchers who are leaders in this field. The 2010 PFAA Days III conference was the largest and most successful yet, with almost 300 participants from seven different countries presenting their most recent work and using the opportunity to meet with friends and colleagues to plan new collaborations. As is often the case with small specialty conferences, the attendees of this meeting shared an enthusiastic spirit of cooperative interest and dedication to research on PFCs. This Focus Issue captures the spirit of PFAA Days III by containing many of the original ideas and important research papers presented during this conference. The Focus Issue helps underscore both the progress that has been made while also defining where important research remains to be accomplished. Among the many topics included are: state of the art assessments of the occurrence of PFCs in environmental and biological media; new measurement methods for new media; detailed evaluations of important environmental sources, including house dust, wastewater treatment plants, and land application of biosolids; occurrence and trends in human populations and environmental species; new details on sources of human exposure; relationships with human health outcomes; and the identification and characterization of previously unreported PFCs. We hope that this Focus Issue will be a useful reference for everyone interested in PFCs while also providing many excellent ideas for future research. We greatly appreciate the support and interest of this entire research community in helping to create this Focus Issue. We thank all the authors who submitted their work for consideration and all of the reviewers for their careful reviews and comments. The work presented here is truly a product of the entire research community and the peer review process, reflecting some of the best of what has been accomplished at this time. We hope that this will help stimulate excellent ongoing research in this important area. Andrew B. Lindstrom,†,* Mark J. Strynar,† E. Laurence Libelo,‡ and Jennifer A. Field§ Special Issue: Perfluoroalkyl Acid Published: September 29, 2011 7951
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Environmental Science & Technology †
U.S. Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, North Carolina 27711, United States
‡
U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington, D.C. 20460, United States
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compounds in dosed rodents and humans. Further application of these findings to highly exposed (occupational) or susceptible (pregnant women, children) populations may be used to mitigate risk to select xenobiotic compounds.
Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States
’ AUTHOR INFORMATION Corresponding Author
*Phone: 919-541-0551; fax: 919-541-0905; e-mail: lindstrom.
[email protected].
’ BIOGRAPHIES
Andrew B. Lindstrom is a research physical scientist with the US EPA’s National Exposure Research Laboratory in Research Triangle Park, NC. He earned a Ph.D. degree from the University of North Carolina at Chapel Hill in environmental health sciences where he focused on the use of protein adduct biomarkers to determine exposures to activated aromatic carcinogens. Lindstrom has continued to specialize in biomarker methods development and has been working with the PFCs since 2003. His research efforts have included evaluations of surface water, dust, food, animal tissues, and other matrices important for characterizing environmental transport and fate and human exposure. His group continues to focus on analytical methods development and the application of advanced mass spectrometry techniques for identifying and quantifying emerging contaminants.
Mark J. Strynar is a research physical scientist with the EPA’s National Exposure Research Laboratory in Research Triangle Park, NC. He earned his Ph.D. from the Pennsylvania State University in Soil Sciences where he focused on the interaction between xenobiotic compounds and soil humic material using NMR and 14C-labeled tracer techniques. After joining the EPA in 2002 his research focus has involved the development of analytical methods for the determination of perfluorinated compounds in complex biological and environmental matrices. Through ongoing collaborations with academia, industry and government colleagues, Strynar continues to expand on these research efforts. He is currently investigating the use of accurate mass Time of Flight Mass Spectrometry (TOFMS) for the identification of unique biomarkers of exposure to xenobiotic
E. Laurence Libelo is a senior scientist with the U.S. EPA Office of Chemical Safety and Pollution Prevention. His main areas of interest are environmental fate and transport for new and existing chemicals, exposure and risk assessment, and providing scientific support for chemical policy and regulation. He has worked on pesticides and industrial chemicals, nanomaterials and other emerging chemicals of concern. For the last ten years, he has worked to understand the sources, environmental behavior and exposure pathways of PFCs. Dr. Libelo earned his Ph.D. at the College of William and Mary in Marine Science studying the physical and chemicals processes which control movement of chemicals between groundwater and surface water. Prior to joining EPA, he conducted his postdoctoral research at the U.S. Air Force Research Laboratory studying groundwater remediation processes (including fire training sites contaminated with PFCs). He holds a B.S.in Geology and M. S. Environmental Science and Engineering, and has additional experience with the USGS and as a consultant in groundwater geochemistry and interactions between crystalline materials and microwave radiation.
Jennifer Field, Associate Editor Jennifer A. Field is a professor in the department of environmental and molecular toxicology at Oregon State University. Field holds a Ph.D. in geochemistry from the Colorado School of Mines and was a postdoctoral fellow at the Swiss Federal Institute of Aquatic Science and Technology (Eawag). Field’s general research focuses on the development and application of quantitative analytical methods for organic micropollutants and their transformation products in natural and engineered systems. Her current research in environmental analytical chemistry concentrates on the use of largevolume injections with liquid chromatography/mass spectrometry as a quantitative approach for the analysis of aqueous environmental samples. Applications currently include the determination of illicit drugs in municipal wastewater as an indicator of community drug use. Current projects include determining the occurrence and fate of fluorochemical generated from municipal waste under anaerobic landfill conditions and in military base groundwater contaminated by aqueous 7952
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film-forming foams (AFFF). In 2007, Field was appointed as an associate editor of ES&T.
’ ACKNOWLEDGMENT The United States Environmental Protection Agency through its Offices of Research and Development and Chemical Safety and Pollution Prevention funded and managed this effort. It has been subjected to Agency review and approved for publication but does not necessarily represent official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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