Tamar Schlekat, SETAC Scientific Affairs Manager
More than 400 international experts, representing 16 countries, gathered last month in Durham, North Carolina, at the SETAC North America Focused Topic Meeting on “Environmental Risk Assessment of Per- and Polyfluoroalkyl Substances (PFAS).” In typical SETAC fashion, the meeting organizing committee, as well as the participants, represented a diversity of expertise from academic, business, government and non-profit sectors. The goal of the meeting was to gather environmental professionals with a wide range of technical knowledge from various fields and stakeholder groups to review new and emerging information on PFAS and to formulate a roadmap for a risk assessment approach for PFAS.
Mark Johnson, one of the meeting chairs, opened the meeting and gave an overview of the objectives. Johnson then introduced Linda Birnbaum, the departing director of the National Institute of Environmental Health Sciences (NIEHS) and National Toxicology Program, who gave an impassioned plenary presentation. Birnbaum asserted that people are exposed to PFAS through various means including food, packaging material and consumer products. She urged environmental professionals gathered at the meeting to move beyond the issue of PFAS in drinking water and take a more holistic approach to risk assessment of PFAS.
Immediately after the plenary, a series of invited talks were presented over the first two-and-a-half days. The meeting had been intentionally organized to reflect the major components of a risk assessment, and the talks within sessions covered the following five areas: analytical chemistry and fate and transport, exposure, ecotoxicity, human toxicity and risk characterization. At the end of the series of invited talks, participants huddled into breakout groups, led by panels of experts, for in-depth discussions on specific issues in those five areas. The meeting ended with a summary session where the various breakout group chairs reported back the results of the group deliberations to all participants. Despite record-high temperatures in the region and the length of the meeting, most attendees chose to stay until the last minute to learn as much as possible about this important topic.
PFAS are a large group of more than 4,700 chemical compounds with varying length fluorocarbon chains and a polar functional group used in many applications such as non-stick coatings on cookware and fabric and firefighting foams. Some of them are persistent in the environment and bioaccumulate. Although the industrial use of some of these compounds has been halted, many are still in commerce and more are under development. When released into the environment, some PFAS species degrade to form other PFAS species. This is especially true with PFAS variations in aqueous film forming foam. To complicate matters, many of the PFAS degradation products are persistent in the environment. The use of some of these substances has led to PFAS being identified and measured in air, soil and water in many locations throughout the globe. Further, PFAS have also been measured in fish, dairy, produce and other agricultural products, and the occurrence of PFAS in water supplies has raised public concerns about drinking water in some areas. These issues have all singled out PFAS as a class of contaminants of emerging concern. Researchers and managers from regulatory authorities, industries and businesses, as well as consumers are now all facing the challenge of understanding and managing these chemicals.
The complexity pertaining to PFAS was underscored at the meeting by the repeated reflection that due to the sheer number of PFAS compounds, the multitude of environmental exposure pathways, and the dearth of toxicological data available for most of these compounds, the scientific community needs to collaborate and move fast. The experts also stressed the need for the research community to standardize analytical tools, reference materials, modeling techniques, as well as toxicity testing, exposure assessment and risk characterization methods.
All experts agreed that since PFAS compounds are present in the environment as mixtures, determining a way to study them as classes, or a group of sub-classes is a top priority. The experts highlighted the need for prioritizing studies on PFAS based on compound production volume and use. Scientists also stressed the need to consider both the chemical properties of the various PFAS compounds (e.g., solubility, persistence and bioaccumulation potential) as well as their toxicity potential when prioritizing study efforts. The human toxicologists in the group acknowledged the need to evaluate toxicity based on laboratory data as well as epidemiological data. The ecotoxicologists, on the other hand, emphasized the need for both lab and field studies. All acknowledged that data on the toxicity potential of these compounds is scarce, but the limited data available has shown that they could be associated with adverse effects on both ecological and human receptors. Because of the large number of compounds and the need to produce data on many of them in a timely fashion, the experts pointed to new approach methods that take advantage of high-throughput techniques and focus on reduced animal testing as a recommended path forward to gathering the necessary data. Throughout the meeting, all researchers understood that there is a strong need for transparent and clear communication of risk from exposure to PFAS, not only amongst the environmental professional community but also in the public domain.
SETAC members are invited to view available platform and poster presentations from the meeting online as provided by the presenters. Further, all interested parties are invited to review the virtual issue on Environmental Risk Assessment of PFAS compiled from articles published in the SETAC journals.
The meeting organizers plan to publish a series of papers to communicate the outcomes of the meeting in the SETAC journals. They have also planned a special session to disseminate those findings at the SETAC North America 40th Annual Meeting, which will be held from 3–7 November 2019 in Toronto, Canada, and hope to continue the discussion at the SETAC Europe 30th Annual Meeting next year in Dublin, Ireland.
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