The EPA finalizes PFOA and PFOS toxicity assessments to support the first PFAS Drinking Water Rule

Based on public health concerns about per- and polyfluoroalkyl substances (PFAS), or “forever chemicals,” the Environmental Protection Agency’s (EPA) Office of Water developed PFAS national primary drinking water standards. PFAS are a group of chemicals commonly found in products such as pans, rain jackets, and food wrappers due to their grease-, water-, and heat-resistant properties. These chemicals are referred to as “forever chemicals” because they are slow to break down in the environment, which leads to accumulation over time in the water, soil, plants, animals, and in the human body. PFAS exposure can result in numerous human health impacts, including cardiovascular toxicity, developmental toxicity, cancer, and immune toxicity.

Once implemented, the EPA’s new rule is predicted to prevent thousands of deaths and reduce tens of thousands of severe PFAS-attributable illnesses. ICF’s multidisciplinary, cloud-based approach supported the rulemaking and was integral in developing toxicity assessments for this new rule.

Challenge

In 2021, in response to growing concern about the health effects of PFAS exposure, the EPA’s PFAS Council developed the PFAS Strategic Roadmap to research, restrict, and remediate PFAS. One key action outlined in the Roadmap was to propose a national drinking water standard by the end of 2022, which included standards for PFOA and PFOS, two of the most ubiquitous and well-studied PFAS. However, development of the regulation was challenging and time-consuming, in part due to the extensive volume of health literature available for PFOA and PFOS. Analyzing the health outcomes—such as cardiovascular disease and cancer—associated with PFOA and PFOS chronic exposure is highly complex systematic work and requires the review of thousands of papers and modeling of numerous endpoints. The EPA worked to ensure that the national drinking water standard was developed using a systematic review approach in order to identify the best available science as required by the Safe Drinking Water Act.

Solution

In support of the EPA’s efforts, our team provided research and leveraged cutting-edge data analysis and modeling methods to determine the human health impacts associated with PFOA and PFOS—in other words, we were able to estimate the health benefits from substantially lowering PFAS exposure.

To do it, we completed systematic literature reviews of over 7,000 references, which included screening, study quality evaluation, and data extraction, and worked with the EPA to conduct dose-response modeling of health effects data for five major health outcome categories: cardiovascular, developmental, immune, liver, and cancer.

We developed processes, including customized forms on our systematic review tool Litstream as well as the use of machine learning capabilities, to efficiently sift through the high volume of literature and build successful workflows for an emerging approach to evidence synthesis. An interactive literature flow diagram was developed to track movement of over 7,000 studies through the review workflow. Our multidisciplinary team’s systematic review expertise and knowledge of tools enabled the EPA to meet its deadlines.

Results

In April 2024, the Biden-Harris Administration and EPA published the PFAS National Primary Drinking Water Regulation and finalized the supporting PFOA and PFOS toxicity assessments. The new drinking water standard is the first enforceable limit of forever chemicals in American drinking water and will affect 6%-10% of our public drinking water systems—protecting 100 million people from the harmful effects of PFAS. The EPA also announced $1 billion in new funding to help states, territories, and private well owners fight PFAS contamination and continue to improve water quality for generations to come.