Guideline levels for PFOA and PFOS in drinking water: the role of scientific uncertainty, risk assessment decisions, and social factors

Abstract

Communities across the U.S. are discovering drinking water contaminated by perfluoroalkyl and polyfluoroalkyl substances (PFAS) and determining appropriate actions. There are currently no federal PFAS drinking water standards despite widespread drinking water contamination, ubiquitous population-level exposure, and toxicological and epidemiological evidence of adverse health effects. Absent federal PFAS standards, multiple U.S. states have developed their own health-based water guideline levels to guide decisions about contaminated site cleanup and drinking water surveillance and treatment. We examined perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) water guideline levels developed by the U.S. Environmental Protection Agency (EPA) and state agencies to protect people drinking the water, and summarized how and why these levels differ. We referenced documents and tables released in June 2018 by the Interstate Technology and Regulatory Council (ITRC) to identify states that have drinking water and groundwater guideline levels for PFOA and/or PFOS that differ from EPA’s health advisories (HAs). We also gathered assessment documents from state websites and contacted state environmental and health agencies to identify and confirm current guidelines. Seven states have developed their own water guideline levels for PFOA and/or PFOS ranging from 13 to 1000 ng/L, compared to EPA’s HA of 70 ng/L for both compounds individually or combined. We find that the development of PFAS guideline levels via exposure and hazard assessment decisions is influenced by multiple scientific, technical, and social factors, including managing scientific uncertainty, technical decisions and capacity, and social, political, and economic influences from involved stakeholders. Assessments by multiple states and academic scientists suggest that EPA’s HA is not sufficiently protective. The ability of states to develop their own guideline levels and standards provides diverse risk assessment approaches as models for other state and federal regulators, while a sufficiently protective, scientifically sound, and enforceable federal standard would provide more consistent protection.

Enrichment-free analysis of anionic micropollutants in the sub-ppb range in drinking water by capillary electrophoresis-high resolution mass spectrometry

“…PFOS and PFOA were found in all DWPP samples from 0.1 to 0.7 μg/L, according to the calibration data. Since these findings are much higher than typical concentrations found in drinking water [27], a contamination of the samples cannot be excluded. However, blank values and laboratory tap water samples did not show any signals of PFOS or PFOA above LOQ.…”

Per and polyfluoroalkyl substances scientific literature review: water exposure, impact on human health, and implications for regulatory reform

“…Of these, the two most widely studied and well-known are PFOA and PFOS. Both are no longer produced within the USA [5]. In fact, PFOS had been listed under the Stockholm Convention on Persistent Organic Chemicals and PFOA was being considered for listing by 2017.…”

Civil Society and the Governance of Water Services: German Political Parties’ Reactions to Right2Water

“…This is especially the case in areas or countries that produce their drinking water, both from groundwater and, in high percentages, from surface waters [5]. In these cases, conventional treatment methods, which primarily aim to reduce pathogens and nutrient loads, are not sufficient to provide drinking water free from chemicals [6] or pharmaceuticals [4,7]. Consequently, drinking water has to go through additional treatment steps based on, for example, active carbon nanofiltration or reverse osmosis membrane treatment, which creates additional costs.…”