How Should We Interpret the New Water Quality Regulations for Per- and Polyfluoroalkyl Substances?

Water quality regulations for per- and polyfluoroalkyl substances (PFAS) are currently in turmoil given the toxicological evidence of human health effects at background levels of exposure. Many countries are currently considering regulating the usage of PFAS as a group while also lowering the water quality standards for drinking water. It is somewhat disconcerting that different countries have different approaches to regulate PFAS in drinking water, focusing either on specific PFAS targets (such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)) or on larger groups of PFAS ranging from 12 to roughly 30 target PFAS compounds. Considering that there are between 5000 and over 10 000 estimated potential PFAS compounds and that they may transform into one another in the environment, this poses significant regulatory challenges and may cause incoherent regulations across various jurisdictions. Regulatory policies for drinking water have evolved much more rapidly than other pathways of exposure, i.e., food, soil, dust, and atmospheric exposure. We must ensure that proposed regulations are coherent to minimize exposure and risks and that remediation approaches are balanced to reduce overall exposure across the various sources of exposure.