Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large group of manufactured chemicals used in industrial applications such as firefighting foam, and many household products including non-stick coatings, waterproofing and stain repellants. These substances have been used in these products since the late 1930s. PFAS compounds are sometimes referred to as “forever chemicals” as they persist in the environment and do not readily decompose.
Due to widespread use of PFAS for decades, these compounds have been detected in the blood of people and animals around the world. Some studies have linked exposure to PFAS to harmful health effects in humans and animals, but the results of animal studies don’t always correlate with human health effects. The health effects of PFAS exposure are still being studied by many agencies. The characteristics of PFAS are attributable to their structure and chemical composition, and are often described as long- or short-chain. The longer chain compounds persist longer in the environment and in the human body.
PFAS readily dissolve in water. In the United States, PFAS has been found in drinking water sources including lakes, rivers and groundwater. These compounds are introduced to water sources via runoff from areas where firefighting foams are used, and from manufacturing facilities that use these compounds in their products.
The City of St. Louis Water Division is committed to protecting public health. Since 2020, we have performed periodic voluntary sampling for PFAS from the rivers that provide our source water and from our finished drinking water at each of the City’s two drinking water treatment plants. The City is also currently participating in the EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5). This rule includes testing for 29 different PFAS compounds. Our most recent testing from samples collected at both treatment plants in June, 2024 indicate that all PFAS levels were below detection limits.
The EPA provides additional information concerning PFAS.
