Sources of PFAS
Where DC Drinking Water Comes From
Sourced from DC Water 2022 Annual Report.
District of Columbia drinking water is drawn from the Potomac River. Because Washington, DC drinking water comes from the Potomac River, the water quality of the Potomac is essential to the quality of DC’s drinking water. Water is then treated at the Washington Aqueduct, which is federally owned and operated. DC Water is the utility responsible for tap water distribution in the District of Columbia. It is also responsible for collecting and treating wastewater in DC and parts of Virginia and Maryland.
DC Water, the utility responsible for providing drinking water in DC, currently does not include testing for PFAS in its annual report on water quality. DC Water did not respond to the researchers’ Freedom of Information requests regarding the utility’s testing for PFAS in drinking water. With incredibly limited information on the quality of Washington, DC drinking water with respect to PFAS contamination, researchers conducted exploratory water testing. We detected PFAS in three different samples of drinking water across DC. According to the experts we spoke to, below are some of the sources of PFAS water contamination in the DC area.
Military Sites
Military sites are a major source of PFAS water contamination. This is because many military sites use aqueous film-forming foam, or AFFF, a firefighting foam often used in training exercises and to extinguish fuel fires. There are over 400 military sites that have been identified by the Department of Defense itself as either confirmed or suspected sources of PFAS water contamination. These sources have led to comparatively extreme levels of PFAS in on-base groundwater and water in the surrounding areas. And, as Brent Walls explained to us, “Everything’s connected to our rivers and streams through groundwater,” meaning contamination of groundwater, streams, and rivers can have implications for entire watersheds and the sources of drinking water within those watersheds.
Industrial Sites
The video below from Vox discusses the history of PFAS and their widespread contamination of waterways and drinking water.
Industrial sites are a clear source of PFAS contamination to water and drinking water. Many industrial manufacturers use per- and polyfluoroalkyl substances in the manufacturing process, particularly if their products have any sort of water, stain, or heat resistant component. Industrial sites discharge wastewater into bodies of water and water treatment plants, which can later lead to it entering drinking water.
Industrial manufacturing sites that use PFAS have been a notorious source of PFAS water contamination, affecting the groundwater and drinking water of entire towns. Most famously, a DuPont plant in Parkersburg, West Virginia discharged PFOA into waterways, affecting the town’s drinking water supply. This was depicted in the popular 2019 movie Dark Waters, which followed the case against DuPont for the company’s exposure of Parkersburg residents to PFAS.
Other Sources
Another major source of drinking water contamination can be wastewater treatment plants themselves. Almost all wastewater treatment plants have detectable levels of PFAS in their outputs. This PFAS contamination largely comes from sources and processes that contaminate water before it enters treatment plants. PFAS enter treatment plants in the form of wastewater from industrial manufacturing and water mixed with consumer products containing PFAS. Water entering municipal wastewater treatment plants might be mixed with soaps, shampoos, cosmetics, and detergents containing PFAS before it goes down the drain and ultimately reaches treatment plants.