PER- and POLY-FLUOROALKYL SUBSTANCES (PFAS)
WHAT ARE PFAS?
Per- and Polyfluoroalkyl Substances (PFAS) are synthetic chemicals used since the 1950s in a variety of consumer products for their stain-resistant, water-resistant, and non-stick properties. These substances are found in items like food packaging, outdoor clothing, non-stick cookware, and in certain types of firefighting foams used by the military, airports, and local fire departments.
WHAT IS THE CONCERN WITH PFAS?
PFAS chemicals are a public health concern because they do not break down in the environment, can travel large distances in groundwater, build up in animals and humans over time, and may lead to harmful health effects.
PFAS have been discovered above recommended federal and state levels in the drinking water supplies of millions of Americans, including in Washington State. In humans, it can take many years for PFAS to leave our bodies. As a result, exposure to levels above recommended limits over time may lead to harmful health effects.
PFAS IN DRINKING WATER
In January 2022, the Washington State Department of Health (DOH) took proactive steps to address PFAS in drinking water. DOH enacted regulations to require public water systems to begin testing for PFAS and established State Action Levels (SAL) for five (5) select PFAS chemicals. SALs are levels of chemicals that DOH has set for long-term daily drinking water to protect people's health. The PFAS SALs are set below levels that caused health effects in animal studies. Consuming water with PFAS above an SAL does not mean a person will get sick or have health problems.
Exceeding the SAL triggers purveyors to perform follow-up actions, including notifying affected customers of an SAL exceedance, increased monitoring and testing, identifying potential sources of the substance, and to develop strategies to reduce the contaminant. Exceeding the SAL does not prohibit a water purveyor from continuing operations of the contaminated source.
TESTING IN HIGHLINE WATER DISTRICT
In response to the new DOH standards, Highline Water District tested all its groundwater sources for the regulated PFAS in early 2022. Testing confirmed that one source, the Tyee Well, contained 11.9-13.1 parts per trillion (ppt) of Perfluorononanoic Acid (PFNA). The State Action Level (SAL) for PFNA is set at 9 ppt. No other District water sources were found to exceed the SAL for any PFAS chemicals.
IMMEDIATE ACTION TAKEN
Upon confirmation of the presence of PFNA in June 2022, Highline Water District took swift action:
- - Tyee Well Shut Down:The well was immediately taken out of operation to ensure there is no further exposure to PFAS.
- - Alternative Water Supply:The District permanently discontinued using the Tyee Well and instead began purchasing supplemental water from Seattle Public Utilities (SPU) to meet demand.
- - Public Notification:The District notified affected customers by letter who may have potentially received water from the Tyee Well more than the SAL. If you did not receive a letter, you are not located in an area receiving Tyee Well water or source water that would exceed the SAL.
IMPACT ON THE COMMUNITY
The Tyee Well historically contributed about 4.5% of the District's total water production annually, serving a limited portion of the District's service area. By suspending operations and purchasing water from SPU, the District maintains its commitment to providing safe, high-quality drinking water.
MOVING FORWARD
On April 10, 2024, the Environmental Protection Agency (EPA) announced the final National Primary Drinking Water Regulation (NPDWR) for six (6) types of PFAS. EPA has now established legally enforceable levels, called Maximum Contaminant Levels (MCLs), for the regulated PFAS in drinking water. The EPA rule now supersedes the DOH regulations. Because PFAS is now regulated, the EPA rule will prohibit the District from resuming operation from Tyee Well without sufficient treatment processes in place. The District does not plan to resume Tyee Well operations and will explore other options to repurpose the Tyee Treatment Plant.
LEARN MORE
For more information about PFAS and their regulation in Washington State, visit the DOH website: https://doh.wa.gov/community-and-environment/contaminants/pfas or the EPA Website: https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas
