Preliminary Per-and Polyfluoroalkyl Substances (PFAS) in surface waters in the West Plains Region of Spokane County

Faculty Mentor

Chad Pritchard

Presentation Type

Poster

Start Date

5-8-2024 9:00 AM

End Date

5-8-2024 10:45 AM

Location

PUB NCR

Primary Discipline of Presentation

Geosciences

Abstract

Per-and Polyfluoroalkyl Substances (PFAS) have become a national issue as regulatory limits for these toxins have recently been added to the Clean Water Act. The West Plains has been significantly impacted by PFAS contamination due to the decades-long use of aqueous film-forming foam (AFFF) for firefighting training at both Fairchild Airforce Base and the Spokane International Airport. Though research is still underway, it is known that PFAS contamination in West Plains groundwater is significant and widespread. This study focuses on West Plains surface waters, as there is currently little information about how these water bodies are impacted by PFAS.

In 2016, Department of Ecology sampled surface water from West Medical Lake (Mathiew and McCall, 2017). The data showed PFOS levels between 6.71 and 9.21 part per trillion (ppt), PFHxA between 32.5 and 33.1 ppt, and PFOA between 42.5 and 55.1 ppt. Total PFAS levels ranged from 153 to 170 ppt. However, West Medical Lake has been the effluent sink for Eastern State Hospital and now the City of Medical Lake’s wastewater treatment plant. The Spokane River at Nine Mile was also sampled during the same study. Total PFAS ranged from 9.37 to 11.3 ppt. It is less clear where PFAS may be entering the river.

This study expands on West Plains surface waters and includes multiple lakes, creeks, and springs, as well as samples of rain, snow, and lake surfactant foam. Since West Plains groundwater and surface waters generally flow northeast towards the Spokane River, we also include samples from multiple locations along the river to determine if PFAS levels change downstream. This study is part of the larger West Plains PFAS Fate and Transport Study, which is being conducted to gain a comprehensive understanding of PFAS sources and to determine their pathways and distribution throughout water on the West Plains.

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May 8th, 9:00 AM May 8th, 10:45 AM

Preliminary Per-and Polyfluoroalkyl Substances (PFAS) in surface waters in the West Plains Region of Spokane County

PUB NCR

Per-and Polyfluoroalkyl Substances (PFAS) have become a national issue as regulatory limits for these toxins have recently been added to the Clean Water Act. The West Plains has been significantly impacted by PFAS contamination due to the decades-long use of aqueous film-forming foam (AFFF) for firefighting training at both Fairchild Airforce Base and the Spokane International Airport. Though research is still underway, it is known that PFAS contamination in West Plains groundwater is significant and widespread. This study focuses on West Plains surface waters, as there is currently little information about how these water bodies are impacted by PFAS.

In 2016, Department of Ecology sampled surface water from West Medical Lake (Mathiew and McCall, 2017). The data showed PFOS levels between 6.71 and 9.21 part per trillion (ppt), PFHxA between 32.5 and 33.1 ppt, and PFOA between 42.5 and 55.1 ppt. Total PFAS levels ranged from 153 to 170 ppt. However, West Medical Lake has been the effluent sink for Eastern State Hospital and now the City of Medical Lake’s wastewater treatment plant. The Spokane River at Nine Mile was also sampled during the same study. Total PFAS ranged from 9.37 to 11.3 ppt. It is less clear where PFAS may be entering the river.

This study expands on West Plains surface waters and includes multiple lakes, creeks, and springs, as well as samples of rain, snow, and lake surfactant foam. Since West Plains groundwater and surface waters generally flow northeast towards the Spokane River, we also include samples from multiple locations along the river to determine if PFAS levels change downstream. This study is part of the larger West Plains PFAS Fate and Transport Study, which is being conducted to gain a comprehensive understanding of PFAS sources and to determine their pathways and distribution throughout water on the West Plains.