Faculty Mentor

Dr. Chad Pritchard

Presentation Type

Poster

Primary Discipline of Presentation

Geosciences

Abstract

In 2021 Cheney Water Well #5 was closed due to toxic per- and polyfluoroalkyl substances (PFAS) levels above the current State Action Limits and the National Drinking Water Protection Act (https://www.cityofcheney.org/207/Water), which is a concern since PFAS has been associated to types of cancer, birth defects, and other negative human and environmental health concerns (https://doh.wa.gov/communityand-environment/contaminants/pfas). The City of Cheney also tested two downgradient deep-groundwater-wells (Cheney wells #6 and 7) and halted investigation due to the wells being below state and federal drinking water standards. However, a local resident’s shallow groundwater well tested to be above federal and state levels of PFOS, which is a type of PFAS. In a 2023 report by Esvelt Environmental Engineering and Budinger and Associates, a time series sampling during pumping of the well resulted in increasing levels of PFAS variations, including a long-chain 6:2 FTS that is normally associated directly with contamination, indicating the contamination is near or above the well. Therefore, more work is needed to delineate PFAS contamination in the shallow groundwater that many residences use down groundwater gradient from Cheney Water Well #5. EWU sample nine wells, which the five in the shallow Wanapum Basalt aquifer tested above the drinking water standard. Wells sampled in the lower aquifers, Grande Ronde Basalt were generally non-detect for PFAS. Groundwater is between 80ft and 250ft in the Wanapum Basalt and Grand Ronde aquifers, respectively. Based on these findings it seems likely that contamination came from near the Cheney Water Well #5 and has migrated to the SW in the shallow basalt.

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Preliminary Geologic Assessment and PFAS Occurrence in Western Cheney, Washington

In 2021 Cheney Water Well #5 was closed due to toxic per- and polyfluoroalkyl substances (PFAS) levels above the current State Action Limits and the National Drinking Water Protection Act (https://www.cityofcheney.org/207/Water), which is a concern since PFAS has been associated to types of cancer, birth defects, and other negative human and environmental health concerns (https://doh.wa.gov/communityand-environment/contaminants/pfas). The City of Cheney also tested two downgradient deep-groundwater-wells (Cheney wells #6 and 7) and halted investigation due to the wells being below state and federal drinking water standards. However, a local resident’s shallow groundwater well tested to be above federal and state levels of PFOS, which is a type of PFAS. In a 2023 report by Esvelt Environmental Engineering and Budinger and Associates, a time series sampling during pumping of the well resulted in increasing levels of PFAS variations, including a long-chain 6:2 FTS that is normally associated directly with contamination, indicating the contamination is near or above the well. Therefore, more work is needed to delineate PFAS contamination in the shallow groundwater that many residences use down groundwater gradient from Cheney Water Well #5. EWU sample nine wells, which the five in the shallow Wanapum Basalt aquifer tested above the drinking water standard. Wells sampled in the lower aquifers, Grande Ronde Basalt were generally non-detect for PFAS. Groundwater is between 80ft and 250ft in the Wanapum Basalt and Grand Ronde aquifers, respectively. Based on these findings it seems likely that contamination came from near the Cheney Water Well #5 and has migrated to the SW in the shallow basalt.