ADEQ to Protect the City of Tucson’s Drinking Water Supply

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Central Tucson PFAS Project Moves Forward with $3.3 Million from State Water Quality Assurance Revolving Fund

(PHOENIX) Arizona Department of Environmental Quality (ADEQ) officials announced today that field work to address the Perfluorinated Alkyl Substances (PFAS) threat to the City of Tucson’s drinking water supply is well underway and continues moving ahead. ADEQ has dedicated $3.3 million from its limited Water Quality Assurance Revolving Fund (WQARF) to stop PFAS from impacting key Tucson drinking water sources (view map). ADEQ’s Central Tucson PFAS Project is focused on delineating and capturing PFAS-contaminated groundwater. This is to prevent it from impacting additional drinking water production wells. 

ADEQ Announces Actions to Protect the City of Tucson’s Drinking Water Supply

ADEQ’s Plan to Protect the Drinking Water Supply

Multiple and distinct areas of groundwater contaminated with PFAS above the U.S. Environmental Protection Agency’s (EPA’s) Health Advisory Level (HAL) have been identified in Tucson. Additionally, some of this contamination is encroaching on Tucson Water’s backup drinking water supply wells. PFAS caused eighteen Tucson Water backup drinking water supply wells to shut down. Furthermore, this resulted in a loss of 10 percent system well capacity. Particularly, Tucson Water estimates an associated unfunded future replacement cost for these wells at tens of millions of dollars. Without this additional work by ADEQ, more drinking water supply wells in Tucson could be impacted.

PFAS originating from Davis Monthan Air Force Base

Tucson Water identified PFAS originating from Davis Monthan Air Force Base (DMAFB) as a priority threat to the City’s water supply. The U.S. Department of Defense is actively investigating sources of PFAS contamination from federal facilities. Tucson Water also requested ADEQ’s assistance to expedite action. This is concurrent with the ongoing federal environmental investigation to prevent additional well impacts in the short-term. The city disconnected the backup wells north of DMFAB from the drinking water distribution system in 2018 to ensure that the public water supply remains safe to drink. While Colorado River water is the primary drinking water source for Tucson today, the aquifer in the Central Basin is critical. It serves as an alternate drinking water supply for over 600,000 residents in the future.

“Ever since the initial detection of PFAS in this portion of our aquifer, we have been fortunate to have collaborated with the various agencies and organizations working to address this problem. We are grateful to the State of Arizona and ADEQ as they move forward with the process of drilling monitoring wells to help understand the extent of the contamination and identify possible solutions to keep it from spreading further,” said Deputy Director of Tucson Water John Kmiec.

“The security and availability of healthy drinking water for the second largest metropolitan area in Arizona is critical,” said ADEQ Waste Program Division Director Laura Malone. “That’s why ADEQ has prioritized limited WQARF funding to proactively protect Tucson’s water supply from additional impacts from PFAS. WQARF is uniquely designed to allow ADEQ to take swift action and immediately provide mitigation needs for Tucson residents.”

Central Tucson PFAS Project Work Plan

Firstly, ADEQ had to complete a Central Tucson PFAS Project (CTPP) Work Plan in June 2020. The CTPP Work Plan calls for installation of a network of up to 16 new groundwater monitoring wells. Additionally, the plan includes collecting and analyzing soil, sediment and groundwater data to determine the location and extent of two PFAS compounds. 

ADEQ initiated field work for the CTPP in October 2020, and will use the data collected to design as well as construct a remedy to prevent movement of the PFAS-impacted groundwater. Installing a wellhead treatment system near the PFAS-source area will both remove PFAS and begin the process of containment. Subsequently, ADEQ has already initiated design, planning and permitting for a field pilot test. The test is set to be conducted in early summer 2021 at a City of Tucson supply well. ADEQ is informing residents and businesses in the area of the field work. They are also coordinating closely with Tucson Water. 

Nevertheless, residents and businesses who receive their drinking water from Tucson Water are continuing to receive drinking water. It must not only meet EPA’s HAL for PFAS, but also meets Tucson Water’s more conservative internal operating targets for PFAS.

BACKGROUND:

PFAS sources in multiple areas of Tucson groundwater have not been fully identified and environmental investigations are ongoing. Moreover, environmental sampling and testing results have confirmed the presence of PFAS in groundwater in excess of EPA’s HAL near the Tucson International Airport, DMAFB and the Arizona National Guard’s 162nd Wing located on the northern side of Tucson International Airport. 

ADDITIONAL INFORMATION:


Contact | ADEQ Public Information Officer

602-540-8072 (Cell) | Email >

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