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Pima County asks Tucson Water to limit chemicals in water pumped to Santa Cruz

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Pima County asks Tucson Water to limit chemicals in water pumped to Santa Cruz

  •  Water from the Santa Cruz River Heritage Project, which recharges water by sending it down the watercourse near Downtown Tucson, flows in the river in 2019.
    Dylan Simard/Cronkite News Water from the Santa Cruz River Heritage Project, which recharges water by sending it down the watercourse near Downtown Tucson, flows in the river in 2019.

The Pima County Board of Supervisors has asked Tucson Water to treat new discharges into the Santa Cruz River for PFAS, after the city utility announced plans to pump millions of gallons of water from the Tucson Airport Remediation Project.

The supervisors unanimously approved a recommendation at its meeting Tuesday that water pumped by the city into the river be treated for per- and polyfluoroalkyl substances, though the county does not currently have authority to regulate PFAS — a chemical linked to some cancer risks — in the environment.

The city recently announced plans to pump treated water from the Tucson Airport Remediation Project as part of a $2 million project designed to discharge 3.5 million gallons per day into the Santa Cruz just north of Irvington Road, or to the city's Reclaimed Water System.

Tucson officials, including Mayor Regina Romero, decided to halt operations in June at the water plant on the South Side as a precaution after tests showed increasingly high-levels of PFAS — a chemical that was once used in firefighting foam by airports and military units — moving in a plume toward the TARP, a water treatment effort designed to mitigate the presence of other chemicals, including the industrial solvent known as trichloroethene, or TCE.

Supervisors and county officials want guarantees that water from the TARP will be treated to remove as much of the PFAS compounds as possible to prevent the further spread of the chemicals.

“PFAS compounds persist in the environment and the risks of human exposure of are not fully understood.  For this reason, it is critical that we do everything possible to minimize the likelihood that these compounds enter the drinking water supply,” said Dr. Francisco Garcia, the county's chief medical officer. “There are some studies that have linked PFAS exposure with potentially increased risks for certain cancers, impaired kidney, liver and thyroid function, immune system disorders, and even developmental issues.”

PFAS could be further dispersed through the region as water released into the river settles into the groundwater system, county officials said.

"The treated water planned as a new discharge from the TARP to the Santa Cruz River will infiltrate into the sands and percolate into a porous portion of the aquifer, carrying potential contaminants with it," said Ursula K. Nelson, director of the Pima County Department of Environmental Quality. "The added water creates a recharge mound beneath the stream causing lateral flow. Also the water flowing in the river is within 1000 feet of a well with PFAS greater than 70 ppt (parts per trillion)."

"We recommend the standard for the new discharge to this new location be set to 18ppt or lower for both perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)," said Nelson in a memo to County Administrator Chuck Huckelberry.

The Environmental Protection Agency has established the health advisory levels for PFAS at 70 parts per trillion, and EPA Administrator Michael Regan stated during his confirmation hearing that PFAS safety is among the top priorities of the Biden administration, with regulations under the Safe Drinking Water Act coming soon.

PFAS can be found in groundwater near several military bases and airports in the state, including the Arizona Air National Guard facility at the Tucson International Airport as well as around Davis-Monthan Air Force Base.

The city of Tucson received $2 million from the state in late June when Gov. Doug Ducey sent money to restart the water plant that had been closed by the military pollution. Tucson Water had announced on June 8 that, due to rising levels of newer contaminants in the area groundwater, it would suspend operations on June 21 as it sought alternative end-uses for the treated water. The Arizona Department of Environmental Quality completed the transfer of $2 million in funding to the city on July 30 to restart the treatment plant and initiate construction for the new Central Tucson PFAS Project.

The city also received $3.3 million from the state’s Water Quality Assurance Revolving Fund in December 2020 to stop PFAS from impacting key Tucson drinking water sources, over $5.3 million in state funding over the past year.

ADEQ broke ground in June on construction of the Central Tucson PFAS Project demonstration remedy designed to remove PFAS from groundwater and contain the PFAS plume in the area north of Davis-Monthan Air Force Base. The demonstration remedy involves installing a wellhead treatment system to protect Tucson’s central wellfield, an important part of the area’s long-term drinking water supply. THe system aims to prevent additional drinking water well impacts in the short-term while the U.S. Department of Defense (DOD) continues to investigate sources of PFAS related to the base.

Tucson Water officials emphasized in a June 21 news release that building the pipeline does not mean it will be discharging untreated water into the Santa Cruz River.

“When TARP reopens, we’ll still be treating this water to a very high standard prior to any discharge to the river.” said Interim Tucson Water Director John Kmiec.

In April, Gov. Ducey sent a letter to U.S. Secretary of Defense Lloyd Austin calling on the Pentagon to take prompt action to address military-related groundwater contamination near Arizona’s defense installations.

At a hearing in June, U.S. Sen. Mark Kelly told the Senate Armed Services Committee that efforts to clean up PFAS contamination should be added to the 2022  National Defense Authorization bill, requiring the DOD's own Environmental Restoration Program to prioritize cleanup of the chemical compounds.

Kelly, along with U.S. Sen. Krysten Sinema, joined by U.S. Reps. Raúl Grijalva, Ann Kirkpatrick and Tom O'Halleran, sent a letter demanding DOD help cleanup the plume.

Tucson City Councilman Steve Kozachik criticized an announcement from the Arizona Air National Guard that said it would take until 2024 to "finish studying the mess they’ve created out by Tucson International Airport." 

"Waiting until 2024 for them to study the issue is simply irresponsible," he said. "Our water utility will be spending millions of dollars during that time on containing and cleaning the pollutants. Yes, we’re keeping track so when the DOD gets around to making us whole, we’ll have records of what our ratepayers are paying to clean up their mess," Kozachik wrote.

Tucson Water has spent over $8 million to address PFAS locally, the governor's office said, continuing to test all drinking water sources for the compounds across its 390 square mile service area, turning off contaminated wells and drilling new ones in clean areas, and removing PFAS at TARP.

"The utility is spending millions more to make a connection to the reclaimed system," Ducey said.

"City-state partnership has been and will continue to be important to ensure the safety and long-term security of our local water supply," said Mayor Romero. "Tucson’s mayor and Council have already invested millions of local dollars to treat PFAS contamination," she said. "Still, there is an urgent need for the federal government and responsible parties to initiate or provide funding for large-scale PFAS cleanup efforts."

The city of Tucson has filed a lawsuit against the manufacturers of PFAS compounds, and "will pursue all of its available legal remedies to obtain reimbursement for all of the city’s — and now ADEQ’s — expenses from these and other potentially responsible parties," the governor said.

"Tucson Water ratepayers are not responsible for PFAS contamination and should not be left with the bill," Romero said.

Construction of the project has begun and discharge of treated water into the Santa Cruz is expected to begin in early October.

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