In 2009, environmental scientists discovered some unexpected chemicals in the groundwater along the Santa Cruz River. The chemicals turned out to be PFAS (per- and poly-fluoroalkyl substances), which are used in everything from adhesives to non-stick cooking surfaces to electrical wire insulation. They do not naturally break down in the environment, instead seeping into the soil where they can cause a variety of damage.
After further testing, Tucson Water and the Arizona Department of Environmental Quality began the Central Tucson PFAS Project to prevent the chemicals from impacting additional water sources.
On Wednesday, Jan. 12, 2022, the City of Tucson and ADEQ unveiled a pilot groundwater treatment facility in a quiet suburb in southeastern Tucson that is working to remove PFAS. According to the City, the facility uses a former Tucson Water supply well to pump contaminated water from the aquifer, cleaning as much as 360,000 gallons per day.
“Even though these types of projects are not the sexiest, they’re one of the most important that we can make in the quality of life of our residents and Tucson Water customers,” said Tucson Mayor Regina Romero at the ribbon cutting. “This is a success… Still, there is much work to do to clean up and remediate PFAS throughout the Tucson region.”
The Central Tucson PFAS Project covers roughly five square miles just north of the Davis-Monthan Air Force Base, which has admitted to previously allowing chemicals to wash into the soil and sewers. To date, Tucson Water has discovered PFAS in more than a dozen wells throughout the Tucson basin, with the highest concentration of the chemical detected near Davis-Monthan and along the Santa Cruz River. However, the vast majority of wells throughout Tucson have no detectable PFAS.
The central well fields within the Central Tucson PFAS Project area serve as the primary drinking water source for more than 65,000 people year round, and as the secondary drinking water supply for another 600,000 people year round, and are a key source to Tucson’s drinking water supply.
“As a reminder to our community, this treatment plant is a groundwater clean-up project, not a drinking water project. Tucson’s drinking water is safe,” said Tucson Water interim director John Kmiec. “We have avoided certain areas of the aquifer system where PFAS is present, and continue to use our renewable water supplies, like the Central Arizona Project water, to meet the daily needs of the Tucson Water customer.”
According to the CDC’s Agency for Toxic Substances and Disease Registry, high levels of PFAS may result in an increased risk of kidney or testicular cancer, decreases in infant birth weights, decreased vaccine response in children, increased cholesterol levels, and changes in liver enzymes. However, the agency says scientists are still learning about the health effects of exposures to mixtures of different PFAS.
Romero said she recalled how the dumping of the solvent TCE, or trichloroethylene, affected Tucson’s south side after the chemical was discovered in drinking water in the 1980s.
“We are all too aware of the painful history of water contamination throughout our region, especially those impacting disadvantaged communities,” Romero said. “Tucsonans know what happens when environmental impacts go unchecked.”
The Central Tucson PFAS Project began in March 2020 when the City of Tucson asked the State of Arizona for assistance in stopping PFAS from reaching drinking water sources. ADEQ dedicated $3.3 million from the limited state Water Quality Assurance Revolving Fund to address the City of Tucson’s request.
“These partnerships demonstrate that environmental projects need not take years and years before we take action,” said ADEQ director Misael Cabrera. “These partnerships demonstrate that we can coalesce to address an urgent need, the need to address chemicals that are contaminating our groundwater. This project represents one of the fastest large-scale investigations designed, and commencement of operations, that any of us who’ve been in the business can remember.”
In 2018, the City of Tucson and Town of Marana moved forward with lawsuits against five companies, including the chemical manufacturer 3M, to pay for the removal of the chemicals from the groundwater. 3M has previously been smacked with paying an $850 million settlement in Minnesota for PFAS pollution.
“Returning this aquifer to the PFAS-free condition is what our challenge is, so as to ensure Tucsonans of the future can come back to this part of the central well fields for their water supply, if needed,” Kmeic said.
For more information about PFAS in Tucson, visit tucsonaz.gov/water/pfas