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As the EPA narrows in on PFAS regulations, Tucson hopes for federal priority

PFAS are a group of widely-used, human-made chemicals linked to health issues like cancer and thyroid disease. The Environmental Protection Agency is expected to release a long-awaited set of drinking water standards for the chemicals this year. But contamination has already been found in thousands of communities around the country like Tucson.

The chemicals are found in a range of consumer and industrial products — including a special firefighting foam called AFFF used at airports and military sites like Davis-Monthan Air Force Base in the city’s southside. 

Groundwater here is thought to have been contaminated when that foam mixed with effluent and stormwater and seeped into the ground. Tucson Water Director John Kmeic says chemicals spread out from here.

“So groundwater slowly travels, but it still travels from central Tucson to the northwest towards Marana,” he said. “You see impacted groundwater at those two facilities — Davis Monthan, as well as the Morris Air National Guard Base — but then you see groundwater underneath, where the washes and streams, then the Santa Cruz River, going north all the way through the town of Marana.”

Marana is more than 30 miles away from the military sites clustered in Tucson’s southside. But, PFAS still show up in the water here.

“You’re looking at our PFAS treatment plant and 1,4 dioxane. UVA-LP inside there, and then we have our activated carbon in these vessels here,” said Paul Martinez, water operations manager at the Marana Water Department.

He’s pointing out these huge cylinders filled with activated carbon. Groundwater is pumped into one part of the facility and treated for contaminants like 1,4 dioxane using a giant UV light. Those carbon-filled cylinders are where remaining PFAS are absorbed. 

It’s a smaller version of the process underway at another treatment facility closer to the military sites in Tucson — where the highest concentrations of PFAS have been found. Today, Kmiec says no residents are drinking water with detectable PFAS levels.  

“So where Tucson Water and Marana Water sit is, a lot of people around the country are going to be jealous of us, because we’ve already proactively built these facilities,” he said.

But it’s been a long and costly road to get here. The city of Tucson has put some $50 million municipal funds into PFAS testing and treatment. Martinez says Marana has spent around $16 million. Wells where contamination was exceptionally high have been shut down. 

Now, the EPA is on the brink of releasing the first, legally enforceable federal standards for the chemicals. The agency has already issued several health advisories for PFAS over the years. But the upcoming regulations, known as the Maximum Contaminant Levels, will set formal limits on six types of PFAS identified as dangerous. Last March, the agency proposed limiting PFOS and PFOA, two of the most well-known types of PFAS, to 4 parts per trillion in drinking water. Put another way, one part per trillion is the equivalent of a single drop of food coloring in 18 million gallons of water.

A map showing where PFOS, one of the PFAS the EPA is proposing regulations on, has been found in Tucson's south side during testing over the last few years. The pink shaded area shows the TCE plume originally identified by the EPA. Arizona Department of Environmental Quality


Alisa Reznick is a senior field correspondent covering stories across southern Arizona and the borderlands for the Tucson bureau of KJZZ's Fronteras Desk.