Dec 02, 2019

Tucson, Arizona, South-Side Aquifer Wells PFAS Levels Spike

Tests of Tucson, Arizona, south-side aquifer water found levels of per- and polyfluoroalkyl substances (PFAS) contamination 200 times above the the U.S. EPAs health advisory limit. 

well water

High levels of per- and polyfluoroalkyl substances (PFAS) were found in Tucson, Arizona's south-side’s aquifer.

PFAS levels peaked at 13,850 ppt, which is 200 times the U.S. EPAs health advisory recommendation for drinking water of 70 ppt, according to the Arizona Daily Star.

Five monitoring wells total containing PFAS concentrations were discovered in Tucson water samples taken in early June. A second round of samples from late September confirmed the earlier findings, reported the Arizona Daily Star

In separate testing done by the state, one of the three private wells had PFAS levels of 2,300 ppt, according to an email written to the city council by Tucson Water Director Tim Thomure. Another well came in at just above 70 ppt, while the third well’s level was not disclosed.

The Arizona Department of Environmental Quality (ADEQ) is providing bottled water to residents with contaminated private wells who lack an alternative source.

ADEQ has so far tested eight wells in the south-side area and will eventually test 90 wells, according to the Arizona Daily Star. The highest concentrations discovered are among the worst examples of PFAS pollution found nationally in areas associated with a military base but lying outside the base. 

The city’s three private wells are north of an Air National Guard base adjoining Tucson International Airport.

The Air Force suspects the military spilled or discharged PFAS compounds at 401 military bases around the country, where the chemicals have been used in firefighting foam.

The section of the south-side Tucson aquifer has not supplied Tucson with drinking water for several decades, since an earlier discovery of another groundwater contaminant, trichloroethylene, in the early 1980s. 

There is concern that the newly discovered contamination could overwhelm the Tucson Water Treatment Plant in the future. The plant has undergone upgrades to increase its ability to treat PFAS, but not anywhere near the concentrations recently discovered.

“We don’t anticipate this contamination being in Tucson Airport Remediation Project wells at those concentrations for years. I can’t put a number on it, but we have time,” said Thomure. “It’s urgent but not an emergency.”

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