PHOENIX – The U.S. Environmental Protection Agency is asking the U.S. Air Force and Arizona National Guard to take action after concentrations of toxic “permanently chemicals” are rising in groundwater at a historically contaminated site on the south side of Tuscon, Arizona.
The EPA discovered that the contamination was coming from nearby military properties and ordered them to clean up the contamination. High concentrations of PFAS, or per- and polyfluoroalkyl substances, were detected in Tucson’s groundwater near Tucson International Airport on a National Guard base and on property owned by the US Air Force.
Contaminants threaten groundwater extracted at a water treatment plant run by Tucson Water in the area of the Tucson Airport Remediation Project, known as TARP. That water was intended for drinking, the EPA said in its May 29 order.
Samples taken at the treatment plant showed PFAS concentrations of up to 53,000 parts per trillion, which is 5,300 times the allowable amount. The permissible limit in drinking water ranges from 4 parts per trillion to 10 parts per trillion, depending on the type of PFAS.
To prevent further migration of contamination into the city’s wells, the agency gave the Air Force and Air National Guard 60 days to develop a remediation plan. Morris Air National Guard Base, which runs the rehabilitation project, did not respond to The Arizona Republic, part of the USA TODAY Network, and its requests for comment.
Tucson Water, the city’s water utility, said wells affected by the contamination are out of service and customers are not being served contaminated water. But with PFAS concentrations continuing to rise, the issue remains a concern for the city.
“When we have an area where water quality is affected and we’re not able to serve it to customers, that’s an added cost. It really reduces the resource that we have available,” said Natalie DeRoock, a spokeswoman for Tucson Water . She noted that in addition to the Colorado River water that the city pumps, Tucson depends on groundwater, a limited resource.
The water utility stopped serving TARP-treated water to residents in 2021, when increased levels of PFAS caused the plant to temporarily shut down as the filter system that captures the contaminants could not handle the increase.
What are PFAS?‘Forever chemicals’ are common and dangerous.
What will rehabilitation look like?
DeRoock said the water treated at the TARP facility exceeds state and county standards for clean water, so the city decided to divert the water to the Santa Cruz River instead of using it as drinking water. She said the city wanted people to feel confident about their drinking water and instead decided to use that water to maintain water levels in the Santa Cruz River and help restore riparian habitat.
As part of the EPA order, the remediation plan submitted by the Air Force and National Guard must ensure that the water is clean enough to be used as drinking water.
“With the appropriate response, Tucson Water will be able to resume delivering water from the TARP facility to the drinking water system as it was originally designed to do,” said Joshua Alexander, a spokesman for the EPA.
Alexander said the repair is a complicated process that could take years. It may require the creation of new water treatment facilities or the modification of existing existing facilities to handle an increased volume of water.
He pointed to several technologies that successfully remove PFAS from water, including granular activated carbon, a filtration system that uses carbon to remove contaminants from drinking water. He noted that new technologies are also being developed around the world to remove PFAS from drinking water.
PFAS is a public health hazard
PFAS are long-lived chemicals that have been used since the 1940s in a wide range of industries and products – from fire retardants and popcorn bags to personal care items and clothing – that can now be found in water globally. PFAS are considered hazardous substances that can cause serious health problems with long-term exposure, even at low traces.
Studies show that exposure to PFAS can negatively affect the body’s immune and cardiovascular systems, as well as vaccine response. Studies have also linked oral exposure to PFAS to adverse health effects in the liver, kidneys and immune system, and cancer, according to the EPA.
Although residents on Tucson’s south side do not get water from contaminated TARP wells, past exposures and their effects worry residents. Many argue that more extensive health screenings and compensation are still needed.
The site has a long history of contamination
The area has a history of contamination from decades of defense and industrial activities. The Tucson Airport Remediation Project area is a superfund site contaminated with several pollutants.
One of the main contaminants is trichlorethylene, or TCE, formerly used as a general purpose solvent and degreaser. Another contaminant found on site is 1,4-dioxane, which was used as a stabilizer to increase the life of the solvent bath for degreasing the manufactured parts.
These and other hazardous materials were dumped at the airport and eventually began to seep into the groundwater, contaminating the regional aquifer. The area was declared a superfund site in 1983 and listed as a national priority area for long-term cleanup.
Other contaminants at the site include dichloroethene, chloroform and chromium. A carcinogenic compound, polychlorinated biphenyls and metal contamination were also found in some soils of the area. According to the Arizona Department of Environmental Quality, the “pollutants of concern” may change as new data becomes available.
Contact the reporter at sarah.lapidus@gannett.com. The Southern Arizona Republic’s coverage is funded, in part, by a grant from Report for America. Support Arizona news coverage with a tax-deductible donation to supportjournalism.azcentral.com.
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