Seven of Marana’s wells contain chemicals at levels exceeding the Environmental Protections Agency’s health advisory recommendations.
Six out of the seven wells comprise two water systems, which serve a number of residential areas including Saguaro Bloom, Continental Reserve, Happy Acres, La Puerta del Norte, Milligan’s Acres, Ironwood Reserve and Sunset Ranch Estates, as well as households not within a subdivision. The other well is not on a water system, and only serves one user. There are 2,700 households affected, making up 35 percent of Marana Water users. There are two contaminants in question. One is a form of dioxane.
According to an EPA fact sheet, dioxane is a synthetic chemical widely used in goods such as paint strippers, dyes, greases and antifreeze, as well as personal products, including deodorant, shampoo and cosmetics. According to the EPA, it’s “likely to be carcinogenic to humans.”
There is no federal maximum contaminant level for drinking water, but the EPA has a health advisory level of 0.3 parts per billion. The Marana website states “a person may have a health affect after drinking two liters per day for 70 years of water that is at or above the health advisory of 0.35 ppb.”
The other contaminate consists of two per- and polyfluoroalkyl substances, PFOA and PFOS, or PFAS for short. These chemicals were recently found at high levels in two Tucson wells, which the city closed, just north of Davis-Monthan Air Force Base.
PFAS can be found in household products like stain repellent, non-stick pans, water repellent fabrics, polishes, waxes, paints and cleaning products as well as fire-fighting foams. The EPA said there’s evidence that exposure to PFAS have adverse side effects, such as increased cholesterol levels, low infant birth weights, effects on the immune system, cancer and thyroid distribution.
Like dioxane, PFAS has no federal maximum contaminant level for drinking water, but the health advisory level is 70 parts per trillion.
Marana first knew of the possibility of elevated dioxane levels in October 2016. The town performed tests with the help of Tucson Water, and sent out notices to all Marana Water users that December. At that time, they began testing for elevated levels of PFAS, using a third-party lab, and sent those notices out last March.
Marana Water’s Deputy Director Scott Schladweiler said there are at least two schools served by the affected water systems as well: Rattlesnake Ridge Elementary and Leman Academy.
When Marana found out about the elevated levels, they hired a consultant to prepare a treatment alternative evaluation and implementation plan, which was completed last December. Among other items, the plan included other possible water sources and treatment alternatives.
“We’re waiting on additional guidance from the EPA and the state to see whether the guidelines on these compounds are going to change,” Schladweiler said. “Should we move forward with treatment, we know what to do.”
There are no treatment requirements currently from the EPA. The health advisories are recommendations while the EPA does more study.
Erin Jordan, public information officer for the Arizona Department of Environmental Quality said that “because there are no EPA standards for these unregulated compounds, there is no guidance for local entities to develop a plan to address the findings of the study.”
Jordan said in an email that ADEQ hired a hydrogeology and engineering company last year to investigate the prevalence of PFAS and dioxane in the area. She said potential sources of the contamination “cannot be identified due to a lack of historical sampling data” and that it can’t be confirmed that the contamination in Tucson wells and Marana wells are related. She also said that because the compounds are not regulated by the EPA, “potential sources are not required to monitor or report any potential releases.”
Schladweiler said if the EPA or the state decides to regulate either contaminant, Marana would decide how to implement their plan and how to fund it. To build infrastructure to treat both water systems would cost $12 million to $15 million.
Schladweiler said Marana Water is working with Tucson Water, the Metropolitan Water District and Pima County Wastewater to determine the source of the contaminants. Some public officials, including Tucson City Councilmember Steve Kozachik, lay the blame square on the Davis-Monthan Air Force Base, which said it washed fire and vapor suppression foam containing PFOS and PFOA into the sewer with permission from the county, in a letter D-M sent to a reporter with the Arizona Daily Star.
Marana Mayor Ed Honea minces no words on who he holds responsible.
“We know it came from Davis-Monthan,” he said. “It came through the Tucson sewers and the Pima County wastewater plant, and they put it in the river.”
Honea said this is not a problem that can be fixed overnight. The Marana Water Department is an enterprise fund, meaning it pays for itself through user fees. Honea said if the town spends millions on treatment “before the fed says, ‘You have to do this,’ the customers are going to pay that bill.”
He said even low levels of mercury and lead are allowed in potable drinking water, adding that the EPA has not said the chemicals in question are dangerous. But the town is watching the contamination levels and changing landscape on recommendations very closely.
Schladweiler said the water that Marana provides meets or exceeds all requirements.
“We drink the water,” he said. “Nowhere has Marana said that you should not drink the water.”
Schladweiler said Marana is continually monitoring the contaminant levels and will put updates on their website at maranaaz.gov/water-quality, where a host of information on the contamination can currently be found.