Iowa officials suspect chemical contamination at a military base in Sioux City could be reaching other wells in the area, including the private drinking wells of local residents. Recently published test results show a class of chemicals known as per- and polyfluoroalkyl substances, or PFAS, were detected at the base at levels 100 times federal guidelines.
Iowa Public Radio first reported in February that preliminary test results showed high levels of surface water and groundwater contamination at the Air National Guard base, seven miles south of downtown Sioux City. A finalized report, conducted by a military contractor and published this month, confirms those results.
Analysts detected PFAS levels of 8,610 parts per trillion at one groundwater well, significantly more than the U.S. Environmental Protection Agency’s recommended level of 70 parts per trillion.
The chemicals are thought to be linked to the use of firefighting foams at the base, which were routinely used since around the 1970s, but were phased out around 2016.
The report authors and staffers at the Iowa Department of Natural Resources also suspect the plume of PFAS contamination is extending beyond the base and into the local community, potentially leaching into private wells used by residents for drinking, eating and washing.
David Cwiertny heads the Center for Health Effects of Environmental Contamination at the University of Iowa, and reviewed the report. He said the impacts could extend far beyond the base, noting PFAS plumes in other states have impacted wells five miles away from the source.
“The fact that we’re seeing these levels, not for uses of chemicals yesterday, but from years ago, shows that these things do stick around and they’ve had some time to move,” Cwiertny said.
The DNR is requesting the Air National Guard, or ANG, test approximately 12 wells within a two mile radius south and southwest of the base, including private wells and the Southbridge collector well, owned by the city of Sioux City.
In a letter to ANG officials, DNR staffer Daniel Cook identified the potentially contaminated off site wells as a serious concern.
“Because of the potential age of the release, the stability of PFAS in the environment, and the estimated groundwater flow direction, Iowa DNR considers the potentially impacted off site wells as an aggravated risk,” Cook wrote.
Iowa Administrative Code defines “aggravated risk” as “a contamination situation which presents a potentially catastrophic or an immediate and substantial risk of harm to human life or health or to the environment." The designation means the DNR can compel the ANG to expedite the sampling process.
The DNR is asking the ANG to submit a plan to test the off-site wells by April 5, with testing completed by the end of June. A plan to continue further testing on the base to determine the scope of the contamination is due by the end of April.
In an interview with Iowa Public Radio last month, an Iowa Air National Guard official said he supported further testing on and off the base. Brigadier General Shawn Ford is the Deputy Adjutant General of the IANG.
“We’re taking every step that we can and not hindering the process to make sure we can identify any problems that exist,” he said in a February interview. “We're just as concerned about this issue as everybody else is."
Cwiertny said the DNR seems to be “doing the best they can” to push the testing forward.
“They lay out a pretty aggressive timeline in there about a sampling plan by April, early April. And then completed results by the end June. And so I think that’s all really good,” Cwiertny said. “I think it’s important that the DNR is using its authority through Iowa state code to make sure that the Air National Guard is moving as quickly as possible.”
Some 57 public water systems participated in voluntary PFAS testing lead by the EPA between 2013 and 2015, and no chemicals were detected at that time. DNR staffer Roger Bruner is a water monitoring supervisor and said based on those results he’s “confident” the state’s municipal water systems are safe.
“We the DNR don’t believe it’s a huge risk in Iowa at this point,” Bruner said, “but we don’t want to neglect any potential issues that might crop up either.”
But Cwiertny said the results from Sioux City demonstrate these chemicals do pose a threat.
“We know the source of these. We know it’s widespread but highly localized. We should be doing everything we can to identify those localized inputs,” Cwiertny said. “So it’s probably worth our time to be proactive and think about where else there might be sources that we know are known sources elsewhere in the U.S. and see how relevant they are in Iowa.”
PFAS is found in firefighting foams and a wide range of industrial and consumer products, including food wrappers, stain-resistant fabrics and cleaning products. Other states have detected significant contamination around airports, fire training centers and certain factories.
Currently there are no legally enforceable limits for PFAS at the federal or state level, meaning public drinking water systems don’t routinely test for the chemicals. Existing private wells in Iowa don’t have to test for any contaminants, leaving them especially vulnerable. Bruner said at this point the DNR is relying on the ANG to act, and to pay for the sampling.
“The Air National Guard’s taking the lead on this, they’re the appropriate agency,” Bruner said. “I’m sure they’ll be doing the right thing.”