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Iowa DNR Plans To Look Into Manganese Issues In Public Water Across The State

Courtesy of CDC.gov
Manganese naturally occurs in soil, water and even foods we eat like nuts and seeds. Too much manganese can turn water brown and is even linked to nervous system disorders.

Iowa environmental officials are working on a plan to find out how many public water systems in the state are having problems with an element called manganese. High levels of this contaminant were recently found in a west-central Iowa city. 
Manganese is an element that naturally occurs in soil, water and even foods we eat like nuts and seeds. It’s considered to benefit bone health. But too much of it can turn water a brownish color and is even linked to nervous system disorders.

Levels of manganese recently tested at 1.4 milligrams per liter in the west-central Iowa city of Bagley in Guthrie County, leading the Iowa Department of Natural Resources to recommend that residents there drink bottled water and use bottled water for cooking. According to the city, Bagley’s entire population of roughly 300 people all get their drinking water through the city’s public water supply system. The DNR approved the city’s preliminary plans to build a new water treatment plant to resolve the issue.

Guidelines from the U.S. Environmental Protection Agency recommend adults don’t drink their tap water if manganese levels are higher than 1 milligram per liter. For infants, that guideline is .3 milligrams per liter. The EPA has also set lower guidelines for appearance, smell and taste concerns associated with manganese in water.

As for how Bagley's manganese levels were found to be above the EPA's guidelines, Mark Moeller, a supervisor with the Iowa DNR's Water Supply Engineering Section, said it has to do with the aquifer where the community pulls its groundwater from.

"There's differing manganese levels in each aquifer and in each area of the state," Moeller said. "It just depends on where you're at and what aquifer you're utilizing."

Though guidelines have been set for manganese, there currently is no federal or state law that would punish a company or a city for having high levels of manganese in water that may be linked to health concerns. But Iowa environmental officials are working on a plan to monitor the element in public water supply systems across the state, said Corey McCoid, a supervisor with the Iowa DNR’s Water Supply Operations Section.

“We’ll look at testing all the different water supplies across the state to determine what their [level of] manganese is in their source water,” McCoid said.

McCoid said an internal group at the DNR is looking at developing a voluntary program where public water supply systems can opt for the state to test their water for manganese. The state would pay for the testing and would contract with certified labs to conduct it.

“We don’t have a good idea at this point of who all would be affected by this,” McCoid said.

It’s unclear what the timeline is, or how much funding this plan would require.  

"It's not unreasonable to assume private well owners are also susceptible." -David Cwiertny, Center for Health Effects of Environmental Contamination

Known health effects associated with manganese include tremors, shaking and unsteady walking – all impacts to a person’s nervous system. State Toxicologist Stuart Schmitz says the levels of manganese found in Bagley are not raising any alarms for serious health impacts. He said he would be concerned about neurological health impacts if Bagley's manganese levels were at 2 milligrams per liter or higher.

“We would be more concerned about the exposure if you’re inhaling manganese, as in exposure to welding fumes in an occupational exposure,” Schmitz said. “That’s where the serious health impacts are more seen.”

In an email, a spokesperson for the EPA said when the agency sampled drinking water across Iowa and six other states in the Midwest between 2013-2015, about 450 of the roughly 35,000 drinking water samples had manganese. 

Recently, the EPA has been looking more closely at manganese. A spokesperson said it's one of 30 unregulated contaminants they're focusing on between 2018 to 2020 as part of a federal law that protects public drinking water.

The law requires the EPA to publish a new list every five years of unregulated pollutants that may pose health risks

"The agency is currently conducting sampling as part of this review to determine if any further regulatory decision is necessary for manganese," an EPA spokesperson said in an email.

McCoid said the reason the Iowa DNR started thinking about looking at manganese now is because of the EPA’s focus on it.

The DNR does not have plans to test private wells for manganese. David Cwiertny, the director for the Center for Health Effects of Environmental Contamination at the University of Iowa, said because manganese is naturally occurring in soil and aquifers, “we really should be thinking about private wells.”

“If we’re seeing manganese pop up as a problem in a public water system, it’s not unreasonable to assume private well owners are also susceptible,” Cwiertny said. “We need to be more conscientious about what vulnerabilities we might have for that community in Iowa.”

Updated at 5:15 p.m. March 5 to include the EPA's response.

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Katie Peikes was a reporter for Iowa Public Radio from 2018 to 2023. She joined IPR as its first-ever Western Iowa reporter, and then served as the agricultural reporter.