Iowa DNR Has Found Manganese Above EPA Health Advisory In A Small Number Of Public Water Systems
The Iowa Department of Natural Resources is making progress on testing every public water supply system in the state for a metal that can contaminate drinking water.
Manganese is an essential nutrient, but too much of it could damage a person’s nervous system. The U.S. Environmental Protection Agency doesn’t have an enforceable standard for manganese, but the agency has set recommendations for how much is too much in drinking water. The EPA’s health advisory for manganese says babies exposed to manganese in concentrations of 0.3 mg/L for more than 10 days in a year could be at risk of neurological issues. The EPA also recommends that anyone else should not drink water that has more than 1 mg/L of manganese for more than 10 days per year.
The DNR is two years into a three-year study and roughly two-thirds of the way through sampling the state’s more-than 1,800 public water supply systems, said Corey McCoid, a water supply operations supervisor with the DNR. The environmental department has required 26 public water supply systems to tell their communities to not use their water because of manganese. Those 30 public water systems had concentrations of manganese above health advisory standards set by the EPA. McCoid said the DNR has worked with communities to remedy the problem.
“We don’t have the authority to require them to install treatment,” McCoid said, “but we can require them to let the public know that there is an issue and what some of those options are – whether they’re bottled water or what would be some of the treatment options.”
McCoid said the DNR also has funding available to help communities afford fixes to their water systems.
The DNR is finding higher concentrations of manganese in the western part of the state because of the area’s geology, McCoid said.
“We kind of knew that going into the study that we would see more in that area,” McCoid said. “But really, it does go all the way across the state and we can have them in eastern Iowa as well.”
The DNR started collecting water samples from state’s more than 1,800 public water supply systems for manganese in July 2019 after the EPA brought up concerns with manganese turning the western Iowa city of Onawa’s water brown.
The EPA looked at manganese as part of a study where the agency monitored 30 chemicals in public water supply systems around the country between 2018 and 2020. It found that more than 26,000 of nearly 38,000 results had detectable amounts of the metal.