Brooklyn Center has stopped pumping water from one of its nine groundwater wells to reduce the level of manganese in tap water after readings exceeded the state's recommendations.
Manganese, a naturally occurring element, is widespread in central and southwestern Minnesota, said Buddy Ferguson, information officer with the Minnesota Department of Health.
Brooklyn Center's average manganese level in tap water was 380 parts per billion, which is somewhat higher than the 300 parts per billion limit recommended by the health department.
"We were actually made aware there may be an issue by a consultant who contacted us about doing a pilot study," said City Manager Curt Boganey.
Shutting down the one well with high manganese concentrations and mixing water from the remaining eight wells should bring manganese down to recommended levels, Boganey said.
Manganese is beneficial to humans at low levels but may affect learning and behavior in infants and young children when concentrations are too high, according to the health department. Health effects in children have only been measured in large studies of school-aged children.
"The idea is to keep those numbers below where we would see any health effects," said Ferguson.
Brooklyn Center city wells tap into the Prairie du Chien-Jordan aquifer. In addition to health risks, cities watch manganese levels because the element can give tap water a bitter metallic taste and a brown to black color, according to City Council documents.
The city is also exploring other solutions, including the feasibility of building a water treatment plant, according to city documents.
Even though the city is taking steps to deal with the manganese, the city meets all safe drinking water quality standards. "They are being proactive about this, and that's what we would recommend," Ferguson said.
Even after manganese levels in the city's water come down, health officials recommend that households with children under the age of 1 use bottled water, carbon filters or faucet filter systems. For that age group, the health department recommends a limit of 100 parts per billion. Filters can remove half the manganese from drinking water.
Shannon Prather • 612-673-4804