The South Dakota Department of Environment and Natural Resources is reviewing available manganese data from regulated public drinking water systems to determine if levels in Pierre’s water are higher than EPA health advisory levels published in 2004.
Manganese is a common, naturally occurring mineral found in rocks, soil and water. It’s also a natural component of most foods and is an essential nutrient for our bodies.
To date, Pierre’s public water supply system is the only one in South Dakota required to take actions due to elevated manganese levels. The city of Pierre issued a drinking water advisory yesterday (March 27, 2019), which says manganese can be mitigated with a properly maintained, in-home water softener or reverse osmosis treatment system. The advisory pertains only to those customers served by the city’s system which pulls ground water with high manganese levels out of the shallow aquifer along the Missouri River. Nearby systems operated by Fort Pierre, Mid-Dakota, Mni-Wiconi and West River/Lyman Jones Rural Water are not impacted because they pump water from the Missouri River.
DENR has posted information about manganese on its website.
Under the health advisory, for infants up to 6 months of age, EPA identified that water with manganese levels equal to or less than 0.3 mg/L for more than 10 days per year have shown no adverse health effects and can be used for making formula. For the general population, EPA identified that water with manganese levels equal to or less than 1.0 mg/L over a 10 day exposure has shown no adverse health effects. Samples of the City’s water show manganese levels of 2.5 mg / L. Much lower levels of manganese in drinking water can result in noticeable staining and taste complaints. It is for this reason EPA has a secondary drinking water guideline of 0.05 mg/L.
Infants are more at risk than older children and adults because their brains and bodies are developing quickly. Formula-fed infants get enough manganese from formula to meet their dietary needs. However, they may get too much manganese (above the recommended amount for nutrition) in their bodies when formula is mixed with water that contains high levels of manganese.
EPA has not established a drinking water standard for manganese, but has renewed efforts to review information by requiring drinking water systems serving 10,000 or more people to collect manganese data through their fourth round of sampling for the Unregulated Contaminant Monitoring Rule (UCMR4).
