Manganese is a naturally occurring chemical element found across the Earth in rocks, soil, water, and even some foods. It is an essential nutrient to both humans and animals. However, it is important to note that high levels of manganese can be toxic, which is why it is more recently being investigated as a contaminant of concern.
In water, manganese can appear as black flecks or cause the water itself to be tinted black/dark brown. It does not have a noticeable taste however.
Manganese in drinking water is found primarily as a naturally occurring mineral in formations rich in iron and other metallic ores. For example, in the Upper Peninsula, the Banded Iron Formation, BIF, is rich in iron and other metals, thus a concern for manganese water contamination. Mining and landfill leachate are also potential sources of manganese in water.
Initially, manganese in drinking water was primarily viewed as an aesthetic issue due to its tendency to cause a brownish tint to water, which is generally undesirable but does not affect taste. However, recent research has highlighted potential health risks associated with elevated manganese levels, leading to its classification as a contaminant of emerging concern. Studies have shown that prolonged exposure to high levels of manganese can have adverse effects on human health, particularly impacting cognitive and neurological functions, especially in children. Other affects are muscle weakness, lethargy, deficits in memory and motor skills, and damage to reproduction and the nervous system. As a result, regulatory agencies and environmental organizations are increasingly focusing on monitoring and mitigating manganese levels in drinking water to safeguard public health beyond aesthetic considerations. This shift underscores the evolving understanding of manganese as a potential health hazard and the need for comprehensive strategies to address its presence in water sources.
Currently, there is no regulatory mandate for public water supplies to routinely test for manganese. However, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) is addressing this concern through initiatives like the Statewide Manganese Occurrence Study (SEECS). Scheduled to commence in 2025, this study will focus on sampling water from 41 counties, encompassing 600 community water supply systems and 400 non-community systems across Michigan. The goal is to identify areas at risk of elevated manganese levels and provide insights into mitigation strategies.
Another upcoming initiative is the EC-SDC Grant- Emerging Contaminants in Small and Disadvantaged Communities. This program is designed to support communities in identifying and addressing emerging contaminants in drinking water sources. The two areas of focus in the state of Michigan are Gogebic County and Marquette County, both in the Upper Peninsula.
If you have a concern about your drinking water, find more information or report a concern via the Office of the Clean Water Public Advocate’s Drinking Water Concern System.
Emerging Contaminants Unit
Drinking Water and Environmental Health Division
P.O. Box 30473
Lansing, MI 48909-7973
