The Hidden Dangers of Manganese in Drinking Water

Article | May 21, 2018

Source: MazzeiInjectorCompany, LLC

Evidence indicates that manganese (Mn) is more than a nuisance: it's a threat to health. It's time to get serious about removing it from drinking water.

Manganese (Mn) has long been recognized as a nuisance — its brown-to-black stains and metallic taste can make well water unpleasant, to say the least. If you think of drilling a well as a process of mining water, it's no surprise that the mine also yields other minerals dissolved or suspended in the groundwater. In many areas across the U.S. and around the world, there's plenty of manganese to be found. High levels of Mn occur in the U.S. along the Appalachian and Adirondack ranges in the East. In the West, it's common along the Sierras, Cascades, and Coastal ranges. Dr. Samantha Ying of the University of California, Riverside studied the Glacial Aquifer that underlies 26 U.S. states and supplies drinking water to 41 million people, and found that 16.4 percent of the wells tested were contaminated with either Mn, arsenic, or both.

Because many countries, including the U.S., do not list manganese as a contaminant — just a nuisance — it is not included in many water quality monitoring protocols, which Ying notes could lead officials to underestimate the number of wells contaminated with the element. A paper by Ying in Environmental Science and Technology alludes to a growing body of research that indicates that manganese may present a significant threat to health and development.

For example, Dr. Brad Racette of the University of Washington in St. Louis, Missouri, has studied welders who are routinely exposed to high levels of Mn and found a correlation with increased occurrence of manganism — a long-recognized syndrome that resembles Parkinson's Disease, with symptoms that range from slurred speech and loss of balance to an emotionless, mask-like set of the face. The inhalation of Mn appears to kill neurons in a part of the brain called the striatum, which is also affected by Parkinson's Disease.

You don't have to be a welder to encounter Mn at levels that are raising concerns. For instance, neural damage can occur in children exposed to well water with high manganese levels. A study of 362 students in Quebec noted that the average IQ of children who consumed well water that was in the top 20 percent for Mn content had IQs an average of 6 points lower than their peers whose water had lower levels of manganese. A 2004 health advisory by EPA noted that manganese (which the report notes is most often encountered in high doses through inhalation or diet rather than in water) can correspond to lower sperm count in adults and developmental delays.

Oxidation Opens Opportunities

Removing manganese (and iron, which often appears alongside it) from water is not very difficult. Oxygenating the water oxidizes the Mn into manganese dioxide (MnO2) precipitate which can then easily be filtered from the stream. When comparing oxidizing agents, ozone — which contains three oxygen atoms per molecule — is most effective, followed by oxygen (O2) and then air (21 percent of which is oxygen).

Other common oxidizing agents include chlorine, chlorine dioxide, potassium permanganate, and sodium permanganate.

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