At right: Blue Hole Branch Falls. Photo by Chuck Sutherland.
Manganese, like iron, is abundant in the Earth’s crust and many rock and soil types, and can be washed into waterways when these surfaces are eroded. The mineral also has many anthropogenic sources, such as petroleum processing or the additive MMT in fuel. According to the US EPA, manganese is currently detectable in 97 percent of US surface waters, but these levels are often well below safety limits. Though humans and animals require manganese to function, once it accumulates in an ecosystem, serious problems may result.
Precipitated manganese can render water turbid, decreasing the light entering the water and leading to fish and plant death. Excess ingested manganese in humans has been linked to muscular stiffness or weakness. In fish, it has been conclusively shown to cause a significant reduction in growth and reproduction as well as decreased white blood cell and hemoglobin counts in certain species. Unfortunately, not much information is available on the effects of manganese on aquatic ecosystems; due to their necessity at low doses, studies have neglected to investigate its more deleterious effects.
Because manganese is very difficult to remove from water, the focus tends to be on preventing its entry into the ecosystem. Manganese can be present in storm water runoff or effluent from industrial areas.
How To Help (And Who Can Help You)1. Allow for natural growth near waterways.2. Limit impervious surfaces.3. Plant a rain garden.4. Plan for a better future.5. Contact your representatives. 6. Support your local watershed stewards.7. Spread the word.
Ready To Make A Difference?Pledge to do one or more of these mitigation activities!