Manganese is a naturally occurring element found in rock, soil, water, and air. It is an essential nutrient for all forms of life. The primary source of manganese for most people is food. Daily intake typically ranges between 1,000 and 10,000 micrograms (μg) per day.
There is no federal regulation for concentrations of manganese in drinking water for health reasons. However, there is a federal secondary standard of 50 ppb (ppb = μg/L) based on aesthetic considerations such as taste and color. The EPA recommends that infants under six months of age and people with liver disease not consume water with more than 300 ppb for more than 10 consecutive days.
A recent research article has suggested a possible link between manganese in drinking water and the impairment of intelligence in school-age children. The levels at which impacts on IQ were seen are higher than those routinely observed in Madison tap water. Nevertheless, the Water Utility will continue its efforts aimed at lowering the amount of manganese in Madison drinking water. These actions include water main flushing, replacing older water mains, and either filtering or reducing the operation of wells with elevated manganese.
RESOLUTION TO ESTABLISH WATER QUALITY AND TREATMENT POLICIES FOR IRON AND MANGANESE
The Water Utility Board adopted policies to guide the Water Utility in dealing with future indications of iron and manganese. Levels recommended by the American Water Works Association (AWWA) and the American Society of Civil Engineers (ASCE) are intended to reduce customer complaints based on aesthetics. Read the resolution here.
REPORTS & ARTICLES
Potential link between manganese and impairment of intelligence in school-age children (September 2010)
Controlling the Nuisance – a presentation delivered at the 89th Annual Wisconsin Water Association Meeting (September 2010) – VERY LARGE FILE (5.9 MB)
Manganese in Madison’s Drinking Water – article written by Public Health Madison & Dane County staff describing Madison’s experience with manganese-discolored drinking water (December 2008)
Manganese Monitoring Report – report on the Water Utility’s 2006 residential tap sampling study (June 2007)