Manganese is a metal that occurs naturally in some groundwater in Maine.  Historically, it was used as a pigment, and was used in the 30,000-year-old Lascaux cave paintings. It is also used industrially in the production of steel.

While manganese is critical to the functioning of all living things, it can be toxic at high doses.  Fortunately, manganese imparts a "oily vinyl or metallic" flavor to drinking water that warns of its presence.

Manganese in drinking water is sometimes associated with an iron/manganese-loving bacteria that generates a "rotten egg" smell due to the creation of hydrogen sulfide.  When the manganese and iron are removed, the smell goes away.  Alternately, the bacteria can be killed by bleaching.  ...See also "What is Iron Bacteria/Red Slime?".

 

Exposure Limits

Maine Maximum Exposure Guideline limit: 0.3 mg/L
USA Primary Drinking Water Standard limit: n/a
USA Secondary Drinking Water Standard limit: .05 mg/L (nuisance level - black to brown color; black staining of fixtures; bitter metallic taste)

Resources

Wikipedia, "Manganese"
LOCAL: Maine.gov, "Manganese in Drinking Water: Questions and Answers" (webpage)
US EPA, "Drinking Water Health Advisory for Manganese" (pdf report, 55 pg.)
CDC Toxic Substances Portal, "Manganese" (website)
MinDat.org, "Manganese" (non-profit mining information website)

 

MEL Test Methods for Manganese

Drinking Water - EPA 200.5, 200.7 (SDWA Compliant)
Wastewater - EPA 200.7  Rev. 4.4 (NPDES Compliant)
Solids & NPW - EPA 6010C Rev. 3 (SW846) (RCRA Compliant)

Sample Requirements

Drinking Water:

Container: plastic, glass
Volume: 150 mL
Hold time: 2 weeks
Preservation: n/a

Wastewater:

Container: plastic, glass
Volume: 250mL
Hold Time: 6 months if preserved with HNO3 to pH<2, otherwise 2 weeks
Preservation: HNO3 to pH<2

Solids:

Container: plastic, glass, baggie
Volume: a least 150g
Hold Time: 6 months
Preservation: n/a