One of the common ores of manganese, 'pyrolusite', has a deep black colour and has been known since pre-history. The cave paintings in Lascaux, France were painted over 30,000 years ago with pigments derived from pyrolusite.
Manganese ores were known to the ancient Greeks to decolourise glass; their name for pyrolusite was magnesia nigra (the black ore) named after the region in which it was found. In the 16th century, the Tuscan physician Michele Mercati renamed it as 'manganesa' from which the modern-day manganese is derived.
Around 90% of the manganese produced globally is used in the production of steel. Although steel is typically only 0.3% to 1.5% manganese the metal is essential for transforming brittle cast iron into strong steel. Mangalloy can be created by alloying 15% manganese with steel and is very resistant to abrasion making it particularly suitable for mining applications.
Manganese is an essential micronutrient to plants; a deficiency can lead to yellowing of the leaves. The manganese ion helps catalyse many biological processes such as photosynthesis. Manganese is also an essential micronutrient to animals, enzymes that contain manganese play important roles in their metabolic pathways.
Manganese is an essential micronutrient for humans, in small quantities manganese is good for us and helps maintain a healthy body. In higher concentrations manganese is toxic and harmful to our health. Manganese helps with the formation of bones and connective tissues, helps with blood clotting, and is important for the production of sex hormones. Low levels of manganese can lead to infertility, fatigue, bone malformation and seizures. However, it is relatively easy to gain the recommended dietary intake (RDI) from our diet - heavy tea drinkers may have a higher manganese intake that the general population.
While small amounts of manganese are essential to health, large amounts of manganese are toxic. Humans exposed to elevated manganese levels over long periods of time develop a syndrome known as 'manganism'. The symptoms of manganism are similar to those of Parkinsons Disease and include weakness, anorexia, muscle pain, apathy, slow speech and slow, clumsy movement.
Manganese is found naturally in both surface water (rivers and lakes) and ground water (bore holes) sources. In addition to natural sources, manganese contamination may occur from water mains and supply pipes. At levels above 100 ppb, manganese affects both the colour and taste of water. High levels of manganese in drinking water are almost always associated with hight levels of iron.
At levels of 200 ppb, manganese may form a coating on the inside of water pipes that can become detached during maintenance work leading to yellow or brown discoloured water. The US Environmental Protection Agency (EPA) have implemented a manganese health advisory level of 300 ppb and a secondary drinking water guideline of 50 ppb. The World Health Organisation has a health-based value of 400 ppb.
Manganese in your drinking water can be detected by the following tests.
Manganese can be reduced or removed from your drinking water using the following methods.
