What Are the Effects of Manganese Poisoning?

In toxic concentrations, manganese has detrimental effects on human health.

What Are the Effects of Manganese Poisoning?

Manganese is a chemical element with atomic number 25 and symbol Mn. It exists in combination with other elements like iron in the form of minerals, but is not found in nature in the free elemental state. Physically, manganese is silvery-gray in color. Manganese has a wide range of industrial uses, particularly in stainless steel. Despite the fact that compounds of manganese are less toxic compared to compounds of other metals such as copper and nickel, exposure to manganese fumes and dust that exceed the ceiling value of 5 mg/m3 can result in toxicity. Exposure to such amounts of manganese has been linked to cognitive disorders and motor skill impairment.

Sources of Manganese Poisoning

Sources of manganese poisoning can include drinking water, gasoline and tobacco smoke. Manganese found in water has a greater bio-availability than manganese found in food. Studies show that the presence of high levels of manganese in drinking water is linked to reduced intelligence quotients and intellectual impairment in children. The tobacco plant accumulates heavy metal such as manganese from the soil. The metals are subsequently inhaled during smoking, which poses a health hazard. Methylcyclopentadienyl manganese tricarbonyl (MMT), which is a gasoline additive, contains 24.4–25.2% manganese and is responsible for increased atmospheric amounts of manganese from automobiles. In toxic concentrations, the detrimental effects of Mn on human health include childhood developmental disorders and manganism.

Childhood Developmental Disorders

Recent studies reveal that chronic exposure to manganese in children is linked to childhood developmental disorders such as increased hyperactive and oppositional behavior, diminished IQ scores, low performance on tests of manual dexterity and rapidity, visual identification and short-term memory. These studies have been conducted in various parts of the world such as the Chinese province of Shanxi, Bangladesh, and the Canadian province of Quebec.


Manganism, otherwise referred to as manganese poisoning, is a rare neurological disorder that results from the ingestion or inhalation of excess manganese. Manganism was first described in 1837 by British academic John Couper after he studied two people employed in the processing of manganese and its alloys. Manganism occurs in two phases, an early phase, and a late phase. During the early phase, the patient exhibits symptoms such as psychosis, mood swings, depression, and compulsiveness. As the diseases progress to the late stage, the patient shows symptoms similar to Parkinson’s disease (PD), which include problems with gait and balance, rigidity, tremors, slowed speech, weakness, and monotone. However, patients are unresponsive to therapies used in the treatment of PD. Accumulation of manganese in the basal ganglia has been linked to abnormal movements in manganism, while a mutation in a transporter protein of manganese (SLC30A10 gene) is linked to the occurrence of Parkinson's-like symptoms.

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