The study of the negative effects on the human body through prolonged exposure to Manganese led to the identification of Manganism or manganese poisoning – a toxic condition resulting from chronic exposure to manganese – in 1837 by James Couper.
Generally, exposure to ambient manganese air concentrations in excess of 5 micrograms Mn/m3 can lead to Mn-induced symptoms.
In initial stages of manganism, neurological symptoms consist of reduced response speed, irritability, mood changes, and compulsive behaviors. Upon protracted exposure symptoms are more prominent and resemble those of idiopathic Parkinson’s disease, as which it is often misdiagnosed, although there are particular differences in both the symptoms (nature of tremors, for example), response to drugs such as levodopa, and affected portion of the basal ganglia. Symptoms are also similar to Lou Gehrig’s disease and multiple sclerosis.
Reference: Manganism on Wikipedia.
There used to be an extensive monitoring programme on the Manganese Ore Dust within the Port of Port Elizabeth but it appears that the once highly visible collection stations that dotted the Port have gone walkabout.
One wonders if the findings were too alarming for the study to continue?
Bazooka – Cocaine-Base and Manganese