Manganese and iron are thought to share absorptive and metabolic pathways. Manganese can interfere with
the absorption of dietary iron and long-term exposure to excess levels may result in iron-deficiency anemia.
This can be one of the effects of industrial pollution, with workers in the manganese processing industry
most at risk. Manganese poisoning has been found among workers making batteries. Symptoms of toxicity
also mimic those of Parkinson's disease (tremors, stiff muscles) with hypertension in subjects older than 40
years. In this respect the toxicant effect of manganese is thought to be related to depletion of brain
dopamine, with a syndrome of motor dysfunction and memory loss resembling Parkinson disease