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Air

Compared to 1953, levels of manganese in air have dropped. Generally, exposure to ambient Mn air concentrations in excess of 5 μg Mn/m can lead to Mn-induced symptoms. Increased ferroportin protein expression in human embryonic kidney (HEK293) cells is associated with decreased intracellular Mn concentration and attenuated cytotoxicity, characterized by the reversal of Mn-reduced glutamate uptake and diminished lactate dehydrogenase leakage.