4/18/2023 0 Comments Vezer industrialEmphasis has been placed on the health effects of compounds containing inorganic manganese in the Mn(II), Mn(III), or Mn(IV) oxidation states, since these are the forms most often encountered in the environment and the workplace. The inorganic forms include manganese chloride (MnCl 2), manganese sulfate (MnSO 4), manganese acetate (MnOAc), manganese phosphate (MnPO 4), manganese dioxide (MnO 2), manganese tetroxide (Mn 3O 4), and manganese carbonate (MnCO 3). This profile will discuss key manganese compounds in both forms, with inorganic compounds discussed first. Manganese can exist in both inorganic and organic forms. Chronic exposure to much lower levels of manganese (as with occupational exposures) has been linked to deficits in the ability to perform rapid hand movements and some loss of coordination and balance, along with an increase in reporting mild symptoms such as forgetfulness, anxiety, or insomnia.Ĭhemical Forms of Concern. It is clear that chronic exposure to manganese at very high levels results in permanent neurological damage, as is seen in former manganese miners and smelters. Case reports and occupational studies address this continuum of nervous system dysfunction and help to characterize the apparent dose-response relationship. In other words, mild or unnoticeable effects may be caused by low, but physiologically excessive, amounts of manganese, and these effects appear to increase in severity as the exposure level or duration of exposure increases. It has been suggested that these adverse health effects, especially neurologic effects, are occurring on a “continuum of …dysfunction” that is dose-related ( Mergler et al. Although manganese is an essential nutrient, exposure to high levels via inhalation or ingestion may cause some adverse health effects. The nutritional role of manganese is discussed in Section 3.4. Manganese has been shown to activate numerous enzymes involved with either a catalytic or regulatory function (e.g., transferases, decarboxylases, hydrolases) ( Wedler 1994). Manganese, in its activating capacity, can bind either to a substrate (such as adenosine triphosphate, ATP), or to a protein directly, thereby causing conformational changes ( Keen and Zidenberg-Cher 1990). Enzymes that contain manganese include arginase, pyruvate carboxylase, and manganese-superoxide dismutase (MnSOD) ( Keen and Zidenberg-Cher 19 Wedler 1994). Manganese acts as both a constituent of metalloenzymes and an enzyme activator. In humans and animals, manganese is an essential nutrient that plays a role in bone mineralization, protein and energy metabolism, metabolic regulation, cellular protection from damaging free radical species, and formation of glycosaminoglycans ( Wedler 1994). Manganese is a naturally occurring element found in rock, soil, water, and food. It contains descriptions and evaluations of toxicological studies and epidemiological investigations and provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health.Ī glossary and list of acronyms, abbreviations, and symbols can be found at the end of this profile. The primary purpose of this chapter is to provide public health officials, physicians, toxicologists, and other interested individuals and groups with an overall perspective on the toxicology of manganese.
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