Exposure to Mn: Military Relevance
Several primary industrial activities of the Department of Defense involve exposure to manganese. Results of the MHRP will have application to active duty servicemen and women, veterans, and civilian contractors and suppliers whose work or duties involve exposure to manganese. Department of Defense (DoD) activities including welding, steel fabrication, the use of batteries, and the use of manganese-based fuel additives create a demand for research on the health effects of manganese in order to devise proper safeguard measures for workers and to maintain the strength of our armed forces. As Department of Defense workers are intimately involved with the following processes and products, particularly with welding, it is essential to determine whether interaction with manganese in these activities might predispose individuals to neurological deficits later in life.
Manganese is a component of coated welding rods and various steel alloys. As a result, there can be significant exposures to a finely divided dust/fume in welding operations, and massive exposures which have been associated with a debilitating neurological disease. Welding is one of the primary industrial activities in defense department activities common to all of the armed forces.
Steelmaking / Steel Alloys
Manganese contributes greatly in the makeup and characteristics of steel. In fact, steel cannot be produced without manganese. Today’s advances in the steel making process would not have been possible without manganese. Specifically, manganese performs three functions in steel: (1) it removes sulfur from liquid raw steel – in order for steel to be hot rolled or forged, the sulfur must be removed, (2) it deoxidizes the steel – manganese and oxygen combine to form an oxide which is taken out of the steel through the slag, and (3) it acts as an alloying agent – manganese increases the toughness and elasticity of steel allowing higher resistance to wear.
Manganese dioxide is used as the cathode in zinc-manganese dioxide dry cells. Current world consumption exceeds 30 billion units per year. In the United States, primary (single use) alkaline cells dominate the market and are ubiquitous in powering countless electronic and lighting devices including those that are essential to military operations. Although produced in much smaller numbers, lithium-manganese dioxide primary cells are used in higher performance communications devices – many of which are of interest to the military
An organic manganese compound known as MMT (methylcyclopentadienyl manganese tricarbonyl) is used on a small scale as an octane booster or anti-knock agent in gasoline. MMT is a suitable alternative to lead gasoline additive. MMT can dramatically improve oil combustion, reducing boiler slagging, lowering soot, and improving visibility due to smoke abatement.
Potassium permanganate is one of the best known manganese products. It is a powerful oxidizing agent with bactericidal and algaecidal properties, which enable it to be used in purifying drinking water and treating waste water. It is also used for odor control, including deodorization of discharges from paint factories, fish, fish-processing plants, etc. Permanganate has a variety of other applications as an oxidant.
MnO, MnCl2, MnCO3, MnO2, and MnSO4.3H2O are manganese based substances normally used as micro-nutrients in the agriculture industry. These inorganic manganese based substances are normally used at varying concentrations singly or blended to form micronutrient fertilizers. The concentration of each of these substances used in the manufacture of fertilizes depends on the target plant species, and soil types. The main function of these manganese based substances is to activate some important enzymes involved in chlorophyll formation. Therefore, Manganese deficient plants will develop chlorosis -yellowing or whitening of normal green plant tissues such as the leaves.