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Substance Profile

 

Manganese & compounds

The background information page contains information and concepts that will be useful in understanding some of the issues surrounding the NPI. It is strongly recommended that you read this before reading the information presented below.

For an explanation of some of the terms used in this page, see the Glossary

Substance name Manganese & compounds
CASR number 7439-96-5
Molecular formula Mn
Synonyms Colloidal manganese, elemental manganese, cutaval.
Manganese compounds include manganese acetate (CASR# 638-38-0), manganese carbonate (CASR# 598-62-9), manganese chloride (CASR# 7773-01-5), manganese tetroxide (CASR# 1317-35-7), manganese dioxide (CASR# 1313-13-9), potassium permanganate (CASR# 7722-64-7), manganese gluconate (CASR# 6485-39-8), manganese oxide (CASR# 1344-43-0), and manganese sulfate (CASR# 7785-87-7).
 

Physical and chemical properties

Physical properties:
Manganese is a very brittle, hard metal of white-grey colour.
Atomic Number: 25
Atomic Mass: 54.9
Melting Point (°C): 1244
Boiling Point (°C): about 2000
Specific Gravity: 7.2 to 7.4

Manganese is very similar to iron in its physical and chemical properties, the chief difference being that manganese is harder and more brittle but less refractory. Properties vary widely depending on the particular compound.
  • Manganese acetate comes in the form of brown crystals.
  • Manganese carbonate is a pink-to-white hygroscopic powder with specific gravity 3.1.
  • Manganese chloride comes in the form of pink cubic hygroscopic crystals with melting point 650 °C and boiling point 1190 °C.
  • Manganese nitrate is a colourless or pink solid in crystal form.
  • Manganese dioxide is a black crystalline solid or powder with melting point 535 °C and specific gravity 5.0.
  • Manganese gluconate comes in the form of a light pink powder or coarse pink granules.
  • Manganese oxide comes in the form of green cubic crystals or green powder.
  • Manganese sulfate comes in the form of reddish crystals or pale red, slightly efflorescent crystals.
  • Potassium permanganate comes as dark purple crystals with blue metallic sheen. The crystals have a specific gravity of 2.7, a vapour density of 5.4 and melt at 240 °C.

Chemical properties:
Manganese exists mostly in the (II) oxidation state in natural compounds. It can also appear as manganese (IV) in manganese dioxide. Synthetic compounds are known in nearly all oxidation states between (III-) and (VII+). The metal decomposes in water and readily dissolves in dilute, non-oxidising acids and reacts vigorously with many non-metals at elevated temperatures. Finely divided manganese can combine explosively with a number of materials. Solubility of manganese compounds in water ranges from poorly soluble (manganese dioxide, manganese tetroxide, manganese carbonate, and manganese sulfide) to soluble (manganese sulfate, manganese chloride, manganese nitrate, permanganate ion).

  • Manganese acetate is soluble in alcohol and water, and decomposes in cold water.
  • Manganese carbonate decomposes before reaching its melting point. It is soluble in dilute acid, and insoluble in water, alcohol, and ammonia.
  • Manganese chloride is soluble in water and alcohol, and insoluble in ether. It is deliquescent (i.e. if exposed to air, it absorbs moisture from the atmosphere to such an extent that it will dissolve).
  • Manganese gluconate is soluble in water, and insoluble in alcohol and benzene.
  • Manganese oxide is soluble in acids and ammonium chloride, and insoluble in water.
  • Manganese sulfate is soluble in alcohol, and insoluble in ether.
  • Manganese tetroxide is insoluble in water, and soluble in hydrochloric acid.
  • Manganese dioxide is insoluble in water, and inert to most acids except when heated. With hot hydrochloric acid chlorine is evolved.
  • Potassium permanganate is soluble in water, sulfuric acid and acetone.

Common uses

Manganese is predominantly used to produce ferromanganese, or metallic manganese, which is used in the production of steel to improve hardness, stiffness, and strength. It is used in carbon steel, stainless steel, high-temperature steel, and tool steel, along with cast iron and superalloys. Manganese finds further applications in a number of non-ferrous alloys, especially with aluminium, magnesium, copper and zinc.
Applications for various manganese compounds follow.
  • Manganese dioxide is commonly used in the production of batteries, matches, fireworks, porcelain, glass-bonding materials and amethyst glass, as the starting material for production of other manganese compounds, and as an oxidising agent.
  • Manganese chloride is used as a precursor for other manganese compounds, as a catalyst in the chlorination of organic compounds, as dietary supplement/food additive, in animal feed to supply essential trace minerals, in paint driers, fertilisers, in dyeing, disinfecting, purifying natural gas, and in dry-cell batteries.
  • Manganese sulfate is used in glazes, varnishes, ceramics, dyeing, fertilisers, fungicides, and ore flotation. It is also used in medicines and as a nutritional supplement.
  • Potassium permanganate is used as an oxidising agent, a disinfectant, as an anti-algal agent, in metal cleaning, in tanning, bleaching, and as a preservative for fresh flowers and fruits.
  • Manganese gluconate is used as a feed additive, food additive, and dietary supplement.
  • Manganese oxide is used in textile printing, ceramics, paints, coloured glass, animal feeds, fertilisers, and in welding. It is used as a catalyst in the manufacture of allyl alcohol, as food additive and a dietary supplement.
  • Manganese nitrate is used as a colour agent in porcelain and ceramic manufacture, as a catalyst, and in the production of manganese dioxide.
  • Manganese acetate is used in textile dyeing, fertilisers, food packaging, feed additives, and in manufacturing paints and varnishes.
  • Manganese carbonate is used as a pigment, drier for varnishes, in medications, and as a plant nutrient. It is used in the manufacturing of manganese salts, pharmaceuticals, animal feeds, and ceramics.

Sources of emissions

Point sources
Problems with air pollution can arise during the mining, crushing, and smelting of ores, during steel production, and from battery factories.
Diffuse sources, and point sources included in aggregated emissions data
Some agricultural and gardening applications may use products containing manganese. Some hazardous waste sites may leach manganese.
Natural sources
Manganese is a naturally occurring element, although it is not naturally found in the metallic form. The earth's crust contains approximately 0.1 % manganese on average, with low levels present in lakes, streams, and the ocean. Nodules containing manganese oxides have been found on the seabed of the Pacific. More than 100 manganese minerals are known, including sulfides, oxides, carbonates, silicates, phosphates, and borates. The most important manganese mineral is native manganese dioxide (pyrolusite). Manganese ores very often occur together with iron ores.
Mobile sources
Mobile sources are normally not associated with emissions of manganese.
Consumer products which may contain Manganese and compounds
Alkaline and dry cell batteries, some vitamin/mineral dietary supplements, some fertilisers, some disinfectants, some porcelain and ceramic goods. Some drinking water supplies may contain small amounts of manganese.

Health effects

How might I be exposed to Manganese and compounds?
Most exposure will be associated with drinking water and consuming foods containing manganese. Exposure to manganese and its compounds may also occur during mining and processing of the ore, manganese smelting, ferrous and non-ferrous alloying, welding/brazing processes (either from electrodes/rods or parent material), battery (dry cell and alkaline) manufacture, and production and use of manganese chemicals and fertilisers, for those involved in these industries.
By what pathways might Manganese and compounds enter my body?
Manganese can be inhaled or ingested. Absorption of inorganic manganese through the skin appears to be negligible. However, with organo-manganese compounds there can be significant absorption through the skin.
Relative health hazard
On a health hazard spectrum of 0 - 3 Manganese and compounds registers 1.3. A score of 3 represents a very high hazard to health, 2 represents a medium hazard and 1 is harmful to health. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the evaluation of its tendency to cause, or not cause cancer and/or birth defects. It does not take into account exposure to the substance. Human exposure is reflected in the NPI rank given to this substance (see comparative data below). A substance that scores highly as a health hazard is arsenic at 2.3 and one of the lowest scores is ammonia at 1.0.Health Hazard Rating
Health guidelines
Australian Drinking Water Guidelines (NHMRC and ARMCANZ, 1996):
Health
Maximum of 0.5 mg/L (i.e. 0.0005 g/L)
Aesthetic
Maximum of 0.1 mg/L (i.e. 0.0001 g/L)
Worksafe Australia has set the exposure standard for manganese dust, fume, and compounds (as manganese) to 1 mg/m3 (TWA). The recommended short term exposure level (STEL) for manganese fume should not exceed 3 mg/m3.


See the Additional Information page for current health information. The Australian NOHSC National Exposure Standards Database link is probably the most useful source of information.

Note that the emissions data in the NPI database is not directly comparable with these guidelines.
What effect might Manganese and compounds have on my health?
Manganese is an essential element for humans, in fact for all living organisms including animals, plants and bacteria. Its naturally occurring concentrations are hardly toxic and relatively large doses can be tolerated without adverse effects. It is found in all human tissues, with the highest manganese concentrations in the liver, pancreas, intestinal tract and kidneys. Food is the major natural source of manganese intake and the amount of manganese in a normal diet is enough to meet daily needs with no ill health effects. Its absorption can be influenced by dietary level of manganese and iron, the type of manganese compound, iron deficiency and age. Occupational exposure to manganese can be substantial. In its acute form, manganese poisoning has an effect characteristic of other heavy metals, leading to 'metal fume fever' if dust or fume is inhaled in sufficient quantity. An airborne concentration thought to be immediately dangerous to life or health is in the order of 10,000 milligram/m3. Chronic exposure to manganese can express itself in two major ways, namely bronchitis/pneumonitis after inhalation of manganese dust, and 'manganism'. Manganism may also result from inhalation. However, the airborne manganese concentration which gives rise to these effects is different. Manganism is the effect of chronic manganese poisoning. This disease, which arises from damage to the central nervous system (CNS), usually begins with psychological symptoms such as hallucinations, emotional instability and disturbances in behaviour. These may be followed by neurological symptoms such as muscular weakness, speech disturbances and headaches, as well as symptoms resembling those of Parkinson's disease (tremors, stiffness, motor dysfunction). If exposure is terminated soon after the neurological symptoms appear, the individual generally recovers, but some speech and balance problems may remain. Individual susceptibility to the adverse effects of manganese varies considerably. The minimum dose that produces effects on the CNS is not known, but signs of adverse effects may occur at manganese concentrations ranging from 2 to 5 milligram/m3 in air. Deficiencies in the diet may predispose workers to anaemia, thus increasing susceptibility to manganese. An increased incidence of pneumonia has been reported among individuals exposed to manganese. A common effect in men who are exposed to high levels of manganese dust in air is impotence.

Environmental effects

Environmental Fate
Manganese occurs everywhere and can be found in nature at background levels in air, soil, water and food. Iron-manganese oxides in waters are carriers for many other inorganic and organic pollutants and are thus sources and sinks of them in aquatic environments including sediments. Airborne manganese particles settle and accumulate in the upper part of the soil and its availability for plants depends on the form of the manganese compounds and pH value of the soil.
Environmental Transport
Manganese can be transported as particles released into the atmosphere or as dissolved compounds in natural waters.
Relative hazard to the environment
On an environmental spectrum of 0 - 3 Manganese and compounds registers 1.3. A score of 3 represents a very high hazard to the environment and 0 a negligible hazard. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the measure of its ability to remain active in the environment and whether it accumulates in living organisms. It does not take into exposure to the substance. Environmental exposure is reflected in the NPI rank for this substance (see comparative data below). A substance that scores highly as an environmental hazard is oxides of nitrogen at 3.0 and one of the lower scores is carbon monoxide at 0.8.Environmental Hazard Rating

Environmental guidelines
See the Additional Information page for current environmental guidelines.

No national guidelines.
What effect might Manganese and compounds have on the environment?
Manganese is an essential element for all living organisms including animals, plants and bacteria. Manganese and its compounds have moderate acute and chronic toxicity to aquatic life. Insufficient data are available to evaluate or predict the short-term and long-term effects of manganese and its compounds on plants, birds, or land animals. Most plants have a very high tolerance for manganese.

Comparative data

NPI Rank
Approximately 400 substances were considered for inclusion on the NPI reporting list. A risk ranking was given based on health and environmental hazard identification and human and environmental exposure to the substance. Some substances were grouped together at the same rank with 208 ranks in total. Manganese and compounds was ranked as 75 out of the 208 ranks. Total hazard score (human health + environmental criteria) = 2.6.Total Hazard Rating

Sources of information used in preparing this article

  • ChemFinder WebServer Project (1995), Manganese (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese (II) acetate (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese (II) chloride (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese (II) gluconate (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese (II) oxide (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese (II) sulfate (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese (IV) dioxide (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese tetroxide or Manganese (II, III) oxide (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Manganese(II) carbonate (accessed, May, 1999)
  • ChemFinder WebServer Project (1995), Potassium permanganate (accessed, May, 1999)
  • Environmental Health Center (a division of the National Safety Council) Environment Writer - Chemical Backgrounders (July 1, 1997), Manganese (accessed, May, 1999)
  • Environmental Health Center (a division of the National Safety Council) Environment Writer - Chemical Backgrounders (November 17, 1998), Manganese compounds 2 - Manganese gluconate, Manganous oxide, Manganese sulfate (accessed, May, 1999)
  • Environmental Health Center (a division of the National Safety Council) Environment Writer - Chemical Backgrounders (October 16, 1998), Manganese compounds 1 - Manganese acetate, Manganese carbonate, Manganese chloride (accessed, May, 1999)
  • Integrated Risk Information System (IRIS, September 26, 1988), Manganese (accessed, May, 1999)
  • Merian, E. (editor, 1991), Metals and Their Compounds in the Environment Occurrence, Analysis, and Biological Relevance, VCH.
  • National Environment Protection Council (1998), National Environment Protection Measure for the National Pollutant Inventory. (accessed, May 1999)
  • National Health and Medical Research Council (NHMRC) and Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) (1996), Australian Drinking Water Guidelines.
  • Open Data Solutions, EPA factsheets for regulated toxic chemicals (January, 1987), Manganese Nitrate (accessed, May, 1999)
  • Open Data Solutions, EPA factsheets for regulated toxic chemicals (January, 1989), Manganese (accessed, May, 1999)
  • Open Data Solutions, EPA factsheets for regulated toxic chemicals (July, 1986), Manganese Dioxide (accessed, May, 1999)
  • Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
  • US EPA TTNWeb and US OAQPS UATW, Health Effects Notebook for Hazardous Air Pollutants (December 1994), Manganese and Compounds (accessed, May, 1999)
  • WebElements The periodic table on the WWW (May 1999), Manganese (accessed, May, 1999)
  • Worksafe Australia (1996), Exposure Standards Database, Manganese (accessed, May, 1999)
  • Worksafe Australia (1996), Hazardous Substances Database, Manganese (accessed, May, 1999)
  • Worksafe Australia (1996), Hazardous Substances Database, Manganese dioxide (accessed, May, 1999)
  • Worksafe Australia (1996), Hazardous Substances Database, Potassium permanganate (accessed, May, 1999)
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