Chemical Composition • Symbol: Hg • Atomic number: 80
Reactivity • Moderately active • Mercury reacts at about 350°C to form Mercury II oxide 2Hg(s) + O2(g) → 2HgO(s) A red powder form of mercury • Mercury does not react with non-oxidizing acids but it reacts with concentrated nitric acid, HNO3, and concentrated sulfuric acid, H2SO4
Physical characteristics • Silver liquid at room temperature • Melting point: -38.87 °C • Boiling point: 356.58 °C • High surface tension • Good electricity conductor • Insoluble
Movement • Environment: Mercury vapor emitted from both natural and anthropogenic sources is distributed in the atmosphere. It returns as a water-soluble form in precipitation and ends up in bodies of water. • Cells: Mercury is inhaled (vapor), ingested (eating fish exposed to mercury vapor or methyl mercury), or injected ( ethyl mercury used in vaccines) into cells.
Major sources • Natural sources: some mercury is released from natural sources like volcanoes and forest fires and as a result of normal breakdown of minerals in rocks and soil through exposure to wind and water • Anthropogenic sources: coal burning power plants, industrial boilers, waste combustors, thermometers, blood pressure gauges, clinical reagents, lab chemicals, dental amalgams, fluorescent light tubes, switches, batteries, cosmetics, paint additives, pesticides Complete list of sources http://www.glrppr.org/docs/mercury_in_industry.htm
Toxicity • Mercury and all of its compounds are toxic, exposure to excessive levels can permanently damage or fatally injure the brain and kidneys • Organic compounds of mercury such as methyl mercury are considered the most toxic forms of the element. • Exposures to very small amounts of these compounds can result in devastating neurological damage and death
Environmental damage • Mercury in the air may settle into water bodies and affect water quality • Methyl mercury accumulates in fish at levels that may harm the fish and the other animals that eat them.
Health risks • Disruption of the nervous system • Damage to brain functions • degradation of learning abilities, personality changes, tremors, vision changes, deafness, muscle incoordination and memory loss. • Allergic reactions • skin rashes, tiredness, and headaches • Reproductive effects, such as sperm damage, birth defects and miscarriages • DNA damage and chromosomal damage