Mercury is the closest planet to the sun. It's average distance from the sun is approximately fifty-eight million km and it's diameter is 4875 km, making it the second smallest planet in our solar system. It's volume and mass are about 1/18 that of the earth and it's average density is approximately equal to that of the earth. Mercury's magnetic field is one-hundred times weaker than that of Earth's. Mercury has the shortest revolution of all the planets in our solar system and revolves around the sun in about eighty-eight days. Radar observations of the planet show that its period of rotation is 58.7 days online history courses, or two-thirds of its period of revolution. That means that Mercury has one and one-half days in it's year. Mercury doesn't have an atmosphere service that write book report for you, but it does have a thin layer of helium. NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone what is research methodology in dissertation, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service. Another source of mercury pollution is the combustion of fossil fuels. Coal on an average contains unto 0.5 ppm of mercury while in fuel oils mercury levels range between 0.1 - 0.35 ppm. It has been estimated that on global scale about 5000 tons of mercury are released from the combustion of fossil fuels alone. Mercury vapours readily diffuse across alveolar membrane and are lipid soluble. Mercury has an affinity for red blood cells and central nervous system. Absorption of metallic mercury from the gastro-intestinal tract (about 0.01%) is not of any toxicological significance. Two major episodes of mercury poisoning have occurred in Japan, in Minamata bay and Naigata as a consequence of industrial discharge of mercury compounds. Mercury was absorbed, bio-accumulated and bio-magnified to high levels. Fishes collected from Minamata bay and Agano River contained as much as 10-12 mg of mercury per kg of their flesh and bones. The largest epidemic of methyl mercury poisoning, however, took place in 1971-72 in Iraq when scarecity forced people to eat wheat grains treated with methyl mercury based fungicide which were intended to be used as seeds. The average methyl mercury content of these grains was about 4.8 - 14.6 mg per kg. About 6000 people were affected with the poisoning and some 500 deaths occurred (Bakir et al, 1973). The neurons in focal areas of cerebral cortex undergo degenerative changes and necrosis. This result in tremours review my essay for free, inability to co-ordinate voluntary movements, paralysis, impairment of vision essay on the use of the internet, loss of hearing, speech and coma in severe cases. There is no effective treatment known for alkyl-mercury poisoning Mercury has teratogenic action and is capable of inducing abortions and embryo toxic effects (Goldwater, 1972).
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