Human body mercury

Mercury poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 0.4 p,g Hg/mL, what is the total mass in kilograms of mercury in the lake (The lake has a surface area of 100 mi and an average depth of 20 ft.)... 

Iodine occurs to a minute extent (less than 0.001 %) in sea water, but is found in greater concentration, combined in organic form, in certain seaweeds, in oysters and in cod livers. Crude Chile saltpetre, or caliche contains small amounts of sodium iodate, NalOj. from which iodine can be obtained (see below). Some insoluble iodides, for example liiose of silver and mercury(II), occur in Mexico. Iodine is found in the human body in the compound thyroxin in the thyroid gland deficiency of iodine in diet causes enlargement of this gland (goitre). 

Modern temperature scale proposed by G. Fahrenheit, defined by a thermometer, a law and three fixed points. Fahrenheit s thermometer was a mercury-in-glass one. Thermal expansion versus temperature was assumed linear. Three fixed points were defined 0°F temperature of a mixture of water, ice and ammonium chloride 32°F temperature of melting ice 96°F temperature of human body... 

Parsons et al.66 reported on the determination of total mercury as a toxic element in urine at the trace level using ICP-MS. The main sources of exposure in the human body are inhalation of Hg vapour released from dental amalgams and the consumption of fish species that accumulate, for example, methyl mercury (MeHg). 

Thus one cannot, without error, confound this Humid Radical with Innate Fire. The latter is the inhabitant, the former the habitation, the dwelling. It is, in all the Mixts, the laboratory of Vulcan the hearth on which is preserved that immortal Fire, the prime-motor created from all the faculties of individuals the universal Balm, the most precious Elixir of Nature, the perfectly sublimated Mercury of Life, which Nature distributes by weight and measure to all the Mixts. He who will know how to extract this treasure from the heart, and from the hidden center of the productions of this lower world, to despoil it of its thick elementary shell, which conceals it from our eyes and to draw it from the dark prison in which it is enclosed and inactive, may boast of knowing how to make the most precious MEDICINE to relieve the human body. 

He adds that as mercury and sulphur are sufficient for the making of all metals, so of these may be composed a universal medicine, or metal, for curing all the sick which some by an error have understood as a universal metal, efficacious in all the diseases of the human body. 

Mercuric chloride, like other soluble salts of mercury, is very poisonous when taken internally. The mercUric ion combines strongly with proteins in the human body it acts especially on the tissues of the kidney, destroying the ability of this organ to remove waste products from the blood. Egg white and milk are swallowed as antidotes their proteins precipitate the mercury in the stomach. ... 

Mercury and all of its compounds are extremely poisonous, and mercury is one of the few substances known to have no natural function in the human body. Classified as a heavy metal, mercury is difficult for the body to... 

Methylmercury is rapidly and nearly completely absorbed from the gastrointestinal tract 90-100% absorption is estimated. Methylmercury is somewhat lipophilic, allowing it to pass through lipid membranes of cells and facilitating its distribution to all tissues, and it binds readily to proteins. Methylmercury binds to amino acids in fish muscle tissue. The highest methylmercury levels in humans generally are found in the kidneys. Methylmercury in the body is considered to be relatively stable and is only slowly transformed to other forms of mercury. Methylmercury readily crosses the placental and blood/brain barriers. Its estimated half-life in the human body ranges from 44 to 80 days. Excretion of methylmercury is via the feces, urine, and breast milk. Methylmercury is also distributed to human hair and to the fur and feathers of wildlife measurement of mercury in hair and these other tissues has served as a useful biomonitor of contamination levels. 

There is no indication that mercury compounds in the concentrations and forms found in either the atmosphere or drinking water supplies contribute significantly to the methylmercury burden in human body. The available data shows that almost all the methylmercury in the human diet comes from fish, other seafood, and possibly red meat. 

Because the two major sources of mercury body burden include dietary intake and intake from dental amalgams, mercury is present at low concentrations in a variety of human tissues. Mercury has been detected in blood, urine, human milk, and hair in individuals in the general population. Inhalation of... 

Boijesson J, Alpsten M, Huang S, et al. 1993. In vivo x-ray fluroescence analysis with application to platinum, gold and mercury in man-experiments, improvements, and patient measurements. In Ellis KJ, Eastman JD eds., Human body composition. New York NY Plenum Press. 

The concentrations of pollutants in air and water are also measured as ppm. If these concentrations exceed a fixed value, they may be considered hazardous. For instance, when the concentration of mercury in drinking water reaches 0.5 ppm, this level is regarded as harmful to health. That level refers to 0.5 g in 1000 kg of water. Lead is also dangerous at a certain level. 0.250 ppm lead can cause delayed cognitive development in children. Carbon monoxide is a significant factor in air pollution. 750 ppm of carbon monoxide by volume in the air we inhale is considered to be lethal. All these examples show that the relationship of the human body to the ecological system is very finely balanced. Even a small increase in concentrations of pollutants may result in dire consequences. Therefore, scientists have been working on the problem of pollution in order to help maintain the relative purity of our vital natural resources. 

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