Human body mercury toxicity

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). 

Bones are actually living protein networks to which minerals attach themselves. Not aU of the minerals deposited on bones are essential to bone building. There are at least two dozen elements in bones that have no known function in the human body, as well as a handful of nonessential elements, such as boron, strontium, silicon, barium, bismuth, and arsenic (yes, arsenic), that are believed to do some good. Five toxic elements—lead, cadmium, mercury, polonium, and radium—are often found in human bones. As long as they are stabilized in the bones, they do no apparent harm. 

Nature cannot be subjected to increasing concentrations of man-made substances that natural systems will not purge. Example The emissions of pesticides, PCBs, mercury, chloro-fluorocarbons, mine wastes, and innumerable other toxics and cancer-causing substances have contaminated food supplies, drinking water, ecosystems, and every human body on the planet. 

Certain organic mercury compounds, such as phenyl mercury and methoxyalkyl mercury, are metabolized relatively fast in the human body and are excreted in urine. In contrast to methyl mercury, these compounds do not accumulate in the body nor do they cause toxicity in the central nervous system. On the other hand they affect renal function, and mercury-... 

Samples such as hair, nails, blood, urine, and various tissues are analyzed by NAA for both essential and toxic trace elements (Bhandari et al. 1987, Lai et al. 1987). The analysis can be related to determine their effect on disease outcomes. These authors have reported that the diet and environment contribute largely towards the trace elements in the human body. It is has been demonstrated in other works that the selenium concentration in human nails is an accurate monitor of the dietary intake of selenium. As a consequence, the nail monitor has been extensively used to study the protective effect of dietary selenium against cancer and heart disease in numerous prospective case-control studies. In another study by Kanabrocki et al. (1979) on human thumbnails in USA, using thermal NAA technique, the average concentration of metals studied in clinically symptom-free adult female and male subjects were found to be zinc, 184 vs. 153 ppm chromium, 6.8 vs. 4.2 selenium, 0.9 vs. 0.6 gold, 2.6 vs. 0.4 mercury, 1.9 vs. 0.4 silver 0.7 vs. 0.3 cobalt, 0.07 vs. 0.04. In another study, the fluorine concentration in bone biopsy samples was... 

Of all turnover rates in the human body, the total excretion rate seems to be the lowest. This means that the body can be looked upon as a one-compartment system in which the intake is balanced by the excretion. In 1968 (Berglund and Berlin, 1969), we therefore proposed a model for the mercury accumulation in the human body, a model which has been widely used (see Fig. 8). However, it may be pointed out that this model is an approximation and valid pnly at non-toxic dose le vels. The indications from animal experiments are that at increasing dose levels the elimination rate goes down. Close to toxic blood levels the brain shows an increasing tendency to accumulate methyl mer-... 

Despite its availability and current use, coal is not as widely used today as the other fossil fuels. Coal s major weakness is that it does not burn cleanly. It often contains trace amounts of other elements, including mercury, arsenic, and sulfur, and when it burns, it releases these toxic substances into the air. Over time, coal pollution builds up in the environment. Mercury released during coal combustion, for example, settles in water and builds up in the bodies of fish and shellfish. When these fish and shellfish are eaten by humans and other animals, harmful amounts of mercury can be ingested. In 2008, bluefm tuna served in expensive New York restaurants was found to contain unacceptably high levels of mercury. These fish eat smaller organisms in the ocean, and when these small organisms contain mercury, the toxic element becomes concentrated in the body of the tuna. 

Chronic toxicity studies provide information on the long-term health effects of chemical substances. Adverse health effects in exposed animals and subsequent severe damage are known to occur after repeated exposure to low doses over a period of time. The slow accumulation of mercury or lead in the body or after a long latency period from exposure to chemical carcinogens is an example. Chronic or prolonged periods of exposure to chemical substances may also cause adverse effects on the reproduction and behavior of animals and humans. The symptoms caused after chronic exposure usually differ from those observed in acute poisoning from the same chemical. In fact, when exposed to low concentrations of chemical substances, as is the case with chronic toxicity studies, the industrial worker and common public are unaware of the exposure. 

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