Mercury (Symbol= Hg , Latin hydrargyrum or mercurius) - A metallic element. Unlike other metals, mercury is liquid at room temperatures. Mercury and its salts have been used as antiseptics, purgatives, astringents, antisyphilitics, as well as for other uses. Mercury is toxic to the human. Therefore, use in therapy is becoming less frequent.
Industrial uses of mercury include the manufacture of batteries, explosives, thermometers, paint, and electrical apparatus. Dimethyl and diethyl mercury is used in the the treatment of seeds.
Toxicity of Mercury
The fatal dose of mercury salts is approximately 1 gram. Ingested metallic mercury is usually not "immediately" toxic to other tissues in the body because metallic mercury is not immediately absorbed from the GI tract. In fact, a radiograph (X-ray) of a patient's abdominal area after swallowing mercury is quite an extraordinary thing to see, clearly showing the aggregated globules of mercury along the route of the intestine. However, the mercury can cause immediate and severe local inflammatory reactions to the intestine where is first ends up after swallowing. But this local delay does bide some time to obtain quick emergency treatment to rid the body of mercury. Remember, inducing vomiting yourself is not enough, because some of the ingested mercury is Furthermore, mercury inhaled into the lungs can cause severe pneumonitis. Mercury vapour (monatomic state) is lipophilic (lipid soluble), and thus, can pass through the lipid membrane of cells, Brain cells can accumulate mercury, as well as cells of other tissues in the body. Once in the cells, the mercury is oxidised from Hg+1 to the Hg+3. This is a difference of one electron in the mercury atom, and consequences of this are that the mercury then has more toxicity on the cells. Mercury decreases the action of cellular enzymes. Keep in mind that enzymes are proteins, and proteins are long chains of amino acids. Some of these amino acids contain sulfur-hydrogen (-SH). Mercury deactivates cellular enzymes by combining with the sulfur-hydrogen (-SH) portions of the enzyme. Without these enzymes working properly, the cell cannot function properly (depending on the need of the enzyme) and can result in cell death. If many cells in a tissue are affected, tissue death results. As the kidney attempts to rid the body of mercury, it concentrates mercury from the blood into urine. Since the kidney accumulates large amounts of mercury, they can deposit in the glomeruli (functional units of the kidney) and cause specific tissue damage to these areas. Tissues most affected from mercury poisoning are the gastrointestinal tract, renal (kidney), and lung. The gastrointestinal tissues are obviously affected, because after swallowing, this is where the mercury initially ends up. Massive inflammation and corrosion can ensue. In the lung, severe inflammation can ensue, with the inhalation of even minute amounts. There are no guidelines and this is why mercury vapours in industry must be carefully controlled. Kidney damage is caused as explained above. Hepaitc (liver) damage is also observed in mercury poisoning. Keep in mind that the first place food and other absorbed substances travel to is the liver. Therefore, the liver is subjected to a variety of insults when we eat. From acute mercury poisoning, death is usually from uraemia (uremia, or increased levels of nitrogen containing compounds in the blood due to kidney failure). This can occur weeks after mercury poisoning, and kidney failure becomes apparant as urine output suddenly decreases, or ceases.
Treatment of mercury poisoning
There are many mercurial compounds (chemicals mixed with mercury) in existence. Compounds of mercury are sometimes more poorly absorbed than others, and of course, this is encouraging in cases of accidental ingestion (eg., children swallowing). Howver, other mercurial compounds can be more dangerous, because the other portions of the compound may increase absorption. It is always important to rapidly obtain medical treatment in cases of accidental ingestion. In regards to mercury, it is particularly important, because emergency measures can be employed to remove the mercury from the body. At present, penicillamine and dimercaptol are used in treatment of mercury poisoning. Additionally, supportive measures are employed for damage to any of the organ/tissue systems.
In summary
Acute or immediate mercury poisoning results in stomach pain, vomiting, bloody diarrhoea, metallic taste in the mouth, decreased or no urine output, and ulceration of the digestive tract. Chronic poisoning, either through ingestion of small doses, inhalation, or absorption through the skin results in a blue line along the gum borders, hypertrophied (thickened) gums. tremors, incoordination, salivation, bleeding gums and loosened teeth and stomatitis (inflammation of the oral mucosae).