Mercury (200,59 a.m.u.) not a vital element, toxic, present in tracer amount. Mercury is the only metal being a liquid at room temperature. Source of mercury in environment – natural evaporation from the Earth crust, industrial pollution (chloride production, alkali production, electro-technical industry, pharmacy, production of cellulose and paper) burning of black coal.
Mercury is used in medicine and cosmetology (unguents, creams, disinfection solutions) in dentistry (amalgamate filling materials), mercury agents are used as fungicides for grain poisoning. Elementary metallic mercury in case of absence of chemistry and biology systems, which could transform it is of low toxicity. When transformed into ionized (non-organic) form it becomes toxic. Further transformations of non-organic mercury by some microbes into organic mercury (methylmercury) results in creation of high-toxic compounds of mercury, which are being selectively bond by tissues with high concentrations of lipids.
Methylmercury is lipophilic with high affinity to nervous tissues rich of lipids. Myelin is very sensitive to such damaging treatment. Mercury methylation is performing in bottom sediments of seas, lakes and other waterbodies. Intake of some species of fish and molluscs could be dangerous for humans (Minamata syndrome) indicating by toxic encephalopathy. Source of intoxication with methylmercury could be food of wildfowl from the regions where mercury-containing fungicides were used. Metallic mercury is easily absorbed when inhaling vapours, in gastro-intestinal tract it is almost not absorbing. Non-organic mercury is being hardly absorbed from gastro-intestinal tract. Organic mercury is absorbed easily from lungs and from gastro-intestinal tract. More than 99% of blood mercury is bond with erythrocytes (haemoglobin).
Non-organic mercury is excreted with urine, organic – secreted into bilis, goes to the gastro-intestinal tract, but then again absorbed in blood-stream. Toxic features of mercury are caused by the fact that its ions are easily binding with sulfhydryl protein groups. It changes their structure and features, including antigen characteristics in autoimmune reactions. Acute intoxication with mercury is mostly caused by intake of non-organic compounds of mercury, damaging the gastro-intestinal tract and kidney tubules. Chronic intoxication is mostly caused by inhaling or intake of small amounts of mercury. It could become the reason of gingivitis, stomatitis, extreme irritability, tremor, neurotic syndrome, colitis, anaemia and erythredema of children (Feer’s disease). Profession intoxication with mercury vapours – mercurialism is caused by the fact that mercury is a thiol poison. It is being indicated by nephropathy and hepatopathy.
Intoxication with organic mercury in indicating in sense of fatigue, headaches, loss of memory, apathy, mood swing, changes of sensibility, movement coordination, speech disorders, eyesight and hearing disorders. In severe cases intoxication could result in coma and death.
Whole blood is a recommended specimen to assess the intoxication with methylmercury.
Urine – recommended specimen to assess the effect of non-organic mercury.
Hair is used for retrospective evaluation of mercury effect on the body for long previous period.
