Selenium (Se) is a chemical element of main group VI group of the periodic system of D. I. Mendeleev. Serial number 34, atomic weight (mass) 78,96, contained mainly in the soil in the form of impurities in Ceret. Exists in the form of a number of modifications: amorphous, crystalline, glassy, grey metallic. Is not dissolved in water, soluble in concentrated acids, react with Halogens, with metals forming selenides, with hydrogen - selenium-hydrogen, oxygen forms a series of oxides - SeO, SeO2, SeO3. Selenium is used in metallurgical, glass, ceramic and other industries for the manufacture of optical and signaling devices, selenium rectifiers in the television set, to get ruby glass, discoloration green glass, etc., the EQS for the air of industrial premises amorphous selenium 2 mg/m3, Se02 - 0.1 mg/m3.
Selenium compounds are poisonous metal selenium less toxic) and remind the effect of arsenic compounds (see).
The greatest danger in production conditions are vapours and dust se anhydride SeO2 and elemental selenium. In the body selenium comes through the respiratory tract, gastrointestinal tract and intact skin. The toxic effect is due to blocking of SH-groups of many enzymes. In acute poisoning selenium observed irritation of the mucous membranes of the upper respiratory tract and eyes, weakness, headache and dizziness, nausea, in more severe cases, fever, hemorrhagic acute rhinitis , laryngitis, bronchitis, sweats, hypotension, gastrointestinal symptoms (vomiting, diarrhea, sometimes with blood), pain in the liver and spleen, convulsions, sometimes paralysis. Victims feel a metallic taste in the mouth, garlic smell exhaled air. Acute intoxication se hydrogen may develop pulmonary edema.
In chronic selenosis patients complain of fatigue, lack of appetite, headaches, dizziness, weight, and tightness in the chest, nausea, vomiting, diarrhea, pain in the right hypochondrium. Objectively observed depletion of the victims, sometimes there are signs of parenchymatous hepatitis, hypotension, functional lability vessels, chronic bronchitis (sometimes asthmatic nature), phenomena of hyperthyroidism.
Selenium is excreted in the milk. In experiments on animals the possibility of penetration through the placenta.
Selenium causes dermatitis dystrophic and allergic nature. Se acid and chlorosis selenium have a pronounced prijigatm action in contact with skin and mucous membranes.
Prevention: sealing equipment, good ventilation of working premises, prior and current medical tests, the transfer of pregnant women and nursing mothers to another job. The use of personal protective equipment (rubber gloves, dust respirators). During pregnancy and breastfeeding women should translate to work, not connected with selenium.
Treatment. Along with the regular events that are applied with the defeat of the respiratory organs and the liver, it is recommended to use sonodeliaursa amino acids, a diet rich in proteins, methionine, intravenous sodium thiosulfate, vitamins C, B1 B12. Burns from SeO2 - solutions, emulsions with a 10% solution of sodium thiosulfate (restores SeO2 to elemental Se).