hydrogen sulfide, H2S, is a flammable colorless gas with a typical rotten egg smell. Hydrogen sulfide is rarely used in industrial production, and the hydrogen sulfide in contact is generally the product of certain chemical reactions and the natural decomposition process of proteins, or exists in the form of impurities. The industries that are more exposed to hydrogen sulfide in the city include sewage treatment, papermaking, petroleum processing, fertilizer manufacturing, chemical fiber manufacturing, and the manufacturing of certain chemical raw materials.
Human inhalation of hydrogen sulfide can cause acute poisoning and chronic damage. Acute hydrogen sulfide poisoning can be divided into three levels, mild poisoning, moderate poisoning and severe poisoning, and the clinical manifestations of different degrees of poisoning are obviously different. Mild poisoning is manifested as photophobia, tearing, eye tingling, foreign body sensation, runny nose, burning sensation in the nose and throat, etc., in addition, there may be mild dizziness, headache, fatigue, nausea, vomiting, ataxia and other symptoms, there may be temporary disturbances of consciousness, and at the same time, it can cause respiratory mucosal irritation symptoms and eye irritation symptoms, and the examination can show dry or wet rales in the lungs, ocular conjunctival congestion, edema, etc. Severe poisoning manifests as obvious symptoms of the central nervous system, first dizziness, palpitations, dyspnea, and slowness of movement, followed by irritability, confusion, vomiting, diarrhea, abdominal pain and convulsions, quickly entering a coma, and finally death due to respiratory paralysis. When exposed to very high concentrations of hydrogen sulfide, "shock-like" poisoning can occur, and the contact person suddenly collapses within seconds and stops breathing. Repeated inhalation of hydrogen sulfide over a long period of time can cause hyposmia, as well as neurasthenic syndrome and autonomic dysfunction.
People with obvious respiratory diseases, organic diseases of the nervous system, psychosis and severe neurosis, and obvious cardiovascular diseases should not engage in hydrogen sulfide work.
Before entering the workplace where hydrogen sulfide may be present, especially in sewers, septic tanks, well bottoms and other places, mandatory ventilation can be carried out first, and then small animals can be put in to observe whether there is poisoning, or use a direct-reading tester or lead acetate test strip to test the on-site air to confirm that the workplace is safe or there is no hydrogen sulfide gas before entering the operation.
Physical and chemical properties: Hydrogen sulfide (Hydrogen sulfide) is a colorless gas. Has a rotten egg smell. Molecular formula: H2-S. Molecular weight 34.08. Relative density 1.19. The upper limit of combustibility is 45.5%, and the lower limit is 4.3%.
Contact opportunities: hydrogen sulfide is produced in mining and extracting copper, nickel, cobalt, etc. from ore, low-temperature coking of coal, mining and refining of sulfur-containing oil, rubber, rayon, tanning, sulfur dyes, papermaking, pigments, vegetable pickling, sugar beet sugar, animal glue and other industries; Excavation and remediation of marshes, ditches, wells, sewers, culverts, tunnels and removal of garbage, sewage and manure, as well as the exposure of hydrogen sulfide to analytical chemistry laboratory workers; Natural gas, mineral water, volcanic eruptions, and undermine water are also often accompanied by hydrogen sulfide. Since hydrogen sulfide is soluble in water and oil, it can sometimes flow away from the source with water or oil, causing accidental poisoning accidents.
Introduction to Toxicology
Hydrogen sulfide is a nerve agent. It is also an asphyxiating and irritating gas. The main targets of its toxic effect are the central nervous system and the respiratory system.
The acute toxicity of hydrogen sulfide can vary depending on its different concentrations and exposure time. The higher the concentration, the more obvious the central nervous system inhibition, and the relatively low concentration is the more obvious mucosal irritation. People inhale 70~150 mg/m3/1~2 hours, respiratory and eye irritation symptoms, olfactory fatigue after 2~5 minutes of inhalation, and no longer smell the smell. Inhalation of 300 mg/m3/1 hour, acute eye irritation symptoms occur in 6~8 minutes, and pulmonary edema is caused by prolonged exposure. Inhalation of 760 mg/m3/15~60 minutes causes pulmonary edema, bronchitis and pneumonia, headache, dizziness, unsteady gait, nausea, and vomiting. Inhalation of 1000 mg/m3/seconds quickly causes acute poisoning, rapid breathing, respiratory paralysis, and death.