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Mercury is widely used in industry, and there are also many opportunities to come into contact with it in daily life. Mercury and its compounds have similar toxicity; excessive intake into the body can cause poisoning. Mercury is the only liquid metal at room temperature. Silver-white in color, easy to flow. Specific gravity 13.59. Melting point -38.9°C. Boiling point: 356.6°C. The specific gravity of vapor is 6.9. Mercury can volatilize at room temperature, and mercury vapor tends to adhere to walls or clothing, often forming a secondary source of mercury that continuously contaminates the air. In industry, in addition to metallic mercury, there are many inorganic and organic compounds of mercury as well. The solubility of mercury compounds varies greatly; for example, mercuric chloride is soluble in water, acetophenylmercury is slightly soluble in water, while methylmercuric chloride is insoluble in water. Mercury is widely used in modern industry. Mercury poisoning is one of the more common occupational diseases, occurring in activities such as the mining and smelting of mercury, the production of amalgams, and the manufacturing and maintenance of experimental and measuring instruments. The chemical industry uses mercury as a cathode in the electrolysis of salt to produce caustic soda and chlorine. The use of fulminite in military manufacturing, mercury as a catalyst in the plastics and dye industries, and the use of mercury-containing preservatives, fungicides, algaecides, and herbicides in pharmaceuticals and agricultural production, among other applications. If proper protection is not in place, it can all lead to mercury poisoning. In daily life, the breaking of mercury thermometers, excessive consumption of mercury-containing medications such as cinnabar and calomel, or inhalation of smoke from burned mercury-containing traditional medicines can all lead to mercury poisoning and cause harm to the human body. I. Routes of mercury entry into the human body: Under production conditions, metallic mercury enters the body primarily in the form of vapor through the respiratory tract. The amount that enters the human body accounts for about 80% of the inhaled amount. The amount of metallic mercury absorbed through the digestive tract is extremely small and can be disregarded. Due to accidents (such as a broken thermometer), metallic mercury can also enter the body through the skin. Mercurides can enter the body through the respiratory tract, digestive tract, and skin. II. The hazards of mercury to the human body: The damage caused by mercury and its compounds to the human body is related to the amount of mercury that enters the body. The harms of mercury to the human body primarily affect the central nervous system, digestive system, and kidneys; in addition, it also has certain effects on the respiratory system, skin, blood, and eyes. The mechanism of mercury poisoning is not yet fully understood. It is currently known that the Hg-S reaction is the basis for mercury’s toxicity. Once metallic mercury enters the body, it is quickly oxidized to mercury ions. These ions can bind to various negatively charged groups in enzymes or proteins within the body, such as thiol groups, thereby affecting many metabolic pathways in cells – including energy production and the synthesis of proteins and nucleic acids – and thus impacting the function and growth of cells. Mercury hinders cell division by affecting nucleic acids, nucleotides, and nucleosides. Both inorganic mercury and organic mercury can cause chromosomal abnormalities and have teratogenic effects. Furthermore, mercury can bind to the thiol groups on cell membranes, causing changes in membrane permeability and leading to severe disruptions in membrane function. The activity of adenylyl cyclase, Mg and Ca-ATPases, as well as Na, K-ATPases located on the cell membrane is strongly inhibited, which in turn affects a range of biochemical reactions and cellular functions, and may even lead to cell necrosis. Due to their different types, mercury and its compounds accumulate in various parts of the body after entering it, thereby causing damage to those areas. For example, metallic mercury is primarily accumulated in the kidneys and brain ； Inorganic mercury is primarily accumulated in the kidneys, while organic mercury is mainly accumulated in the blood and the central nervous system. Mercury can also cross the placental barrier and enter the fetus, inhibiting the migration of neurons from the central brain to the peripheral cortical areas, thereby causing cerebral palsy. Studies have shown that mercury poisoning can occur when the urinary mercury level exceeds 0.05 mg/1. Mercury poisoning is divided into acute poisoning and chronic poisoning. 1. Acute mercury poisoning. After a large amount of metallic mercury or mercurides enters the body through the respiratory or digestive tract, symptoms such as dizziness, general weakness, fever, stomatitis, as well as nausea, abdominal pain, and diarrhea can occur within a few hours to a few days. In severe cases, it can lead to acute pulmonary edema and acute renal failure (proximal tubular necrosis). 2. Chronic mercury poisoning. Occupational poisoning caused by long-term exposure to low concentrations of mercury and its compounds is chronic mercury poisoning. It can be divided into mild poisoning, moderate poisoning, and severe poisoning. (1) Mild mercury poisoning a. Neurotic syndrome, such as general fatigue, dizziness, headache, sleep disorders, etc. b. Mild mood changes, such as impatience, irritability, and tendency to cry. c. Mild tremors of the fingers, tongue, and eyelids. d. Digestive tract dysfunction; the patient has stomatitis and a metallic taste in the mouth. (2) Moderate mercury poisoning a. Significant changes in mental personality. b. Memory is significantly reduced, affecting work and daily life. c. Tremors of the hands, tongue, and eyelids are prominent, and they intensify when under emotional stress. (3) Severe mercury poisoning a. Obvious neuropsychiatric symptoms. b. Mercury toxic encephalopathy, characterized by coarse tremors in the limbs and throughout the body, ataxia, and dementia. III. Measures to prevent mercury poisoning 1. Improve working conditions by replacing toxic substances with less toxic or non-toxic ones. In the felt-making industry, non-mercury compounds are used, and electronic thermometers and bimetallic thermometers are employed in place of mercury thermometers. Reduce the level of mercury vapor in the air, and make use of mechanization and automation as much as possible in production. Areas where mercury vapor is generated should be enclosed and equipped with exhaust systems; in areas that cannot be enclosed, thorough ventilation must be implemented. The floors, walls, and ceilings of production workshops should be made of smooth materials to prevent the adsorption of mercury. The worker’s console should be smooth and have a slight slope to facilitate cleaning and rinsing, with a water storage mercury collection tray located at the lower part. For workshops already contaminated with mercury, fumigation with 1 g/m³ of iodine in alcohol can be used to produce mercury iodide, which is less volatile. The working environment of workers should be regularly monitored to ensure that the concentration of mercury vapor in the air remains below the maximum allowable level, as well as the concentration of metallic mercury