The harm of benzyl alcohol to human body

I believe everyone knows that toluene is quite harmful, but has anyone ever understood the harm of toluene in detail? Toluene is actually a chemical, and toluene is generally of low toxicity. For example, toluene may cause acute poisoning, resulting in vomiting, confusion, etc. Long-term exposure to toluene may also cause mental breakdown. The following is a detailed introduction.

Health hazards: Xylene is irritating to the eyes and upper respiratory tract, and has an anesthetic effect on the central nervous system at high concentrations.

Acute poisoning: Inhalation of high concentrations of nuclear weapons in a short period of time may cause obvious irritation symptoms to the eyes and upper respiratory tract, conjunctival and pharyngeal congestion, dizziness, nausea, vomiting, chest tightness, limb weakness, confusion, and unsteady gait. In severe cases, there may be agitation, convulsions or coma, and some may have hysterical attacks. Chronic effects: Long-term exposure can cause neurasthenia syndrome, menstrual abnormalities in female workers, and dry, chapped skin and dermatitis in workers.

2. Toxicological Information and Environmental Behavior

Toxicity: Low toxicity.

Acute toxicity: LD501364mg/kg (mouse intravenous)

Reproductive toxicity: Minimum toxic concentration (TDL0) for rats by inhalation: 1500 mg/m3, 24 hours (used during pregnancy day 7 to 14), embryotoxic.

Sources of pollution: Xylene is an important chemical raw material. Wastewater and exhaust gas from production plants of organic synthesis, synthetic rubber, paints and dyes, synthetic fibers, petroleum processing, pharmaceuticals, cellulose, etc., as well as unsealed production equipment and workshop ventilation are the main sources of xylene in the environment. Overturning, leakage and fire during transportation and storage can also cause accidental pollution accidents.

Metabolism and degradation: In humans and animals, except for 3% to 6% of inhaled xylene that is directly exhaled, the three isomers of xylene are metabolized into corresponding benzoic acids (60% o-xylene, 80% to 90% m- and p-xylene), and then these acids react with glucuronic acid and glycine. In this process, a large amount of o-benzoic acid combines with glucuronic acid, while p-benzoic acid almost completely combines with glycine to generate the corresponding methylhippuric acid and is excreted from the body. At the same time, a small amount of corresponding xylenols (phenols) and hydrogenated 2-methyl-3-hydroxybenzoic acid (less than 2%) may be formed.

Residue and accumulation: In occupational exposure, xylene enters the body mainly through the respiratory tract. For all xylene isomers, the absorption of their vapor by the lungs is the same, with a total amount of 60% to 70%, which is relatively constant throughout the contact period. Xylene solution can be absorbed through intact skin with an average absorption rate of 2.25µg/(cm3·min) (range 0.7~4.3µg/(cm3·min)). The percutaneous absorption of xylene vapor is negligible compared to direct contact with liquid. The residue and accumulation of xylene are not serious. As we have said above, xylene that enters the human body can generate methylbenzoic acid in the presence of NADP (transferase II) and NAD (transferase I) in the human body, and then combine with glycine to form methylhippuric acid, which is almost completely excreted from the body within 18 hours. Even the 3%-6% of xylene that remains in the lungs after inhalation will be completely exhaled within 3 hours after exposure (half-life is 0.5~1 hour). The residual test for evaluating exposure to xylene mainly measures the content of methylhippuric acid in urine. Some people also suggest measuring the content of xylene in exhaled gas or blood, but the results of the latter are often inaccurate. Because methylhippuric acid does not occur naturally in urine and because it is almost entirely retained as a xylene metabolite, measuring its presence is the best confirmation of xylene exposure. Xylene can remain in drinking water for quite a long time. When the concentration of xylene in tap water is 5 mg/L, its odor intensity is equivalent to level 5, and the unique odor of xylene will take 7 to 8 days to disappear; when the odor intensity is level 3, it will take 4 to 5 days. The smell of xylene in river water lasts for a short time, which is related to the initial concentration. It usually lasts for 3 to 5 days.

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