Tham khảo tài liệu 'paints, coatings and solvents episode 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Toxicology and Occupational Health 305 . Toxicology and Occupational Health . Toxicology a Acute and Chronic Toxicity. Solvents act with different intensities on human animal and plant organisms. Their effects depend on the amount of solvent and the exposure time. Under short-term exposure to high solvent doses acute damage may occur whereas the absorption of smaller amounts over a longer period leads to chronic damage and sensitization. The chronic effects are more dangerous since they are accompanied by an acquired tolerance with the result that they are often not detected early enough. In order to evaluate the solvent toxicities their LD50 values oral administration to rats are listed in Table 23. Since most cases of solvent poisoning are caused by inhalation of solvent vapors the LC50 values are also given. Inhaled solvent vapors pass via the lungs and blood circulation into the body where they accumulate in tissues with high lipid content . nerves brain bone marrow adipose tissue liver and kidneys The cells can either be damaged by the solvents or by their decomposition products. Solvents can also pass into the body via cutaneous or more rarely gastrointestinal absorption Symptoms of acute solvent poisoning include dizziness drowsiness headache loss of consciousness and narcotic effects which are attributed to disturbances of the central nervous system. Chronic poisoning is initially undetectable but subsequently causes damage to organs that are specific for each solvent Solvents have two effects on the skin 1 they dissolve the natural fatty layer the skin therefore cracks and microorganisms and dirt particles can penetrate more easily and cause infection 2 solvents can act directly to cause inflammation or blistering. The following solvents are absorbed very readily through the skin and pass into the body aniline benzene butyl glycol butyl glycol acetate dimethylacetamide dimethylformamide dioxane .
