Discussion on the harm of dichloromethane in shandong jinhao chemical co. LTD

Invasion: inhalation, ingestion, percutaneous absorption.

Health hazard: dichloromethane has anaesthetic effects, mainly affecting the central nervous system and respiratory system. The main route of human contact is inhalation. It has been measured that high concentrations of dichloromethane exist in indoor production environments when dichloromethane is used as paint remover. The general population is exposed to much lower doses through ambient air, drinking water and food. It is estimated that about 80% of the world's production of dichloromethane is released into the atmosphere, but the compound's rapid rate of photolysis makes it impossible for it to accumulate in the atmosphere. The initial degradation products are phosgene and carbon monoxide, which are converted into carbon dioxide and hydrochloric acid. When dichloromethane is present in surface water, much of it evaporates. In the presence of oxygen, it tends to biodegrade, so bioaccumulation seems unlikely. But its behavior in the soil still needs to be determined.

Toxicological data and environmental behavior

Toxicity: transoral toxicity is moderate.

Acute toxicity: LD501600 ~ 2000mg/kg(rats via mouth); Lc5056.2g /m3, 8 h (mouse inhalation); The mice were killed by inhalation of 67.4g/m3×67 min. 20 ~ 50ml, mild poisoning; 100 ~ 150ml of human oral passage was fatal; People inhaled 2.9 ~ 4.0g/m3 and became dizzy 20 minutes later.

Subacute and chronic toxicity: rats inhaled 4.69g/m3,8 h/day, 75 days, no pathological changes. Exposure time increased with mild hepatic atrophy, steatosis, and cell infiltration.

Mutagenesis: microbe mutagenesis: salmonella typhimurium 5700ppm. DNA inhibition: human fibroblast at 5000ppm/ h (continuous).

Reproductive toxicity: the rats inhaled the lowest toxic concentration (TCL0) of 1250ppm(7 hours, 6-15 days of gestation), causing musculoskeletal dysplasia and abnormal development of the urogenital system.

Carcinogenicity: IARC carcinogenicity review: animal positive, unclear in humans. Animal experimental data and human epidemiological data are insufficient on whether patients should consider dichloromethane as a carcinogen in animals and humans. However, given the recent findings in inhalation studies in rats and mice, and the data available after the task force meeting, dichloromethane should be considered as a potential carcinogen to humans.