1,1-Dichloroethane

CAS RN:75-34-3

Toxicity Summary

IDENTIFICATION AND USE: 1,1-Dichloroethane is a colorless, oily liquid. It is used as a chemical intermediate in the production of vinyl chloride and of 1,1,1-trichloroethane. It is also a grain fumigant and has limited use as a solvent for plastics, oils, fats, paint, and varnishes. 1,1-Dichloroethane is used in the manufacture of high vacuum rubber and silicone grease. The chemical can also be used as a coupling agent in antiknock gasoline, for metal degreasing, organic synthesis, and ore floatation. It was formerly used as an anesthetic but it is of no importance in this field today. HUMAN STUDIES: Symptoms of exposure to this compound may include liver and kidney damage, skin and eye irritation, dermatitis, skin burns, unconsciousness, CNS depression, drowsiness, nausea, vomiting, faintness, irritation of the respiratory tract, salivation, sneezing, coughing, dizziness, lacrimation, reddening of the conjunctiva, cyanosis, and circulatory failure. ANIMAL STUDIES: No toxic effects were observed in rabbits dermally exposed to an upper limit dose of 2 mL 1,1-dichloroethane/kg bw for 24 hr during a 14-day observation period. In a study of acute toxicity to adult male rats, there was significant mortality at a concentration of 8.0 g/kg. Intraperitoneal doses of 1000 mg/kg produced no renal necrosis in mice but some evidence of tubular swelling was reported. Urinary protein was increased after injection of 2000 mg/kg and urinary glucose increased after 4000 mg/kg. Rats survived an 8 hr inhalation exposure to 4000 ppm but were killed at 16,000 ppm. Anesthetic effects in mice that inhaled 8,000-10,000 ppm 1,1-dichloroethane for 2 hours were observed, with a minimal lethal dose of 17,300 ppm. Single intraperitoneal injections of 150, 300, 500, and 750 mg 1,1-dichloroethane/kg bw to guinea pigs failed to elicit a change in serum ornithine carbamoyl transferase activity and produced no histological changes in the liver. Pregnant female rats were exposed on days 6 to 15 of gestation to 3800 or 6000 ppm 1,1-dichloroethane vapors, 7 hr/day. No effect occurred in either the dams or fetuses except for slight but statistically significant decreases in food consumption and weight gain by the dams and delayed ossification in the fetuses. No teratological effects were related to exposures. Liver weights of a group of nonpregnant rats were increased by similar exposure, but no histological changes were apparent grossly or microscopically. Chronic 1,1-dichloroethane exposure led to increased incidence of mammary gland adenocarcinomas and hemangiosarcomas in female rats and an increased incidence of hepatocellular carcinomas and benign uterine polyps in mice. 1,1-Dichloroethane has a genotoxic potential as measured by the bone marrow chromosomal aberrations and micronuclei formation tests in mice. Test for cytogenetic effects in cultured Chinese hamster ovary cells indicated that 1,1-dichloroethane induced sister-chromatid exchanges, but did not cause an increase in the number of chromosomal aberrations either with or without metabolic activation. It was not mutagenic in Salmonella/microsome test (Ames test). ECOTOXICITY STUDIES: Effects of a series of chlorinated ethenes and ethanes on hybrid poplar (Populus deltoides x nigra DN34) were assessed in laboratory experiments. Adverse effects were found to increase with increasing number of chlorine atoms within a homologous series of ethenes or ethanes. Ethenes were more toxic than similarly chlorinated ethanes.
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