VOL.: 71 (1999) (p. 641)
Chem. Abstr. Name: 1,2-Dibromoethane
Exposure to ethylene dibromide (1,2-dibromoethane) may occur in pest control, petroleum refining and waterproofing. Dermal exposure is possible when handling leaded gasoline containing ethylene dibromide. It has been detected at low levels in air and water.
5.2 Human carcinogenicity data
Three cohort studies have included workers exposed to ethylene dibromide, but because of their low statistical power and/or lack of information about individual exposures, little can be concluded about the carcinogenicity of this compound in humans.
5.3 Animal carcinogenicity data
Ethylene dibromide has been tested for carcinogenicity by oral administration in mice, rats and fish, by inhalation in mice and rats and by skin application in mice. Following its oral administration, it produced squamous-cell carcinomas of the forestomach in rodents of both species, an increased incidence of alveolar/bronchiolar lung tumours in mice of each sex, haemangiosarcomas in male rats, oesophageal papillomas in female mice and liver and stomach tumours in fish. Following its inhalation, ethylene dibromide produced adenomas and carcinomas of the nasal cavity, haemangiosarcomas, mammary gland tumours, subcutaneous mesenchymal tumours, an increased incidence of alveolar/bronchiolar lung tumours in animals of each species and an increased incidence of peritoneal mesotheliomas in male rats. It induced skin and lung tumours in mice after skin application.
5.4 Other relevant data
In rodents and humans, ethylene dibromide is metabolized both by cytochrome P450 and GST enzymes; the latter seem to be responsible for DNA adduct formation. In rodents, covalently bound radioactivity has been detected in the epithelial lining of a number of organs.
In humans, acute high-dose exposure leads to liver and kidney damage. In rodents, inhalation exposure causes primarily proliferative lesions in nasal cavities. After intragastric administration, liver and kidney were the main target organs. Some evidence of adverse effects on reproduction was observed both in humans and rodents.
Ethylene dibromide is mutagenic in bacteria and Drosophila, and in rodent and human cells in vitro. It induced DNA breakage but not chromosomal aberrations or micronuclei in vivo in rodents. It gave negative results in dominant lethal tests in mice and rats. It did not induce either chromosomal aberrations or sister chromatid exchange in humans in vivo.
Ethylene dibromide binds to DNA in vitro and in vivo in rodents.5.5 Evaluation
There is inadequate evidence in humans for the carcinogenicity of ethylene dibromide.
There is sufficient evidence in experimental animals for the carcinogenicity of ethylene dibromide.
Ethylene dibromide is probably carcinogenic to humans (Group 2A).
In making the overall evaluation, the Working Group took into consideration that ethylene dibromide is genotoxic in a broad range of in-vitro and in-vivo assays and binds covalently with DNA in vivo.For definition of the italicized terms, see Preamble Evaluation.
Previous evaluations: Vol. 15 (1977); Suppl. 7 (1987)
Last updated: 13 April 1999
See Also: Toxicological Abbreviations Ethylene dibromide (ICSC) Ethylene dibromide (FAO Meeting Report PL/1965/10/2) Ethylene dibromide (FAO/PL:CP/15) Ethylene dibromide (FAO/PL:1967/M/11/1) Ethylene dibromide (FAO/PL:1968/M/9/1)