International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 52 (1991) (p. 179)

CAS No.: 75-27-4

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Bromodichloromethane is found in chlorinated drinking-water as a consequence of the reaction between chlorine, added during water treatment, and natural organic substances in the presence of bromide. The major route of human exposure to bromodichloromethane is via drinking-water. It has been detected in chlorinated drinking-water in many parts of the world; it has also been detected in some untreated waters, but at much lower levels. Bromodichloromethane is a major component of the organohalides produced by marine algae.

5.2 Experimental carcinogenicity data

Bromodichloromethane was tested for carcinogenicity in two-year studies in male and female Fischer 344 rats and B6C3F1 mice by oral gavage, in life-span studies in male and female Wistar rats and in CBA x C57Bl/6 hybrid mice by administration in drinking-water. In the gavage studies, bromodichloromethane increased the incidences of adenomatous polyps and adenocarcinomas of the large intestine and of tubular-cell adenomas and adenocarcinomas of the kidney in male and female rats, of tubular-cell adenomas and adenocarcinomas of the kidney in male mice and of hepatocellular adenomas and carcinomas in female mice. In the study by administration in drinking-water, it induced neoplastic nodules and adenofibrosis of the liver in rats; no increase in tumour incidence was seen in mice. In a screening test for lung adenomas by intraperitoneal injection, bromodichloromethane did not increase the incidence of lung tumours in strain A mice.

5.3 Human carcinogenicity data

No relevant data were available to the Working Group.

5.4 Other relevant data

Repeated exposure of rats and mice to bromodichloromethane resulted in toxic effects in several organs, including the liver and kidney.

A study of developmental toxicity in rats given bromodichloromethane throughout the period of major organogenesis showed skeletal variations in the presence of maternal toxicity but no teratogenic effect.

Bromodichloromethane induced mutations in some studies with bacteria and, in a single study, in cultured mammalian cells. Chromosomal aberrations but not sister chromatid exchange were observed in cultured mammalian cells. In single studies, sister chromatid exchange was observed in cultured human cells and in mouse bone marrow in vivo. In one study, bromodichloromethane did not induce micronuclei in bone-marrow cells of mice treated in vivo.

5.5 Evaluation

There is inadequate evidence for the carcinogenicity of bromodichloromethane in humans.

There is sufficient evidence for the carcinogenicity of bromodichloromethane in experimental animals.

Overall evaluation

Bromodichloromethane is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.

Subsequent evaluation: Vol. 71 (1999)

Synonyms for bromodichloromethane

Last updated: 13 April 1999

    See Also:
       Toxicological Abbreviations
       Bromodichloromethane (ICSC)
       Bromodichloromethane  (IARC Summary & Evaluation, Volume 71, 1999)