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

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 73 (1999) (p. 481)

Chem. Abstr. No.: 7758-01-2
Chem. Abstr. Name: Bromic acid, potassium salt

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Exposure to potassium bromate may occur during its production and use as a dough conditioner and food additive. Bromate may also be found in some drinking-water samples as a by-product of ozone disinfection.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

Potassium bromate has been tested by oral administration in several studies in rats and in one study each in mice and hamsters. In rats, it produced renal tubular tumours (adenomas and carcinomas) and thyroid follicular tumours in animals of each sex and peritoneal mesotheliomas in males. In mice, it produced a low incidence of renal tubular tumours in males. In hamsters, the incidence of renal tubular tumours was marginally increased. Potassium bromate did not increase tumour incidence in bioassays in newborn rats and mice, but it enhanced the induction of kidney tumours by N-nitrosoethylhydroxyethylamine in several experiments.

5.4 Other relevant data

No data were available on the absorption, distribution, metabolism or excretion of potassium bromate in humans, and limited information was available on rats. Bromate was found to be rapidly absorbed in rats and eliminated (or degraded).

A number of case reports of acute poisoning by potassium bromate have been reported. Potassium bromate is highly toxic. It produces lipid peroxidation and oxidative DNA damage in rat kidney. There is also evidence that it increases the amount of a 2u-globulin in male rat kidney. The available data, including evidence of genetic toxicity, indicate, however, that potassium bromate causes renal tumours through a mechanism involving oxidative damage.

No data were available on the developmental and reproductive effects of potassium bromate. Howwever, in a single, short-term assay to screen for reproductive toxicity, involving exposure of male and female rats to sodium bromate before and during gestation, no developmental toxicity was observed. A decrease in epididymal sperm concentration was found in males.

No data were available on the genetic and related effects of potassium bromate in humans. It is genotoxic in experimental systems in vivo and in rodent cells in vitro. No conclusion could be drawn with respect to its mutagenicity to bacteria.

5.5 Evaluation

There is inadequate evidence in humans for the carcinogenicity of potassium bromate.

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

Overall evaluation

Potassium bromate is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluations: Vol. 40 (1986); Suppl. 7 (1987) (p. 70)

Last updated: 30 September 1999

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       Toxicological Abbreviations