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

(Group 3)

For definition of Groups, see Preamble Evaluation.

VOL.: 53 (1991) (p. 467)

CAS No.: 150-68-5
Chem. Abstr. Name: N'-(4-Chlorophenyl)-N,N-dimethylurea

5. Summary of Data and Evaluation

5.1 Exposure data

Monuron is a nonselective systemic herbicide which inhibits photosynthesis. It was introduced in 1952 and has been used for the control of grasses and weeds in non-cropland areas, such as rights-of-way, industrial sites and drainage ditch banks. It has been used at lower application rates in agricultural areas in some countries as a pre- or post-emergence herbicide.

Monuron has been formulated for use as wettable powder and granules.

Exposure may occur during its production and use and, at much lower levels, from consumption of foods containing residues.

5.2 Carcinogenicity in humans

No data were available to the Working Group.

5.3 Carcinogenicity in experimental animals

Monuron was tested adequately for carcinogenicity in one study in mice and in one study in rats by oral administration. No increase in tumour incidence was found in mice. In rats, dose-related increased incidences of renal and liver-cell tumours were observed in males.

5.4 Other relevant data

Monuron forms chloroaniline-haemoglobin adducts in rats. In one study, it increased the number and volume fraction of enzyme-positive foci in rat liver.

No data were available on the genetic and related effects of monuron in humans.

Monuron induced micronucleus formation, chromosomal aberrations and abnormal sperm in mice in vivo. It induced chromosomal aberrations in cultured mammalian cells, insects and plants, sister chromatid exchange and cell transformation in cultured mammalian cells and mutation in plants.

5.5 Evaluation

No data were available from studies in humans.

There is limited evidence in experimental animals for the carcinogenicity of monuron.

Overall evaluation

Monuron is not classifiable as to its carcinogenicity to humans (Group 3).

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluations: Vol. 12 (1976) (p. 167); Suppl. 7 (1987) (p. 67)


Last updated: 21 November 1997

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       Toxicological Abbreviations