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

(4-CHLORO-2-METHYLPHENOXY)ACETIC ACID (MCPA)

VOL.: 30 (1983) (p. 255)

5. Summary of Data Reported and Evaluation

5.1 Experimental data

No adequate study of the carcinogenicity of MCPA to animals was available to the Working Group.

MCPA and maternally toxic doses of its ethyl ester were teratogenic and embryotoxic to rats.

MCPA was not mutagenic in bacterial systems in plate or host-mediated assays. A questionable result was obtained with MCPA in yeast, but its methyl ester was mutagenic. Recessive lethal mutations, but no chromosome loss, non-disjunction or X-Y chromosome rearrangement, were induced in Drosophila melanogaster. No overall evaluation of the mutagenicity of MCPA could be made.

5.2 Human data

MCPA was introduced in 1945. The production and formulation of this compound and of its derivatives and their use as herbicides in agricultural applications are potential sources of exposure, both of workers and of the general population.

No data were available to evaluate the teratogenic or chromosomal effects of MCPA in humans.

Exposure to MCPA alone was reported for some cases in one of three case-control studies and in one case report. The case-control studies are also discussed in detail in the section 'Cancer Epidemiology of Pesticide Manufacturers, Formulators and Users', in this volume.

5.3 Evaluation

No adequate data were available to evaluate the carcinogenicity of MCPA to experimental animals. The data on humans were also considered to be inadequate.

The available data are insufficent to evaluate the carcinogenicity to humans of MCPA alone.

For definition of the italicized terms, see Preamble Evaluation.

Subsequent evaluations: Suppl. 7 (1987); see also Vol. 41 (1986) (Chlorophenoxy herbicides, occupational exposure to)


Last updated: 16 April 1998






















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       Toxicological Abbreviations
       Mcpa (ICSC)