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Genotoxicity of selected herbicides
Abstract:
Twenty-two herbicides were studied in 67 tests for induction of DNA damage, gene mutation and chromosomal changes in vitro and in vivo. Triazine and urea-type herbicides were found to be inactive in all but one test. Of 4 thiocarbamates, molinate and vernolate caused chromosomal changes, namely increased incidence of sister chromatid exchanges and chromosomal aberrations in vitro and increased frequency of micronucleated polychromatic erythrocytes in mouse bone marrow. These compounds, however, did not cause gene mutation and only molinate gave equivocal positive result in bacterial repair test. Out of 11 miscellaneous herbicides, ethofumesate, alachlor, dichlorprop and fluorodifen proved to be positive only in one or two tests. In the light of clastogenicity of some thiocarbamates, serious consideration should be given to start animal carcinogenicity studies with these chemicals.
Insights
Certain thiocarbamate herbicides, including molinate and vernolate, induced DNA damage and chromosomal changes in laboratory tests. Further animal carcinogenicity studies are recommended for these specific herbicide compounds.
Area of Science:
- Environmental toxicology
- Genetics
- Chemical safety
Background:
- Herbicides are widely used in agriculture, necessitating rigorous safety assessments.
- Understanding the genotoxic potential of herbicides is crucial for environmental and human health protection.
Purpose of the Study:
- To evaluate the genotoxic effects of 22 herbicides across various test systems.
- To identify specific herbicides that may pose a risk due to DNA damage, gene mutation, or chromosomal changes.
Main Methods:
- Conducted 67 in vitro and in vivo tests to assess DNA damage, gene mutation, and chromosomal aberrations.
- Utilized bacterial repair tests, sister chromatid exchange assays, and micronucleus tests in mouse bone marrow.
Main Results:
- Triazine and urea herbicides showed minimal genotoxic activity.
- Molinate and vernolate (thiocarbamates) induced chromosomal changes, including sister chromatid exchanges and aberrations.
- Other herbicides like ethofumesate, alachlor, dichlorprop, and fluorodifen showed limited positive results in specific tests.
Conclusions:
- Some thiocarbamate herbicides exhibit clastogenic potential, indicating a capacity to cause chromosomal damage.
- Further animal carcinogenicity studies are warranted for molinate and vernolate due to observed genotoxic effects.