Genotoxic effect of substituted phenoxyacetic acids

The potential toxic and mutagenic action of 2,4-dichlorophenoxyacetic acid has been studied in different test systems, and the obtained results range from increased. chromosomal damage to no effect at all. We reexamined the e ffect of this herbicide by simultaneous using three tests based on yeast, t ransformed hematopoietic, and mouse bone marrow cells. The results obtained demonstrated that 2,4-dichlorophenoxyacetic acid: has cytotoxic and mutage nic effects. The positive response of yeast and transformed hematopoietic c ells was verified in kinetics and dose-response experiments. The analysis o f metaphase chromosomes indicated a statistically proved induction of break s, deletions, and exchanges after the intraperitoneal administration of 2,4 -dichlorophenoxyacetic acid in mice. The study of phenoxyacetic acid and it s differently chlorinated derivatives showed that cytotoxicity and mutageni city are induced by chlorine atoms at position 2 and/or 4 in the benzene ri ng. The mutagenic effect was abolished by introduction of a third chlorine atom at position 5. Thus 2,4,5-trichlorophenoxyacetic acid was found to hav e very weak, if any mutagenic effect; however, the herbicide preserved its toxic effect.