Chromosome aberration test for the insecticide, dichlorvos, on fish chromosomes

Chromosome aberration test was applied for an organophosphorus insecticide, dichlorvos, using fish as model. Channa punctatus, an ophiocephalid, having a small number (2n = 32) and a rather large size of chromosomes, was used for the purpose. Dichlorvos, with O,O-dimethyl-2,2-dichlorovinyl phosphate as the active component, was dissolved in the aquarium water at concentration level equal to that found in drainage from agricultural fields (0.01 ppm). The chromosomal preparations were made from the kidney cells of the fish after 24, 48, 72 and 96 h intervals. Controls were kept in ordinary water. The aberrations observed were chromatid gaps, sub-chromatid gaps, centromeric gaps, precocious separation of chromatids and polyploidy. These were found to be significantly higher as compared to that of the controls. This test proved its efficacy in the fish model without the administration of the chemical by injection.