Aberrations in the Chromosomes of Cirrhinus mrigala (Hamilton) upon Exposure to Butachlor

Background: Cirrhinus mrigala, one of the important fish widely consumed in India,was used for karyological observations and to evaluate the toxic effect of butachlor, anextensively used herbicide in rice fields in terms of chromosomal aberration test.Methods: Fishes were collected from “National Fish Seed Farm” Jyotisar with meanbody weight of 20-50g. The experimental fishes were kept in two treatments each withreplicate of two. There were 15 fish each in the control group (T1) without exposure tobutachlor and in T2 where fishes were exposed to butachlor.Results: Karyotype revealed the 2n=50 chromosome from the somatic cell.Chromosomal aberrations were reported after 24 hrs, 48 hrs, 72 hrs, and 96 hrs fromkidney cell preparation in fishes exposed to 1.0 ppm, sublethal concentration ofbutachlor. Frequencies of chromosomal aberration revealed a significant (P<0.05) timedependentresponse. Stickiness and clumping appeared at 24 and 48 hrs of exposure,end to end joining appeared after 72 hrs and chromosomal fragmentations wereobserved after exposure for 96 hrs.Conclusion: These studies clearly revealed the genotoxic potential of butachlor evenat low dose level (1.0 ppm) and suggest that butachlor interferes with cellular activities infishes at genetic level, inducing chromosomal aberrations. Therefore, the results ofthese investigations suggest a serious concern towards the potential danger of butachlorfor aquatic organisms and the environment suggesting judicious and careful use of thispesticide in agricultural area. These aberrations in chromosome from kidney cellpreparation illustrate the risk that butachlor possesses.