Genotoxic effects of monocrotophos, an organophosphorous pesticide, on an estuarine bivalve, Meretrix ovum.

Genotoxicity studies evaluate the effects of pollutants on organisms and consequently, their implications on human health. Meretrix ovum was exposed to different concentrations of monocrotophos, viz. 5.5, 11.0 and 16.5mg/L continuously for four different time periods viz. 2, 3, 7 and 14 days. Gills of these animals were collected immediately after exposure at the above time intervals and analyzed for genotoxic effect employing micronucleus test and effect on somatic growth by estimating the total RNA/DNA ratio. Data were analyzed employing Student's 't' test and ANOVA. Significant increase of micronuclei observed in the present study in a dose dependant manner indicates the possible chromosomal damage induced by monocrotophos in this species and thereby reveals its genotoxic potency. Significant reduction of the total RNA/DNA ratio observed in a time dependant manner indicates a considerable retardation of somatic growth in monocrotophos treated mussels. Results of the present study indicate that monocrotophos is genotoxic on M. ovum and also induces a pollution stress related retardation of somatic growth of this mussel. Further, this study indicated the possibility of using MN test in bivalves as a marker for screening/monitoring the genotoxic potential of pollutants in aquatic ecosystems.