EFFECTS OF 30 DAY SUB-LETHAL EXPOSURE OF CADMIUM AND LEAD MIXTURE ON DNA DAMAGE IN FISH.

The present study was undertaken to examine the DNA damage induced by binary metal mixture (cadmium-lead) in peripheral blood erythrocytes of freshwater carp, Cyprinus carpio by using Comet bioassay. The 96-hr LC50 value of mixture was estimated for 180-old fingerlings of Cyprinus carpio in a static system and then four sub-lethal concentrations viz. SL-I (10.42mgL-1), SL-II (7.81mgL-1), SL-III (6.25mgL-1) and SL-IV (5.21mgL-1) were calculated and fish were exposed to these concentrations, separately in glass aquaria for 30 days along with negative and positive control at constant water temperature (30°C), pH (7.75) and total hardness (225mgL-1). Peripheral erythrocytes were sampled after 30 day exposure for DNA damage assessment. Statistically significant effects were observed at sub-lethal concentrations in-terms of percentage of DNA damage, cumulative tail lengths (μm) and genetic damage index. Concentration dependent response was observed in fish erythrocytes with induction of maximum DNA damage, due to positive control, followed by at highest concentration (SL-I) of mixture. This study also concluded that comet bioassay can be used for in-vivo experiments, using fish as a model for the screening of genotoxic and mutagenic pollutants in aquatic environment. [ABSTRACT FROM AUTHOR]