Umwelt- und analytische Toxikologie

Impact of Genotoxic Contaminants on DNA Integrity of Copepod from Freshwater Bodies in Chennai, Tamil Nadu, India

Abstract

Gomathi Jeyam M and Ramanibai R

In the present study, we evaluated the DNA damage of freshwater copepod Mesocyclops aspericornis collected from Chembarambakkam, Velachery and Retteri Lake during Premonsoon(PRM) and Post-monsoon (POM) by alkaline comet assay. The highest DNA integrity was observed at Velachery Lake (21.52 ± 0.31 Mean % Tail DNA) followed by Retteri Lake (13.84 ± 0.019 Mean % Tail DNA) during both season, whereas the lowest DNA integrity occurred at Chembarambakkam (0.16 ± 0.14 Mean % Tail) and identified as the reference site. The single cell gel electrophoresis of M. aspericornis clearly showed relatively higher olive tail moment from the contaminated sites Velachery and Retteri Lake (4.66 ± 0.055; 1.42 ± 0.12). During study period we observed the lowest pH and dissolved oxygen levels in the contaminated sites than the reference site. Moreover high level of genotoxic contaminants especially heavy metals (Zn, Cr, Mn, Pd, Ni, Cu, Co) are widespread in all sites, which could be mainly attributed to the high integrity of DNA in freshwater copepod. The results obtained in this study provide an early warning signal of contamination of the freshwater bodies of Chennai by genotoxic contaminants and explore the importance to conservation of those water bodies.