SESSION-7: Monitoring and Modelling
PAPER-4: Monitoring of the Noyyal River for Genotoxicity
Using the Alkaline Comet Assay on Fish and Earthworm Tissues
Rajaguru P., Suba S., Elayaraja T., Palanive M., and Kalaiselvi K.

Abstract:

The Noyyal river, a tributary of the Cauvery, originates in the Western Ghats in the Coimbatore district, Tamilnadu and passes through two industrial cities, Coimbatore and Tirupur before it mixes with the Cauvery river. The river is severely polluted by the industrial effluents and sewage released from Coimbatore and Tirupur. Since industrial wastewater and sewage are reported to contain genotoxic substances, in this study genotoxicity of water and sediments collected from Noyyal river was determined in fish ( Cyrpinus carpio ) and earthworm ( Eisenia foetida ) using the alkaline single cell gel electrophoresis assay (Comet assay). Upon electrophoresis extensive DNA damage, measured as the DNA length:width ratio of the DNA mass was observed in erythrocytes, liver and kidney cells of fish exposed to polluted water samples, and the amount of damage increased with the duration of exposure. Similarly the mean DNA length to width ratio was significantly higher in the coelomycetes of earthworms placed in sediment samples. The results of this study indicate that the Noyyal river system is contaminated with substances that are genotoxic to fish and earthworms, and that the comet assay has sufficient sensitivity to detect the genotoxicity of environmental samples.