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.
Address:
Department of Environmental Sciences,
PSG College of Arts & Science,
Coimbatore - 641 014. Tamil Nadu, India
E-mail: prajaguru1@rediffmail.com
Phone: 0422 271012.
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