STUDY ON EFFECT OF POLLUTION ON GENOTOXIC DAMAGE IN CIRRHINUS MRIGALA ANA CATLA CATLA FROM RIVER CHENAB  

Shahid Mahboob1, Bilal Hussain2, Tayyaba Sultana2, Salma Sultana2 and K. A. Al-Ghanim1
1. Department of Zoology, College of Science P.O. Box 2455, Riyadh 11451, Saudi Arabia
2. Department of Zoology, GC University, Faisalabad, Pakistan
Email:shahidmahboob60@hotmail.com

 

 

Industrial development, expansion of urban populations and increased coverage of industrial, domestic water supply and sewerage give rise to larger quantities of municipal wastewater. Disposal of toxic sewage wastes with large volume of water could reduce biological oxygen demand to the lethal level by removing entire oxygen from the water body. Some very toxic chemicals are released into the lakes, streams and rivers e.g., compounds of mercury, Zinc, Lead and Copper etc. causing death of aquatic populations even at very low concentrations. This can cause metabolic activation giving rise to toxic metabolites in the nervous tissues. Comet and Micronucleus assays have been used to assess DNA damage in Catla catla and Cirrhinus mrigala collected from polluted areas. Heavy metals Cd, Cu, Mn. Zn, Pb, Cr, Sn and Hg were detected by atomic absorption spectrophotometry in River Chenab water. All physicochemical parameters and heavy metals were found beyond the tolerable limits. Comet assay showed significant (p<0.05) DNA damage in Catla catla as 17.33±2.42, 11.53±2.14 and 14.17% DNA in tail. Tail moment was 10.06±2.71, 3.11±0.74 and 14.70±1.89, Olive moment was 8.85±1.84, 3.83±0.76 and 7.11±0.73, respectively. Highly significant (p<0.01) damage was reported in Cirrhinus mrigala as 37.29±2.51%, 34.96±2.53% and 38.80±2.42% DNA in comet tail, tail moment was 23.48±3.90, 19.78±4.26 and 14.30±1.82, olive moment as 16.22±2.04, 13.83±1.96 10.99±0.90 from three different sites of the polluted area of the River Chenab. Significant (p<0.05) differences were reported polluted and farmed fish but non-significant (p>0.05) differences in farmed and non-polluted upstream. Micronucleus assay showed similar findings for single and double micronucleus induction as 23.20±4.19, 2.80±1.07 in Catla catla and 44.80±3.73, 06.20±0.97/thousand cells, respectively in Cirrhinus mrigala. Nuclear abnormalities were found as 6.00±0.84 and 09.60±1.72/thousand cells, respectively in both species. These findings infer that these novel fish DNA damage assays to detect genotoxicity, could be used as expedient toxicity screening of aquatic environments