Time scale changes in the water quality of the Ganga River, India and estimation of suitability for exotic and hardy fishes
The water quality of rivers is an issue of serious concern today. Rivers are heavily impacted due to their use for carrying off the industrial, municipal, agricultural and domestic effluents. Water samples were collected for the present study from the Ganga River at Kanpur, Allahabad and Varanasi sites, during the period 2011-2012. The minimum temperature (17°C) was recorded in winter season. The pH, TDS, EC, sulphate, phosphate, nitrate, BOD and COD values exhibited their minimum at Allahabad site. The chloride and dissolved oxygen were recorded minimum at Kanpur site while alkalinity and total hardness had their lowest values at Varanasi site. The water quality of the Kanpur site was very poor compared to Varanasi and Allahabad sites. However, the Ganga river waters could host some tolerant fish species such as the exotic Cyprinus carpio and Oreochromis niloticus and also catfishes. All these species are very hardy, in respect of poor water quality, thus they (exotic species) have powerfully invaded in degraded systems worldwide.