IMPACT OF SEWAGE DISCHARGE ON WATER QUALITY AND BENTHIC DIVERSITY OF KOTA BARRAGE, KOTA, RAJASTHAN, INDIA

摘要

The water of Kota Barrage is mainly used for domestic uses and bathing, besides irrigation and aquaculture. Seasonal variations in benthic fauna and selected physico-chemical parameters of Kota Barrage Dam have been studied on the basis of the samples collected during monthly surveys for a period of one year (November, 2004 to October, 2005) which revealed interesting interrelationship among various factors. This Dam is affected by pollution (industrial specially Thermal Power Plant effluents and domestic) as indicated by low dissolved oxygen. Based on the depth of visibility values Kota Barrage Dam could be categorized as “Moderately eutrophic” whereas nitrate nitrogen values of Kota Barrage dam indicated “Mesotrophic” status. On the other hand hardness values of this Dam were “Moderately hard”. The species diversity was found to influence due to water pollution in Kota Barrage. Despite this the biodiversity of macroinvertebrates was appreciably high with recorded 27 species. Most dominant benthic species encountered were Melanoides tuberculata, Bellamya bengalensis, Gyraulus convexiusculus, Indoplanorbis exustus and Lymnaea acuminata. The seasonal abundance of benthos in Kota Barrage During investigation period varied between 869 to 1100 No./m2. Lymnaea acuminata and Chironomus larvae may be used as pollution indicators in Kota Barrage. Richness of organic matter in this water body might have favoured the species composition and abundance of benthic fauna. Discharge of large quantities of waste causes thermal pollution and it affects the ecology of the ecosystem of Kota Barrage Dam.