Volume: 3: Issue-1: Jan - Mar-2012 ISSN 0976-4550 Accepted: Dec-2011 Research Article AN ASSESSMENT OF WATER QUALITY OF RIVER CAUVERY AND ITS TRIBUTARIES ARASALAR WITH REFERENCE TO PHYSICO-CHEMICAL PAREMETERS AT TANJORE DT, TAMILNADU, INDIA G. Annalakshmi¹* and. A. Amsath¹ ¹P.G. and Research Department of Zoology Khadir Mohideen College, Adirampattinam- 614 701, Tamil Nadu, India. Email: annalaksmi80@yahoo.com ABSTRACT : Present work deals with an assessment of some physico chemical parameters of the water bodies of two rivers (Cauvery and Arasalar) which is suitable for human consumption have been carried out during the period of one year (January 2010 to December 2010). Analysis of some physico-chemical characteristics like air temperature, water temperature, transparency, electrical conductivity, total solids, total dissolved solids, total suspended solids, pH, free carbon dioxide, dissolved oxygen, BOD and COD has been done during the investigation period. BOD values were not compiling with WHO guide lines in the River Cauvery and total solids and BOD values were not compiling with WHO guide lines in the River Arasalar. Study indicates the rivers were slightly polluted by anthropogenic performance due to local anthropogenic activities, agricultural runoff and discharge of untreated municipal sewage, religious credence and subject to amend owed to seasons, climate and flows and influx of waters from various tributaries. In addition present study points out that the river Arasalar facing severe pollution followed by the river Cauvery. Key Words: Physico-chemical characteristics; River Cauvery; River Arasalar; Seasonal variations. INTRODUCTION Rivers are a vital component of the biosphere. Although they contain less than one percent of the world's freshwater, their ecological and social significance is enormous. They have many values such as economic (fishing, electricity generation, transport and irrigation), aesthetic (recreation), ecological (biodiversity), water for consumption (water supply for domestic and industrial uses) and conveying waste water discharges (treated or untreated). To maintain these values and their sustainable use, given water quality standard must be met. However, they have been utilized for so long that nature has shown signs of ecological imbalance due to widespread pollution, continuous human activities, and natural phenomena. Water quality is at present a global issue, especially when considering its implications to humanity in terms of water borne diseases. The deterioration of water quality has led to the destruction of ecosystem balance, contamination and pollution of ground and surface water resources. Water quality degradation world-wide is due mainly anthropogenic activities which release pollutants into the environment thereby having an adverse effect upon aquatic ecosystems. Water quality can be regard as a net work of variables (pH, oxygen concentration, temperature etc.,) that are linked and co linked; any changes in these physical and chemical variables can affect aquatic biota in a variety of ways. For every use of the river water different set of contaminants or water quality parameters play deterministic role for water quality assessment. For irrigation use dissolved solids (TDS), pH, sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) are the most important. For other uses dissolved oxygen (DO), Biochemical Oxygen Demand (BOD), carbonaceous oxygen demand (COD), inorganic nitrogen (ammonia and nitrite), phosphorus, suspended solids, hazardous substances, organic pollutants (e.g. petroleum and hydrocarbons) and heavy metals (e.g. mercury and cadmium) are also considered. The contamination by hazardous substance can pose risk to human health in particular via the food chain. However, it becomes more and more difficult to meet such water quality standards because of continuous economic expansion, urban development and growing population pressure. One such resource is the Cauvery River, the major river system of south India and Arasalar is tributary to the river Cauvery. International Journal of Applied Biology and Pharmaceutical Technology Page: 269 Available online at www.ijabpt.com