Spatial changes in water quality of urban lakes in Chennai (India)--a case study.

Manifold increase in population of Chennai city (India) has resulted in a rapid decrease in the groundwater level due to its over exploitation. The Government of Tamil Nadu has been exploring various ways and means to combat this problem. The present study was undertaken to assess the quality of water in three important major lakes of Chennai and its suburbs such as Porur lake, Puzhal lake and Chembarambakkam lake which recharge the groundwater as well as these lakes are harnessed by the Tamil Nadu Government to supply potable water to the residents of Chennai. The parameters studied were colour, odour, taste, turbidity, temperature, pH, Dissolved Oxygen, Biological Oxygen Demand, Chemical Oxygen Demand, alkalinity, acidity, chlorides, Total Suspended Solids, Total Dissolved Solids and total hardness. Results indicate that the quality of water from these lakes is within the acceptable values. However, the TDS values were on the higher side in all the three lakes even though within the permissible limit prescribed by BIS. All the three lakes appear to be vulnerable to pollution as they are situated within or in close proximity to heavily populated areas.