Role of Electrical Conductivity as an Indicator of Pollution in Shallow Lakes

Abstract

A major portion of water based recreational activity of human race centres around the thousands of lakes, reservoirs and other small, relatively quiescent bodies of water, which has drawn the attention of the researchers to a great extent during the recent times. Water quality is closely linked to many physical and chemical aspects of lake. Control on various physical, thermophysical and chemical properties of lake water has to be maintained so that their values remain within permissible limits. Electrical Conductivity (EC) is such a thermophysical property of lake water, which has strong interrelationship with pollution level. Experiments carried out at Subhas Sarovar (lake) and Rabindra Sarovar (lake), Kolkata, indicates that EC has a linear relationship with Total Dissolved Solids (TDS), which is validated by the findings at various other lakes throughout the world. Since EC increases with temperature, the values are corrected to a standard value of 25°C and then are technically referred to as specific electrical conductivity. It is also observed that EC increases with increase in TDS, which in turn indicates increased concentration of sulphates and other ions. Therefore, measured value of EC indirectly indicates the level of pollution in lake waters and further studies on the sources of pollutants and possible remedies can then be made. Moreover, measurement of EC is much easier than direct measurement of TDS, thus showing an easier path for pollution monitoring in shallow lake waters.