Geo-Chemical Evaluation of Heavy Metals in The Lakes of South Chennai, Tamil Nadu, India

The salient geochemical features of heavy metals in the lakewater and the seasonal variations were determined. Forty water samples were collected in the South Chennai lakes of TamilNadu, South India and the concentration of heavy metals were determined to characterize and evaluate the hydrogeochemical nature and water quality. Results of total dissolved solids(TDS)show that all the lake water samples in the study area during both monsoon periods are found to be higher than the desirable limit of 500mg/L. Among the heavy metals, Copper (Cu) concentration in the water reveals that about 60% of the samples exceed the desirable limit of 0.05mg/L but no sample exceeds the maximum permissible limit of 1.5mg/L. The concentration of Iron (Fe) in these water is found to be high which could be attributed to the leaching of waste dumps adjacent to the lakes as well as inside the lakes and further leaching from the soil/rock due to rock-water interaction also increases the iron content in these water. Spatial distribution of Cr illustrates that the eastern and northeastern part of the study area are found to have the highest concentration of chromium. Results of Lead concentration in the lakes of the region illustrates that all the values during both the monsoon periods found to exceed the permissible limit which could be attributed to the higher content of e-waste including Lead (Pb)based batteries in the solid wastes, dumped inside the lake area which has been continuously leached into the lake water by way slow dissolution. Correlation analysis show highly significant correlation between manganese (Mn)and zinc (Zn) and also Mn have good correlation with cobalt (Co) indicating the industrial activity of the region increases the concentration of the metals in this water.