Potential Impacts of Leachate Generation from Urban Dumps on the Water Quality of Pallikaranai Marsh- the only Surviving Freshwater Wetland of Chennai City in India

Wetlands near urban centres are under great environmental pressure due to residential, industrial and commercial developments. In south of Chennai, we have the Perungudi dumpsite in the Pallikaranai Marsh which is a low lying area and closes to the sea level. It is poorly drained and consists of an extensive area of marshy land permanently wet and seasonally inundated. This dumpsite does not have proper lining to prevent leachate migration into underlying and surrounding groundwater environment. There is no importance given for measurement of potential impacts of leachate generation from dumpsite on groundwater quality. Hence, the present works is taken to study the impact on groundwater quality around the Perungudi dumpsite. The study determines the major physico-chemical quality of groundwater and besides it compares COD for the pre-monsoon and post monsoon periods in the water samples in six observation wells in the same location both in dug wells and tube wells. The pH indicates alkaline nature in all the water samples and the EC content in post monsoon period reduces due to the rains which dilutes the water. In the present study, the total dissolved solids in all the water samples were high and exceeded the desired limit of the CPHEEO, 1999. In the case of Hardness, the values are higher during the premonsoon period and exceed the maximum permissible limit. COD in the water samples are higher in pre monsoon and lower in the post monsoon period. Pallikaranai is the only surviving wetland ecosystem of the Chennai city which is a curious watch for environmentalists and stakeholders. This study emphasizes the need to protect the dwindling common property resource.