Tamil Nadu - Chennai

“Groundwater around Perungudi turning worse”

CHENNAI: Groundwater within a 5-km area around the Perungudi solid waste dumping yard is contaminated beyond acceptable limits, a research done by IIT-Madras shows.

Detailed samples of solid waste, soil below the dumping site, the leachate trickling from the waste and well water show presence of heavy metals that can cause serious health problems. “If the unmindful dumping of solid waste continues, by 2015 most of the water sources in areas such as Velachery, Perungudi, Taramani, Thoraipakkam and Madipakkam will be beyond redemption. But for the Buckingham Canal this contamination would have spread further to areas such Besant Nagar, Neelangarai and Pallavakam,” says S.Mohan, Professor, Environmental and Water Resources Engineering, IIT Madras.

Analysis of water samples taken from 17 dug wells and 3 borewells shows that the lead in all locations ranges from 0.121 milligram per litre (mg/l) to 0.23mg/l. The maximum permissible limit is 0.05 mg/l. Similarly copper and nitrate concentrations are also above the permissible level of 0.05mg/l and 45 mg/l respectively. In all wells, the total dissolved solids concentration exceeds the limit laid down for drinking water (500 mg/l).

The 36 samples of solid waste, taken at different depths, are no better. They reveal the presence of 408 milligram per kg (mg/kg) of lead as against the permissible limit of 100 mg/kg. Similarly 335 mg/kg chromium is present whereas the permissible level is only 41 mg/kg.

This research was done by R. Gandimathi and guided by Prof. Mohan between 2005 and 2007 and is a part of the environment technology group, one of the 14 inter-disciplinary groups of IIT Madras. The research recommends that simple methods such a 2-cm lining of fly ash with sand spread over the other can prevent as much as 20 per cent of contamination from reaching the groundwater. “It [methods] is not so expensive”, says Prof. Mohan.

“New samples are to be taken shortly and this time around the results will be only worse. The method of dumping waste has not changed and it is still carried out without effective liner at the bottom.

The open site dumping must be stopped and proper sanitary landfill must be adopted. Attempts to bio-remedy the Perungudi site are going to be difficult. If proper methods are followed, there is some hope of containing the spread in another 20 years,” he explains.

“The worst affected will be the poor because they live on this contaminated water and heavy metal concentration may even lead to issues like blue baby syndrome and lead poisoning. This must be attended urgently”, he cautions.

When contacted, Chennai Corporation Commissioner Rajesh Lakhoni said that a consultant had already been appointed to advise the Corporation on bio-remediation of the Perungudi dump site and sanitary landfill measures along with treatment of solid waste will be undertaken.

About 3,200 tonnes of waste a day is generated in Chennai city.

Half of this is dumped at Kodungaiyur and the remaining at Perungudi. The Perungudi site covers a surface area of 400 acres and has been in operation since 1985.

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