The Hindu : Tamil Nadu News : Groundwater polluted in Pondy after tsunami: study

Online edition of India's National Newspaper
Wednesday, Feb 09, 2005

Tamil Nadu

Tamil Nadu

Groundwater polluted in Pondy after tsunami: study

By Rajesh Nair

PONDICHERRY, FEB .8. Seawater intrusion following the tsunami strike has increased the percentage of dissolved solid contents in groundwater at some places in the Union Territory.

A study conducted by the State Groundwater Unit and Soil Conservation Department in Pondicherry and Karaikal found that the Total Dissolved Solids (TDS) went up to 1000 parts per million (ppm) and in certain areas it crossed1000 ppm.

TDS is a measurement of minerals or salts in water. Bicarbonate, chloride, sulphate, calcium, magnesium and sodium are the major components normally found in water. High levels of some of these elements are a potential concern.

"Normally, the TDS level in water in the coastal areas of Pondicherry up to a depth of 20-30 feet will be 120-250 ppm. A spot analysis of samples collected from filter points in and around Kalapet, where the inundation was up to a distance of 0.5-1 km, showed that the TDS level was 860-1000 ppm," V. Radhakrishnan, hydrogeologist-11, State Groundwater Unit and Soil Conservation, told The Hindu.

More serious in Karaikal

The situation is more alarming in Karaikal, where even in normal times groundwater is saline. After the tsunami, the TDS level crossed 1000 ppm in some of the areas, Mr. Radhakrishnan said.

Besides disturbing the groundwater level, the tsunami has increased salinity in the Ariankuppam estuary, Pondicherry, and in the Nandalar, Arasalar, and Thirumalairajanar in Karaikal.

Water samples have been sent to the National Environmental Engineering Research Institute, Chennai. Organisations such as the U.S. Environmental Protection Agency say the contamination level can go up to only 500 ppm (one litre) of TDS. Mr. Radhakrishnan said rain could bring down the TDS level.

There was some good news as well. The groundwater level, which has been on the decline from the late 1980s northwest of Pondicherry, has shown signs of improvement after the monsoon.

At places like Kattarikuppam, the groundwater level went down to 55 metres because of the presence of sugar industries and also of limestone, which reduced percolation.

During the recent monsoon the groundwater level rose up to 20 metres at Kattarikuppam, Mr. Radhakrishnan said.

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