High concentration of heavy metals like cadmium and nickel has been found in groundwater in around 45 locations in Chennai, according to a study. The study on groundwater contamination was conducted in pre and post monsoon periods in 2022. The study found that in groundwater samples collected from 45 locations in Greater Chennai city, presence of cadmium and nickel was 15 and 7 times higher than what is prescribed by the World Health Organisation (WHO).

The study found that the presence of lead was high in 25 locations while that of nickel in higher volume was present in 13 locations. Cadmium and chromium were also present above the normal values in the ground water samples collected from some areas of the city.

The report found that at Nagalkeni, the concentration of cadmium was 15 times higher than what was prescribed. In Villivakkam and Vasantham Colony in Chennai, the amount of nickel was seven times higher than the prescribed value. Pammal was the most vulnerable in terms of groundwater contamination with heavy metals present much above the prescribed standards in all the areas in the zone.

Another important factor that the study revealed was that lackluster Metrowater supply had led to increased household expenditure for water. People have to spend money to buy water purifiers due to contaminated groundwater while the poor supply of Metrowater leads to buying bottled and canned water from informal sources. The study also brought to light the fact that a poor man spends one out of every 10 rupees he earns on drinking water. This drops to 50 paise and 25 paise among the lower middle-income groups.