In the four decades she has spent in the Department of Mines and Geology, chief chemist M.V. Shashirekha has seen Bangalore's groundwater go from potable to a toxic cocktail of heavy metals and bacterial pollution.

There is however one upward trend Dr. Shashirekha is pleased about: the growing queue of citizens who come to her to test the water they consume.

“Every day I have at least 10 to 15 people come to the department to get their water analysed. This is more than I have ever seen in 40 years,” says Dr. Shashirekha. “But we need these numbers to increase. Every resident who relies on groundwater for drinking or cooking should test their water every year. We can no longer assume it is safe.”

Unfit for consumption

Indeed, last week, a comprehensive study by the department showed that 50 per cent of the city's groundwater is not fit for consumption.

While industrial areas such as Peenya showed alarming quantities of heavy metals, including carcinogenic chromium, borewells elsewhere in the city yielded water contaminated with sewage and chemicals such as nitrate and fluoride.

In the public sector, the Department of Mines and Geology and the Public Health Institute test water on various parameters for a fee, and private agencies now also offer similar services too.

Metals and chemicals

“There is still a lack of awareness about the hazards of water pollution. The public often falsely believe that a water purifier is the answer to all forms of water pollution,” Dr. Shashirekha says. She explains that conventional water purifiers only remove bacteria, not heavy metals and chemicals. Boiling does the same, but is not always innocuous as it increases the concentration of chemicals such as nitrate in water.

So would she recommend the more rigorous reverse osmosis (RO) filter? “RO does remove some forms of heavy metals and other chemicals such as nitrate. But it turns the water too soft, which is unhealthy for the heart, and strips it of all essential minerals.” RO also wastes water, she adds.