DECEPTIVE CLEANLINESS: Left with no alternative, women in Devarjeevanahalli are forced to use contaminated water from a borewell. — Photo: K. Murali Kumar

BANGALORE: When eight-year-old Selvi's finger nails turned blue, a doctor's diagnosis revealed that she suffered from methemoglobinemia, a condition he associated with nitrate poisoning.

Having ruled out other sources of poisoning, the doctor recommended that her family get the borewell water at Hosakerehalli tested.

The test revealed high levels of nitrate contamination in the water.

Nitrate levels in Banashankari are as high as 300 mg/l (the permissible limit is 45 mg/l) in some places because of sewage contamination of groundwater.

Timely treatment meant that Selvi was saved. But nitrate poisoning, which depletes the oxygen-carrying capacity of haemoglobin, can be fatal.

The most vulnerable to nitrate poisoning are infants aged below 6 months, in whom it can cause the "blue baby syndrome" when their skin, lips or nail beds turn blue because of the poor blood oxygenation.

Lack of testing facilities

At St. Johns National Academy of Health Sciences, one of the very few facilities in the city for a methemoglobin test, 31 such cases were reported in 2006-07.

Of these, only two have been confirmed as caused by consumption of organic nitrate, not connected with water contamination.

The rest, says T. Venkatesh, professor at the Department of Biochemistry and Biophysics, could have come from anywhere, including from consumption of contaminated water.

Awareness

Emphasising on the need for a re-look at environmental health, Dr Venkatesh says, "Civic authorities need to inform the public, including medical practitioners, about possible geographical clusters that might pose hazards to health — whether chemical or biological".

Health risks

Nitrate poisoning is only one among the many health risks associated with contamination of water by sewage.

At Shampura, for instance, not only are the nitrate levels nearly 20 times the permissible limit, the Ambedkar Medical College receives 500 cases of typhoid every year from the surrounding slums.

Dr. Ravi Naik of the medical college attributes this to high level of bacteriological contamination in groundwater, though he says he did not realise how serious the level of contamination was.

The coliform count, according the reports of Department of Mines and Geology, is 900 mpn per 100 ml (the permissible is zero), and nitrate levels a critical 747 mg/l in the groundwater at Shampura.

"The BMP's Health Department and Karnataka State Pollution Control Board must take seriously the water contamination," says Thelma Narayan of the Community Health Cell.

Lack of awareness

"It is the Government's social responsibility to give this information to the appropriate authorities, doctors and citizens so they can take action", she says.

Without a holistic understanding of a disease, doctors may treat the patients symptomatically and "send them back into an environment from where they contracted the problem," says Dr. Venkatesh.

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