A New Threat Turns Real

Bangalore relies up to 60 p.c. on groundwater. Seepage of polluted water alarms.
Groundwater sample from BTL Engineering College, Bommasandra, was sent for testing to the Chemical Laboratory, Department of Mines and Geology, last week. They found it contained 316 mg/per litre of nitrate as against the permissible limit of 45 mg/per litre.
A couple of days before, groundwater sample from Reva College of Engineering, Yelahanka, was sent for testing. It had 2.5 mg/per litre of fluoride as against the permissible limit of 1.5 mg/per litre.
In June 2006, a similar test was conducted on groundwater at K R Market. It contained 154 mg/per litre of nitrate.
Other random tests in the recent past have revealed that groundwater is highly contaminated in several areas in the City. In Thippasandra, nitrate content was as high as 415 mg/per litre, in Byatarayanapura, it was found to contain 278 mg of nitrate per litre and in areas after Hebbal it was 331 mg/ per litre.
Groundwater sample in Dinnur was found to contain 2.38 mg/per litre of fluoride.
Nitrate causes cancer and fluoride. It is a known agent of fluorosis, which largely affects the bones. According to an unpublished report, based on a survey conducted in June 2006, by the Department of Mines and Geology, 74 per cent of groundwater in Bangalore City has bacteriological contamination.
“This could be due to the sewage or manure, used in public and private gardens, seeping into the groundwater,” said Ms Shashirekha, Chief Chemist, Department of Mines and Geology.
“Around 35 per cent of groundwater contains nitrate and 15 per cent has iron content,” she said. An increased intake of iron can cause cenothrix—a stomach-related disorder.
The only areas where groundwater is potable are Sadashivanagar, Mekhri Circle, R T Nagar and Rajajinagar, she said.
Reasons
The main reasons for nitrate contamination in groundwater are untreated sewage, open pits, agricultural runoff and industrial pollution. “We have received complaints from people falling sick after consuming contaminated water. In Frazer Town, an entire family fell sick and doctors were unable to diagnose the disease. They later asked them to get the groundwater tested. They brought a sample to us and we found it contained nitrate which was more than 200mg/per litre,” Ms Shashirekha said.
Awareness programmes
“In Hebbal, there are cases of abortion because of high contamination of groundwater. Even in areas surrounding Lalbagh, water is contaminated. Most of the contamination is largely because untreated sewage has seeped into the groundwater,” she added.
When contacted, Mr Muniyappa, Managing Director, Bangalore Water Supply and Sewerage Board (BWSSB), said though 65 per cent of sewage is being treated, the contamination could be because some of it may have seeped into the borewells.
“This is more acute in areas, which are close to the four valleys—Vrishabhavathi, Chalaghatta, Belandur and Koramangala.
“We are aware of the problem and are carrying a public health awareness campaign to educate the people,” he said.
Sewage leakage?
Chief Engineer (Quality Assurance) Vasudevan said, sewage may have leaked because of low capacity storm water drains. “But now the drains have been desilted and Bruhat Bangalore Mahanagara Palike (BBMP) is arresting the flow of sewage into water canals by constructing concrete walls of four and a half feet,” he added.
—Bala Chauhan