New Delhi. STUDENTS OF 170 Delhi Government and MCD-run schools may already have or are at risk of contracting fluorosis from drinking water Tests showed the water at these schools contained too much fluoride, a chemical which attacks the nervous system and weakens bones and teeth.

The schools provide ground water for drinking even though authorities are aware the quality of ground water in the city is very poor.

Of the over 3,000 water samples taken from schools and houses and tested for fluoride in the first phase of a school-based survey (part of the Fluorisis Mitigation Programme of the Delhi Government), 550 contained more than the permissible limit of 1.5 ppm (parts per million).

Danger signs

• Longterm intake of excess fluo ride may lead to severe, permanent bone and joint deformation
• Symptoms are discoloured teeth, pain and stiffness of joints, headache, stomach ache
• In advanced stage movement severely restricted

Some of the samples tested even had over 4 p.m.

Some areas where ground water was found to have excess fluoride are Kanjhawala, Qutabgarh and Najafgarh in west and southwest Delhi. Parts of east Delhi too have contaminated ground water. In fact, a very high percentage of students at the Government Boy's Senior Secondary School at New Kondli in east Delhi were found to he drinking water with too much fluoride.

In the second phase of the survey, another 4,000 samples, including those taken from 130odd schools, are being analysed "We suspect the figures of fluorosis victims will go up," says chief medical officer in charge of the survey Dr P Raju.

The water samples were collected after teachers at the schools were asked to identify students over 8 with discoloured teeth. "After (such) students were tracked down, our teams collected water from the schools and from their homes," Dr Rajll adds.

Delhi Jal Board CEO. P.K. Tripathi clears the board of any responsibility for quality of ground water. "We can only advise people to test the water before drinking," he says.