Hyderabad: Analysis of groundwater in the city by the National Institute of Nutrition has found that areas including Uppal, Alwal, Medchal and Miyapur had fluoride more than the permissible limits of 1 microgram/litre.

“Of the 27 water samples, all had fluoride content more than the permissible limits. Using groundwater for cooking and drinking regularly would result in various symptoms of fluorosis,” said Dr Arjun L. Khandare, Scientist E (deputy director), Food and Drug Toxicology Research Centre, NIN. Even analysis by the Central Groundwater Board has revealed similar facts.

“Out of the total number of samples (171) analysed in the pre-monsoon period, 40 samples (23 per cent) showed high fluoride values beyond permissible limits.

The concentration of fluoride is relatively high in deeper groundwater ranging from 0.50-2.57 mg/l. At certain places, the concentration of fluoride is beyond permissible limits.” Damodhar Rao, regional director, Central Ground Water Board, said.

High fluoride was observed in samples collected from urban areas like Shivam, Amberpet, Nampalli, Raj Bhavan, Balanagar, Nallakunta etc., at suburban areas like Nacharam, Mallapur, Malkaram, Ahmedguda, Kondapur, Bandlaguda and Jeedimetla etc and in periurban parts of the study area in Gopanapalli, Brahmanapalli, Raipol, KR Peta, Maheswaram, Raidurg and Shapurnagar, New Boiguda, BJR Nagar, Borabanda areas. etc.

However, the experts said that the fluoride content in the groundwater might not necessarily be continuous in the same locality or area.

Mr Rao said, “The fluoride content in water is mainly in the form of dissolved minerals and it occurs mainly due to drilling of rocks in the ground. Hence, the fluoride content may vary from one borewell to other borewell.

NIN scientist Dr Arjun L. Khandare said, “Since most of the individual houses in the area have borewells and use the water for potable purpose when metropolitan water is not supplied, the groundwater should be used only after analysis.”

“There were also water samples supplied by the city metropolitan water board, however, the fluoride content was within the permissible standard 1 milligram/ liter, which is safe,” he added.

Medical experts say that symptoms of fluorosis take longer to appear in a person as it gets deposited in the bone and other body parts, said H. Kishan, a senior doctor, at Apollo hospital.

Another medical expert, Dr Srinvivas Rao, said, “Fluoride in minimal level helps in building bones. In excess levels it causes deformation of bone, crooked teeth, straining and affects overall lifestyle. Hence, whoever is using groundwater should used filters and home-based purifiers.”

“People come to know about it only after 10-15 years when the bones start showing deformity. It increases the thickness of the bone, causes stiffness of the spine. However, in growing children below 15 years the deformity is seen early.”

Since in urban areas the population is not largely dependent on groundwater, consumption of water with excess fluoride would only emerge at a much later stage.