Hyderabad: Rapid depletion of ground water levels in Hyderabad, resulting in borewells being dug deeper and deeper, is posing a fluoride risk. Chaemicl analysis conducted by the state groundwater department has shown that the fluoride content in water is above the permissible limits.
Areas that do not fall under the city water board’s network and depend on groundwater are at high risk as even a 0.1 per cent higher than normal reading is not safe over a long period, state experts.
Areas in the city that have the highest fluoride content in groundwater are Qutubullapur (2.08 mg/l), Dulapally (2.08 mg/l) and Nizampet (1. 58 mg/l) in Hyderabad district. While in Ranga Reddy, Balanagar tops the list followed by Shamshabad and Shamirpet; these areas have tested high in fluoride prior to the monsoons.
K. Dhanunjaya, deputy director of the groundwater board, said, “The deeper the borewells are dug, the higher the fluoride content. The layers underground comprise fluoride as a mineral. Once these rocks are drilled, the fluoride mixes into the groundwater. Hyderabad is a hard rock area, below the surface, there are multiple rock layers formed through pressure and water is available between these layers. The surface water is safe for consumption. However, as one digs deeper, one hits the rock, which comprise several minerals including fluoride. Thus fluoride is found as dissolved minerals in water. “As per the Ground Water Act, more than 400 metre deep borewells for irrigation are not allowed. However there is no limit for drinking or agriculture borewells. In certain areas drilling goes beyond 1,500 feet, especially in the elevated areas in the city,” added Mr K. Dhanunjaya .
Greater Hyderabad is not entirely covered by the city water board network. Also, areas that receive irregular and less supply rely on groundwater or mineral plants that draw ground water and filter it (however not as per the standards).
“Canned” water is purchased by household for events etc., which is nothing but filtered ground water.
Anuradha Kapoor, a resident of Quthbullapur said, “The tap water supply is very irregular (once in five days) and with low pressure, we depend mostly on the mineral water cans. But we don’t know the source. There is no check on the mineral plants regarding the filtration.” “Also, contamination or dissolved solids cannot be identified. If water analysis is done in each area, the quality of water will be known.”