Hyderabad: If the latest assessment report of the Central Ground Water Board (CGWB) is to be believed, there is no district in Telangana state or Andhra Pradesh where groundwater is safe for drinking.
However, heavy metal contamination has been found in the groundwater of only Ranga Reddy and Nalgonda districts in both the states. Groundwater in almost all the districts is contaminated with nitrates or fluoride.
The concentrations were found to be above the permissible limits prescribed by the Bureau of Indian Standards.
In the country, as a whole, 276 districts have high flouride contamination and 387 districts have high nitrates contamination.
According to the norms prescribed by the BIS, flouride content should be below 1.5 mg per litre and nitrates content should be 45 mg per litre.
According to the CGWB assessment report, all districts in TS, barring Nizamabad, have flouride contamination in groundwater. In AP, barring Srikakulam and East Godavari, groundwater in all districts has flouride above the BIS limits.
“Flouride contamination generally occurs naturally. This current situation could be because the groundwater levels are going down and as a result concentration of flouride is increasing,” said Dr Syeda Azeem Unnisa, assistant professor, Department of Environmental Engineering, Osmania University.
Even the contamination of nitrates is highly prevalent in the two states. All the 23 districts in TS and AP have groundwater nitrates contamination. Experts say that nitrates contamination is mainly due to the seepage of sewerage water into the groundwater.
However, the CGWB report said that groundwater in Ranga Reddy is also contaminated by toxic heavy metals like lead, cadmium and chromium. Lead has also been found in Nalgonda.
Dr Syeda Azeem Unnisa said this means that industries are not discharging effluents after treating them. “We don’t know what is happening inside industries. There could be boreholes drilled and they are probably filling effluents into these boreholes,” she said. These two are among the 115 districts in the country where heavy metal contamination is beyond BIS limits.
