The groundwater level in the southern part of Hyderabad is much higher, according to the Telangana Groundwater Department officials. But it carries a caveat. The water has higher nitrate content than the surrounding areas of the city. A higher nitrate content is usually a result of improper disposal of animal and human waste.
A 2013 study found that the nitrate (NO3) content is more than permissible limits of BIS drinking water standards in 72% of samples at Moosapet, Alwal, Qutub Shahi tombs, Tarnaka, Amberpet, Moosarambagh, Lalapet, Nallakunta, Secunderabad, Kavadiguda, Ranigunj, Gosha Mahal, Golconda fort, Langar house, Tolichowki, Sanath Nagar, Tadbund and Chandrayangutta.
The key indicator of untreated sewage is coliform count. At Nagole Bridge, the bacteria count indicated by coliform has gone up from 97 MPN/100 ml (most probable number/100 millilitres) in 2014 to 906 in 2015 and to 1,215 in 2016, dropping to 514 in 2017 before reaching 1,214 in 2018.
The stress on water quality can be seen over the past five years from the data analysed by Telangana State Pollution Control Board. The other indicator of health of river water is biochemical oxygen demand (BOD). Rivers are expected to have a BOD below 1 mg/L. Moderately polluted rivers have a BOD value in the range of 2 to 8 mg/l. Rivers get classified as severely polluted when BOD values exceed 8 mg/L. The BOD of the Musi River ranged between 2 at Osmansagar and in double digits at Bapughat, Moosarambagh and Nagole bridge and beyond.
Another indicator of the health of a river is the presence of dissolved oxygen. Decaying organic matter uses up the dissolved oxygen. The rotting organic matter gives off a foul stench that pervades through the city where the Musi flows. In the river, all three sample testing stations in the city recorded less than 4 mg/l of dissolved oxygen. This puts the river water in the ‘C’ category as per Central Pollution Control Board standards. When dissolved oxygen dips below 4 mg/l, it can no longer support aquatic life.
