HYDERABAD: Another round of water quality testing by the Pollution Control Board (PCB) at Sunnam Cheruvu has revealed persistent and alarming results. The reports, accessed by TNIE, span four months from January to April and consistently indicate dangerously low dissolved oxygen (DO) levels of 0.3 mg/l—far below the ideal range of 6.5-8 mg/l.
Experts say this level is incompatible with aquatic life. “This is a grave situation. The water is categorised as ‘E’, unfit even for bathing or irrigation,” said Prasanna Kumar, senior social scientist, PCB. “The National Green Tribunal (NG T) has directed that the lake must be improved to at least a ‘D’ grade. Drawing water from here is strictly inadvisable.”
Asked about remediation, the official explained that the inflow of pollutants must be stopped and treated, clean water introduced, and the lake water treated, though the last is nearly impossible under current conditions.
The Biochemical Oxygen Demand (BOD)—which indicates the amount of organic matter in the water—increased from 6 mg/l in January to 10 mg/l in April. This suggests rising pollution from untreated sewage or organic waste.
Similarly, the Chemical Oxygen Demand (COD), which indicates both organic and chemical contamination, rose from 76 mg/l in January to 119 mg/l in April, pointing to chemical pollutants entering the lake.
Other indicators, such as conductivity (1,670 to 1,751 mS/cm) and phosphate levels (0.55 to 0.62 mg/l), suggest continued nutrient inflow, which may trigger algae growth and reduce oxygen further.
Heavy metals were also detected: cadmium (0.020 mg/l), copper (0.030 mg/l), lead (0.037 mg/l), nickel (0.100 mg/l), zinc (0.149 mg/l) and iron (0.527 mg/l). While pH values stayed within normal limits, the overall data reflect a water body under severe ecological stress.
“The lake is suffering from limited ecological flow, local runoff and waste discharge,” the official added. Environmentalists note that Sunnam Cheruvu, once home to local biodiversity and seasonal recharge, is now reduced to a stagnant, dysfunctional ecosystem.
Locals dismiss water contamination claims
Despite the data, many residents claim the findings are exaggerated. “We’ve been using this water for years and are fine. How can it be contaminated now?” said Narayana, a local. Others suspect a political motive.
“They demolished our legal building recently. Since then, HYDRAA has been using this water issue to silence us,” said another. Residents allege that the contamination narrative is timed to deflect community protests.