According to data released by the TSPCB, the water quality at Necklace Road, one of the prime locations around the lake, has witnessed a consistent degradation in crucial parameters throughout 2023
Published Date – 22 February 2024, 11:30 PM
The increasing levels of toxic substances in the lake water paint a grim picture. — Photo: Anand Dharmana
Hyderabad: Hussain Sagar lake in the city is now grappling with a concerning decline in water quality with recent measurements from Telangana State Pollution Control Board (TSPCB), indicating steady degradation of vital parameters that show the quality of water.
According to data released by the TSPCB, the water quality at Necklace Road, one of the prime locations around the lake, has witnessed a consistent degradation in crucial parameters throughout 2023. The levels of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and total coliform bacteria (TCB) have all exceeded permissible limits.
Despite the pH levels of the lake water remaining relatively stable, fluctuating within the range of 6.63 to 7.63, other indicators paint a grim picture. The electrical conductivity (EC) values have consistently shown high levels, suggesting an abundance of dissolved salts and minerals.
Dissolved oxygen (DO) levels, crucial for supporting aquatic life, have remained insufficient throughout the monitoring period, falling below recommended thresholds.
Of particular concern is the alarming rise in total coliform bacteria, including faecal coliform, surpassing safe limits, indicating potential faecal contamination and the presence of harmful pathogens.
In contrast, data from monitoring the lake at midstream, near the Buddha statue, presents a slightly better scenario in some parameters compared to Necklace Road. While pH levels fluctuated between 6.26 and 8.02, indicating some variability in water acidity or alkalinity, EC values suggested varying levels of dissolved salts and minerals.
Though DO levels fluctuated, they generally remained within a range considered adequate for supporting aquatic life, ranging from 3.0 to 4.8 mg/L. However, BOD and COD levels fluctuated, indicating varying degrees of organic and inorganic pollution. Despite some improvements, total coliform and faecal coliform bacteria levels still exceeded safe limits at times.
Commenting on the situation, senior social scientist WG Prasanna Kumar of the Telangana State Pollution Control Board emphasised the impact of freshwater inflows, particularly from rainfall, on the lake’s water quality. He noted the influence of seasonal variations, such as reduced water levels and increased evaporation during summer months, leading to concentration spikes in pollutants.
Kumar highlighted the significant strides made in sewage treatment around Hussain Sagar over the years, with treatment plants playing a pivotal role in improving water quality.
However, he stressed the need to address issues like leakage from sources like Banjara nala to further enhance water quality and ensure sustained improvements in the future.
“The intensity of rains or fresh water significantly impacts the quality of water in Hussain Sagar Lake,” Kumar explained. “Presently, Hussain Sagar is more or less receiving only treated water. However, if leakage from Banjara nala could be stopped, the water in Hussain Sagar would be purely treated water.”
He also mentioned that water quality has improved over a decade, crediting the successive establishment of treatment plants for the improvement.
Reasons for deteriorating water quality
• Steady decline of water quality at Hussain Sagar
• Biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids levels beyond permissible limits
• Coliform bacteria and faecal matter levels exceeded safety limits
• Dissolved oxygen levels crucial to support aquatic life remained insufficient
• Leakage from Banjara nala to Hussain Sagar continues
• Inflow of freshwater through rains is crucial for water quality at Hussain Sagar
