Note4Students
From UPSC perspective, the following things are important :
Prelims level: BOD
Why in the News?
The National Green Tribunal (NGT) has raised concerns over the water quality of the Ganga at Triveni Sangam in Prayagraj, Uttar Pradesh. The river is failing to meet bathing standards due to high Biological Oxygen Demand (BOD) and faecal coliform contamination.
Key Findings of the Ganga Water Quality Assessment at Triveni Sangam:
- Water is unsafe for bathing as per Central Pollution Control Board (CPCB) standards.
- BOD levels exceeded the permissible limit of 3 mg/L on multiple days in January 2025.
- Government releasing 10,000-11,000 cusecs of fresh water to improve quality.
- Faecal coliform levels (E. coli) far exceed safe limits due to sewage contamination.
- Safe limit: 2,500 MPN/100 ml; Detected levels: 49,000 MPN/100 ml (Ganga) and 33,000 MPN/100 ml (Yamuna).
What is Biological Oxygen Demand (BOD)?
- BOD measures the amount of oxygen required by bacteria to break down organic matter in water.
- Higher BOD levels indicate higher organic pollution, which can lead to oxygen depletion and aquatic life destruction.
- Safe limit for bathing water is below 3 mg/L.
- Excessive BOD levels suggest sewage, industrial waste, or decomposing organic matter contamination.
- BOD levels above safe limits can cause waterborne diseases and disrupt aquatic ecosystems.
PYQ:[2017] Biological Oxygen Demand (BOD) is a standard criterion for: (a) Measuring oxygen levels in blood (b) Computing oxygen levels in forest ecosystems (c) Pollution assay in aquatic ecosystems (d) Assessing oxygen levels in high-altitude regions |
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