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Chandigarh Drains: Oxygen Dead Zones Persist
3 Oct
Summary
- Patiala-Ki-Rao drain had zero dissolved oxygen for three months.
- Ammoniacal nitrogen in Sukhna Choe rose sharply, indicating sewage.
- Attawa Choe shows better water quality but needs sustained monitoring.
The waters of Patiala-Ki-Rao in Chandigarh were found to be completely devoid of dissolved oxygen for three consecutive months: April, May, and June. This alarming situation, a clear indicator of severe organic pollution, was reported by the city's pollution watchdog.
While biochemical oxygen demand (BOD) and suspended solids improved, Patiala-Ki-Rao carried a heavy pollution load, with BOD nearly six times the permissible limit. Chemical oxygen demand (COD) and ammoniacal nitrogen also remained high. The Chandigarh Pollution Control Committee (CPCC) attributed the pollution primarily to the drain entering from Punjab.
Sukhna Choe also presented a serious concern, with ammoniacal nitrogen, commonly linked to sewage, rising significantly from 6.5 mg/l in April to 17 mg/l in June. This suggests an increasing sewage-derived load, particularly during monsoon periods.
In contrast, Attawa Choe maintained relatively better water quality. Its pH remained stable, and although dissolved oxygen saw a slight decline, BOD showed a dramatic fall in May before a marginal rise in June. However, the improvement needs sustained monitoring.
