Yamuna Water Quality Dips As Levels of Faecal Bacteria Spike 4,000 Times Above Safe Limit: Report
New Delhi: The water quality of the Yamuna dipped in July when compared to the previous month, with levels of faecal coliform – a kind of bacteria caused primarily by untreated sewage – rose to 4,000 times the safe limit, according to a report by The Indian Express.
Per the report, based on a new status report released by the Delhi Pollution Control Committee (DPCC), levels of dissolved oxygen and biochemical oxygen demand – two other important parameters of water quality - were also well above the prescribed safe limits.
Shocking faecal coliform levels
The DPCC submits monthly reports on water quality at eight locations in the Delhi stretch of the Yamuna (the river flows in the union territory for 22 kms) on directives laid down by the National Green Tribunal.
Figures in the July report show that the faecal coliform level in the Yamuna flowing through Delhi has spiked drastically, per The Indian Express.
The safe limit of faecal coliform bacteria set by the Central Pollution Control Board (CPCB) is 2,500 MPN (Most Probable Number)/100ml.
At Palla – where the Yamuna enters Delhi – the faecal coliform levels were 2,700 MPN/100 ml in July (up from 2,100 in June), and 3,900 MPN/100 ml in Wazirabad (up from 2,600).
At ITO Bridge, it was a staggering 92,00,000 MPN/100 ml – over 4,000 times the permissible limit.
Downstream, the levels were more than 1,000 times the maximum permissible limit, per the report. Faecal coliform levels were at 28,00,000 at ISBT Bridge; 11,00,000 at Nizamuddin Bridge, 22,00,000 at Okhla Barrage, 21,00,000 at the Agra Canal near Okhla, and 7,90,000 at Asgarpur.
Per the report, ITO recorded the highest pollution levels in terms of faecal coliform this year.
High dissolved and biochemical oxygen levels too
Biochemical oxygen demand or BOD is the amount of oxygen required to break down organic material in the water. Per the report, the BOD at Palla - where the river enters Delhi and then goes on to flow for 22 km in the union territory - is 8 mg/l, far higher than the safe limit of 3 mg/l or less set by the Central Pollution Control Board.
At ITO Bridge, this rose to 70 mg/l in July.
In June, BOD levels at the same sites were significantly lower. Per the report, it was 5 mg/l at Palla, 8 mg/l at Wazirabad, 31 mg/l at ISBT, 46 mg/l at ITO Bridge, 40 mg/l at Nizamuddin, 30 mg/l at Okhla Barrage, 38 mg/l at Agra Canal, and 44 mg/l at Asgarpur.
Meanwhile, levels of Dissolved Oxygen or DO – which is the amount of oxygen in the water that is available for aquatic life to survive - dropped in Delhi’s Yamuna too.
At Wazirabad, DO levels plummeted from 6.3 mg/l in June to just 3.4 mg/l in July, below the minimum safe threshold. Further downstream, oxygen levels fall to zero, and only slightly recover to 0.9 mg/l at Asgarpur. Per the report, the “near-total depletion of oxygen renders large stretches of the Yamuna uninhabitable for aquatic organisms”.
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