New Delhi: The water quality of the Yamuna has gone down significantly and its faecal coliform levels went up last month, a report of Delhi Pollution Control Board has revealed.
Faecal Coliforms (FC) are a group of bacteria present in human faeces. If the FC levels in a water sample are higher than the prescribed norms, it is indicative of the fact that the untreated sewage comprising human fecal waste is being discharged into the water body – making it unhealthy for consumption.
According to India’s water pollution standards, the FC levels in a water body should ideally be not more than 500 million units per litre. The maximum permissible limit is 2,500 units per 100 millilitres.
Quoting a Delhi Pollution Control Board, Times of India reported that the FC level at Asgarpur was 160 lakh units per 100 ml in February – 6,400 times higher than the maximum permissible limit. Also, the concentration found in February was about three times higher than January.
Similarly the FC levels at the ITO bridge and ISBT bridge were 43 lakh units per 100 ml and 4 lakh units per 100 ml, respectively.
Sewage treatment plants (STPs) are installed at the entire stretch of any river to ensure that untreated sewage does not enter it. A higher FC level, therefore, reveals that there are not adequate numbers of STPs along the stretch of the river or that the existing ones are not functioning optimally.
Another indicator of a river’s water quality is its ‘biological oxygen demand (BOD) levels’. The aquatic life thriving in a river needs ‘dissolved oxygen’ in order to decompose or break down organic matter (or pollutantants) in it, so that it can thrive. The larger the concentration of pollutants, the higher the demand of biological oxygen. A higher level of BOD indicates, therefore, a larger concentration of the organic pollutants in the water.
According to India’s pollution standards, the BOD should be less than 3 milligrams per litre of water. Except for Palla, the BOD levels did not meet pollution norms at any other point – Wazirabad, ISBT Bridge, ITO Bridge, Nizamuddin Bridge, Agra Canal at Okhla Barrage, Okhla Barrage or Asgarpur. At Asgarpur the BOD level was 72 milligram per litre, Hindustan Times reported. The river exits the city at Asgarpur.
The poor water quality of the Ganga at Prayagraj during the recently concluded Mahakumbh recently became a controversial issue. The Central Pollution Control Board in a report, which was published in February when the Muhakumbh was going on, said the water in the Ganga was not fit for bathing due to high FC levels. It led to a hue and cry, following which the CPCB did a U-turn and said the ‘statistical analysis’ of the previously collected data revealed that the water was fit for taking a dip.
