If Paris’s Seine can, why can’t our Hooghly: PCB and ISI plan study
Times of India | 21 October 2024
Kolkata: The West Bengal Pollution Control Board, in collaboration with the Indian Statistical Institute (ISI), will assess the water quality of the Hooghly river to determine if it meets the required standards for bathing. This initiative parallels the Seine river in Paris, where, ahead of the Olympics 2024, mayor Anne Hidalgo swam a stretch of the river to demonstrate its safety.
Athletes were allowed a plunge after a 100-year ban. The assessment aims to ensure that the Hooghly reaches a similar level of water quality, making it safe for public use.
The first-its-kind initiative will involve year-long water quality monitoring, health impact on people, socio-cultural significance associated with mass bathing vis-a-vis water quality and generate awareness among the bathers and people living within a kilometre from four popular ghats in Bengal, two in Kolkata, one at Howrah, and one at Hooghly — Babughat, Dakshineswar, Ramkrishnapur and Triveni.
“The Seine river event was a major eye-opener for everyone. Since thousands of people bathe in the Hooghly, it is important to carry out a public health assessment of its water. Right after the Puja, work will start and continue till the end of next year’s festivity, covering all major bathing events. We are also trying to create an early alert system to make people aware of the water quality at a particular time with advisories,” said WBPCB chairman Kalyan Rudra.
“People use Gangajal for puja, without understanding that the same water is being treated and supplied to each household as drinking water. Without hurting anybody’s belief, it is our duty to highlight the fact and science,” said an officer.
Three important criteria determined the bathing standard of a water body — dissolved oxygen (DO), biochemical oxygen demand (BoD) load, and coliform bacteria count. Total coliforms organism’s “most probable number (MPN)” per 100 ml shall be 500 or less, dissolved oxygen 5mg/l or more, biochemical oxygen demand (BOD) 5 days at 20°C — 3 mg/l or less. The data of 15 WBPCB water quality monitoring stations revealed a wide seasonal and tidal variability of water quality.
BOD is defined as the amount of dissolved oxygen needed by an aerobic biological organism in a water body to break down the organic material present in a water sample, at a specific temperature and specific period. Higher BOD indicates more oxygen is required, which is less for oxygen-demanding species to feed on, and signifies lower water quality. The presence of fecal coliform, on the other hand, in aquatic environments may indicate that the water is contaminated with the fecal material of humans or other animals. Fecal coliform bacteria can enter rivers through the direct discharge of waste from mammals and birds, from agricultural and storm runoff, and from human sewage.
While we managed to attain the DO and BOD standard, the total coliform count remained high. Because of the robustness of the river, the count changes rapidly with time. It is always a challenge to clean up the river at the fag end of the course. The river gets critically polluted as it flows through congested industrial zones in Uttar Pradesh, Bihar before entering Bengal. In Bengal also, industrial discharge in the Hooghly is 1360 MLD (million litre a day).