Biological monitoring of the Ganga has shown that two major tributaries, Pandu and Varuna, are increasing pollution load of the river as they are “severely polluted” before their confluence point, a Central Pollution Control Board (CPCB) report has said.
In Uttarakhand, the outlet from a sewage treatment plant in Jagjeetpur is also “adding a lot of pollutants” as observed by the change in biological water quality from Category B (outdoor bathing) to Category C (drinking water source after conventional treatment) downstream of the plant, the report says.
The draft report from June 2018 by the Bio-Science Division of the CPCB also concludes that physico-chemical and bacterial parameters such as Biochemical Oxygen Demand, Chemical Oxygen Demand and Dissolved Oxygen, total coliform and faecal coliform provide “only the momentary account of water quality i.e. water quality that prevails at that particular time of monitoring”. It says that “Biological monitoring, on the other hand, has much longer dimension since the aquatic biota can be affected by chemical and/or hydrological events that may have lasted only a few days, months or even years before monitoring was carried out.”
The report was released by the CPCB on Thursday along with 12 other reports following the Supreme Court direction asking the apex pollution monitoring body to release all its studies regarding impact of environmental pollution on health and economy. Ten of the reports are on the river Ganga and three on the air quality in Delhi NCR.
“On mainstream of river Ganga, although none of the locations were found to be severely polluted, most are in moderate pollution range. Therefore, efforts must be made to control the pollution so that all locations may comply with at least ‘B’ class water quality,” the report states.
Report a warning ahead of Kumbh Mela
The CPCB report on biological monitoring of river Ganga is essential ahead of the Kumbh Mela, which begins next month. More than 12 crore people are expected to attend the event, hosted on the floodplains in Prayagraj. The report makes an important distinction between physico-chemical/ bacterial parameters and biological parameters. The latter is important to see the effects of pollutants on biota in the water body. The findings serve as a warning to clean up an important river, so that efforts may be made to make water fit for bathing at least.
The report summarises water quality of the river during four rounds of biological testing in the Uttarakhand stretch, and reveals that at the Haridwar barrage biological water quality improves from slight pollution to clean. “However, downstream of Jagjeetpur STP outfall is one of the most impactful location on entire stretch where a gradual deterioration of water quality was observed from clean to heavy pollution in consecutive four years,” it states.
In Uttar Pradesh stretch, biological water quality is “consistently moderately polluted in all the rounds during the period from 2014 to 2018 except river Ganga of mainstream in Kannauj after confluence with 2 tributaries of river Ramganga and Garra where river water is in heavy pollution range in post-monsoon season during 2017-18.
“Tributaries such as Ramganga, Pandu, Varuna etc. were found to be more impactful locations with respect to biological water quality before confluence with the mainstream of river Ganga. (2017-18),” the report states.
Further downstream in Bihar, Gandhi Ghat in Patna city was in heavy pollution range during 2015-16 while all other locations in all rounds of bio-monitoring were consistently found moderately polluted. In West Bengal, “downstream of Srirampore was found in slight pollution range during 2017-18 (pre-monsoon) while all other locations in all rounds of bio-monitoring were consistently found in moderate pollution range.”
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