GUWAHATI, May 13 - Deepor Beel, the lone Ramsar Site wetland of the State, is now breathing normally taking advantage of the gap provided by the monthlong lockdown after decades of atrocious anthropogenic activities virtually forcing it to gasp, said Dr H Bialung, Director (Additional Charge) of the Paschim Boragaon-based Institute of Advanced Studies in Science and Technology (IASST).
Since 2016, the IASST is monitoring the health of this wetland in every season of the year, collecting samples from 25 locations at constant intervals, from the bank to the core, so as to have a measure of the physico-chemical parameters of its water and sediments.
Dr Bailung said, �This time, we observed a remarkable recovery of the wetland�s water quality, after nearly a month of lockdown. We started collecting water samples from designated spots during the first week of May. You cannot expect the opportunity provided by the lockdown so easily nowadays,� he said.
Dr Bailung conceived the idea of this comparative water quality study.
He informed that the most important parameter measured was the Dissolved Oxygen (DO) level and it was found to be in the range of 5.61-6.82 milligram per litre (mg/L). This indicated Deepor�s dramatic regaining of its water quality. A healthy water body should have its DO level above 6.5 mg/L to 8.0 mg/L.
The IASST scientists engaged in this study also found that the present Deepor Beel water-related data have indicated significant improvement in its water quality concerning two more parameters, too.
The Chemical Oxygen Demand (COD) of the wetland was found to be 8-42 mg/L, while its Biochemical Oxygen Demand (BOD) was found to be 1.2-2.2mg/L. Its pH value is also recovering and it is close to the normal range of 7.68-8.63.
The higher its DO, the more different species of plants and water animals a water body can support. During the past four years (2016-19), the wetland�s pre-monsoon (March-April) water quality-related findings were not encouraging. Its average DO range was between 1.55�5.11mg/L, with the minimum value found in the proximity of the industrial effluent inlet and the garbage dumping site.
Bacteria in water bodies consume oxygen if there exists any decaying organic matter. Excess organic material in a water body thus leads to its �death� causing an oxygen-deficient situation.
On the other hand, a BOD level of 1-2 mg/L in water is considered to be very good, suggesting lesser amount of organic waste. BOD level 3-5 mg/L is considered as moderately clean. Concurrently, higher COD in water means a larger amount of oxidizable organic matter, posing a threat to the aquatic life, said Dr Bailung.
IASST research scholar Bhaswati Devi, who collected the water samples aboard a fisherman�s boat, said she had a �terrific feeling� when she touched Deepor Beel�s clean and cold water, while its transparent water was stunning.
Dr Arundhati Devi, Associate Professor, Environment and Eco-System Research Section, who is leading the IASST water and soil quality research, was also exuberant about these positive developments.
