Odisha Sun Times Bureau
Bhubaneswar, Sep 15:
With contaminated sewage and effluents from Odisha capital draining into rivers Daya and Gangua, experts apprehend fishes and other aquatic creatures will vanish from these rivers in a few years.
Environmentalists have expressed deep concern over high pollution levels in these two rivers flowing through the capital city.
The Odisha State Pollution Control Board (OSPCB) last year submitted a monitoring report on pollution levels in some major rivers of the state in which it has been indicated that Biological Oxygen Demand (BOD) rate has gone abnormally high in rivers Daya and Gangua flowing through the capital city.
With reduction of oxygen level in water, BOD requirement for aquatic creatures increases. Water samples drawn from river Daya in three phases in 2014 in the three principal seasons indicated of abnormal reduction in oxygen levels in the river.
Test reports of water samples drawn from river Daya have indicated of 3mg of dissolved oxygen (DO) per litre while BOD rate remained 12mg per litre. Besides, the PH value of water samples collected from river Daya were found to be between 7.2 and 7.4. Under the prevailing conditions existence of aquatic life in river Daya is endangered.
“Higher BOD rate and traces of dissolved oxygen (DO) water of river Gangua like in that of river Daya is a big danger to aquatic life,” informed Dr Subhendu Adhikari, senior scientist Central Institute of Fresh Water Aquaculture (CIFA), Kaushalayaganga.
The capital city has more than 100 factories, two large industrial areas and 34 water polluting factories. Rivers Gangua, Daya and Kuakhai have been badly polluted with effluent discharge from these industrial areas and sewage flowing into them.
Every day 261 tonnes of waste water is generated from areas under Bhubaneswar Municipal Corporation (BMC). This waste water is discharged into rivers Gangua and Kuakhai through ten main drains of the BMC, Daya West canal and Puri canal. While nine out of these drains discharge waste water into river Daya after directly falling into river Gangua, waste water from Patia drain no.1 flows directly into river Kuakhai.
Results of tests and surveys of water samples obtained from these drains done earlier have clearly indicated presence of heavy metals like arsenic, nickel, lead, cadmium, chromium, iron, zinc, mercury and manganese; synthetic detergent, soap, nitrogen, ammonia, sulphide, methane, phosphorus, potassium and organic waste containing several harmful bacteria and micro organisms. As a consequence of which oxygen level is falling day by day and BOD rate is increasing in the water of rivers Daya and Gangua.
A few days back, dead fish in large numbers were seen floating in the waters of rivers Daya and Gangua which had led to scare among residents of suburban areas around the capital city.
“With reduced oxygen level in water, fish die after having problems with respiration,” said Dr Adhikari.
“Why only fish, it will not be possible for other aquatic life to survive in higher BOD rate and less dissolved oxygen,” he added.
“Research shows, increasing presence of organic waste leading to rapid fall in oxygen level in waters of river Daya and Gangua has affected olfactory, sight and reproductive capacities of fishes. Primarily, losing these three capacities fish gradually get weaker and finally die,” said Adhikari.
While admitting the fact that untreated wastes are being discharged to the rivers, BMC mayor Ananta Narayan Jena said, a high power waste water treatment plant will be set up in the near future.