Subernarekha in Jamshedpur is yet to be its swelling self this monsoon. (Animesh Sengupta)
Polluted Subernarekha is gasping for air, but experts are not pressing the panic button yet hoping that the river, which is the lifeline of Singhbhum, will recuperate once the monsoon current is revived.
A recent study carried out by the Jamshedpur regional office of Jharkhand State Pollution Control Board (JSPCB) and the East Singhbhum district fisheries department revealed a significant drop in dissolved oxygen (DO) levels, which helps aquatic life survive, besides catalysing precipitation and dissolution of inorganic substances.
While the desirable limit of dissolved oxygen is 5mg/litre and the permissible limit 10mg/litre, the figures for places like Chandil, Maubhandar and Jamshola ranged between 2.06mg/litre and 4mg/litre.
District fisheries officer Shatrughan Prasad Singh said they collected samples from the river last week. “The level of dissolved oxygen was found to be less following the advent of a weak monsoon. Pollutants and filth had drained in the river with rain, resulting in this drop in DO level. But, there is nothing to panic. The level will become normal once monsoon is stronger and results in abundant rainfall,” he said.
Regional officer of JSPCB R.N. Choudhary said they were constantly monitoring the DO level. “We will again test water samples in the next few days. This time, various other parameters like pH value, total hardness of water and dissolved solids will be checked,” he added.
Meanwhile, a separate study conducted by the Analytical and Environmental Engineering Laboratory, a wing of NGO Yugantar Bharti too has found rising pollution level in the river between Jamshedpur and Baharagora.
The NGO, which has been spearheading campaigns against river pollution, picked up samples from different places like Muri, Chandil, Domuhani, Lupungdih, Maubhandar, Gopivalabhapur and Jamshola in April-May this year.
Reports show that levels of cadmium and lead, both considered toxic, had exceeded their permissible limits in some places. Also, the level of dissolved oxygen was low.
Environmentalist and adviser to Yugantar Bharti K.K. Sharma said: “The dissolved oxygen level in the river water is low owing to various factors — one of them being discharge of industrial effluents without proper treatment. Domestic and other solid wastes, which get carried into the river with the first spell of monsoon rain, is also behind the plunging DO level.”
He, however, echoed Singh and added that the level would be restored once the monsoon, which is now weak over Jharkhand, made a comeback and resulted in downpour.
Is monsoon alone responsible for dipping DO level?