Kerala

Summer may trigger fish kills, colour change in Periyar

Allowing water to flow is expected go a long way in reducing fish kills due to low oxygen levels and turbidity.

Allowing water to flow is expected go a long way in reducing fish kills due to low oxygen levels and turbidity.   | Photo Credit: Sudhakara Jain

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Crucial suggestions of Cusat report, including those on cleaning up silt and sludge in the waterbody, yet to be implemented, says scientist

Over the past month, the Eloor-Edayar stretch of the Periyar river has not only changed colours, but also witnessed fish kills. This is likely to happen more regularly as the summer progresses and water flow decreases, says scientist Bijoy Nandan, professor at the Cochin University of Science and Technology (Cusat).

The scientist, who was commissioned by the Kerala State Pollution Control Board (KSPCB) to study fish kill in this stretch of the Periyar, says their report – submitted nearly four years ago and which found low dissolved oxygen levels in the water as well as high concentrations of heavy metals in some areas – had made numerous recommendations to revive the river over the long term and improve water quality. However, many crucial suggestions have not been implemented, he adds.

Call for action

The report had required that the KSPCB and other governmental agencies take “immediate action” to desilt and desludge waste and other matter that had settled on the river bed, both upstream and downstream of the Pathalam regulator-cum-bridge. Other recommendations included establishing a common treatment facility for all industrial effluents (into which wastes from houses, slaughter houses and other small scale industries can also be released) after which the treated water could be used for irrigation purposes, and regular, detailed studies to understand water quality related concerns better.

Restricted access

Apart from these, numerous other steps can be taken now, says Dr. Nandan. Since it is a thickly populated area, assigning even a thin buffer zone on both sides of the river with restricted access will help prevent the dumping of waste. Bringing good hydrologists to study the river’s flow and patterns will be crucial too, he says.

Allowing water to flow will reduce the fish kills due to low oxygen levels and turbidity, and as water levels dip in the summer, it will be a good time to clean up the silt and sludge in the river, he adds.

However, these actions cannot be taken by the KSPCB alone, says its Chairman Sajeevan K. Several government departments have mandates over the stretch (for instance, only the Irrigation Department can take up cleaning activities and the Industries Department will have to initiate the setting up of the effluent treatment facility), and unless the State and Central agencies give directions, nothing can be done, he adds.

“We had already forwarded the report to the respective authorities at that time,” he said. “However, we will send the report once again urging urgent action to the State’s Environment Department.”

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Printable version | Dec 14, 2019 8:57:15 PM | https://www.thehindu.com/news/national/kerala/summer-may-trigger-fish-kills-colour-change-in-periyar/article26156835.ece

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