Massive fish kill in Periyar river attributed to industrial pollution

Sub: Environment

Sec: Pollution

Context:

The Periyar River witnessed a severe fish mortality event in May, due to which fishers and cage fish farmers incurred heavy financial losses.

Details:

Upon inspection, they found that fish showed signs of distress and later died due to polluted water from nearby factories entering the river when the regulator shutters were opened.
The pungent odour from dead fish made living conditions difficult, and no proper action or compensation was provided.
The Periyar River serves 5 million residents of central Kerala for various needs.
The fish kill significantly affected residents of industrial areas, including Edayar, Eloor, and others.
Causes of mass fish mortality:
- The fish mortality was caused by the opening of the gates at the Pathalam regulator bridge upstream, leading to the release of polluted water.
- The discharged water contained toxic substances which reduced oxygen levels in the water, leading to a significant number of fish dying downstream.
- The pollution led to the production of harmful gases and elevated levels of hydrogen sulphide, ammonia, and heavy metals.

Government Response:

The Kerala government directed the Department of Irrigation to develop a protocol for lifting the regulator-bridge shutters at Pathalam.
A coordination committee was formed, and a total compensation of Rs. 13.55 crores was announced for the affected fish workers, though it has not yet been received.

Periyar river:

Source: Chokkampatti Mala, Periyar Tiger Reserve, Kerala.
Mouth: Arabian Sea, Vembanad Lake, Kerala.
It is the longest river and the river with the largest discharge potential in the Indian state of Kerala.
It is one of the few perennial rivers in the region and provides drinking water for several major towns.
Idukki dam is on Periyar river.
Tributaries:
- Left- Cheruthoni
Right- Mullayar, Perinjankutti, Muthirapuzha, Edamala