At least two rivers in eastern Meghalaya have turned blue again apparently due to "high acid content", resulting in death of scores of fishes.
The Lukha river in East Jaintia Hills district and certain sections of the the Myntdu river in West Jaintia Hills district have changed their colour to a bright sky blue indicating a very high acid content.
"We have observed that the Lukha has slowly changed its colour in the past few days after the monsoon rainfall subsided. The colouration has worsened and the whole river has turned into bright sky blue," Sonapyrdi headman J S Lamare told PTI.
Although the colouration was first detected way back in 2007, no one has been able to find out the reason for the colouration, leaving scientists and environmentalists baffled.
The Meghalaya State Pollution Control Board (MSPCB) in its 2012 report blamed acid effluents from coal mines as the major probable causes of water pollution in the area.
The Delhi-based Central Laboratory of Central Pollution Control Board had earlier ruled out the possibility of the water sustaining any life form due to its high acid content besides declaring it unfit for human consumption.
MSPCB member secretary J H Nengnong said the Lukha river had been included in the National Water Monitoring Program, and water samples had been collected periodically to conduct various tests.
While blaming the water run-off from the coal mines, the official, however, said that even the CPCB was still struggling to find out why the river turned blue.
Local environmentalist H H Mohrmen has demanded a thorough and independent test to find out the causes.
"In most parts of the rivers, we could find fine dust-like particles at the bottom. The fly ash released from cement factories located a few km from the water bodies could also be the reason," he said.
In the past years, scores of dead fishes were seen in the rivers and this year too, fishes were found floating in the blue rivers.
The Lukha river, originating from Narpuh Wildlife Sanctuary areas, has been seen changing its colour on meeting with the Lunar river at Khatdung. The latter originates from Myndihati and Lumshnong areas known for heavy extraction of coal and limestones respectively.
Local anglers have found that another river Myntdu has also started to change its colour over the years.
The Meghalaya Electricity Corporation Ltd (MeECL), which has a run-of-the-river power project at Leshka confluence, has also reported that high acidic content of the water in the river are constantly corroding their machinery.
