A large number of fish were reported dead due to water pollution of three major rivers -- Kolong, Kopili and Kiling -- in Morigaon district, causing concern among environmentalists.
According to information received by the Revenue Department, arsenic poisoning from the ground water was suspected to have mixed with the rivers in spate resulting in the death of various types of fish during the last three days.
Satating thousands of dead fish were seen floating on the rivers, Revenue Department sources feared other aquatic beings might also have been affected.
Arsenic pollution was also reported in neighbouring district of Karbi Anglong and parts of Nagaon's western and southern parts, besides along the inter-state Meghalaya border causing outbreak of viral diseases affecting the throat.
The Revenue Department has informed the Geological Survey of India about the situation and asked them to study the soil and the exact cause for the pollution.
Environmentalists were also concerned about the loss of fish in the three rivers.