Fish deaths at Deepor beel: PCBA scientists moot joint investigation, forensic tests to unearth the mystery

For the past several years dead fishes floating on the surface of Deepor Beel, a unique natural wetland on the western boundary of Guwahati, has been a regular phenomenon. However, enviornmental scientists of the Pollution Control Board, Assam (PCBA) are perplexed by the findings of lab analysis of water samples from this only Ramsar site in the state, as the tests have not revealed presence of any chemical pollutant that could have caused death of fishes of the wetland.   

The PCBA has written to the Kamrup (Metropolitan) district administration and the Forest Department underlining the need for a joint investigation to unearth the mystery.

PCBA scientists, while sharing the findings of their tests with this reporter, suggested that the joint study could be carried out with institutions like Gauhati University, Indian Institute of Technology, Guwahati. They have also called for forensic examination of fish samples.   

On November 16, the PCBA collected six water samples from midpoint, eastern side, and confluence of Bashitha Bahini and Mora Bharalu river with the wetland and conducted tests to determine dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD) , Total Dissolved Solids (TDS),Total Suspended Solids (TSS) including Bio-essay test.  The report states that all these important water quality parameters were found to “Below Detectable Level” in the test samples.

 “Our job is to examine if the industrial units have caused any pollution and in this regard we have found no chemical effect that could be instrumental in fish death,” B K Baruah, chief Environmental Scientist, PCBA told nezine.com about the findings of the tests of the water samples.

Baruah underlines the need for collection of water samples at different hours round the year needed and conducting the joint study during pre-monsoon, monsoon and post monsoon period.

Another senior environmental scientist of PCBA, M D Adhikary underlines the need for collection of fish samples for forensic examination. “The forensic tests of the fish samples might reveal something,” says Adhikary.

The Fishery department too carried out on the spot test of water samples using water testing kits. “Presence of carbon dioxide, nitrate and total alkalinity were within normal range,” says fishery Extension officer, Pratul Barman.  

According to Ramsar Sites Information Service, about 50 fish species are found in Deepor Beel, which provide livelihoods for residents of a number of surrounding villages. In November 2002, Deepor Beel was included in the Ramsar list as site number 1207. However, the Assam Forest Department is still clueless about the area covered by this lone wetland of the state with this important global tag. Assam government declared a part of the wetland as Deepor Beel Wild life Sanctuary in 2009. However, the Guwahati Wildlife Division took the possession of wildlife sanctuary only in May 2014.

Kishore Talukdar

(Kishore Talukdar is an independent journalist based in Guwahati. His areas of interest include Development journalism and Environment journalism. He can be contacted at [email protected] )