Test conducted to verify what killed fishes in the Dungsamchhu last year

Environment: A water sample test, the National Environment Commission (NEC) conducted on the water discharged from the sewerage treatment plant in Samdrupjongkhar, ruled out any kind of chemical or toxic contents in the water.

The sample was sent to confirm what caused fishes in the Dungsamchhu, near the treatment plant, to die in November last year. The treated water runs from the treatment plant to Dungsamchhu where scores of fishes were found dead.

The final effluent test results show that most of the parameters were within the maximum permissible limit as per the Environment Standards 2010 (NECS).

The result, which was released about a week ago declares the treated water as clean.

Although, this would mean the treated water was not responsible for the death of the fishes, there was no mention of what killed the fishes.

The sample was earlier sent to Guwahati in India, which also ruled out any content of toxicity and chemical, but NEC again tested the water sample in December 2015 to meet Bhutan’s environment standard.

Three samples, IN-LET (raw sewerage), Effluent (after treated) water and Dungsamchhu water were sent for the test. The effluent test of pH balance, bio-chemical oxygen (BOD) and chemical oxygen demand (COD) were found under the desirable limit.

A thromde official said although the river from Dungsamchhu is the main source for drinking water that is supplied to the Samdrupjongkhar town, the thromde supplies only after the water is treated.

“There is no other water source or spring, which is why we have to depend on tributaries of Dungsamchhu for drinking. But we treat and disinfect the water before it is supplied.”

The official said that the fishes could have died because many people across the border come to the river to wash dishes and clothes.

Yangchen C Rinzin,  Samdrupjongkhar