GUWAHATI: Laboratory tests results of samples of the dark water of Siang river in Arunachal Pradesh carrying slag from Tibet have confirmed the high turbidity that has made the principle constituent of Brahmaputra river and the lifeline of the people unfit for human consumption and has turned it into a river of death for aquatic life.
Deputy commissioner of East Siang district Tamyo Tatak told TOI that the river continues to flow with the same dark colour for nearly two months now and chief minister Pema Khandu will be flying to Pasighat (district hq) on Saturday to see unusual Siang river for himself.
The report of the state public health engineering (PHE) department, which had taken samples of the river water on November 27 to the laboratory, shows that Nephelometric Turbidity Unit (NTU), the measure of turbidity of water caused by concentration of suspended or dissolved particulate materials in water that scatter light making the water appear cloudy or murky, especially clay and silt, is 425 NTU, which is more than 400 times higher than the permissible limit of 5 NTU for drinking water.
According to a report of study of environmental impact by the state pollution control board, Siang river's turbidity measure should have been between 12 and 15 NTU at this time of the year. Even in monsoon season (September) Siang's turbidity is between 295 and 329 NTU only but that too clears after a short time.
The PHE lab test report states, "Such a high level of turbidity more than 425 NTU exposed for a long period may affect fish survivability leading to choking of gills leading to death of fishes. The majority of studies including suspended sediments (turbidity) effects on fish have formed an exposure and mortality rates of affected eggs and larvae has resulted in dwindling of fish population." The deputy commissioner confirmed that large number of fishes have died in the last one month.
The Siang, which flows as Yarlung Tsangpo from southern Tibet in China into Arunachal Pradesh through its northern limit, becomes the Brahmaputra after joining with Lohit river and several other tributaries just outside the boundary with Assam to become the mighty Brahmaputra river.
The lab result also shows a higher degree of iron content in the Siang water, 10 PPM (particles/million) against the permissible limit of just 0.1 to 2 pm.
Deputy commissioner of East Siang district Tamyo Tatak told TOI that the river continues to flow with the same dark colour for nearly two months now and chief minister Pema Khandu will be flying to Pasighat (district hq) on Saturday to see unusual Siang river for himself.
The report of the state public health engineering (PHE) department, which had taken samples of the river water on November 27 to the laboratory, shows that Nephelometric Turbidity Unit (NTU), the measure of turbidity of water caused by concentration of suspended or dissolved particulate materials in water that scatter light making the water appear cloudy or murky, especially clay and silt, is 425 NTU, which is more than 400 times higher than the permissible limit of 5 NTU for drinking water.
According to a report of study of environmental impact by the state pollution control board, Siang river's turbidity measure should have been between 12 and 15 NTU at this time of the year. Even in monsoon season (September) Siang's turbidity is between 295 and 329 NTU only but that too clears after a short time.
The PHE lab test report states, "Such a high level of turbidity more than 425 NTU exposed for a long period may affect fish survivability leading to choking of gills leading to death of fishes. The majority of studies including suspended sediments (turbidity) effects on fish have formed an exposure and mortality rates of affected eggs and larvae has resulted in dwindling of fish population." The deputy commissioner confirmed that large number of fishes have died in the last one month.
The Siang, which flows as Yarlung Tsangpo from southern Tibet in China into Arunachal Pradesh through its northern limit, becomes the Brahmaputra after joining with Lohit river and several other tributaries just outside the boundary with Assam to become the mighty Brahmaputra river.
The lab result also shows a higher degree of iron content in the Siang water, 10 PPM (particles/million) against the permissible limit of just 0.1 to 2 pm.
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