DIMAPUR, Dec 4 � The National Water Quality Monitoring Programme (NWQMP) under the Central Ministry of Environment and Forest has listed Dhansiri river, running along the stretch of Dimapur, under the category of �Polluted Rivers� in the country.
Indicating that the water quality of Dhansiri river is degrading further beyond human consumption or even bathing, the NWQMP report states that the organic pollution measured in terms of bio-chemical oxygen demand (BOD) indicated an average of 3-6 mg per litre, varying on different points or sources.
Revealing this at the awareness programme organised by the Dhansiri River Flood Control Board (DRFCB) under the theme, �Save our Dhansiri river� at Naharbari village, Assistant Environmental Engineer, NPCB, Aghali Swu said the permissible or desirable limit of BOD is only 2 mg per litre.
She informed that the listing of Dhansiri under the polluted river category by the NWQMP was affirmed through analysis carried out by the NPCB which is closely monitoring the water quality of the river, adding that the categorisation is specific to Dimapur area only and does not include parts that flow along Golaghat district of Assam.
However, the contamination report of Dhansiri is not anything new. As reported earlier, toxic waste, domestic and municipal waste and untreated sewage dumped randomly into the river all add up to the infectivity. Earlier this year, the Nagaland Pollution Control Board (NPCB) had revealed that the BOD at Dhansiri was 2.7 mg per litre.
Unlike other states where industrial waste is the main source of river pollution, Swu pointed out that there are no major industries in Dimapur that can cause such serious contamination, which means the pollution can be attributed to domestic waste and municipal solid waste which is being dumped into the river without much ado by the citizens as well as the civic body.
Biological Oxygen Demand (BOD) is one of the most common measures of pollutant organic material in water. BOD indicates the amount of putrescible organic matter present in water. Therefore, a low BOD is an indicator of good quality water, while a high BOD indicates polluted water.
Divisional Forest Officer of Dimapur, Kocha Meyase, dwelling on the environmental impact of Dhansiri river, which leads to frequent and unpredictable flooding, stressed on the need to plant more deep rooted trees and vegetation along the river sides to bring back balance to the eco-system.
While unmonitored extraction of sand and gravel from the riverbed is one major concern that disturbs the river eco system, Meyase maintained that the main reason might lie in the deforestation of the catchment areas where the absence of vegetation has made it unable to hold the rain water.
It should be mentioned that indiscriminate extraction of resources like sand and gravel from the riverbed is most disastrous as this activity threatens the very existence of the river eco-system.
Dhansiri originates from Laisang Peak of Nagaland and flows 352 kms from South to North before joining the Brahmaputra.
