GUWAHATI, Jan 21 - While the city�s historic Dighalipukhuri finds itself at the centre of a raging controversy over the construction of war memorial on its northern bank, which many believe will damage its heritage and ecology, no one seems bothered about the growing pollution-induced degradation of the water-body.
The apathy of the government authorities to the tank�s well-being should be evident from the fact that even a Gauhati High Court order for demolition of a restaurant of the Tourism Department inside the Dighalipukhuri campus was not honoured.
Periodic water quality monitoring by the Pollution Control Board, Assam (PCBA), has shown the tank water�s biological oxygen demand (BOD) to be in excess of the prescribed norm. BOD, a key parameter for assessing surface water quality, is measured in milligram per litre.
The average (mean) BOD in Dighalipukhuri water in 2015 was 9.3 mg/litre, with the maximum and minimum being 13 mg/litre and 3.6 mg/litre respectively. In 2014, the average, maximum and minimum BOD were 7.7 mg/litre, 20 mg/litre and 1.4 mg/litre respectively. The corresponding figures in 2013 were 7.2 mg/litre, 12.8 mg/litre and 1.2 mg/litre.
In 2008, the average BOD was 5.6, while the maximum and minimum were 6.2 and 4.8 respectively.
The positive aspect, though, has been that most other core water quality parameters such as temperature, dissolved oxygen, pH, conductivity, nitrate N, total coliform, etc., were still more or less within the permissible limits.
�As of today, we cannot say that pollution levels in Dighalipukhuri are alarming, as most of the parameters except BOD are within the permissible range. But that does not mean that there is no room for concern. The average BOD has shown trend on the higher side. The need is to identify the sources behind the pollution resulting in higher BOD and check those before it attains alarming proportions,� a senior PCBA official said.
The sewage generated by restaurant inside the tank campus is finding its way into the water-body. It is also likely that the drainage near the Rabindra Bhawan is contributing to the tank�s pollution.
Earlier also, waste generated in the Fishery office and the GMC junkyard on the northern bank (the area where the war memorial is now under construction) contributed to the pond�s degradation.
A few years back, an analysis of the tank�s water by the State Public Health Laboratory had revealed presence of harmful chemicals and other compounds which cause skin allergy and breathing problems.