Consumption of such water can be fatal’

Kathmandu, December 21:

Drinking water in the metropolitan, including Kathmandu Valley, has been found to be contaminated. Two different studies on the quality of drinking water in these areas revealed that almost 90 per cent of the total drinking water samples tested were found crossing the WHO guidelines in terms of the presence of coliform-intestinal bacteria. Though this bacteria is not harmful on its own, it indicates the presence of other pathogenic bacteria.

Anup Muni Bajracharya of the Central Department of Microbiology (CDM) and a team from the Nepal Academy of Science and Technology (NAST) tested 114 water samples from stone spouts, taps and tube wells.

Bacteriological analysis revealed the presence of coliform in 90.35 per cent of the samples — 97 per cent in tube well water, 73 per cent in tap water and 100 per cent in water from stone spouts.

In another study, conducted by Tista Prasai of NAST, Binod Lekhak and Dev Raj Joshi of CDM and Madhav Prasad Baral of the National School of Sciences, 132 water samples randomly collected from tube wells, wells, taps and stone spouts were tested. It revealed that 92.4 per cent of the samples crossed the WHO guideline value for drinking water regarding coliform count.

During the study, 238 isolates of enteric bacteria, which cause various health related problems, were identified including Escherichia coli, Enterobacter spp, Citrobacter spp, Salmonella typhi, Proteus vulgaris and Vibrio cholera.

Tista Prasain said detection of the pathogenic enteric bacteria in different sources of water reveals the possibility of water borne epidemics in the Valley.

During the period between June 29 to July 19 this year, 1,753 water borne disease cases were reported in Valley, according to the data provided by the Epidemiology and Diseases Control Division.

Bacteriological pollution could either be due to the failure to disinfect water at treatment plants or inflow of sewage through cross connection and leakage points, said Prakash Amatya, executive director of Urban Water and Sanitation (NGOFUWS).

NGOFUWS has conducted various studies which has shown that the water supply utilities have not complied with the National Drinking Water Quality Standards 2060 and Implementation Guidelines issued by the government in June 2006.