INDICATIONS OF SURFACE WATER CONTAMINATION OF DRINKING WATER IN THE SAGARMATHA NATIONAL PARK, NEPAL

The Sagarmatha National Park (SNP) in the southeastern Nepali Himalaya Mountains encompasses the southern slopes of Mt. Everest. Established as a World Natural Heritage, the SNP is the highest altitude protected area in the world and forms the main headwaters for major river systems, such as the Ganges, Yangtze and Indus Rivers.

We have been analyzing the fecal bacterial content of drinking water in the SNP and focusing on drinking water sources (first point of use), which are primarily shallow groundwater-fed springs. To date, sampling has occurred during the pre-monsoon dry season, Spring 2016 and 2017. Our primary goal has been to identify coliform bacteria and E. coli, reliable indicators of contamination, in drinking water sources.

Results show a predictable trend whereby physical and biochemical parameters correlate with altitude. Water temperature decreases, whereas pH and conductivity increase with increasing altitude. Total coliform bacteria counts correlate with temperature and altitude/population: more populated, lower altitude areas had higher levels of E. coli and coliform bacteria. However, there are no correlations between bacterial content, conductivity, and pH.

There is a noteworthy difference between the 2016 and 2017 bacterial data. In 2016, 4 samples (out of the 30 samples tested) met the Nepali National Drinking Water Quality Standard of 0 colonies/100 ml sample. The majority of the drinking water sources fell into the “Low Risk” category defined by the World Health Organization (WHO) with fewer than 10 E. coli colonies/100 ml sample whereas nine samples tested were categorized as “Moderate Risk” category (10 -100 E. coli colonies per 100 ml) and no “High Risk” samples were found. In 2017, however, only 2 samples (out of the 32 samples tested) met the Nepali National Drinking Water Quality Standard. Again, majority of the drinking water sources fell into the “Low Risk” category defined by the WHO whereas 11 samples tested were categorized as “Moderate Risk” category. In addition, 3 “High Risk” samples were found. In general, the 2017 samples contained higher levels of both E. coli and total coliforms. We suggest that the difference is a result of increased precipitation between 2016 and 2017, which causes greater surface water contamination of the shallow springs used for drinking water.