TY - JOUR
T1 - Drinking water quality in Nepal's Kathmandu Valley
T2 - A survey and assessment of selected controlling site characteristics
AU - Warner, Nathaniel R.
AU - Levy, Jonathan
AU - Harpp, Karen
AU - Farruggia, Frank
N1 - Funding Information:
The authors would like to acknowledge the numerous supporters whose time, effort and funding have made this research possible. The project was funded by a Hampton Grant from Miami University, the Department of Geology, Miami University, and the Geological Society of America. Dr. Janardan Subedi and Dilip Croung gave us guidance, logistics, and support while within Nepal and made the sampling process a possibility. Apex Trekking also provided guidance and language interpretation while in Nepal. We would also like to thank The Hotel Tibet, Kathmandu for providing housing and laboratory facilities. K. Harpp would like to acknowledge support for ICP-MS operation from NSF grant CHE-9996136.
PY - 2008/3
Y1 - 2008/3
N2 - Water was sampled from over 100 sources in Nepal's Kathmandu Valley, including municipal taps, dug wells, shallow-aquifer tube wells, deep-aquifer tube wells, and dhunge dharas (or stone spouts, public water sources that capture groundwater or surface water). Information was gathered on user preference and site and well characteristics, and water was examined for indicators of contamination from sewage, agriculture, or industry. Most problematic were total coliform and Escherichia coli bacteria, which were present in 94 and 72% of all the water samples, respectively. Contamination by nitrate, ammonia and heavy metals was more limited; nitrate and ammonia exceeded Nepali guidelines in 11 and 45% of the samples, respectively. Arsenic and mercury exceeded WHO guidelines in 7 and 10% of the samples, respectively, but arsenic never exceeded the less strict Nepali guideline. Significant differences existed in contamination levels between types of sources; dug wells and dhunge dharas, being the shallowest, were the most contaminated by bacteria and nitrate; deep-aquifer tube wells were the most contaminated by arsenic. Whereas E. coli concentrations decreased with depth, iron and ammonia concentrations increased with depth. These relationships account for people choosing to drink water with higher levels of bacterial contamination based on its superior (non-metallic) taste and appearance.
AB - Water was sampled from over 100 sources in Nepal's Kathmandu Valley, including municipal taps, dug wells, shallow-aquifer tube wells, deep-aquifer tube wells, and dhunge dharas (or stone spouts, public water sources that capture groundwater or surface water). Information was gathered on user preference and site and well characteristics, and water was examined for indicators of contamination from sewage, agriculture, or industry. Most problematic were total coliform and Escherichia coli bacteria, which were present in 94 and 72% of all the water samples, respectively. Contamination by nitrate, ammonia and heavy metals was more limited; nitrate and ammonia exceeded Nepali guidelines in 11 and 45% of the samples, respectively. Arsenic and mercury exceeded WHO guidelines in 7 and 10% of the samples, respectively, but arsenic never exceeded the less strict Nepali guideline. Significant differences existed in contamination levels between types of sources; dug wells and dhunge dharas, being the shallowest, were the most contaminated by bacteria and nitrate; deep-aquifer tube wells were the most contaminated by arsenic. Whereas E. coli concentrations decreased with depth, iron and ammonia concentrations increased with depth. These relationships account for people choosing to drink water with higher levels of bacterial contamination based on its superior (non-metallic) taste and appearance.
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U2 - 10.1007/s10040-007-0238-1
DO - 10.1007/s10040-007-0238-1
M3 - Article
AN - SCOPUS:41349083305
SN - 1431-2174
VL - 16
SP - 321
EP - 334
JO - Hydrogeology Journal
JF - Hydrogeology Journal
IS - 2
ER -