HR: 15:10h
AN: H13L-07    [Abstracts]
TI: Hydrogeochemical assessment of arsenic in groundwater and its policy implication: a case study in Terai Basin, Nepal
AU: * Gurung, J K
EM: jkcmane@yahoo.com
AF: Department of Geoscience Shimane University, Nishikawatsu 1060, Matsue, 6908504, Japan
AU: Upreti, B N
EM: bnupreti@wlink.com.np
AF: Faculty of Science and Technology, Tribhuvan University, Kirtipur Kathmandu, Kathmandu, 9085, Nepal
AU: Kansakar, D R
EM: dratna@wlink.com.np
AF: Department of Irrigation Govt/Nepal, Jawalakhel, Lalitpur, 8975, Nepal
AB: Arsenic contamination at levels above the WHO guideline (10 ėg/l) in groundwater is a worldwide problem due to its detrimental effects on health and now known to be a problem also in the Terai Basin of Nepal, posing a serious threat to more than 10 million people. The distribution of arsenic in the basin, however, is patchy. The study emphasizes on the three different types of research into an interdisciplinary package that can be immediately useful to government agencies in Nepal trying to deal with groundwater contamination. They are: hydrogeological assessment of water sources and flow, geochemical analysis of groundwater, and assessment of practical public policy. Basic geochemical analysis gives the abundance and distribution of arsenic along with other physico-chemical parameters of groundwater, whereas, the hydrogeological assessment as an integral part of this study that assist in determining process of mobilization or attenuation of arsenic. Arsenic levels and other key parameters mainly pH, electrical conductivity, chemical oxygen demand, iron, and biological parameter as E-coli were observed at the various locations with different transmissivity values. The study suggests that the flushing rate of an aquifer plays an important role in arsenic content. High flushing rates of an aquifer lead to low levels of arsenic, however the mechanism of this process is still under study. Transmissivity the property of an aquifer that measures the rate at which ground water moves horizontally through a unit is the main factor for controlling flushing. Concentration maps overlaying the base transmissivity map reveals relation of groundwater movement and arsenic concentration. Understanding the relationship between groundwater movement and arsenic content helps planners protect uncontaminated aquifers from future contamination. Also assessment of public policy related to groundwater has identified important changes needed in the existing policy.
DE: 1065 Major and trace element geochemistry
DE: 1831 Groundwater quality
SC: Hydrology [H]
MN: 2007 Fall Meeting