Groundwater quality and community health risk in Lalitpur Metropolitan City, Nepal – a geospatial analysis
Manisha Ghimire, Tejendra Regmi, Sadhana Pradhanang Kayastha, Chandrashekhar Bhuiyan
Abstract
Groundwater is the main source of drinking water in the Kathmandu Valley (Nepal). To assess the groundwater quality of Lalitpur Metropolitan City (LMC) of this valley, samples were collected in winter and post-monsoon seasons from 35 shallow dug wells and 16 parameters: pH, TDS, EC, Na+, K+, Ca2+, Mg2+, Total hardness, Clˉ, HCO3ˉ, NO3ˉ, NH4+, Fe, PO43-, SO42-, and Total Coliform were analysed. Hydrochemical analysis and GIS-based mapping have revealed spatial and seasonal variations in water quality. The concentration of most of the parameters was higher in the winter samples compared to the post-monsoon. Comparison with the WHO and NDWQS guidelines has revealed anomalous water chemistry. Zones hosting groundwater, suitable and unsuitable for drinking and irrigation were demarcated. However, the presence of pathogens in all the groundwater samples put the entire population of LMC under high health risk. This study bears importance in groundwater exploration, management, and prevention of water-borne diseases.