Post-earthquake water quality in Bhaktapur district, Nepal

Abstract

Drinking water quality of Bhaktapur district was analyzed after massive earthquake of 2015. Water samples were randomly collected from the groundwater and surface water sources across the study area. Samples were analyzed for physical (temperature, pH, electrical conductivity and turbidity), chemical (hardness, chloride, ammonia, and nitrate), and microbiological (E. coli and total coliform bacteria) parameters using standard methods. The results demonstrated that the water samples were contaminated mostly with E. coli and total coliform (TC) bacteria. The bacterial population enumerated for E. coli (100 CFU/100 ml) and TC (300 CFU/100 ml) exceeded the National Drinking Water Quality Standard (NDWQS). Physical and chemical parameters analyzed for temperature, pH, conductivity, hardness, chloride, ammonia, and nitrate were within the acceptable limit of the NDWQS. However, the turbidity and ammonia was 34.6 NTU and 3.6 mg/l, were within the maximum values recommended by the NDWQS. This study exhibits that the groundwater and surface water quality of Bhaktapur district is contaminated with E. coli and TC bacteria hence, is vulnerable to drink. The water contaminated with bacteria (E. coli and TC), presence of ammonia and turbidity more than the limit of NDWQS may pose health risks and cannot be accepted for drinking purpose without purification following appropriate scientific methods.