Spatial appraisal of groundwater quality for drinking purposes: A case study of Kalihati Upazila, Bangladesh

Abstract

With the aim of improving public health interventions, this study was conducted to ensure sustainable groundwater quality by adopting Geographical Information System (GIS) and Water Quality Index (WQI) for drinking purposes in Paikara Union, Kalihati Upazila of Bangladesh. Fifteen groundwater samples were randomly collected from different hand tubewells in April 2019 and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), major cations and anions. Almost all physicochemical parameters fell within the acceptable limit of national and international standards, though a few samples exceeded the standard limit considering As₃⁺, Fe₃⁺ and PO₄^{3 -} concentrations. The spatial distribution of the quality parameters across the study area was depicted employing ArcGIS 10.5 software; therein it was revealed that slightly acidic water is dominant in the central and southern parts. Overall, TH–total cation, Cl–NO₃, total anion–NO₃ and total anion–Cl show a very strong correlation, and contrarily, the pairs of pH, EC, TDS are poorly correlated with most of the variables and no remarkable relationship is found between pH and TH. Furthermore, WQI of the samples ranged from 20.42 to 143.36, with 73.7, 24.1, and 2.2% of the entire study area falling under excellent, good, and poor quality categories for drinking pur- poses, respectively. From the results, it can be inferred that the groundwater of the study area is suitable for drinking purposes but awareness-raising on chemical contents in the water at the household level is recommended.