Surface and groundwater quality assessment and identification of hydrochemical characteristics of a south-western coastal area of Bangladesh

In coastal areas of Bangladesh, the problem of getting fresh drinking water is acute since the surface and groundwater of this area are affected by both seawater intrusion and anthropogenic activities. This study aims at assessing the hydrochemistry and quality of surface and groundwater of a south-western coastal area Rupsha Upazila of Bangladesh using geographical information system (GIS) technique. The hydrochemical facies revealed that the surface waters are mainly characterized by Na-Ca-HCO3-Cl and the groundwaters are characterized by Na-Cl-HCO3, indicating mixing composition of the natural water, while the Gibbs diagram indicates mixing processes of both the rock-water and evaporation-crystallization interactions of the surface and groundwater. The comparisons of the water quality parameters with World Health Organization (WHO) and Bangladesh (BD) standards show that surface water quality is better than groundwater in terms of total dissolved solids, chloride, iron, and arsenic concentrations. In surface water, arsenic concentration is within the WHO and BD standard but 40% of the groundwater samples exceeded the standard. Results also showed that 100% of the surface water samples exceeded the Escherichia coli and 62.85% of the groundwater samples exceeded the standard limit. Thus, the surface water of the study area can be a potential source to meet the future challenges for drinking water shortage problems as compared to aquifer water of the area.