Water quality assessments are essential for ensuring human and ecosystem health. This study conducted a water quality assessment on a typical coastal coal-bearing graben basin. Suitability of groundwater quality of the basin for drinking and agricultural irrigation was assessed. Hazards posed to human health by groundwater nitrate were assessed using the objective combined weight water quality index, percent sodium, sodium adsorption ratio, and health risk assessment model. The results indicated groundwater of the basin to be weakly alkaline hard-fresh or hard-brackish, and mean values of pH, total dissolved solids, and total hardness of 7.6, 1464.5 mg/L, and 794.1 mg/L, respectively. The ranks of groundwater cations and anions by abundance were Ca2+>Na+>Mg2+>K+ and HCO3->NO3->Cl->SO42->F-, respectively. The main groundwater type was Cl-Ca, followed by HCO3-Ca. The results of the water quality evaluation indicated that most groundwater in the study area is of a medium quality (38%), followed by poor (33%), and extremely poor (26%). Groundwater quality gradually worsened from inland to the coast. Groundwater of the basin was generally suitable for agricultural irrigation. Groundwater nitrate posed a hazard to over 60% of the exposed population, with infants most at risk, followed by children, adult females, and adult males.
Keywords: Coastal basin; Groundwater; Health risks assessment; Nitrate; Water quality evaluation; Water quality index.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.