Groundwater quality and non-carcinogenic element health risks assessment using multi-technical models: A case of the deep aquifer of the complex terminal in Ouargla city (southeastern Algeria)

Abstract

The purpose of this work was to evaluate the groundwater quality and the health hazards related to non-carcinogenic elements present in the Complex Terminal (CT) Ouargla city. Thirty (30) samples were taken and physico-chemically analyzed collected from deep boreholes located in study area. Fluoride concentrations ranged between 1.07 and 3.7 mg/l, with 54% of samples having a value >1.5 mg/l as per potability limit. According to the fluoride pollution index (FPI), 63.67% of the boreholes were severely contaminated with F−. However, nitrate pollution index (NPI) revealed that approximately 71% of the samples showed no contamination. The pollution index of groundwater (PIG) ranging from 1.34 to 2.85 indicate the majorit of groundwater samples in the search zone was contaminated for human consumption. Based on the entropy water quality index (EWQI), 30% of samples had poor quality, while 70% were unfit for drinking. According to the statistical analysis used in this study, the dissolution of fluoride-rich carbonate rocks under high HCO3− contents enables the liberation of F− from fluorine-bearing minerals like calcite and fluorite. Regarding non-carcinogenic risks, the Hazard quotient (HQ) fluoride was obtained with a huge difference in exposure dose in children (0.89–3.08), women (0.62–2.13) and men (0.54–1.85), respectively. HQ nitrate values ranged from 0.08 to 1.40, 0.06–0.97 and 0.05–0.84 for men, women and children, correspondingly. The total hazard index (THI) clearly show that fluoride presents a higher health risk than nitrate, revealing that 53.3%, 66.7%, and 100% of the samples show that men, women and children, at risk respectively. It has been proven to be more susceptible to health hazards since it may be exposed to non-carcinogenic elements, and to avoid a further worsening of the health situation, those responsible and decision-makers will have to treat the water appropriately, identify the affected people and provide them with the necessary medical care.