Assessment of the dynamics of heavy metal contamination in the alluvial aquifer of the Drean plain, El Taref (North-Eastern Algeria) using GIS indices and water quality analysis

The study was conducted to assess the quality of shallow groundwater in the Drean plain, with a focus on the concentration of heavy metals. The indices employed included the water quality index (WQI), heavy metal pollution index (HPI), and metal index (MI). Spatial distribution maps of heavy metals, as well as pollution indices, were developed based on twenty samples. The physicochemical parameters, including T, pH, EC, DO, and TDS, were measured using standard techniques. Heavy metals, including iron (Fe), lead (Pb), zinc (Zn), chromium (Cr), manganese (Mn), and cadmium (Cd), were analysed through spectrophotometry. The average concentrations of Mn, Cr, Cd, and Pb exceeded the World Health Organization (WHO) drinking water standards, with respective values of 0.16 mg/L, 0.06 mg/L, 0.28 mg/L, and 0.38 mg/L. According to the water quality index (WQI), which ranges from 21 to 800, approximately 50% of the water samples was classified as highly polluted and therefore not recommended for consumption. According to the metal index (MI), the average value is 6.77, with 80% classified as highly polluted. The average value of the heavy metal pollution index (HPI) was 2201, indicating that the water in the plain is severely polluted for consumption, with 100% of the samples classified as unfit for consumption. The study underlines the urgency of reducing the health risks to the urban population and recommends continuous monitoring of the area to assess the evolution of the pollution.