Effects of Gold Mining on the Physicochemical Properties of Soils at the Akbakai Gold Deposit
Abstract
Open-pit gold mining in arid regions can lead to long-term environmental degradation through the accumulation of toxic metal(loid)s in soils. This study investigates soil contamination and quality degradation around the Akbakai gold deposit, located in the Zhambyl region of southern Kazakhstan a semi-desert zone characterized by low organic matter, coarse soil textures, and fragile ecosystems. Field sampling included six representative soil profiles (SP) excavated from man-made mining dumps and surrounding areas. We conducted a comprehensive assessment of physical, agrochemical, granulometric, and geochemical properties, with a focus on total and available concentrations of metal(loid)s using microwave-assisted acid digestion and DTPA extraction methods. The results revealed that surface soils were moderately alkaline (pH 8.1-9.2) and low in organic matter (humus <2%), that are with coarse-textured horizons dominated by medium sand. Soil salinity and sodicity were variable, with total salt content ranging from 0.06% to 1.1% and available sodium percentage reaching up to 23.8%. Risk quotient analysis identified multiple soil horizons where contaminant levels surpassed environmental safety thresholds. The findings confirm significant anthropogenic contamination at the Akbakai gold deposit, especially in upper soil layers formed on mining waste.