Geochemical Characterization and Environmental Risk Assessment of Al-Azraqain Landfill Leachate Using LPI and Multivariate Statistical Analysis
Data on the quality of leachate from the Al-Azraqain landfill in Sana'a, Yemen, is extremely limited. This study aimed to fill this gap by providing the first geochemical characterization of the landfill leachate. Five leachate samples representing all accessible leachate sources within the landfill were collected and analyzed for physicochemical parameters, including pH, EC, TDS, TOC, TKN, and major and heave elements (K, Ca, Mn, Fe, Zn, Cu, As, U, Pb, and Ni) using Total Reflection X-ray Fluorescence (TXRF). The Leachate Pollution Index (LPI) and Hierarchical Cluster Analysis (HCA) were also applied. The results indicate that the landfill has not yet reached the stable methanogenic phase, as evidenced by slightly acidic pH values and elevated concentrations of organic matter, dissolved salts, and major and heave elements. TXRF analysis indicated elevated concentrations of nickel and uranium in most samples. In Sample 5, collected from the main leachate pond downstream of the landfill, TDS, COD, TKN, Fe, Ni, As, and Cu exceeded the proposed Yemeni discharge standards, reaching 25,100, 10,875, 2,242, 28.155, 9.3, 0.828, and 0.257 mg/L, respectively. LPI values ranged from 24.57 to 32.76, substantially exceeding the safe discharge threshold (7.378), indicating that the leachate poses a significant environmental risk to groundwater and surrounding ecosystems. HCA further revealed a close association between organic load and heavy metals, suggesting may enhanced their mobility. This study provides baseline data to support environmental monitoring and remediation planning and recommends future investigations addressing seasonal variations and the impacts of leachate on surrounding groundwater and soils.
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