A systematic review of soil and water contamination in dumpsite leachate impacted environments

Abstract Soil and groundwater contamination associated with unlined (non-engineered) dumpsites constitutes a persistent global environmental challenge, posing serious threats to shallow aquifers and public health, particularly in developing countries. This review synthesizes current knowledge with four objectives: (i) classifying investigation techniques for soil–water contamination assessment; (ii) evaluating the effectiveness of stabilizing agents for potentially toxic element (PTE) immobilization; (iii) examining the role of AI-assisted methodologies in advancing PTE assessment; and (iv) reviewing remediation strategies for contaminated soils and groundwater. The reviewed evidence demonstrates that integrated geophysical, hydrogeochemical, and geotechnical approaches are essential for robust contamination characterization, with leachate migration to depth primarily controlled by subsurface structural features, including weathered zones and fracture networks. Geophysical imaging combined with hydrogeochemical analyses consistently reveals both vertical and lateral leachate transport capable of impacting shallow groundwater systems and, in some cases, adjacent agricultural lands. Pollution indices and human health risk assessments indicate substantial non-carcinogenic and carcinogenic risks, predominantly associated with hand-to-mouth contact and ingestion of contaminated groundwater, with secondary risks from dermal exposure. Recent advances further highlight the effectiveness of data-driven machine learning frameworks—such as Naive Bayes, Random Forest, and Bivariate Local Moran’s I—in predicting PTE distributions and delineating high-risk zones using key environmental covariates. Remediation strategies discussed include stabilization techniques for contaminant immobilization and emerging nanotechnology-based approaches, including nanomaterials and nanoenzymes, aimed at enhancing phytoremediation and microbial degradation. Overall, this review underscores the need for site-specific assessment, regular monitoring, informed urban planning, and integrated remediation frameworks to mitigate the long-term impacts of dumpsite leachate on soil and groundwater quality.