Cadmium Pollution in Mining Areas: Chemical Stabilization Strategies and Their Performance

Abstract

Cadmium (Cd) contamination in mining regions poses significant risks to ecological security and human health. This study synthesizes evidence from more than thirty field investigations, laboratory experiments, and theoretical analyses published between 2000 and 2024. The objectives are fourfold: (i) to summarize the primary sources, concentration ranges, and spatial distribution of Cd in mining environments; (ii) to examine the health hazards associated with Cd exposure; (iii) to compare the mechanisms, removal efficiencies, applicability, and remediation outcomes of various chemical stabilization agents; and (iv) to evaluate monitoring indicators and assessment methods for restoration effectiveness. Literature retrieval focused on mine pit case studies, concentration data, pollutant migration patterns, health risk documentation, and remediation practices, with extracted data subjected to comparative analysis. Results indicate that Cd is highly enriched in tailings, smelting areas, and downstream plains, exhibiting both vertical and horizontal migration. Human exposure occurs mainly through inhalation and food chain accumulation, leading to multiple health disorders. Among chemical stabilizers, CaCO₃ provides rapid but temporary immobilization, FeCl₃–citric acid achieves efficient Cd extraction but may impair soil quality, while natural zeolite offers moderate yet durable stabilization at relatively low cost. Overall, no single technique satisfies all sustainability requirements. Site-specific strategies, such as combining zeolite treatment with controlled pH adjustment, coupled with long-term monitoring, are essential to ensure the safe management and potential reuse of Cd-contaminated mining land.