Remediation and environmental safety of paddy soil temporarily polluted by heavy metals from acid mine drainage

Abstract

This study examines the remediation of paddy soils briefly contaminated by acid mine drainage (AMD) using lime (LM) and steel slag (SS) amendments. The treatment not only boosted rice yields but also significantly lowered Cd and Cu levels in the rice. Additionally, it decreased net acid generation and increased acid neutralization capacity, reducing soil acidification risk, though reacidification potential remains high. Soil amendments improved pH, raising it to neutral, and enhanced cation exchange capacity from 4.35 to 9.23 cmol/kg. Enzymatic activities were also affected: dehydrogenase activity increased, urease decreased after LM and SS application, and sucrose activity varied with the type of amendment. The findings suggest that AMD-polluted paddy soils can be effectively remediated through soil amendments and rice cultivation, but continuous monitoring and further interventions are needed for sustained soil health.