Efficiency and persistence of compost, gypsum, and lime for arsenic and cadmium stabilization in contaminated soil

Abstract

Stabilization, a remediation technique using amendments, reduces the phytoavailability of heavy metal (loid)s in contaminated soils, aiding agricultural soil restoration. Common amendments include lime (L), compost (CM), and gypsum (G), each with distinct stabilization mechanisms. Over time, these amendments may degrade, requiring periodic evaluation of their long-term effectiveness. This study evaluated the persistence of stabilization in arsenic (As) and cadmium (Cd) contaminated soils 7 years post-application of CM, G, and L. Initially treated in 2014, the soils were cultivated with Angelica gigas and later with Brassica rapa L. in 2021 without reapplying amendments. Soil pH, electrical conductivity, and dissolved organic carbon (DOC) were analyzed, along with heavy metal uptake. Results showed there was no significant change in soil chemistry or metal uptake in CM treated soil. In G treated soil after 7 years, pH and DOC increased accompanying with As and Cd uptake increased. In the soil treated with L, soil pH decreased slightly, together with As and Cd uptake increased. These results implied that CM maintained stabilization, while G and L showed diminished efficiency over time, indicating the need for reapplication and management for sustained effectiveness.