Application of Practical Immobilizing Agents for Declining Heavy Metal (loid)s Accumulation by Agricultural Crop (Allium wakegi Araki )

Abstract

In order to reduce the accumulation of toxic metals (As, Cd and Pb) in the chives, various immobilizing agentssuch as a soil pH change-inducing immobilizing agent (lime), sorption agent (compost, spent mushroomcompost), soil pH change and sorption agent (biochar) and, dissolved organic carbon (DOC) coagulator(gypsum) and uncontaminated soil were applied to the contaminated soils in isolation and in combination. Then chives were grown and determined for As, Cd and Pb concentrations accumulated in the edible part atharvest. The Cd and Pb concentrations of the chive plant grown in the contaminated soil (no treatment)exceeded the legislated Korean guideline values (Cd: 0.05 mg kg-1, Pb 0.1 mg kg-1) and As concentration (21mg kg-1) was 1,000 times higher than chives plant grown in uncontaminated environment in Korea. Applicationof lime and gypsum significantly reduced As, Cd and Pb concentrations in all chives examined, due to theincreased soil pH and decreased soil DOC. Also, application of combination treatments involving DOCcoagulator such as gypsum together with lime decreased As, Cd and Pb concentrations from 21, 1.3 and 9.7mg kg-1 to 2.1, 0.1 and 1.1 mg kg-1, respectively. Consequently, it was concluded that pH change-inducingimmobilizing agent (lime) which was already well known and DOC coagulator such as gypsum could be usedas a promising immobilizing agent for safer chives plant production.