Metal contents and fractionation in contaminated soil after column leaching using [S, S]-EDDS

Abstract

Column leaching using [S, S]-ethylene diamine disuccinate ([S, S]-EDDS) on copper tailing soils was carried out to investigate metal content and fractionation after leaching. The soil column was divided into four layers after leaching. Fractionation of Cu, Pb, Zn, and Mn in soil was analyzed using a modified BCR sequential extraction method. Metal contents (Cu, Pb, Ca, Mn) in soil layers increased with the depth of the soil column after leaching in the [S, S]-EDDS treatment. The cumulative extraction efficiency was approximately 43.1% for Cu, 26.8% for Zn, 19.5% for Pb, 10.5% for Ca, 2.07% for Mg, 58.5% for Mn, and 7.92% for Fe. The removal of the reducible fractions of Cu and Mn and the exchangeable fraction of Zn was the most significant in the treatment with [S, S]-EDDS. The exchangeable fraction of Pb was the main fraction that was affected by leaching using [S, S]-EDDS. Distribution of Cu and Mn were severely modified by leaching with [S, S]-EDDS. Percentages of residual fractions of the tested heavy metals in the treatment with [S, S]-EDDS after leaching were much higher than that in the control. Although column leaching using [S, S]-EDDS could remove target metals effectively and impaired their availability, it also dissolved large amounts of major elements and modified the distribution of Mn appreciably.