Influence of washing treatment on the qualities of heavy metal–contaminated soil

Abstract

Soil washing is an efficient method to remove heavy metals from contaminated soils; however, soil properties can be altered during remediation processes. Therefore, changes in physicochemical properties after soil-washing treatments were examined to investigate their effects on the ecological properties of soil. Two types of washing processes using different physical separation methods and extraction reagents were applied to Pb- or Zn-contaminated soil. The physicochemical properties of soil changed following physical separation and chemical extraction processes, resulting in deterioration of soil fertility. Soil texture and particle size showed more uniformity regardless of the original properties. Although sorting improved, water-holding capacity decreased because of an increase in sand content. The ecological properties of soil could not be improved completely after the removal of metals due to adverse changes in the physicochemical properties of soil. Therefore, the decision to reuse or recycle remediated soils should reflect changes in soil quality.