Effect of contaminant aging upon soil washing removal efficiencies for lead contaminated soils

摘要

The objective of this research was to investigate lead removal efficiencies from various soils using a variety of washing solutions. Most soil types have a strong affinity for lead. Thus, it is plausible to expect washing solutions that are capable of removing lead could also remove other divalent heavy metals. Four soil samples from the eastern US were collected and characterized for this study. The study soils were then spiked to approximate lead concentrations of 1,000 and 10,000 mg Pb/kg soil. The efficiencies of six washing solutions in removing lead from the contaminated soils were then investigated via lab-scale batch washing experiments. Unlike current field-scale soil washing practices, all particle size fractions were washed and recovered in these experiments. (Solutions investigated include: tap water, HCl, EDTA, HNO(sub 3), CH(sub 3)COOH, and CaCl(sub 2).) In order to examine the effect of aging upon soil washing efficiencies, some of the spiked soils were washed a second time after an aging period of nearly 2 years.