Extraction and leaching of Pb from two polluted soils as affected by addition of microencapsulated EDTA

Incubation batch and leaching experiments were conducted to study effect of microencapsulated EDTA(Cap-EDTA) on extraction and leaching characteristics of Pb and pH changes in two heavy metal polluted soils.The results showed that pH showed similar change pattern in all treatments in the same type soils.EDTA effectively increased the mobility of Pb in the soil,the cumulative amount leaching of Pb,showed a logarithmic curve,along with the increasing volume of leachate.In comparison with EDTA,Cap-EDTA showed similar leaching pattern but provided lower and more constant water-soluble concentrations of Pb in the soil solution with less cumulative amount of leaching of Pb,indicating that Cap-EDTA application may alleviate the risk of groundwater contamination.