Removal of cesium from contaminated soils using EDTA-Na and DTPAchelating agents

Abstract

Soil contamination with Cs possesses a serious environmental threat; and therefore, its remediation is an obligation to ensure environmental safety. The current study aims at evaluating the efficiency of using either EDTA-Na or DTPA as chelating agents for removal of Cs from contaminated soils. Three soils (a clayey oneand two sandy loam soils differing in the organic matter and CaCO 3 contents) were selected to attain this aim.Samples of the soils under study were artificially contaminated with CsCl at three levels i.e. 50, 100, and 200 mg Cs kg -1 . These samples were subjected to sequential extraction pre- and post- leaching to find out Cs redistribution among the different soil fractions after soil washing. The implications of soil washing with the investigated chelating agents on decreasing the risk assessment hazards associated with Cs hazards are discussed in this study. Key results indicated that DTPA was more efficient in removal of Cs from the contaminated soils than the EDTA-Nadidand both decreased considerably soil Cs, particularly from those which are considered the mobile fractions (water soluble and exchangeable fractions) beside of the carbonate bound fractions. Accordingly, the calculated risk assessment code declined noticeably from ―very high risk‖ levels (more than 50) to ―medium risk‖ levels (ranging from 30 to 50 ) for most spiked soils. In conclusion, DTPA and EDTA-Na are effective chelating agents in reducing the risks associated with Cs contamination in soils.