Metal leaching along soil profiles after the EDDS application – A field study

One concern about the chelant-enhanced phytoextraction is the potential metal leaching associated with chelant application. A field study was carried out and the metal leaching along the 60-cm depth soil profiles were evaluated within 36 days after the biodegradable chelant EDDS was applied. Results showed EDDS significantly increased soluble Cu in the top 5 cm soil layer 1 day after the application, and the increase of soluble metals was generally limited in the top 20 cm soil. Metal speciation analysis indicated all Cu and Zn were in forms of Cu-EDDS and Zn-EDDS complexes in soil solution, and Ca was the major competitor with trace metals to EDDS. The soluble metals decreased quickly with time, and no significant difference was observed in the extractable Cu between EDDS treatments and the controls 22 days after the EDDS addition. The potential leaching associated with biodegradable EDDS addition may be controlled under field conditions. - Highlights: ► Metal leaching associated with EDDS application was evaluated under field conditions. ► Soluble metals were restricted in the top 25 cm layers within 22 d with typical rainfall case. ► EDDS could completely degrade within 36 d after its application. ► The metal leaching risk after EDDS application may be controlled in the field. - The metal leaching risk associated with EDDS application may be controlled under field conditions