Remediation of trace element-contaminated groundwater and soils using redox-sorption and phytoextraction techniques

Abstract

Remediation of trace element-contaminated sites must consider both the nature of the contaminants and environmental surroundings. This thesis examined treatments for two contamination scenarios. The first study characterized chromium dynamics during the redox-sorption treatment of aqueous hexavalent chromium with the reducing agent sodium dithionite and two iron oxides. Results showed that chromium was successfully removed from solution by precipitation and sorption. The iron oxide derived from ferric chloride had a greater sorption capacity for hexavalent chromium than the oxide derived from ferrous chloride. The second study examined the phytoextraction treatment of soils contaminated with multiple trace elements. Deschampsia caespitosa plants had better early growth in the contaminated high-organic matter soil than three Brassica species. However, D. caespitosa plants did not take up sufficient amounts of trace elements during the study to be considered useful for short-term phytoextraction. These findings are applicable to the development of effective trace element remediation methods.