Superfund Research Program
Nano-scale Mechanisms of Metal(loid) Rhizostabilization in Desert Mine Tailings
Project Leader: Jon Chorover
Grant Number: R01ES017079
Funding Period: 2009-2011
Dr. Chorover’s research group is conducting multi-scale experiments to assess mechanisms of toxic metal phytostabilization during revegetation of mine tailings in semi-arid environments. Current research is focused on a set of instrumented mesocosm experiments wherein mine tailings from the Klondyke Arizona State Superfund Site were subjected to (i) tailings and compost, and (ii) tailings, compost and plant (Buchloe dactyloides) treatments, or (iii) not treated as a control. The instrumented mesocosms, monitored for a three month period, show significant declines in core water and leachate metal concentrations. X-ray spectroscopic analyses indicate that reductions in zinc (Zn), lead (Pb), and manganese (Mn) concentrations in the biologically-active systems were likely associated with sorption to solid phase organic matter, as well as biogenic Mn oxide formation and the associated sequestration of Pb and Zn into sorbed forms. Ongoing studies in larger scale mesocosms are now being conducted with arsenic bearing tailings from the Iron King Superfund Site.