Speciation project

Environmental Biogeochemistry Group

Department of Soil, Water and Environmental Science

Research Project:
Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbate Aging on Contaminant Speciation and Mobility
This project aims for a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (137Cs, 90Sr, 129I) fate in caustic waste-impacted sediments across space, time and geochemical gradients that encompass the heterogeneity observed at the Hanford Site WA, USA. Our specific objectives are: (1) to assess the molecular-scale mechanisms responsible for time-dependent sequestration of contaminants (Cs, Sr and I) during penetration of waste-induced weathering fronts; (2) to determine the rate and extent of contaminant release from the sorbed state; (3) to develop a reactive transport model based on molecular mechanisms and macroscopic flow experiments [(1) and (2)] that simulates adsorption, aging, and desorption dynamics.
Group Contacts: Nicolas Perdrial and Jon Chorover Collaborators: Karl Mueller (Penn State), Peggy O’Day (UC Merced), Jeff Serne (Pacific Northwest National Laboratory), Wooyong Um (Pacific Northwest National Laboratory), Carl Steefel (Lawrence Berkeley National Laboratory).
Funding Source: Department of Energy, Office of Science
Selected Project References (click here for full publication list): Chorover, J., S. Choi, M. K. Amistadi, K.G. Karthikeyan, G. Crosson, and K.T. Mueller. 2003. Linking cesium and strontium uptake to kaolinite weathering in simulated tank waste leachate. Environ. Sci. Technol. 37, 2200-2208. Choi, S., M. K. Amistadi and J. Chorover. 2005. Clay mineral weathering and contaminant dynamics in a caustic aqueous system. I. Wet Chemistry and Aging Effects Geochim. Cosmochim. Acta. 69, 4425-4436. Choi, S., P. A. O’Day, N. A. Rivera, K. T. Mueller, M. Vairavamurthy, S. Seraphin, and J. Chorover. 2006. Strontium speciation during reaction of kaolinite with simulated tank-waste leachate: Bulk and microfocused EXAFS analysis, Environ. Sci. Technol. 40, 2608-2614.