Sequestration of Subsurface Elemental Mercury

Research Objectives:

        The primary objective of this proposed research is to develop an improved understanding of the basic science behind the use of mineral sulfides and reduced sulfur-containing materials to abiotically immobilize subsurface mercury (Hg) in situ. The ultimate goal of this work is to develop a fundamental understanding of the potential of this technology, including the long-term stability under environmentally relevant conditions, sufficient to promote successful technology transfer to the field. This objective satisfies one of the critical research needs” of EPA’s persistent bioaccumulative toxic pollutants (PBTs) program, developing “sequestration methodologies for elemental mercury.” The specific goals of this project are to:
1. Elucidate the fundamental thermodynamic and kinetic parameters that control the partitioning (uptake and release) of Hg to sulfide minerals;
2. Investigate the behavior of the best materials under more complex hydrodynamic (i.e., flow-through) and environmental (pH, pO2, NOM, etc.) conditions,  including the long-term stability of the products;
3. Probe the immobilized Hg with state-of-the-art environmental spectroscopic techniques to determine the mechanism(s) responsible for immobilization;
4. Validate and test our understanding by conducting experiments with actual contaminated soils and groundwater from a number of different sites.