Objective

In situ chemical oxidation (ISCO) has proven effective in reducing potential Department of Defense (DoD) liability and health risks by oxidation of organic contaminants in situ. ISCO has been applied widely at DoD and non-DoD sites, and while it is effective for organic contaminant removal, it has also resulted in significant release of metals and metalloids in groundwater. The release of metals and metalloids is not fully understood nor is it predictable; elevated levels of metals in groundwater have recently prohibited a number of site closures and represent significant uncertainty in the remedial selection process. For ISCO to be a cost-effective and predictable remediation method, the unintended reactions that release metals and metalloids need to be understood and mitigation methods need to be developed and demonstrated.

The objectives of this project are to develop a fundamental and predictive understanding of metals release as a result of three common ISCO approaches; develop a mechanistic geochemical model to describe release and to design mitigation measures; experimentally evaluate fate of redox and pH perturbations and elevated metals released; demonstrate efficacy of pre-, co-, or post-treatment metals mitigation measures; and develop guidance for the design community to predict release, understand mechanisms, and design mitigation strategies as well as maximize the utility of ISCO, reduce impacts to groundwater, and minimize life-cycle costs of the remedial technology.