Project Summary (2000-2005)

The goal of this project is to enhance our understanding of the dissolution, bioavailability, and remediation of complex, multiple-component, dense nonaqueous-phase immiscible organic liquids (DNAPLs) in subsurface systems. The specific objectives are: (1) investigate the effect of DNAPL composition and mass-transfer constraints on the dissolution of complex (multiple-component) DNAPL; (2) investigate the bioavailability and biodegradation of complex DNAPLs; (3) investigate the effect of solubilization agents on the dissolution and bioavailability of complex DNAPLs; (4) develop and evaluate advanced mathematical models capable of simulating the dissolution, biodegradation, and transport of DNAPL constituents in heterogeneous porous media. These objectives are addressed by taking a multi-step approach where these factors will first be characterized separately, and then integrated by the combined use of "multiple-factor" experiments and mathematical modeling. The investigators have developed systems that allow the simultaneous characterization of NAPL dissolution, contaminant transport and biodegradation, and microbial activity. The results of the proposed research will enhance the understanding of the dissolution and bioavailability of DNAPL mixtures in subsurface systems. These results will significantly improve the ability to conduct accurate risk assessments of the potential human-health-related impacts of contaminated sites. Furthermore, the results will assist in the design and implementation of more effective remediation systems. The results will also be pertinent to the issue of alternative, risk-based cleanup standards.