ANALYSIS OF SOIL VAPOR EXTRACTION DATA TO EVALUATE MASS-TRANSFER CONSTRAINTS AND ESTIMATE MASS FLUX: HANFORD CASE STUDY

Management of chlorinated-solvent contaminated sites that have contaminant sources located in the vadose zone requires consideration of long-term vapor-phase mass flux processes. Such processes are pertinent to assessing risk, establishing groundwater-based cleanup objectives, and for evaluating the performance of soil vapor extraction (SVE) operations. Evaluation of long-term vapor-phase mass flux at field sites is a complex endeavor, complicated by subsurface material-property heterogeneity, non-uniform contaminant distributions, and nonideal contaminant-transport processes. The objective of this study was to evaluate the utility of SVE rebound data for characterizing the magnitudes, timescales, and temporal dynamics of mass flux associated with vadose zone contaminant sources. SVE operational data collected at the Department of Energy’s Hanford site are used to illustrate the results that may be obtained from analysis of SVE rebound data.