Integrated Stable Isotope - Reactive Transport Model Approach for Assessment of Chlorinated Solvent Degradation

This document presents the results of ESTCP Project ER-201029 Integrated Stable Isotope Reactive Transport Model Approach for Assessment of Chlorinated Solvent Degradation. The objective of this guidance is to help site managers apply a Reactive Transport Modeling RTM approach for improved Compound-Specific Isotope Analysis CSIA data interpretation and to use models to estimate more accurate attenuation processes for chlorinated solvents. The quantification of various destructive and transport processes and how they contribute to plume size and longevity may help extend Monitored Natural Attenuation MNA remedies to sites that have, heretofore, not been able to apply this important technology. In comparison with traditional data interpretation, the approach presented has several important benefits 1 improvement of a conceptual site models by identification and quantification of prevalent attenuation pathways and identification of secondary inputs from DNAPL dissolution or non-degradative sinks such as sorption or volatilization, diffusion or dispersion. 2 amore accurate assessment of degradation of the parent contaminant 3 quantitative assessment of the net degradationaccumulation of the dechlorination intermediates.