Evaluation of Dechlorination Pathways and Contaminant Transport Through a Fractured Aquifer Using Multivariate Statistical Analyses(ABSTRACT)

摘要

Determining the performance of an open bioreactor in the treatment of chlorinated aliphatic hydrocarbons (CAHs) has been challenging due to limited understanding of potential multiple degradation pathways and unknown contaminant transport mechanisms in the underlying fractured aquifer. The open bioreactor was constructed in the location of former landfill trenches at the U.S. Army's Camp Stanley Storage Activity (CSSA) in Boerne, Texas. The system is complex because it responds to seasonal changes, such as recharge and precipitation that result in shifting redox conditions and changes in transport pathways. The objective of this study was to interpret complex data collected over a three-year period to determine the existence of multiple degradation and transport pathways. The data includes: (1) chemical parameters, such as concentrations of CAHs and availability of electron donors and acceptors, (2) biological indicators, such as Dehalococcoides activity, and (3) recent forensic chemistry evidence, such as stable isotope analysis of oxygen and hydrogen in water and Compound-specific Stable Isotope Analysis of CAHs.