| Abstract: | In situ remediation is inherently considered “green remediation.” The mechanisms of destruction by in situ technologies, however, are often unseen and not well understood. Further, physical effects of amendment application affect concentration data in an identical manner as the desired reactive mechanism. These uncertainties have led to the weight‐of‐evidence approach when proving viability: multiple rounds of data collection, bench studies, pilot studies, and so on. Skipping these steps has resulted in many failed in situ applications. Traditional assessment data are often tangential to the desired information (e.g., “Is contaminant being destroyed or just being pushed around and diluted?” and “What is the mechanism of the destruction and can it be monitored directly?”). An advanced site diagnostic tool, “Three‐Dimensional Compound Specific Stable Isotope Analysis” (3D‐CSIA), can assess the viability of in situ technologies by providing definitive data on contaminant destruction that are not concentration‐related. The 3D‐CSIA tool can also locate source zones and apportion remediation cost by identifying plumes of different isotope signatures and fractionation trends. Further, use of the 3D‐CSIA tool allows remediation professionals to evaluate effectiveness of treatment and make better decisions to expedite site closure and minimize costs. This article outlines the fundamentals of advanced site diagnostic tool 3D‐CSIA in detail, and its benefit is highlighted through a series of case studies at chlorinated solvent–contaminated sites. © 2010 Wiley Periodicals, Inc. |
