Interpretation of Progress of In Situ Remediation of TCE–Contaminated Clayey Till by Enhanced Reductive Dechlorination—Monitoring Aspects

摘要

Mette Christophersen and Jan Petersen (Region of Southern Denmark, Denmark) In situ remediation of chlorinated solvent contaminated sites by enhanced reductive dechlorination (ERD) is typically monitored by sampling and analysis of groundwater. Soil sampling and analysis during the remediation is not commonly done. In low permeability media, such as clayey tills, donor and specific degraders are applied by injection in natural fractures and sand stringers or by environmental fracturing (hydraulic/pneumatic). In such media contaminant and donor exchange between matrix and fractures/ sandstringers is diffusion limited. Hence, groundwater sampled from wells screened across the fractures/sandstringers may not be representative of the contaminant composition, redox conditions and donor/degrader availability in the soil matrix. This may lead to misinterpretation of the extend of remediation.