Depth-Resolved Molecular Biological Analysis of Groundwater Contaminant Plumes Using Cryogenic Core Collection

摘要

Monitoring of subsurface bioremediation should ideally identify zones within the contaminant plume in which biodegradation is dominantly occurring. Strategies in which sampling efforts focus mainly on groundwater samples from fixed depths (i.e. from the presumed centerline of the plume may prove inadequate for several reasons. Firstly, contaminant transformations may be confined to discrete areas of the plume in which oxidation and/or reduction conditions are suitable for the microorganisms capable of degradation. For example, degradation may be confined to the fringes of the contaminant plume where overlapping counter-gradients of electron donors and acceptors exist, (the so-called “plume fringe concept”). Even multilevel groundwater sampling may not be adequate to characterize such zones because the resolution of sampling is typically on the scale of meters. Secondly, physical heterogeneities, and temporal variations in hydrologic conditions can contribute to spatial variability of the plume. Finally, many