Oak Ridge National Laboratory is funded by the Department of Energy’s Environmental Remediation Sciences Division to conduct an Integrated Field-Scale Challenge (IFC) project entitled “Multi-scale Investigations on the Rates and Mechanisms of Targeted Immobilization and Natural Attenuation of Metal, Radionuclide and Co-Contaminants in the Subsurface.” The project is being conducted at the Oak Ridge Field Research Center (ORFRC), located on the Oak Ridge Reservation in east Tennessee. The primary objective of the IFC project is to advance the understanding and predictive capability of coupled hydrological, geochemical, and microbiological processes that control the in situ transport, remediation and natural attenuation of metals, radionuclides (i.e., uranium & technetium), and co-contaminants (i.e., nitrate & volatile organics) at multiple scales ranging from the molecular to the watershed. The research focuses on determining the key coupled hydrobiogeochemical factors such as pH, electron donor utilization, and redox conditions along contaminant pathways and specific transition zones that control the fate and transport of contaminants within spatially distributed source zones and groundwater plumes at the ORFRC. A variety of new innovative field investigation techniques have proven effective at the ORFRC for characterizing site conditions and monitoring field scale experiments. These techniques include 1) electrical resistivity, seismic, radar and spontaneous potential surface and borehole geophysics for characterizing lithology and plume distribution 2) repeated analysis of Permeable Environmental Leaching Capsules (PELCAPs) using a handheld X-Ray Fluorescence analyzer (XRF) for determining long-term contaminant uptake and release characteristics in a variety of subsurface environments, and 3) analysis of all major fixed gases (He, Ne, H₂, N₂, O₂, CO, CH₄, CO₂, & N₂O) using passive diffusion samplers and a newly adapted GC methodology to provide a more complete understanding of subsurface geochemistry than standard aqueous groundwater sampling and analysis techniques alone provide. Additional information is available at the ORFRC website (http://www.esd.ornl.gov/nabirfrc/).