Under this FETC-funded program, Biopraxis proposed to demonstrate the feasibility of using its new MOP-UP technology for in situ treatment of metal-contaminated groundwater. Instead of optimizing the technology to demonstrate the feasibility of its use at a single site, the final series of tests were designed to showcase the breadth and flexibility of the MOP-UP technology by demonstrating its capabilities in as many different groundwater environments as possible. Sites that were contaminated with metal pollutants of wide-spread concern to DOE were located; and MOP-UP reagents were screened for their ability to treat any or all of these metals--without any attempt to optimize the technology for use with the new target metals and/or for treating these metals under the diverse conditions found at the sites. Groundwater samples exhibiting a wide range of environments were generously provided by DoD, EPA, and private industry as well as DOE for use in these treatability tests. The tests showed that MOP-UP can readily remove all detectable traces of a wide variety of metals, such as Hg, Pb, Cd, Cu, Cr(VI), As, Ba, Zn, and Al, and take U into the low parts per trillions, in heavily polluted groundwater, with little or no effort needed to optimize the reagent formulation. The second goal of the program was to show that the in situ groundwater MOP-UP technology will either be more cost effective than conventional technologies while achieving the same degree of groundwater purification, or be at least as cost effective as conventional technologies while offering superior performance. MOP-UP far surpassed the goals established for this initial feasibility demonstration. This new technology promises to be extremely effective and very economical whether used in a permeable barrier for treating shallow plumes, or a direct injection or pump-and-treat configuration for treating deep-subsurface plumes of heavy metal, radionuclide, or mixed contamination.