This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 48, Passive Treatment Technology Evaluation for Reducing Metal Loading, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S. Department of Energy. MSE Technology Applications, Inc. performed the technology demonstration. The overall project objective was to evaluate passive treatment media for a given water chemistry that could provide information to identify potential treatment systems to reduce the dissolved metals loading contribution from Canyon Creek by 50%. A 50/50 blend of groundwater retrieved from Canyon Creek sampling site wells CC1508 and MW-CCTW01S was used in column and batch testing. The data from batch testing was used to determine parameters for the column testing. Initial tests determined the equilibrium loading of each passive media. The three media with the highest heavy metals loading were used to determine passive treatment bed design characteristics (mass transfer zone, breakthrough curves, precipitation issues, etc.) during the column study. In EPA Region 10, as well as other EPA regions, research has been initiated to implement and evaluate a variety of reactive media for water treatment at a number of sites. It should be noted that information from this study is not directly transferable to other sites because water chemistry is site-specific and performance of media will therefore vary from site to site.