When landfills are not completely impermeable then underlying groundwater may be contaminated by leachate constituents if these are not adequately retained by soils. Research on industrial waste disposal has centered on use of manufactured products such as plastics and cementing roadbed materials such as asphalt and concrete to alleviate this problem by completely preventing liquid movement out of the landfill. Little attention has been given to use of natural low-cost materials as barriers for minimizing pollution migration out of landfills by retaining contaminants from liquids as they pass. This is a report of the relative effectiveness of natural low-cost liners of crushed limestone, clayey soil, hydrous oxides of iron, and crushed pecan hulls for minimizing the migration of Be, Cd, Cr, Fe, Ni, Zn, and total organic carbon constituents of municipal solid waste landfill leachates. Several leachate variables such as aqueous dilution, aeration, pH, and flux were also studied for their effect on movement of metals through 11 representative U.S. soils. The research was conducted on a laboratory scale using soil columns as a first step in screening for potential liners and manipulation practices. Limestone and hydrous iron oxide were found to be potentially useful as porous liners for retention of metallic leachate constituents. The amounts of these materials in natural soils were also found to be useful predictors of contaminant removal.