Column-leaching experiments were conducted on an acid pyritic coal spoil to determine the influence of acid rain, humic acid (HA), fulvic acid (FA), and undecomposed organic matter (OM) on pH and Al, Fe, Mn, and S0 4 concentrations in the spoil leachate and on the spoil. Simulated acid rain of pH 4.0 was applied for 50 weeks under laboratory conditions to spoil columns modified with 0.5% FA or HA, or 2.0% OM from four forest trees and two herbs. Quality-control methods were used to evaluate

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... tment effects. Addition of HA and tall fescue leaf material to a Lily, KY, spoil created a greater and longer lasting desirable effect on leachate pH and Al, Fe, Mn, and S0 4 than additions of FA or OM of five other species. Results suggest that revegetation resulting in rapid production of matured soil OM may reduce the amount of some ions commonly leached from acid mine spoils.