Prairie grasses are currently being used as biofiltration agents in removing pesticides from surface runoff and have been proposed as possible agents useful for phytoremediation of pesticide-contaminated soil. However, little research has been conducted on the fate of herbicides in prairie grass-soil environments. This study proposes to investigate the fate of metolachlor, atrazine, and pendimethalin in soil that has been planted with prairie grasses. Grasses grown in soil fortified with a radiolabeled herbicide will be placed in a sealed acrylic chamber. Volatile organic metabolites and CO2 will be analyzed throughout the experiment. In addition, plant and soil will be analyzed for total radioactivity, parent compounds and major metabolites after a remediation period. The proposed study will enhance our knowledge of the likelihood of the release of herbicides or possible bioactive metabolites back into the environment during and after biofiltration or phytoremediation. Additionally, insight will be obtained into the mechanisms of remediation, including the role of the plant.