Pyrene Degradation in the Rhizosphere of Tall Fescue (Festuca arundinacea) and Switchgrass (Panicum virgatum L.)

A growth chamber study was conducted to investigate the fate of pyrene in the rhizosphere of tall fescue (Festuca arundinacea) and switchgrass (Panicum virgatum L.). For this study, ¹⁴C-labeled pyrene was used, and distribution of ¹⁴C activity was assessed after plant establishment. After 190 days of incubation, 37.7 and 30.4% of ¹⁴C-pyrene was mineralized in the soil planted with tall fescue and switchgrass, respectively, while 4.3% mineralization was observed for the unplanted control. Only 7.6 and 8.7% of pyrene was recovered from the soil in the two planted treatments, while 31.5% of pyrene remained in the unplanted control. Significant amounts of ¹⁴C were observed for all treatments and controls in the humic/ fulvic fraction of soil at the end of the experiment. This research indicates the potential for pyrene mineralization in planted systems, although the ultimate fate of degradation byproducts is uncertain.