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, C-14-labeled pyrene was used, and distribution of C-14 activity was assessed after plant establishment. After 190 days of incubation, 37.7 and 30.4% of C-14-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 C-14 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.