UPTAKE AND METABOLISM OF ATRAZINE BY POPLAR TREES

Hybrid poplar trees can uptake, hydrolyze,and dealkylate atrazine to l ess toxic metabolites. In whole plant studies, the parent compound atr azine and C-14 ring-labeled metabolites were extracted from poplar tis sues and analyzed via high-pressure liquid chromatography (HPLC) with UV and radiochromatographic detectors in series. The concurrent separa tion and identification of these metabolites has not been previously r eported in higher plants for phytoremediation applications. Unidentifi ed metabolites were also detected. Metabolism of atrazine occurred in poplar roots, stems, and leaves and became more complete with increase d residence time in tissues. In poplar cuttings exposed to atrazine fo r 50 days, the parent compound comprised only 21% of the C-14 label in the leaves, while it constituted 59% of C-14 activity remaining in th e soil. After 80 days, the parent compound remaining in the leaves had decreased to only 10% of the C-14 label recovered in the leaves. Pref erred metabolic pathways were suggested by relative rates of reaction, and a mathematical model was developed to estimate rate constants for the proposed degradation mechanism. This research provides evidence f or vegetative detoxification of contaminants and suggests that phytore mediation of atrazine-contaminated soils may be feasible.