Phytoremediation: Plant uptake of atrazine and role of root exudates

Phytoremediation is an emerging technology for degradation of organic chemicals. The potential of phytoremediation in the cleanup of contaminated sites and prevention of non-point-source pollution was examined with the pesticide atrazine in two experimental systems. Uptake was determined in batch experiments with C-14 ring-labeled atrazine and hybrid poplar trees grown in two soil types, Mineralization was studied utilizing soil microcosms with the addition of root exudates. Results indicate that poplar cuttings were able to uptake the majority of applied atrazine that was not tightly sorbed to the organic fraction of the soil, with no detectable adverse effects to the trees. The addition of root exudate to microcosms showed slight stimulation and the addition of ground-up root biomass revealed large stimulation of mineralization to (CO2)-C-14. From experimentally acquired data, a mathematical model was developed to obtain kinetic rate constants. This research indicates that vegetative uptake and degradation in the rhizosphere can play a major role in remediation at hazardous waste sites.