Decay Kinetics of Toluene Phytoremediation Stimulation

Begonia maculata, Ardisia crenata, and Ardisia japonica plants exposed to 3.5 ppm toluene in air for 12 h displayed a pronounced stimulation (358%, 318%, and 252%, respectively) in subsequent toluene removal potential. The duration of the stimulation effect, monitored over 3 weeks, was short-lived decaying to prestimulation levels within 1 to 7 days depending on species. Elevated phytoremediation rate was dependent on the continued presence of toluene. The rapid rate of increase in phytoremediation and subsequent decay points toward a response mediated by changes in gene expression by the plant, microorganisms within the media, or both rather than an alteration in microbe population. A better understanding of the stimulation response may facilitate the use of plants for indoor air remediation in homes and offices.