Fate and transport of volatile organic compounds (VOCs) in phytoremediation systems

Phytoremediation is the technology of treating contaminated soil and groundwater with plants. Since its advent, phytoremediation has been applied to the treatment of various contaminants. In the phytoremediation of volatile organic compounds (VOCs), several mechanistic pathways have been suggested, but these pathways have not been fully researched and described. This research focused on the processes involved in uptake and volatilization of organic compounds by plants.; The partitioning of VOCs, including several representative chlorinated solvents, were investigated in different media. VOCs were shown to be taken up by hybrid poplar trees and volatilized to the atmosphere, and these processes were quantified in different scales and settings. WE diffusion to the atmosphere declined exponentially along height and concentrations in the transpiration stream also declined in both vertical and radial directions.; Mathematical modeling was developed based on mechanisms studied to predict contaminant profiles, diffusion and also to estimate levels of contaminants in groundwater via tree core sampling. The modeling showed that xylem transport, including advection, dispersion and diffusion through cell walls and subsequent volatilization to the atmosphere can be a major fate for highly volatile organic compounds. The comprehensive model was simplified for easier applications. The modeling demonstrated the exponential decline of both VOCs concentrations in the transpiration stream and VOCs diffusion to the atmosphere along height. The modeling provides insight to other compounds and plants in phytoremediation.