You are here:
A SIMPLE MODEL FOR THE UPTAKE, TRANSLOCATION, AND ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS
Citation:
Sundberg, S. E., J. W. Fisher, J J. Ellington, J J. Evans, AND D. Keys. A SIMPLE MODEL FOR THE UPTAKE, TRANSLOCATION, AND ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS. Presented at Annual Meeting Southeastern Regional Chapter of the Society of Toxicology, Athens, GA, October 31-November 1, 2002.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
A simple mathematical model is being developed to describe the uptake, translocation, and accumulation of perchlorate in tobacco plants. The model defines a plant as a set of compartments, consisting of mass balance differential equations and plant-specific physiological parameters. The tobacco plant was subdivided into four major compartments for the model: solution, roots, stems, and leaves. Transport of perchlorate from the hydroponics solution through the roots, stems, and leaves was modeled by mass flow with the transpiration stream. Growth dilution was described by incorporating measured tobacco growth curves. Data obtained from a 13-day hydroponics growth study was used to determine plant growth curves and xylem flow rates as a function of time. There was good agreement between model predictions and measured concentrations for the solution and leaves, while soil and root concentrations were slightly under-predicted. Data obtained from a separate study with a wider solution concentration range was used to validate predicted leaf concentrations. This model, once adequately validated, can be applied more generally to other plants and chemicals currently used for phytoremediation and ecological risk assessment.