Plant-VOC Interaction: Site Investigation and Monitoring for Phytoremediation

Principal Investigator: Joel Burken (University of Missouri-Rolla)
Project Period: 10/1/03 - 9/30/06

This project will lead to a new understanding of Volatile Organic Compound (VOC) fate in phytoremediation systems. The fate of VOCs has not been elucidated and remains as a major uncertainty stifling regulatory approval. Data gathered will also be used to develop a new monitoring technique that may reduce the primary cost issue associated with phytoremediation, that being the monitoring costs associated with long time periods required. Thus, this project will address two of the main hurdles that limit the use of phytoremediation for VOCs that otherwise are amenable to treatment, and the project will address these issues on a mechanistic level as well as multiple field sites where active phytoremediation has been in place and monitored for years. Condensed objectives of this study are to:

I. Measure direct volatilization rates from hybrid poplars actively translocating VOCs;
2. Establish response relationships for tissue sample analysis and groundwater concentrations and determine the effect specific environmental variables have on the fate ofVOCs;
3. Calculate contaminant mass removal rates for contaminated sites by using transpirations stream measurements and transpiration rates;
4. Develop a comprehensive, mechanism-based model to mathematically explain the phenomenon observed;
5. Verify the use of trees as biosensors at multiple sites, using the results of objectives 1-3.

The overall hypotheses are that: 1) certain VOCs are amenable to uptake and translocation and are subject to volatilization from the transpiration stream, and 2) contaminant fate in plant:groundwater interactions follow laws of physics and biology and can be used to convert the results from easy-to-test plant biomass to groundwater concentrations.