Using Plants to Remediate Petroleum-Contaminated Soil

EPA Grant Number: R827015-01-0
Title: Using Plants to Remediate Petroleum-Contaminated Soil
Investigators: Greg Thoma, Duane Wolf, Craig Beyrouty
Institutions: University of Arkansas
EPA Project Officer: Bala Krishnan
Project Period: September 1, 1999 to August 31, 2000 (N/C Ext. to June 3 0, 2001)
Project Amount: $134,949
Research Category: Phytoremediation



Numerous techniques exist for remediating hydrocarbon contaminated soils. Most of these are expensive and labor intensive, often requiring significant disturbance of the soil to achieve clean up. Thousands of oil drilling rigs remain in operation to delay remediation because current technology is cost prohibitive. Phytoremediation is a process that uses actively growing plant roots to stimulate a diverse population of soil microorganisms, some of which have the capability to metabolize hydrocarbon contaminants. This process is relatively non-invasive, does not require extensive capital investment, and can enhance soil properties. Using plants and the associated rhizosphere (soil adjacent to roots) microorganisms to enhance biodegradation of petroleum contaminants may provide a low-cost option well suited to many sites. The goal of phytoremediation is to increase the remediation rate and to lower the contaminant concentration to an acceptable level.

As environmental control costs spiral and penalties for errors of judgment become more severe, environmental quality management increasingly needs analytical tools founded in an understanding of the processes affecting that quality. The extreme complexity of soil-plant-microbe system makes it apparent that the use of simulation models to help summarize and interpret experimental results, and provide a means of transferring experimental results to unstudied situations, is an important aspect of the growing field of phytoremediation. Thus the proposed research is intended to assess the potential of phytoremediation for clean up of petroleum contaminated soil through carefully designed laboratory, field, and mathematical modeling efforts. The research consists of two experimental components that will provide validation data for the modeling study. First, we will survey and collect plant species currently growing on contaminated sites and assess the plants and rhizosphere microorganisms for their ability to enhance biodegradation of petroleum contaminants in laboratory and greenhouse studies. Using information from the on-site survey and data from the other studies, we will conduct field studies to evaluate the appropriate plants and management systems to enhance phytoremediation of petroleum-contaminated sites.

When completed, the research will provide guidance in the management of phytoremediation projects nationwide.