(519f) A Five-Year Field Study to Evaluate Phytoremediation of a Crude Oil-Contaminated Soil

Authors: 
Thoma, G. J., Chemical Engineering; University of Arkansas
Karim, K., University of Arkansas
Wolf, D., University of Arkansas
White, P., University of Arkansas
Alba, O., University of Arkansas
Davis, K., University of Arkansas


Phytoremediation can be a cost-effective and low-maintenance means of remediating crude oil-contaminated soil. The objective of the field study was to evaluate the effects of vegetation establishment and fertilizer additions on remediation of crude oil-contaminated soil. Four replications of the following treatments were used: non-fertilized vegetation-free control; ryegrass - fescue mixture + fertilizer; or bermudagrass - fescue mixture + fertilizer. Vegetation was successfully established at the site and samples were collected a total of 10 times over a 5-yr period. Soil chemical and biological properties were analyzed and the initial GC/FID total petroleum hydrocarbon (TPH) concentration of 9,175 mg/kg was reduced to a range of 3,000 to 8,000 mg/kg after 57 months. Results indicated bacteria levels were greater in the vegetated + fertilized plots than in the control. Mean shoot biomass yields after 42 months were 110 and 85 g/m2 for the bermudagrass - fescue mixture + fertilizer and ryegrass - fescue mixture + fertilizer, respectively. Mean root biomass after 42 months were 1325 and 5246 g/m3 for the bermudagrass - fescue mixture + fertilizer and ryegrass - fescue mixture + fertilizer, respectively. Bacterial and fungal numbers increased in response to vegetation establishment and fertilizer addition during phytoremediation of the crude oil-contaminated site.