Monday, November 13, 2006

A field study evaluating phytoremedation of a crude oil-contaminated soil.

Khursheed Karim, Greg J. Thoma, Paul White, Kaaron Davis, and Duane Wolf. University of Arkansas, Dept of Chemical Engineering, BELL 3202, Fayetteville, AR 72701

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; fescue + fertilizer; or bermudagrass + fertilizer. Vegetation was successfully established at the site and samples were collected annually for 5 yr. Soil chemical and biological properties were analyzed and the initial GC/FID total petroleum hydrocarbon (TPH) concentration of 18,600 mg/kg was reduced to 7,800 and 5,200 mg/kg for the control and vegetated + fertilized treatments, respectively, after 57 mo. Results indicated bacteria levels were greater in the vegetated + fertilized plots than in the control. Mean shoot biomass yields at 45 mo were 355 and 235 g/m2 for the bermudagrass + fertilizer and fescue + fertilizer, respectively. Mean root length at 45 mo were 159 and 95 km/m3 for the bermudagrass + fertilizer and fescue + fertilizer, respectively.  Bacterial and TPH degrader numbers increased in response to vegetation establishment and fertilizer addition during the study. Phytoremediation of a crude oil-contaminated soil was demonstrated in the field study.