PHYTOREMEDIATION PETROLEUM HYDROCARBON
CONTAMINATED SOIL: RESULTS FROM THE
RTDF COOPERATIVE FIELD TESTS
Peter A. Kulakow*
Kansas State University
Department of Agronomy
2004 Throckmorton Plant Sciences Center
Manhattan, KS 66506-5501
Voice: 785-532-7239
Fax: 785-532-6094
E-mail: kulakow@ksu.edu
B. A. Leven
L. Erickson
Center for Hazardous Substance Research
Kansas State University
Manhattan, KS
Cooperative field trials have been in progress since 1998 to test phytoremediation of weathered petroleum hydrocarbon contaminated soils as part of the Remediation Technologies Development Forum. Participants in the trials include United States Environmental Protection Agency, Environment Canada, United States Department of Defense, petroleum and utility corporations, universities, and environmental consultants. Thirteen test locations include refineries, former manufactured gas plants, spill sites, motor vehicle wastes, and oil production sites. The purpose of the trials is to determine if there is evidence that vegetation enhances progress toward meeting practical environmental management objectives for petroleum sites within a three-year period. A standardized experimental protocol with site-specific adjustments was developed, recognizing that changes in hydrocarbon concentrations are likely to be slow and subtle, contaminant distribution in the soil is variable, and monitoring will be needed for a long time. Most locations included three treatments: an unvegetated control, a cool-season grass/legume mixture, and a locally selected treatment of native plants or trees. Laboratory analyses included estimation of total petroleum hydrocarbons, polycyclic aromatic hydrocarbons, a hopane biomarker, and petroleum hydrocarbon fractions by the TPH criteria working group method. Eleven locations have completed the planned three-year trial period. Statistical analyses showed that observable effects of vegetation treatments on hydrocarbon concentrations varied among locations. Some locations showed strong positive effects of vegetation treatments while others did not show evidence of treatment differences. High variability, especially at refinery sites, decreased the ability to detect treatment differences. Conclusions and lessons learned will be discussed. Appropriate applications of phytoremediation for petroleum sites will depend on contaminant composition, local conditions, and site-specific environmental management objectives.