Microcosm phytoremediation of crude oil using Spartina alterniflora and simulated via a mathematica model

Microcosm phytoremediation of crude oil using Spartina alterniflora and simulated via a mathematica model." ii To my family for all their endless support and to the love of my life Adrianna iii ACKNOWLEDGMENTS First and foremost I would like to thank Professor Jerald Schnoor for letting me work for him, sharing his abundance of knowledge, and being an incredible adviser. Thank you to all of the University of Iowa CEE faculty and students for creating an atmosphere that has felt like home during my many years at Iowa. My gratitude goes to Assistant Professor Craig Just and Professor Keri Hornbuckle for their participation on my thesis committee. A special thanks goes to BP for providing the funding which made this research all possible. Additionally the extra help from David Tsao and Todd Ririe was very much appreciated. iv ABSTRACT Light, medium and heavy crude oils were studied at three concentrations and with two different sediments in experimental microcosm settings to determine the ability of Spartina alterniflora and associated microbes to breakdown total extractable hydrocarbons (TEH) in the water. It was a baseline experiment designed to quantify the rates of biodegradation under relatively quiescent conditions from different crude oils at moderate doses ranging from 0-150 mg/g soil. Upon the completion of the experiment there were several key findings: (1) The lethal dosage for Spartina alterniflora was not reached within the 90 day experiment at these dosages, and all plants survived; (2) More than 97% of the total extractable hydrocarbons (TEH) were shown to be degraded by plants and rhizosphere microorganisms within the 90-day experiment; (3) The dose of oil introduced as a slick (simulated spill) on day zero did not significantly affect the results for TEH degradation within the range of dosages from 50-150 mg/g-these dosages could be degraded by the marsh cord grass system; (4) A sediment type which was acclimated to oil for several months and one which was non-acclimated did not show significantly different results for TEH degradation in the microcosms-both sediment systems resulted in TEH degradation over the 90-day experiment; and (5) A mathematical model was developed which simulated experiment results quite closely including TEH diffusion from the crude oil slick into the water and subsequent biodegradation.