RAPID: Affect of Petroleum Deposit Geometry on Biodegradation Potential and Long-Term Persistence

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

PI: Amy Pruden Proposal Number: 1053221 Institution: Virginia Polytechnic Institute and State University Title: RAPID: Effect of Petroleum Deposit Geometry on Biodegradation Potential and Long-Term Persistence The current Gulf of Mexico oil spill has contaminated an unprecedented expanse of shoreline with crude oil. Thus, the extent of petroleum deposits accumulating along the coast represents a scale never before encountered by humankind. This underscores a critical urgency to develop and apply the best available tools to predict the long term persistence of potential contaminants of concern (PCOCs) derived from these deposits and to inform potential remediation strategies. The proposed RAPID response research project will apply a novel integrated molecular biological and modeling approach to critically examine the role of petroleum deposit geometry in governing the attenuation of PCOCs. Funding is particularly urgent considering the need to characterize petroleum deposits in the field prior to their disruption by hurricanes and also to obtain shoreline samples that have not yet been tainted with oil in order to examine the time scale and importance of microbial adaptation in governing biodegradation potential. While the importance of geometry on the fate and transport of other light non aqueous phase liquid (LNAPLs) has been established, deposit geometry remains an unexplored yet potentially critical factor governing the ultimate fate of the crude oil spilled into the Gulf. A particularly novel aspect of the proposed research effort is the integrated molecular microbiological and modeling approach that will be used to enhance predictions of persistence of crude oil deposits. Thus the three objectives of this research are to: 1) Determine the role of geometry in the attenuation of crude oil deposits via dissolution and biodegradation; 2) Determine the effect of petroleum deposit geometry on predominant electron acceptor conditions, overall biodegradation rates, and time scale for microbial adaptation; and 3) Develop an improved model of petroleum hydrocarbon attenuation considerate of petroleum deposit geometry and microbiological factors. These objectives will be accomplished through a combined field, laboratory, and computational modeling effort, including 3 D tank experiments testing various petroleum deposit geometries. Genome enabled tools targeting genes corresponding to key functions of interest, including aerobic polycyclic aromatic hydrocarbon (PAH) biodegradation and denitrifying, sulfate reducing and methanogenic conditions will be applied to characterize the upper, lower, and lateral surfaces of the petroleum deposits and to support the development of a conceptual model of the microbial contribution to petroleum dissolution and biodegradation. The ultimate outcome will be a computational tool to simulate PHC dissolution rates coupled to microbial activity and aqueous phase transport in marine and beach sediments. This model will be particularly useful in estimating time of remediation of PCOCs derived from crude oil deposits. The urgent nature of the current Gulf of Mexico oil spill crisis is readily apparent. Current estimates are that over 500 miles of shoreline have already been contaminated with an extensive array of tar balls and oil sheets. These oil deposits will be capped intentionally and unintentionally, resulting in persistence for years or perhaps even decades. The proposed work will fill a critical knowledge gap required to predict the long term persistence and ultimate fate of the oil deposits and associated PCOCs and thus will provide critical information to decision makers regarding remedial strategies. Additionally, the project will provide an inspiring training topic for a PhD and an undergraduate student, both of whom will play an integral role in the field sampling effort. The PI is also actively conducting hands on oil spill cleanup activities for underrepresented junior high students via the Virginia Tech College of Engineering Imagination Camp. Both PIs will also be featuring the oil spill case study as a valuable and inspiring learning tool in their respective sections of CEE 2804 Introduction to Civil and Environmental Engineering. The project team aims for rapid dissemination of the results to the scientific community, including peer reviewed publications and presentations at scientific conferences.