Geochemistry and bioremediation of oiled Louisiana salt marshes amended with clay minerals PDF
Preview Geochemistry and bioremediation of oiled Louisiana salt marshes amended with clay minerals
GGeeoorrggiiaa SSttaattee UUnniivveerrssiittyy SScchhoollaarrWWoorrkkss @@ GGeeoorrggiiaa SSttaattee UUnniivveerrssiittyy Geosciences Dissertations Department of Geosciences Summer 6-12-2014 GGeeoocchheemmiissttrryy aanndd bbiioorreemmeeddiiaattiioonn ooff ooiilleedd LLoouuiissiiaannaa ssaalltt mmaarrsshheess aammeennddeedd wwiitthh ccllaayy mmiinneerraallss Jill Ghelerter Follow this and additional works at: https://scholarworks.gsu.edu/geosciences_diss RReeccoommmmeennddeedd CCiittaattiioonn Ghelerter, Jill, "Geochemistry and bioremediation of oiled Louisiana salt marshes amended with clay minerals." Dissertation, Georgia State University, 2014. doi: https://doi.org/10.57709/5661841 This Dissertation is brought to you for free and open access by the Department of Geosciences at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Geosciences Dissertations by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. GEOCHEMISTRY AND BIOREMEDIATION OF OILED LOUISIANA SALT MARSHES AMENDED WITH CLAY MINERALS by JILL E. GHELERTER ` Under the Direction of Dr. Daniel Deocampo ABSTRACT Salt marshes are one of the most difficult environments to remediate due to their sensitive and important ecosystems. Traditional cleanup methods can do more harm to the marsh than the oil itself. Bioremediation is the preferred cleanup approach for these delicate environments. Typically bioremedi‐ ation has been carried out by the addition of nutrients but the results have been inconsistent. Previous laboratory studies conducted in oiled seawater demonstrated that clay minerals enhanced microbial growth and hence oil degradation. However, this had not been tested at field sites or on oiled marine sediments where oil is known to persist. The main objectives of this research were to test clay minerals as a bioremediation alternative for enhancing degradation of oiled salt marsh sediments and evaluate the geochemistry of sediment profiles for heavy metal enrichment. Laboratory experiments were car‐ ried out to evaluate the application of montmorillonite or kaolinite clay minerals on salt marsh sedi‐ ments impacted by diesel oil. Oil biodegradation in control experiments was significantly more success‐ ful than in clay amended experiments. Clay minerals may have caused an increase in pH which inhibited enzyme‐catalyzed processes required for metabolism. Field experiments were carried out in control and clay treatment plots in Louisiana salt marshes impacted by the Deepwater Horizon oil spill. In this re‐ search it was demonstrated for the first time that biodegradation of n‐alkanes and PAHs was significant‐ ly enhanced by the addition of montmorillonite compared to controls. Vegetated treatment plots were slightly more effective than non‐vegetative treatment areas. It is suggested that bivalent cations ad‐ sorbed to montmroillonite’s surface suppressed the diffuse double layer. This allowed the oil along the clay’s surface to be accessible to the bacteria where oil could be readily consumed. Clay minerals may serve as a new and unique bioremediation strategy for oiled salt marsh sediments. Geochemical sedi‐ ment profiles from Louisiana salt marshes showed elevated concentrations of selected heavy metals (Zn > Cu > Pb > V > Cr > Fe > Ni). The Deepwater Horizon oil spill is a likely source of metal enrichment as many of these same metals are also constituents of the Deepwater Horizon oil. INDEX WORDS: Oil spills, Petroleum, Clay minerals, Salt marshes, Bioremediation, Geochemistry GEOCHEMISTRY AND BIOREMEDIATION OF OILED LOUISIANA SALT MARSHES AMENDED WITH CLAY MINERALS by JILL E. GHELERTER A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the College of Arts and Sciences Georgia State University 2014 Copyright by Jill Ellen Ghelerter 2014 GEOCHEMISTRY AND BIOREMEDIATION OF OILED LOUISIANA SALT MARSHES AMENDED WITH CLAY MINERALS by JILL E. GHELERTER Committee Chair: Daniel Deocampo Committee: W. Crawford Elliott Seth Rose Jack Spadaro Electronic Version Approved: Office of Graduate Studies College of Arts and Sciences Georgia State University August 2014 i DEDICATION I dedicate this dissertation to my beautiful wife and best friend of 17 years, Kimberly, for stand‐ ing by me through this journey. Your support, advice, motivation, and love have been the impetus to make this work possible. You have kept me on cloud nine when it was truly needed. I would like to also dedicate this dissertation to my late Grandmother, Bernice Ghelerter, who passed away during the course of this study. Her support, encouragement, and constant love have sus‐ tained me throughout my life. v ACKNOWLEDGEMENTS First and foremost I would like to thank Dr. Deocampo for all his guidance, support, and invalua‐ ble direction. Also, I would like to thank Dr. Elliott who supported me by initially going the extra step to assist me into the program and also for his comments and suggestions. I would like to thank Dr. Rose who challenged me to become an expert and also for his comments and suggestions. Finally, I would like to thank Dr. Spadaro who really pulled through for me and provided me with great challenging com‐ ments. I would like to thank the organizations which helped me fund this research. They include Sigma Xi, Geological Society of America, International Association of Geochemists, and the American Associa‐ tion of Petroleum Geologist. Additionally, I would like to thank Dr. Deocampo again for providing Na‐ tional Science Foundation funding for research support. I would like to thank V. Ryan Perry, Lucy Taylor, Terrell Parker, Jianren Wang, Tim Glover, and Dave Goershel for all their support. Lastly, I would like to thank Bill Updyke for making my full time job less stressful during my writing process. vi TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................................ v LIST OF TABLES ....................................................................................................................... ix LIST OF FIGURES ...................................................................................................................... x LIST OF ABBREVIATIONS ........................................................................................................ xiii 1 INTRODUCTION ................................................................................................................. 1 1.1 Site Description ......................................................................................................... 4 1.2 Louisiana Salt Marsh Ecology ..................................................................................... 4 1.3 Geochemistry of Salt Marshes ................................................................................... 7 1.4 Petroleum Formation and Chemistry ....................................................................... 10 1.4.1 Saturates ............................................................................................................ 11 1.4.2 Aromatics ........................................................................................................... 11 1.4.3 Polars ................................................................................................................. 12 1.4.4 Macondo Crude Oil ............................................................................................. 13 1.4.5 Diesel Oil Composition ........................................................................................ 13 1.5 Biodegradation of Petroleum ................................................................................... 14 1.6 Clay Mineralogy ....................................................................................................... 17 2 LITERATURE REVIEW ....................................................................................................... 36 2.1 Introduction ............................................................................................................ 36 2.2 Oil‐Mineral Interactions ........................................................................................... 36 2.3 Oil‐Mineral‐Microbial Interactions ........................................................................... 42 vii 3 MATERIALS AND METHODS ............................................................................................. 51 3.1 Microcosm Preparation ........................................................................................... 51 3.2 Field Design ............................................................................................................. 52 3.3 Clay Mineral Composition ........................................................................................ 52 3.4 Petroleum Analysis .................................................................................................. 52 3.5 Geochemical Analysis .............................................................................................. 53 3.6 Sediment Characterization ....................................................................................... 54 3.7 Depletion Ratios ...................................................................................................... 54 3.8 First‐Order Kinetics .................................................................................................. 55 4 RESULTS .......................................................................................................................... 59 4.1 Microcosm Experiments .......................................................................................... 59 4.1.1 Total Petroleum Hydrocarbons ........................................................................... 59 4.1.2 Saturated Hydrocarbons ..................................................................................... 62 4.1.3 Polyaromatic Hydrocarbons ................................................................................ 65 4.2 Field Experiments .................................................................................................... 69 4.2.1 Saturated Hydrocarbons ..................................................................................... 70 4.2.2 Aromatic Hydrocarbons ...................................................................................... 73 4.2.3 Geochemistry ...................................................................................................... 75 5 DISCUSSION .................................................................................................................. 113 5.1 Microcosms Experiments ....................................................................................... 113
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