Mercury Diagenesis in the Saguenay Fjord By Geneviève Bernier August, 2005 A thesis submitted to the Office of Graduate and Postdoctoral Studies in partial fulfillment of the requirements for the Degree of Master of Science Earth and Planetary Sciences McGill University Montréal, Québec, Canada © Geneviève Bernier, 2005 Library and Bibliothèque et 1+1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l'édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A ON4 Ottawa ON K1A ON4 Canada Canada Your file Votre référence ISBN: 978-0-494-24618-4 Our file Notre référence ISBN: 978-0-494-24618-4 NOTICE: AVIS: The author has granted a non­ L'auteur a accordé une licence non exclusive exclusive license allowing Library permettant à la Bibliothèque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l'Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans loan, distribute and sell theses le monde, à des fins commerciales ou autres, worldwide, for commercial or non­ sur support microforme, papier, électronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriété du droit d'auteur ownership and moral rights in et des droits moraux qui protège cette thèse. this thesis. Neither the thesis Ni la thèse ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent être imprimés ou autrement may be printed or otherwise reproduits sans son autorisation. reproduced without the author's permission. ln compliance with the Canadian Conformément à la loi canadienne Privacy Act some supporting sur la protection de la vie privée, forms may have been removed quelques formulaires secondaires from this thesis. ont été enlevés de cette thèse. While these forms may be included Bien que ces formulaires in the document page cou nt, aient inclus dans la pagination, their removal does not represent il n'y aura aucun contenu manquant. any loss of content from the thesis. ••• Canada ACKNOWLEDGEMENTS 1 am grateful to the following people, whose help and continuous support are the foundation on which this thesis was built. First and foremost, to Dr. A. Mucci, 1 wish to express my most sincere appreciation and thanks for his guidance and endless patience during the tortuous path of this project, his commitment to his students, as well as for his cheerful stewardship of the field work conducted in the Saguenay Fjord and St. Lawrence. This was a considerable leaming experience for me on many levels, and 1 wish to thank him for giving me the opportunity to continue on with this project. Thanks also must be expressed to C. Guignard, for her support throughout, her considerable problem solving abilities, for maintaining the standards of rigorous laboratory practice, and for many excellent recipes. 1 also wish to thank G. Keating for her technical assistance and S. Musc10w for her cheerful presence and assistance during pyrite analyses, as well as to P. Collin, L. Barazzuol, C. Magen, P. Benoit, G. Chaillou, A. Villegas, S.T. Kim, C. Mann, and numerous others for the camaraderie, assistance, and exchange of ideas that made this project such a pleasant and stimulating experience. This study would not have been possible without fmancial backing from the Fonds pour la Formation des Chercheurs et l'Aide a la Recherche du Québec (FCAR). The Department of Earth and Planetary Sciences at McGill also provided financial support in the form of teaching assistantships and, more importantly, continuous moral and administrative support in the forms of Anne, Carol, and Kristy. Thanks also go to the captain and crew of the Alcide C. Horth, for their tireless work and for making field research such a pleasant experience. My gratitude also goes to J. Hartzler who, during the last stages of this undertaking, provided support and understanding that went beyond the bounds of a roommate's duty; and to S. Rahman for the sanity control, stimulating discussions, and late-night lab fun and laughter during our laboratory years together. Finally, my greatest thanks go to my family. To my brothers, for the cheerfulness and considerable support. To my mom, for her common sense, for always having an eye on the big picture, and always keeping my priorities straight. And to my dad, for the enthusiasm, the endless pep talks and moral support, and for being there at the very best oftimes. ii CONTRIBUTIONS OF AUTHORS This is a manuscript-based thesis divided in three chapters. The first chapter is a general introduction which provides an overview of the present knowledge on the chemistry of mercury and more specifically on the topics presented in this work. The third section includes the author's (Geneviève Bemier's) general conclusions and recommendations for future work. The second chapter was written in manuscript format and will be submitted to the scientific journal Applied Geochemistry. The author and Constance Guignard were responsible for aIl the experimental and analytical work. The interpretation of the results is solely the responsibility of the author who did benefit from critical comments and suggestions from Prof. Mucci. Prof. Alfonso Mucci, supervisor of this M.Sc. project, contributed heavily towards the edition of the manuscript. Funding for this project was provided by Natural Sciences and Engineering Research Council of Canada (NSERC) strategic and research grants to Prof. Mucci. Financial support to the author was provided by the Fonds pour la Formation des Chercheurs et l'Aide a la Recherche du Québec (FCAR) in the form of a post-graduate scholarship, and by the Department of Earth and Planetary Sciences at McGiH University in the form of teaching assistantships. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS II CONTRIBUTIONS OF AUTHORS III TABLE OF CONTENTS IV LIST OF FIGURES VII ABSTRACT IX RÉSUMÉ X CHAPT ER 1 1 INTRODUCTION 1 Sources of Mercury 2 Speciation of Mercury in the Surficial Cycle 4 History and Source of Mercury Contamination to the Sediments of the Saguenay Fjord 6 Diagenetic Behaviour of Mercury 7 Mercury mobility in marine sediments 7 Factors controlling mercury methylation and demethylation 9 Objectives 11 CUAPTER2 14 MERCURY GEOCHEMISTRY IN THE SEDIMENTS OF THE SAGUENAY FJORD: Diagenetic behaviour following a catastrophic depositional event 14 Abstract 15 Introduction 16 Fjord Morphology and Hydrographie Characteristics 18 Materials and Methods 20 Sampling history 20 iv ~.~ Sampling method 21 Analytical methods 22 Results and Discussion 23 Pre-flood conditions 23 Flood mate rial 28 Post-flood geochemistry 29 Summary and Conclusions 48 !:HAl!IERJ ~l Summary and conclusions 51 Recommendations for future work 55 REFERENCES 58 APPENDIX1 72 -----'. APPENDIX2 74 v TABLE OF FIGURES Figure 1: Map of the Saguenay Fjord showing the sampling sites. The number in brackets is the approximate thickness of the flood layer in centimeters. From Mucci et al. (2000) ............................................................................... l9. Figure 2: Geochemical characteristics and steady-state conditions of sediments recovered at SAG-30. a) Vertical distribution ofTHgs (ng goI) on five sampling dates over a 6-year period; b) Vertical distribution of THgd (ng LoI) at SAG-30 from a core recovered in 2001 (SAG-30/2001L ................~~ Figure 3: Geochemical characteristics of pre-flood sediments at SAG-09 from a core recovered in 1995 (SAG-09/1995): a) Corg (wt%), b) Cinorg (wt%) and c) THgs (ng goI) depth profiles............................................................................ ~9. Figure 4: Geochemical characteristics of pre-flood sediments at SAG-05 from a core recovered in 1991 (SAG-05/1991): a) Corg (wt%), b) Cinorg (wt%), c) THgs (ng goI), d) AVS (~mol goI) and e) pyrite (FeS2; ~mol goI) depth profiles. The short-dashed lines mark the approximate location of the upper and lower boundaries of the 1971 St. Jean-Vianney landslide deposit.............................................................................................................. ~~ Figure 5: Geochemical characteristics of sediments at SAG-09 from a core recovered three weeks after the 1996 flood (SAG-09/1996post-flood): a) Corg (wt%), b) Cinorg (wt%) and c) THgs (ng goI). The stippled line marks the approximate location of the contact between the flood material and indigenous sediment ...................................................................................... }l Figure 6: THgs depth profiles at SAG-09 from cores recovered in a) 1997 (SAG- 09/1997), b) 1998 (SAG-09/1998), c) 1999 (SAG-09/1999(1)), d) 1999 (SAG-09/1999(2), e) 2000 (SAG-09/2000), f) 2001 (SAG-09/2001) and g) 2002 (SAG-09/2002). The stippled lines mark the approximate location of the upper and lower boundaries of the flood deposit ................................. }~ Figure 7: Geochemical characteristics of sediments at SAG-09 from a core recovered in 2001 \SAG-09/2001): a) AVS (~mol gol), b) THgs (ng gol) and c) THgd (ng LO ). The stippled lines mark the approximate location of the upper and lower boundaries of the flood deposit.. ................................. }} Figure 8: Geochemical characteristics of sediments at SAG-09 from a core recovered in 2002 (SAG-09/2002): a) AVS (~mol gol), b) THg (ng gol) and c) THg (ng LoI). The stippled