Rare earth elements as emerging contaminants in the Rhine River, Germany and its tributaries by Serkan Kulaksız A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geochemistry Approved, Thesis Committee _____________________________________ Prof. Dr. Michael Bau, Chair Jacobs University Bremen _____________________________________ Prof. Dr. Andrea Koschinsky Jacobs University Bremen _____________________________________ Dr. Dieter Garbe-Schönberg Universität Kiel Date of Defense: June 7th, 2012 _____________________________________ School of Engineering and Science TABLE OF CONTENTS CHAPTER I – INTRODUCTION 1 1. Outline 1 2. Research Goals 4 3. Geochemistry of the Rare Earth Elements 6 3.1 Controls on Rare Earth Elements in River Waters 6 3.2 Rare Earth Elements in Estuaries and Seawater 8 3.3 Anthropogenic Gadolinium 9 3.3.1 Controls on Anthropogenic Gadolinium 10 4. Demand for Rare Earth Elements 12 5 Rare Earth Element Toxicity 16 6. Study Area 17 7. References 19 Acknowledgements 28 CHAPTER II – SAMPLING AND METHODS 31 1. Sample Preparation 31 1.1 Pre‐concentration 32 2. Methods 34 2.1 HCO3 titration 34 2.2 Ion Chromatography 34 2.3 Inductively Coupled Plasma – Optical Emission Spectrometer 35 2.4 Inductively Coupled Plasma – Mass Spectrometer 35 2.4.1 Method reliability 36 3. References 41 CHAPTER III – RARE EARTH ELEMENTS IN THE RHINE RIVER, GERMANY: FIRST CASE OF ANTHROPOGENIC LANTHANUM AS A DISSOLVED MICROCONTAMINANT IN THE HYDROSPHERE 43 Abstract 44 1. Introduction 44 2. Sampling sites and Methods 46 2.1 Samples 46 2.2 Methods 46 2.3 Quantification of REE anomalies 47 3. Results and Discussion 48 4. Conclusions 49 Acknowledgements 49 5. References 49 CHAPTER IV – NATURAL AND ANTHROPOGENIC RARE EARTH ELEMENT DISTRIBUTION OF THE RHINE RIVER AND ITS TRIBUTARIES 51 1. Introduction 53 2. Sampling and Methods 58 2.1 Sample Processing and Analysis 58 2.2 Quantification of anomalies / Extrapolation of missing data 59 2.3 Study Area 60 2.3.1 Rhine River Sections 61 2.3.2 Lake Constance 62 3. Results 63 3.1 Major Ions 64 3.1.1 Rhine River 64 3.1.2 The effect of the input of effluent at Rhine‐km 447.3 75 3.1.3 Tributaries 77 3.1.3.1 Aare 80 3.1.3.2 Main 80 3.1.3.3 Mosel 80 3.1.3.4 Neckar 81 3.1.3.5 Lippe 81 3.1.3.6 Wupper 82 3.2 Rare Earth Elements 82 3.2.1 Rare Earth Elements in the Rhine River 82 3.2.2 Rare Earth Elements in the Tributaries 86 3.2.2.1 Aare 87 3.2.2.2 Main 88 3.2.2.3 Mosel 89 3.2.2.4 Neckar 90 3.2.2.5 Lippe 90 3.2.2.6 Wupper 91 4. Discussion 93 4.1 Natural Rare Earth Elements 93 4.2 Ce Anomaly 94 4.3 Anthropogenic Gd 98 4.3.1 Variation of anthropogenic Gd with weekday 101 4.4 Anthropogenic La 105 4.5 Anthropogenic vs. Natural Rare Earth Elements 107 4.5.1 Anthropogenic La vs. Gd 109 5. Conclusions and Outlook 117 5.1 Rare Earth Elements as Emerging Contaminants 117 5.2 Suggestions and Outlook 118 Acknowledgements 120 6. References 121 CHAPTER V – ANTHROPOGENIC DISSOLVED AND COLLOID/NANOPARTICLE‐BOUND SAMARIUM, LANTHANUM AND GADOLINIUM IN THE RHINE RIVER AND THE IMPENDING DESTRUCTION OF THE NATURAL RARE EARTH ELEMENT DISTRIBUTION IN RIVERS 129 Abstract 130 1. Introduction 130 2. Methods 131 2.1. Sampling and analysis 131 2.2 Quantification of REE anomalies 133 3. Results 134 3.1 Dissolved REE 134 3.2. The truly dissolved and nanoparticulate REE pools 134 4. Discussion 135 4.1 Samarium as another emerging REE microcontaminant 135 4.2 Truly dissolved and nanoparticulate anthropogenic REE 135 4.3 Quantifying anthropogenic REE transport via the Rhine River 135 4.4 Environmental impact of anthropogenic REE 136 5. Conclusions 136 Acknowledgements 136 References 136 CHAPTER VI ‐ ANTHROPOGENIC GADOLINIUM AS A MICROCONTAMINANT IN TAP WATER USED AS DRINKING WATER IN URBAN AREAS AND MEGACITIES 139 Abstract 140 1. Introduction 140 2. Materials and Methods 142 2.1 Sampling 142 2.2 Quantification of anomalies 142 3. Results and Discussion 144 3.1 Distribution of uranium, barium, rubidium and strontium 144 3.2 Rare earth elements 144 3.2 Toxicity of Gd3+ and Gd‐CA 146 4. Conclusions 147 Acknowledgements 147 5. References 147 CHAPTER VII – CONCLUSIONS 151 1. Documenting and quantifying anthropogenic Rare Earth Elements 151 1.1 Anthropogenic Gd 151 1.2 Anthropogenic La 151 1.3 Anthropogenic Sm 152 2. Controls on Rare Earth Elements in the Rhine River Catchment 152 2.1 Natural Rare Earth Elements 152 2.2 Anthropogenic Rare Earth Elements 153 3. The Role of Ultrafiltration 153 4. Rare Earth Elements as Emerging Contaminants in Tap Water 154 5. Closing Remarks 156 APPENDIX 1 159 Shale normalized REE patterns of the Rhine River APPENDIX 2 167 Shale normalized REE patterns of the tributaries of the Rhine River APPENDIX 3 174 Data for the Rhine River in May 2008 APPENDIX 4 179 Data for the Rhine River in May 2009 APPENDIX 5 184 Data for the Rhine River in October 2009 APPENDIX 6 189 Data for the tributaries of the Rhine River in May 2008 APPENDIX 7 194 Data for the tributaries of the Rhine River in May 2009 APPENDIX 8 199 Data for the tributaries of the Rhine River in October 2009 APPENDIX 9 204 Data for the Wiembach Creek and Lake Constance APPENDIX 10 206 General information and references for the tributaries of the Rhine River APPENDIX 11 208 Calculation of Rare Earth Element Anomalies Andreas Gursky’s $4.3m photo (Rhein II, 1999) of the Rhine River1: „The Rhine is the river about which all the world speaks but no one studies, which all the world visits but no one knows, which one sees as it passes but forgets as it flows, which everyone skims but no one plumbs. Still, its ruins lift the imagination and its destiny preoccupies serious minds; and below the surface of its current, this admirable river reveals to the poet and statesmen alike the past and future of Europe.“ Victor Hugo, 1845 1 Fair use rationale: The image is a low resolution copy of the original work, and of such low quality that it will not affect potential sales of the art work. CHAPTER I – INTRODUCTION 1. OUTLINE This dissertation is divided into 7 chapters, with each one focusing on a specific aspect of the general research questions. The first chapter states the objectives of this study and provides an introduction into rare earth elements (REE) in aqueous media. General information on the Rhine River and its tributaries is provided, as well as a map showing sampling locations. Analytical methods are presented in the short Chapter II, including sample preparation, workflows and assessment of the analytical quality of the dataset. Measured elements include ‐ ‐ ‐ 2‐ + + 2+ 2+ ‐ major anions (Cl , Br , NO3 and SO4 ), major cations (Na , K , Mg and Ca ), Si, HCO3 , trace elements such as Ba, Rb, Sr, U, Y and REE (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). Chapter III presents one of the key findings in this study: the first report of anthropogenic La anomalies in rivers worldwide is reported. The source of the La contamination is presented, and possible implications for the environment and natural REE studies are discussed. The La contamination is traced to a point source at Rhine‐km 447.3: effluent discharge from a factory producing fluid catalytic cracking (FCC) catalysts. In the vicinity of the effluent pipe, La concentrations of up to 49 mg/kg are measured, well above ecotoxicological levels. This chapter was published in Vol. 37 of the journal Environment International in 2011 with the title “Rare earth elements in the Rhine River, Germany: First case of anthropogenic lanthanum as a dissolved microcontaminant in the hydrosphere” and can be found online at http://dx.doi.org/10.1016/j.envint.2011.02.018. Chapter IV presents largely unpublished data and represents the first extensive REE dataset on the Rhine River and its tributaries. Sampling was carried out in May 2008, May 2009 and October 2009 covering the Rhine River from the Swiss – German border to the German – Dutch border. Natural REE and anthropogenic REE are discussed separately, with emphasis on anthropogenic REE. Anthropogenic Gd increases steadily going downstream due to its diffuse source nature, while anthropogenic La emerges at approximately Rhine‐km 450 due to its point‐source nature 1 and is then diluted further downstream. The effect of seasonal discharge is discussed with regards to natural and anthropogenic REE. Several tributaries in the Ruhr‐area (a conglomerate megacity in the Middle Rhine) show exceptionally high Gd anomalies due to the increased amount of anthropogenic Gd input and the small discharge of the tributaries. A tendency for reduced Gd anomalies on the first weekdays can also be observed. Based on discharge and concentration data, estimates of yearly export of anthropogenic Gd and La to the North Sea via the Rhine River are given (Gd: 53 – 215 kg/year; La: 862 – 1090 kg/year). This chapter is titled “Natural and Anthropogenic Rare Earth Element Distribution of the Rhine River and its Tributaries” and is in preparation for submission. Chapter V reports on the first occurrence of anthropogenic Sm anomalies in rivers worldwide. The Rhine River has Sm concentrations up to 7.7 times higher than background concentrations. The Sm contamination in the Rhine River has emerged between October 2010 and May 2011 and its source is the effluent pipe of the same facility that produces FCC catalysts.