Vanadium, Arsenic and Fluoride in Natural Waters from Argentina and Possible Impact on Human Health by Wafa Aqib Al Rawahi A thesis submitted to the Department of Chemistry in conformity with the requirements for the Degree of Doctor of Philosophy Faculty of Engineering and Physical Sciences University of Surrey, Guildford, GU2 7XH © 2016 Declaration of Originality This thesis and the work to which it refers are the results of my own efforts. Any ideas, data, images or text resulting from the work of others (whether published or unpublished) are fully identified as such within the work and attributed to their originator in the text, bibliography or in footnotes. This thesis has not been submitted in whole or in part for any other academic degree or professional qualification. I agree that the University has the right to submit my work to the plagiarism detection service TurnitinUK for originality checks. Whether or not drafts have been so-assessed, the University reserves the right to require an electronic version of the final document (as submitted) for assessment as above. i Abstract The composition of water can be influenced by the input of elemental constituents from natural and anthropogenic sources. Elevated levels of vanadium, arsenic, fluoride and other trace elements in water (ground, surface and tap) from various provinces in Argentina (including La Pampa, south east Buenos Aires, Río Negro and Neuquén), were analysed by inductively coupled plasma mass spectrometry (ICP-MS) and ion selective electrode (for fluoride). Vanadium species were determined in water by a newly developed solid phase extraction method (SPE). Vanadate (VV) was found to be the predominant species in water samples. The correlation between vanadium and arsenic species, and total elemental levels are presented. Vanadate (VV) correlates strongly with total arsenic, vanadium, fluoride and also the inorganic arsenic species compared to the vanadyl ion (VIV). However, vanadyl (VIV) had stronger Spearman correlations with the organosenical species. The levels of vanadium, arsenic and other trace elements were analysed in hair and nail samples and in water to evaluate exposure levels. The elemental exposure via drinking water increased in the following order: La Pampa (General San Martin-GSM and Eduardo Castex-EC) > Buenos Aires (Moron-MO) > Río Negro (General Roca-GR). In La Pampa (GSM and EC) and Buenos Aires (South east-SE) many sites showed vanadium, arsenic and fluoride levels exceeded the international regulatory limits for drinking water. La Pampa residents had the widest distribution of vanadium and arsenic in hair, fingernails and toenails compared to other populations in this study. A significant Spearman correlation (P < 0.0001) exists between the levels of vanadium and arsenic in groundwater from La Pampa and hair or nail values. The rural farms in La Pampa have no access to treated water. An electrocoagulation method using aluminium and iron electrodes showed a high level of efficiency in removing vanadium, arsenic and fluoride from groundwater. This may offer clean, and safe drinking water for farmers living in these areas of Argentina. ii Dedication I dedicate this thesis to Almighty Allah, my creator, my strong pillar, my source of inspiration, wisdom, knowledge and understanding. Allah has been the source of my strength throughout this study. I also dedicate this work to my beloved mother, grandmother and husband; whose affection, love, encouragement and prays of day and night made me able to get such success and honor. To my sweet children Wajd and Bishr who have been affected in every way possible by this journey. To My family and my friends who were always there when I needed support. My love for you all can never be quantified. May Allah bless you. iii Acknowledgements I would like to raise all type of thankfulness to ALLAH who gave me the opportunity to continue my higher education in the field that I love the best. Then to my country (Oman) and sponsors for their full financial support of my PhD study. My special appreciation and extreme thanks to my main supervisor Prof. Neil I Ward and my co-supervisor Dr. Carol Crean for their continuous encouragement, full support, guidance, patience and enthusiasm during these years. I would like to thank Prof Neil especially, for encouraging my research and for allowing me to grow as a research scientist. Your advice on research, my career, as well as my family matters have been priceless. I would also like to take this opportunity to thank Professor David Polya and Dr Monica Felipe-Sotelo my viva examiners, for their very helpful comments and suggestions. I would like to express special thanks to the ICP-MS facility team; Dr. Gillian Lord, Dr Andrea Petronda, Dr. Farideh Sahar Hamilton, Maisarah Jaafar, Fernanda Vanoni Matta and Sophie for their support, training with the laboratory instrumentations and proof reading my thesis. Special thanks to Judith Peters and Dr Dan Driscoll who have aided and trained me in the operation of some instruments in the laboratory. I would also like to thank all of my friends who supported me and incented me to strive towards my goal. A heartfelt thanks to my family. Words cannot express how grateful I am to, my mother, my father’s soul that is always with me (May Allah grant you Paradise), my grandmother, my mother-in law, and my father-in-law for all of the sacrifices that you have made on my behalf. Your prayers for me that have sustained me thus far. No rewards in this life can give back to my mother who is behind all my success in my life. I would also like to deeply thank all of my brothers, sisters and sisters-in-law who have supported me in my study, and encouraged me to achieve my goal. At the end I would like to express my deep appreciation to my beloved husband Dawoud, my gorgeous daughter Wajd and my lovely son Bishr who have been by my side living every single minute of my PhD, and without them, I would not have had the courage to embark on this journey in the first place. Dawoud and I have spent many sleepless nights with studying, writing up and he has always been a constant source of strength and inspiration. iv Table of Contents Declaration of Originality ........................................................................................ i Abstract ................................................................................................................. ii Dedication ............................................................................................................ iii Acknowledgements .............................................................................................. iv Table of Contents .................................................................................................. v List of Tables ....................................................................................................... xi List of Figures ..................................................................................................... xx Abbreviations ................................................................................................... xxvii : Introduction ............................................................................... 1 1.0 Introduction ................................................................................................... 2 1.1 Introduction to Trace Elements and Anion Chemistry ................................... 3 1.1.1 Vanadium .......................................................................................... 4 1.1.2 Arsenic .............................................................................................. 6 1.1.3 Fluoride ............................................................................................. 7 1.2 Vanadium, Arsenic and Fluoride in the Environment .................................... 8 1.2.1 Sources............................................................................................. 8 1.2.2 Pathway and mobility ...................................................................... 12 1.2.3 Vanadium, arsenic and fluoride levels in Water .............................. 16 1.2.4 Water quality regulations ................................................................ 19 1.3 Vanadium, Arsenic and Fluoride in Relation to Human Health ................... 21 1.3.1 Essentiality and deficiency .............................................................. 21 1.3.2 Bioavailability and toxicity ............................................................... 24 1.3.3 Metabolism ..................................................................................... 27 1.3.4 Biomarker tissues ........................................................................... 30 1.3.4.1 Scalp hair ......................................................................... 31 1.3.4.2 Fingernails and toenails .................................................... 35 1.4 Vanadium, Arsenic and Fluoride in Argentina ............................................. 37 1.4.1 Methods of Removal ....................................................................... 38 1.4.2 Electrocoagulation (EC) .................................................................. 39 1.5 Aims and Objectives ................................................................................... 42 1.5.1 Objectives ....................................................................................... 43 : Analytical Methodology .......................................................... 45 2.0 Introduction ................................................................................................. 46 2.1 Sample Collection and Preparation: Water ................................................ 48 2.1.1 Collection and field-base preparation ............................................ 48 2.1.2 Physicochemical water parameters ............................................... 49 2.1.3 Sampling strategy ........................................................................... 50 2.2 Sample Preparation: Scalp Hair, Fingernails and Toenails ......................... 55 2.2.1 Collection procedure ...................................................................... 56 v 2.2.2 Sample washing ............................................................................ 56 2.2.3 Acid digestion ................................................................................ 58 2.2.4 Dilution factor selection .................................................................. 58 2.3 Inductively Coupled Plasma Mass Spectrometry (ICP-MS) ....................... 59 2.3.1 Principle of ICP-MS ....................................................................... 59 2.3.1.1 Sample introduction system ............................................. 60 2.3.1.2 Inductively coupled plasma (ICP) .................................... 60 2.3.1.3 ICP interface and ion focussing unit ................................. 61 2.3.1.4 Collision/ reaction cell ....................................................... 62 2.3.1.5 Quadrupole mass spectrometer ...................................... 62 2.3.1.6 Detector ........................................................................... 63 2.3.2 Instrumentation and operating procedures ..................................... 64 2.3.2.1 Interferences..................................................................... 66 2.3.2.2 Dynamic collision cell (DRC) ............................................. 67 2.3.3 Internal standard ............................................................................ 68 2.3.4 Linear dynamic range .................................................................... 69 2.3.5 Limits of detection (LOD) ................................................................ 69 2.3.6 Calibration ....................................................................................... 70 2.3.7 Accuracy and precision .................................................................. 71 2.3.8 Spike recoveries ............................................................................. 74 2.4 Trace Element Speciation of Water ............................................................ 74 2.4.1 Principles of the SPE technique ...................................................... 74 2.4.2 Arsenic speciation analysis ............................................................ 76 2.4.3 SPE methodology .......................................................................... 81 2.4.4 Analytical figures of merit ................................................................ 83 2.5 High Performance Liquid Chromatography (HPLC) .................................... 84 2.5.1 Principles of HPLC .......................................................................... 84 2.5.2 HPLC instrumentation and operating procedures ........................... 85 2.6 Ion Selective Electrodes (ISE) .................................................................... 88 2.6.1 Principle and instrumentation of ISE ............................................... 89 2.6.2 Linear dynamic range .................................................................... 91 2.6.3 Limit of detection ............................................................................ 92 2.6.4 Accuracy and precision ................................................................... 93 2.6.5 Fluoride stability study .................................................................... 95 2.7 Ion Chromatography (IC) ............................................................................ 97 2.7.1 Principles of ion chromatography (IC) ............................................. 98 2.7.1.1 IC Instrumentation and operating parameters ................. 102 2.7.2 Calibration ..................................................................................... 104 2.7.3 Limits of detection (LOD) .............................................................. 104 2.7.4 Accuracy and precision ................................................................. 105 2.7.5 Limitations/Interferences .............................................................. 107 2.8 Statistical Calculations ............................................................................. 108 2.9 Summary ................................................................................................. 108 vi : Vanadium Speciation of Water .......................................... 111 3.0 Introduction ............................................................................................... 112 3.1 Determination of Total Vanadium (VT) by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) ................................................................... 112 3.1.1 Vanadium by ICP-MS ................................................................... 113 3.1.1.1 Agilent 7700x ICP-MS operating conditions for total vanadium (V ) measurement and possible polyatomic T interferences ............................................................................. 114 3.1.1.2 Internal standards - control chart .................................... 114 3.1.1.3 Linear dynamic range (LRD) and calibration curve ......... 116 3.1.1.4 Limit of Detection (LOD) ................................................. 117 3.1.2 Development of methods for SPE/HPLC analysis of eluent by ICP-MS ......................................................................................... 118 3.1.2.1 Solvent Selection ............................................................ 118 3.1.2.2 Methanol and propanol effect on vanadium analysis ...... 119 3.1.2.3 Effect of Na2EDTA and TBA+OH- ................................... 120 3.1.2.4 Effect of ammonium and phosphate ............................... 121 3.1.2.5 Effect of acid levels on vanadium analysis ..................... 123 3.1.3 pH effect ....................................................................................... 124 3.1.4 Validation ...................................................................................... 125 3.1.4.1 Accuracy and precision .................................................. 125 3.1.4.2 Spike recovery ................................................................ 126 3.1.4.3 Summary of total vanadium (VT) analysis ....................... 128 3.2 Solid Phase Extraction .............................................................................. 128 3.2.1 Solid phase extraction relevant to vanadium in water ................... 129 3.2.1.1 Conditioning.................................................................... 131 3.2.1.2 Loaded volume ............................................................... 132 3.2.1.3 Eluent selection .............................................................. 134 3.2.1.4 Vanadium SPE methodology .......................................... 136 3.2.2 Fundamental experiments for VIV and VV using solid phase extraction- inductively coupled plasma (SPE-ICP-MS) ................. 138 3.2.2.1 Calibration ...................................................................... 139 3.2.2.2 Limit of detection (LOD) .................................................. 139 3.2.2.3 VIV and VV speciation using SPE-ICP-MS ....................... 140 3.2.3 Validation ...................................................................................... 143 3.2.3.1 Intra –laboratory comparison with HPLC ........................ 143 3.2.3.2 Japanese mineral water samples ................................... 146 3.2.3.3 Certified reference material (CRM TMDA-54.4) .............. 147 3.3 High Performance Liquid Chromatography (HPLC) .................................. 148 3.3.1 Review of literature for HPLC regarding vanadium speciation ...... 148 3.3.2 Fundamental experiments for VIV and VV using HPLC .................. 151 3.3.2.1 HPLC calibration ............................................................. 152 3.3.2.2 Limit of detection ............................................................ 153 3.3.2.3 Vanadium speciation using HPLC .................................. 154 3.3.2.4 pH effect on vanadium species....................................... 155 vii 3.3.2.5 Effect of other ions .......................................................... 156 3.3.3 Inter-analytical method comparison between SPE-ICP-MS and HPLC with ICP-MS ................................................................ 158 3.4 Application of Vanadium Speciation Analysis of Water Samples from Argentina .................................................................................................. 159 3.4.1 Río Negro ..................................................................................... 160 3.4.2 South east La Pampa (General San Martin) ................................. 162 3.4.3 Central La Pampa (Eduardo Castex) ............................................ 163 3.4.4 Buenos Aires (San German) province .......................................... 165 3.4.5 Stability study ................................................................................ 166 3.5 Summary .................................................................................................. 167 : Trace Element and Fluoride Analysis of Waters in Argentina ..................................................................................... 169 4.0 Introduction ............................................................................................... 170 4.1 Río Negro/Neuquén Provinces ................................................................. 171 4.1.1 Sample locations .......................................................................... 173 4.1.2 Results .......................................................................................... 174 4.1.2.1 Physicochemical parameters .......................................... 174 4.1.2.2 Total vanadium, arsenic, fluoride and arsenic speciation ................................................................................. 176 4.1.2.3 Other trace element levels .............................................. 180 4.2 La Pampa: South East .............................................................................. 181 4.2.1 Sample locations and sampling strategy ...................................... 182 4.2.2 Results .......................................................................................... 184 4.2.2.1 Physicochemical parameters .......................................... 184 4.2.2.2 Total arsenic, vanadium, fluoride and arsenic speciation ................................................................................. 186 4.2.2.3 Other trace element levels .............................................. 190 4.3 La Pampa: Central North .......................................................................... 191 4.3.1 Sample locations .......................................................................... 192 4.3.2 Results .......................................................................................... 193 4.3.2.1 Physicochemical parameters .......................................... 194 4.3.2.2 Total vanadium, arsenic, fluoride and arsenic speciation ................................................................................. 195 4.3.2.3 Other trace element levels .............................................. 199 4.4 Buenos Aires Province .............................................................................. 200 4.4.1 Sample locations .......................................................................... 202 4.4.2 Results .......................................................................................... 203 4.4.2.1 Physicochemical parameters .......................................... 203 4.4.2.2 Total vanadium, arsenic, fluoride and arsenic speciation ................................................................................. 205 4.4.2.3 Other trace element levels .............................................. 209 4.5 Buenos Aires Capital Federal: Moron ....................................................... 209 viii 4.5.1 Sample locations .......................................................................... 210 4.5.2 Results .......................................................................................... 211 4.5.2.1 Physicochemical parameters .......................................... 212 4.5.2.2 Total vanadium, arsenic, fluoride and arsenic speciation ................................................................................. 213 4.5.2.3 Other trace element levels .............................................. 216 4.6 Volcanic Ash Analysis ............................................................................... 217 4.7 Comparison between Río Negro, La Pampa and Buenos Aires Provinces .................................................................................................. 218 4.7.1 Physiochemical properties ............................................................ 219 4.7.2 Vanadium, Arsenic and fluoride .................................................... 221 4.8 Summary .................................................................................................. 233 : Human Exposure Analysis in Hair and Nails ...................... 237 5.0 Introduction ............................................................................................... 238 5.1 Study Populations ..................................................................................... 239 5.1.1 General Roca, Río Negro ............................................................. 240 5.1.2 General San Martin and Eduardo Castex, La Pampa, .................. 242 5.1.3 Moron, Buenos Aires Capital Federal ........................................... 243 5.2 Vanadium and Arsenic in Hair .................................................................. 244 5.2.1 General Roca, Río Negro ............................................................. 246 5.2.2 General San Martin and Eduardo Castex, La Pampa, .................. 248 5.2.3 Moron, Buenos Aires Capital Federal ........................................... 251 5.3 Vanadium and Arsenic in Fingernails........................................................ 253 5.3.1 General Roca, Río Negro ............................................................. 254 5.3.2 General San Martin and Eduardo Castex, La Pampa, .................. 256 5.3.3 Moron, Buenos Aires Capital Federal ........................................... 258 5.4 Vanadium and Arsenic in Toenails............................................................ 259 5.4.1 General Roca, Río Negro ............................................................. 260 5.4.2 General San Martin and Eduardo Castex, La Pampa, .................. 262 5.4.3 Moron, Buenos Aires Capital Federal ........................................... 264 5.5 Comparison of Vanadium/Arsenic levels in Biological Samples from Study Provinces ........................................................................................ 265 5.6 Relationship between Arsenic/ Vanadium Levels in Different Biological Sample Types ........................................................................... 267 5.7 Drinking Water Vanadium and Arsenic Exposure and Scalp Hair and Nails .......................................................................................................... 270 5.8 Relationship between Arsenic, Vanadium and Health Status ................... 272 5.9 Influence of Cofactors on Arsenic, Vanadium and other Trace Elements ................................................................................................... 274 5.9.1 Age ............................................................................................... 275 5.9.2 Gender .......................................................................................... 277 5.10 Summary .................................................................................................. 279 ix