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Influence of natural organic matter on the mobility of arsenic in aquatic systems, soils and sediments [Elektronische Ressource] / vorgelegt von Markus Bauer

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215 pages
INFLUENCE OF NATURAL ORGANIC MATTER ON THE MOBILITY OF ARSENIC IN AQUATIC SYSTEMS, SOILS AND SEDIMENTS Dissertation zur Erlangung des Grades Doktor der Naturwissenschaften (Dr. rer. nat.) an der Fakultät Biologie/Chemie/Geowissenschaften der Universität Bayreuth vorgelegt von Markus Bauer Geb. am 01.05.1977 in Ingolstadt Bayreuth, 23. April 2008 Vollständiger Abdruck der von der Fakultät für Chemie/Biologie/Geowissenschaften der Universität Bayreuth genehmigten Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.). Prüfungsausschuss: Prof. Dr. Stefan Peiffer (Vorsitzender) PD Dr. Christian Blodau (1. Gutachter) Prof. Dr. Egbert Matzner (2. Gutachter) Prof. Dr. Hartmut Frank PD Dr. Bruno Glaser Tag der Einreichung: 20.04.08 Tag des wissenschaftlichen Kolloquiums: 29.10.08 TABLE OF CONTENTS TABLE OF CONTENTS INFLUENCE OF NATURAL ORGANIC MATTER ON THE MOBILITY OF ARSENIC IN AQUATIC SYSTEMS, SOILS AND SEDIMENTS ............................................................................... I TABLE OF CONTENTS ..................................................... I LIST OF FIGURE ............................................................................................. III LIST OF TABLES ................................ V SUMMARY ...................................................
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INFLUENCE OF NATURAL ORGANIC MATTER ON THE MOBILITY
OF ARSENIC IN AQUATIC SYSTEMS, SOILS AND SEDIMENTS



Dissertation zur Erlangung des Grades
Doktor der Naturwissenschaften
(Dr. rer. nat.)
an der Fakultät Biologie/Chemie/Geowissenschaften
der Universität Bayreuth




vorgelegt von

Markus Bauer
Geb. am 01.05.1977 in Ingolstadt

Bayreuth, 23. April 2008






Vollständiger Abdruck der von der Fakultät für Chemie/Biologie/Geowissenschaften
der Universität Bayreuth genehmigten Dissertation zur Erlangung des Grades eines
Doktors der Naturwissenschaften (Dr. rer. nat.).

















Prüfungsausschuss:
Prof. Dr. Stefan Peiffer (Vorsitzender)
PD Dr. Christian Blodau (1. Gutachter)
Prof. Dr. Egbert Matzner (2. Gutachter)
Prof. Dr. Hartmut Frank
PD Dr. Bruno Glaser





Tag der Einreichung: 20.04.08
Tag des wissenschaftlichen Kolloquiums: 29.10.08




TABLE OF CONTENTS

TABLE OF CONTENTS
INFLUENCE OF NATURAL ORGANIC MATTER ON THE MOBILITY OF ARSENIC IN
AQUATIC SYSTEMS, SOILS AND SEDIMENTS ............................................................................... I
TABLE OF CONTENTS ..................................................... I
LIST OF FIGURE ............................................................................................. III
LIST OF TABLES ................................ V
SUMMARY ..................................................................................................... VII
ZUSAMMENFASSUNG .................. IX
EXTENDED SUMMARY ................................................................................................ 1
Introduction ......................................... 1
1. Arsenic health concerns ............... 1
2. Arsenic geochemistry and mobility ............................................................................................. 1
3. Natural organic matter ................................................. 4
4. As mobility in environments rich in organic matter .................................... 7
5. Objectives of the dissertation ...................................................................... 8
I. Redox Chemistry of DOM and Electron Transfer Reactions with As ........................................... 11
1. DOM oxidation and reduction by inorganic compounds (study 1 and 2) . 12
2. DOM redox reactivity with As (study 3) ................................................... 14
Conclusions ................................................................................................................................... 14
II. Aqueous and Surface Complexation Reactions of As and DOM ................. 15
1. Complex and colloid formation in solutions with Fe, DOM and As (study 4 and 5) ................ 16
2. Influence of DOM on As binding to mineral surfaces (study 6) ............................................... 18
3. Aqueous and surface complexation reactions and the redox speciation of As .......................... 18
Conclusions ................................................................................................................................... 19
III. Effect of DOM Load on the As Mobilization (study 7) .............................. 19
IV. Arsenic Mobility and Retention in Organic Matter Rich Peat Soils ........... 21
1. Arsenic in peat mesocosms subject to drying and rewetting (Study 8) ..................................... 22
2. Arsenic in degraded peatland soil (Study 9) .............................................. 23
Conclusions ................................................................... 24
Conclusions and Outlook .................................................................................. 26
References ......................................... 29
Contributions to the Different Studies ............................................................... 37
APPENDIX ....................................................................... 41



- I - - I -I57- TABLE OF CONTENTS

Study 1, APPENDIX 45
Electron Transfer Capacities and Reaction Kinetics of Peat Dissolved Organic Matter

Study 2, APPENDIX 63
Electron Accepting Capacitiy od Dissolved Organic Matter as determined by Reaction with
Metallic Zinc

Study 3, APPENDIX 85
Oxidation of As(III) and Reduction of As(V) in Dissolved Organic Matter Solutions

Study 4, APPENDIX 97
Experimental colloid formation in aqueous solutions rich in dissolved organic matter, ferric
iron, and As

Study 5, APPENDIX 119
Evidence for Aquatic Binding of Arsenate by Natural Organic Matter-Suspended Fe(III)

Study 6, APPENDIX 129
Mobilization of Arsenic by Dissolved Organic Matter from Iron Oxides,Soils and Sediments

Study 7, APPENDIX 143
Mobilization of Iron and Arsenic from Iron Oxide Coated Sand Columns by Percolation with
Dissolved Organic Matter

Study 8, APPENDIX 159
Arsenic Speciation and Turnover in intact Organic Soil Mesocosms during Experimental
Drought and Rewetting

Study 9, APPENDIX 179
Groundwater Derived Arsenic in High Carbonate Wetland Soils: Sources, Sinks, and Mobility

Redox reactions and Redox potentials, APPENDIX 193



- II - - II -II57- LIST OF FIGURES

LIST OF FIGURE
Page
Extended Summary Figure 1 E -pH diagrams for As 3 h
Extended Summary Figure 2 Schematic structure of a DOM molecule 5
Extended Summary Figure 3 Electron transfer reactions of quinones and DOM 5
Extended Summary Figure 4 Aqueous and surface complexes of As and DOM 7
Extended Summary Figure 5 Interactions of As with DOM and Fe 9
Study 1, Fig. 1 Figure 6 Reduction of Fe(III) complexes by DOM 47
Study 1, Fig. 2 Figure 7 Reduction of Fe(III) vs. DOM concentration 48
Study 1, Fig. 3 Figure 8 Reduction of Fe(III) vs. pH 48
0Study 1, Fig. 4 Figure 9 Oxidation of H S and Zn by DOM 49 2
0Study 1, Fig. 5 Figure 10 Oxidation of H S and Zn vs. DOM concentration 49 2
0Study 1, Fig. 6 Figure 11 Dependency of ETC and reaction rate constant on E 50 h
Support, Study 1 Figure 12 Aqueous Fe speciation as modelled by Phreeqc 55
Support, Study 1 Figure 13 Aqueous Fe speciation as mo Phreeqc 56
Support, Study 1 Figure 14 Variability during modelling 58
Support, Study 1 Figure 15 Formation of Fe(II) in DOM solution 59
2+ +Study 2 Figure 16 Zn , H and H turnover in DOM solution 71 2
Study 2 Figure 17 Dependency of Zn release on pH 72
Study 2 Figure 18 Time series of Zn release with different DOM samples 73
0Study 2 Figure 19 Zn oxidation vs. DOM concentration 73
Study 2 Figure 20 Electron accepting capacity vs. DOM concentration 75
Study 2 Figure 21 Reversibility of DOM electron uptake 75
Study 2 Figure 22 Relation of DOM SUVA and FTIR properties to EAC 76
Study 2 Figure 23 Relation of DOM fluorescence properties to EAC 77
Study 3 Figure 24 Time series of As(III) oxidation by DOM 90
Study 3 Figure 25 As(III) oxidation capacity 91
Study 3 Figure 26 Time series of As(V) reduction by DOM 93
Study 3 Figure 27 As(V) reduction capacity 94
Study 4 Figure 28 Colloid formation assays: Standard procedure and variations 101
Study 4 Figure 29 Results of standard colloid filtration experiments 103
Study 4 Figure 30 Time series of formation of Fe-As-DOM aggregates 104
Study 4 Figure 31 Correlation of As, Fe and DOC in aggregates with PPHA 105
Study 4 Figure 32 Dependency of aggregate formation on pH 106
Study 4 Figure 33 ncy of aggregate formation on DOC concentration 107
Study 4 Figure 34 Dependency of aggregate formation on Fe/C ratio 111
Study 4 Figure 35 Filtration results vs. WINHUMIC model calculations 110

- III - - III -III57- LIST OF FIGURES

Page
Figure 36 Support, Study 4 Formation of Fe-As-DOM aggregates with SRDOM 118
Figure 37 Study 5, Fig. 1 Arsenic dialysis experiments without DOM and with SRHPOA 123
Figure 38 Study 5, Fig. 2 Arsenic dialysis experiments with EGFA and SRWW 124
Figure 39 Study 5, Fig. 3 Arsenic mass balance during dialysis experiments 124
Figure 40 Study 5, Fig. 4 DOC and Fe mass balance in dialysis experiments 125
Figure 41 Study 5, Fig. 5 Arsenic complexation dependency on Fe concentration 126
Figure 42 Study 6, Fig. 1 Aqueous As speciation in DOM solution 134
Figure 43 Study 6, Fig. 2 Arsenic sorption on goethite 134
Figure 44 Study 6, Fig. 3 Arsenic desorption from goethite 135
Study 6, Fig. 4 Figure 45 Arsenic desorption by DOM from soil and sediment 137
Study 6, Fig. 5 Figure 46 Time series of As mobilization and speciation 137
Study 7 Figure 47 Breakthrough of chloride and pH in column experiments 148
Study 7 Figure 48 Column effluent concentrations of Fe, As and S 150
Figure 49 Study 7 Dynamics of Fe, S and As within the column 151
Figure 50 Study 7 Column solid phase Fe, S and As content 152
Figure 51 Study 8 Solid phase As and Fe distribution in peat material 164
Figure 52 Study 8 Gas content in the peat cores during drying and rewetting 166
13Figure 53 Study 8 Root activity in the peat cores as determined by d C of CO 166 2
Figure 54 Study 8 Aqueous depth profiles of Fe, S, DOC, and pH 167
Figure 55 Study 8 Temporal dynamics of dissolved As in the peat cores 168
Figure 56 Study 8 Arsenic speciation at the beginning of the drying period 169
Figure 57 Study 8 Temporal dynamics of the As(III) to As(V) ratio 169
Figure 58 Study 8 Temporal dynamics of DMA concentration 170
Figure 59 Study 8 Redox potential values calculated from As, Fe and S couples 170
Figure 60 Study 8 Turnover rates calculated for As and Fe 171
Figure 61 Support, Study 8 Time series of water levels during drying and rewetting 177
Figure 62 Study 9 Aqueous concentration profiles of As, Fe and DOC 183
Figure 63 Study 9 Soil horizon XRD spectra 184
Figure 64 Study 9 Soil content of As, Fe and C in different pools 186
Figure 65 Study 9 Arsenic mobilization by soil organic carbon dispersion 187
Figure 66 Support, Study 9 Setup of the Stella transport model 192
-Figure 67 Support, Study 9 Measured and modelled depth profile of As and Cl 192

- IV - - IV -IV57- LIST OF TABLES

LIST OF TABLES
Page
Study 1, Tab. 1 Table 1 DOM oxidation and reduction experiments 46
Support, Study 1 Table 2 Properties of DOM samples 52
Support, Study 1 Table 3 List of critical stability constants 54
Support, Study 1 Table 4 Thermodynamic calculations 57
Support, Study 1 Table 5 Literature review of EAC and EDC values 60
Study 2 Table 6 Properties of DOM samples 66
Study 3 Table 7 Experiments of As oxidation and reduction by DOM 88
Study 3 Table 8 Thermodynamic calculations 89
Study 4 Table 9 Complexation and colloid formation experiments 101
Study 4 Table 10 Properties of DOM samples 103
Study 4 Table 11 Fe, DOC and As concentrations in different size fractions 108
Study 5, Tab. 1 Table 12 Properties of DOM samples 121
Study 5, Tab. 2 Table 13 Inorganic constituents of DOM solution 121
Study 5, Tab. 3 Table 14 Results of sequential filtration experiments 126
Study 6, Tab. 1 Table 15 Arsenic sorption and desorption experiments from iron oxide 136
Study 6, Tab. 2 Table 16 Characteristics of soil and sediment samples 138
Study 6, Tab. 3 Table 17 Arsenic content in soil and sediment pools 138
Study 7 Table 18 Column hydraulic characteristics 149
Study 7 Table 19 Mass balances for Fe, S, As and C in column experiments 152
Study 8 Table 20 Solid phase Fe, Al and TRIS content 165
Study 8 Table 21 Correlation of As content with major soil constituents 165
Support, Study 8 Table 22 Solid phase elemental content 178
Study 9 Table 23 Applied extraction procedures 182
Study 9 Table 24 Physical and chemical properties of soil horizons 185
Study 9 Table 25 Solid phase Ca, Fe and As content in soil mineral pools 185
Appendix 10 Table 26 Summary of thermodynamic calculations 194/195


- V - - V -V57- LIST OF TABLES




- VI - - VI -VI57-

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