Foreword	5
	Table of contents	7
	1 Theoretical Background	12
	1.1 Equilibrium reactions	12
	1.1.1 Introduction	12
	1.1.2 Thermodynamic fundamentals	15
	1.1.2.1 Mass action law	15
	1.1.2.2 Gibbs free energy	17
	1.1.2.3 Gibbs phase rule	18
	1.1.2.4 Activity	19
	1.1.2.5 Ionic strength	19
	1.1.2.6 Calculation of activity coefficient	21
	1.1.2.6.1. Theory of ion dissociation	21
	1.1.2.6.2. Theory of ion interaction	23
	1.1.2.7 Theories of ion dissociation and ion interaction	25
	1.1.3 Interactions at the liquid-gaseous phase boundary	28
	1.1.3.1 Henry-Law	28
	1.1.4 Interactions at the liquid-solid phase boundary	29
	1.1.4.1 Dissolution and precipitation	29
	1.1.4.1.1. Solubility product	29
	1.1.4.1.2. Saturation index	31
	1.1.4.1.3. Limiting mineral phases	33
	1.1.4.2 Sorption	35
	1.1.4.2.1. Hydrophobic /hydrophilic substances	35
	1.1.4.2.2. Ion exchange	35
	1.1.4.2.3. Mathematical description of the sorption	41
	1.1.5 Interactions in the liquid phase	45
	1.1.5.1 Complexation	45
	1.1.5.2 Redox processes	47
	1.1.5.2.1. Measurement of the redox potential	47
	1.1.5.2.2. Calculation of the redox potential	48
	1.1.5.2.3. Presentation in predominance diagrams	52
	1.1.5.2.4. Redox buffer	56
	1.1.5.2.5. Significance of redox reactions	57
	1.2 Kinetics	60
	1.2.1 Kinetics of various chemical processes	60
	1.2.1.1 Half-life	60
	1.2.1.2 Kinetics of mineral dissolution	61
	1.2.2 Calculation of the reaction	62
	1.2.2.1 Subsequent reactions	63
	1.2.2.2 Parallel reactions	64
	1.2.3 Controlling factors on the reaction rate	64
	1.2.4 Empiric approaches for kinetically controlled reactions	66
	1.3 Reactive mass transport	68
	1.3.1 Introduction	68
	1.3.2 Flow models	68
	1.3.3 Transport models	68
	1.3.3.1 Definition	68
	1.3.3.2 Idealized transport conditions	69
	1.3.3.3 Real transport conditions	71
	1.3.3.3.1. Exchange within double-porosity aquifers	72
	1.3.3.4 Numerical methods of transport modeling	74
	1.3.3.4.1. Finite-difference / finite-element method	74
	1.3.3.4.2. Coupled methods	76
	2 Hydrogeochemical Modeling Programs	78
	2.1 General	78
	2.1.1 Geochemical algorithms	78
	2.1.2 Programs based on minimizing free energy	80
	2.1.3 Programs based on equilibrium constants	81
	2.1.3.1 PHREEQC	81
	2.1.3.2 EQ 3/6	83
	2.1.3.3 Comparison PHREEQC – EQ 3/6	84
	2.1.4 Thermodynamic data sets	87
	2.1.4.1 General	87
	2.1.4.2 Structure of thermodynamic data sets	89
	2.1.5 Problems and sources of error in geochemical modeling	91
	2.2 Use of PHREEQC	95
	2.2.1 Structure of PHREEQC under the Windows surface	95
	2.2.1.1 Input	96
	2.2.1.2 Thermodynamic data	104
	2.2.1.3 Output	105
	2.2.1.4 Grid	106
	2.2.1.5 Chart	106
	2.2.2 Introductory Examples for PHREEQC Modeling	106
	2.2.2.1 Equilibrium reactions	106
	2.2.2.1.1. Example 1: Standard output – seawater analysis	107
	2.2.2.1.2. Example 2 equilibrium – solution of gypsum	109
	2.2.2.2 Introductory examples for kinetics	110
	2.2.2.2.1. Defining reaction rates	111
	2.2.2.2.2. BASIC within PHREEQC	114
	2.2.2.3 Introductory example for reactive mass transport	117
	3 Exercises	122
	3.1 Equilibrium reactions	123
	3.1.1 Groundwater - Lithosphere	123
	3.1.1.1 Standard-output well analysis	123
	3.1.1.2 Equilibrium reaction - solubility of gypsum	124
	3.1.1.3 Disequilibrium reaction - solubility of gypsum	124
	3.1.1.4 Temperature dependency of gypsum solubility in well water	124
	3.1.1.5 Temperature dependency of gypsum solubility in distilled water	124
	3.1.1.6 Temperature and P(CO2) dependent calcite solubility	124
	3.1.1.7 Calcite precipitation and dolomite dissolution	125
	3.1.1.8 Calcite solubility in an open and a closed system	125
	3.1.1.9 Pyrite weathering	125
	3.1.2 Atmosphere – Groundwater – Lithosphere	127
	3.1.2.1 Precipitation under the influence of soil CO2	127
	3.1.2.2 Buffering systems in the soil	127
	3.1.2.3 Mineral precipitates at hot sulfur springs	128
	3.1.2.4 Formation of stalactites in karst caves	128
	3.1.2.5 Evaporation	129
	3.1.3 Groundwater	130
	3.1.3.1 The pE-pH diagram for the system iron	130
	3.1.3.2 The Fe pE-pH diagram considering carbon and sulfur	133
	3.1.3.3 The pH dependency of uranium species	133
	3.1.4 Origin of groundwater	134
	3.1.4.1 Origin of spring water	135
	3.1.4.2 Pumping of fossil groundwater in arid regions	136
	3.1.4.3 Salt water / fresh water interface	138
	3.1.5 Anthropogenic use of groundwater	138
	3.1.5.1 Sampling: Ca titration with EDTA	138
	3.1.5.2 Carbonic acid aggressiveness	139
	3.1.5.3 Water treatment by aeration - well water	139
	3.1.5.4 Water treatment by aeration - sulfur spring	139
	3.1.5.5 Mixing of waters	140
	3.1.6 Rehabilitation of groundwater	140
	3.1.6.1 Reduction of nitrate with methanol	140
	3.1.6.2 Fe(0) barriers	141
	3.1.6.3 Increase in pH through a calcite barrier	141
	3.2 Reaction kinetics	141
	3.2.1 Pyrite weathering	141
	3.2.2 Quartz-feldspar-dissolution	142
	3.2.3 Degradation of organic matter within the aquifer on reduction of redox sensitive elements (Fe, As, U, Cu, Mn, S)	143
	3.2.4 Degradation of tritium in the unsaturated zone	144
	3.3 Reactive transport	148
	3.3.1 Lysimeter	148
	3.3.2 Karst spring discharge	148
	3.3.3 Karstification (corrosion along a karst fracture)	149
	3.3.4 The pH increase of an acid mine water	150
	3.3.5 In-situ leaching	151
	4 Solutions	154
	4.1 Equilibrium reactions	154
	4.1.1 Groundwater- Lithosphere	154
	4.1.1.1 Standard-output well analysis	154
	4.1.1.2 Equilibrium reaction- solubility of gypsum	156
	4.1.1.3 Disequilibrium reaction – solubility of gypsum	157
	4.1.1.4 Temperature dependency of gypsumsolubility in well water	157
	4.1.1.5 Temperature dependency of gypsum solubility in distilled water	157
	4.1.1.6 Temperature and P(CO2) dependent calcite solubility	158
	4.1.1.7 Calcite precipitation and dolomite dissolution	159
	4.1.1.8 Comparison of the calcite solubility in an open and a closed system	160
	4.1.1.9 Pyrite weathering	161
	4.1.2 Atmosphere – Groundwater – Lithosphere	163
	4.1.2.1 Precipitation under the influence of soil CO2	163
	4.1.2.2 Buffering systems in the soil	163
	4.1.2.3 Mineral precipitations at hot sulfur springs	163
	4.1.2.4 Formation of stalactites in karst caves	164
	4.1.2.5 Evaporation	165
	4.1.3 Groundwater	166
	4.1.3.1 The pE-pH diagram for the system iron	166
	4.1.3.2 The Fe pE-pH diagram considering carbon and sulfur	167
	4.1.3.3 The pH dependency of uranium species	168
	4.1.4 Origin of groundwater	170
	4.1.4.1 Origin of spring water	170
	4.1.4.2 Pumping of fossil groundwater in arid regions	170
	4.1.4.3 Salt water / fresh water interface	171
	4.1.5 Anthropogenic use of groundwater	172
	4.1.5.1 Sampling: Ca titration with EDTA	172
	4.1.5.2 Carbonic acid aggressiveness	173
	4.1.5.3 Water treatment by aeration - well water	173
	4.1.5.4 Water treatment by aeration - sulfur spring	173
	4.1.5.5 Mixing of waters	175
	4.1.6 Rehabilitation of groundwater	176
	4.1.6.1 Reduction of nitrate with methanol	176
	4.1.6.2 Fe(0) barriers	177
	4.1.6.3 Increase in pH through a calcite barrier	178
	4.2 Reaction kinetics	179
	4.2.1 Pyrite weathering	179
	4.2.2 Quartz-feldspar-dissolution	182
	4.2.3 Degradation of organic matter within the aquifer on reduction of redox sensitive elements (Fe, As, U, Cu, Mn,S)	183
	4.2.4 Degradation of tritium in the unsaturated zone	186
	4.3 Reactive transport	187
	4.3.1 Lysimeter	187
	4.3.2 Karst spring discharge	187
	4.3.3 Karstification (corrosion along a karst fracture)	189
	4.3.4 The pH increase of an acid mine water	190
	4.3.5 In-situ leaching	192
	References	196
	Index	202
	More eBooks at www.ciando.com	0