Groundwater Geochemistry

by Merkel, Broder J.; Planer-Friedrich, Britta; Nordstrom, Darrell Kirk

• ISBN13: 9783540746676
• ISBN10: 3540746676
• Edition: 2nd
• Format: Hardcover
• Copyright: 2008-08-01
• Publisher: Springer Verlag

Summary

The second edition of "Groundwater Geochemistry ' A practical guide to modeling of natural and contaminated aquatic systems" remains a comprehensive text book offering beginners and advanced modelers alike a minimum theoretical background and a strong focus on the practical solution of geochemical modeling with PHREEQC. The new edition covers the possibility of using the CD-MUSIC concept within the new version of PHREEQC. Examples for reactive transport use PHREEQC´s 1d features as well as the coupled 3d code PHAST with the graphical user interface WPHAST. Implementing uncertainties of thermodynamic data is addressed by means of the program LJUNGSKILE. As in the first edition, detailed descriptions on how to solve each problem guide the user step by step from basic to more and more advanced hydrogeochemical modeling. The computer programs and the solutions for all problems (PHREEQC input files) are enclosed on a CD.

Author Biography

Broder J. Merkel (born 1949) studied geology and hydrogeology in Munich, where he got his master's and PhD degree. He worked as a scientist at the department of water chemistry in Munich and as a hydrogeologist in his own business in Germany and various foreign countries. After his habilitation in 1992 from the Christian-Albrechts University in Kiel he was offered the chair of hydrogeology at the Technische Universitaomlet;t Bergakademie Freiberg that he holds since 1993. His main research interests are on hydrogeochemical and reactive modeling, the influence of acid mine drainage on groundwater systems, and the application of GIS and remote sensing in hydrogeology. Britta Planer-Friedrich (born 1975) studied geology in Wuomlet;rzburg and Freiberg where she obtained her master's degree in hydrogeology and environmental geology in 2000 and her PhD on volatile metals in 2004 as a stipend of the German National Merit Foundation. Her current work as postdoctoral researcher at Trent University, Canada, focuses on analytical chemistry and speciation of trace elements. Since 1999 she teaches computer courses in hydrogeochemical and reactive transport modeling as well as basics of groundwater chemistry and analytics at the Technische Universitaumlet;t Bergakademie Freiberg. Darrell Kirk Nordstrom (born 1946) studied chemistry at Southern Illinois University (BA), geology at University of Colorado (MS), and environmental geochemistry (hydrogeology, surface chemistry, and microbiology) at Stanford University (PhD). He was an Assistant Professor at University of Virginia for four years before accepting a permanent position with the US Geological Survey in 1980. His primary research is on the effect of mining on water quality, especially acid mine drainage, and the application of geochemical models to the interpretation of water-rock interactions, but he has also been involved with research related to radioactive waste disposal and to geothermal chemistry.

Table of Contents

Theoretical Background	p. 1
Equilibrium reactions	p. 1
Introduction	p. 1
Thermodynamic fundamentals	p. 5
Mass-action law	p. 5
Gibbs free energy	p. 7
Gibbs phase rule	p. 8
Activity	p. 8
Ionic strength	p. 10
Calculation of activity coefficient	p. 10
Theory of ion-association	p. 10
Theory of ion-interaction	p. 13
Comparison ion-association versus ion-interaction theory	p. 14
Interactions at the liquid-gaseous phase boundary	p. 17
Henry Law	p. 17
Interactions at the liquid-solid phase boundary	p. 19
Dissolution and precipitation	p. 19
Solubility-product	p. 19
Saturation index	p. 22
Limiting mineral phases	p. 22
Sorption	p. 25
Hydrophobic/hydrophilic substances	p. 25
Ion exchange	p. 25
Mathematical description of the sorption	p. 30
Interactions in the liquid phase	p. 35
Complexation	p. 35
Redox processes	p. 37
Measurement of the redox potential	p. 37
Calculation of the redox potential	p. 38
Presentation in predominance diagrams	p. 43
Redox buffer	p. 47
Significance of redox reactions	p. 47
Kinetics	p. 50
Kinetics of various chemical processes	p. 50
Half-life	p. 50
Kinetics of mineral dissolution	p. 51
Calculation of the reaction rate	p. 52
Subsequent reactions	p. 53
Parallel reactions	p. 54
Controlling factors on the reaction rate	p. 54
Empirical approaches for kinetically controlled reactions	p. 55
Reactive mass transport	p. 58
Introduction	p. 58
Flow models	p. 58
Transport models	p. 59
Definition	p. 59
Idealized transport conditions	p. 61
Real transport conditions	p. 61
Exchange within double-porosity aquifers	p. 62
Numerical methods of transport modeling	p. 63
Finite-difference/finite-element method	p. 65
Coupled methods	p. 66
Hydrogeochemical Modeling Programs	p. 69
General	p. 69
Geochemical algorithms	p. 69
Programs based on minimizing free energy	p. 71
Programs based on equilibrium constants	p. 72
Phreeqc	p. 72
EQ 3/6	p. 74
Thermodynamic databases	p. 76
General	p. 76
Structure of thermodynamic databases	p. 78
Problems and sources of error in geochemical modeling	p. 81
Use of Phreeqc	p. 85
The structure of Phreeqc and its graphical user interfaces	p. 85
Input	p. 88
Database	p. 95
Output	p. 96
Grid	p. 97
Chart	p. 97
Introductory Examples for Phreeqc Modeling	p. 97
Equilibrium reactions	p. 97
Example 1a standard output - seawater analysis	p. 98
Example 1b equilibrium - solution of gypsum	p. 100
Example 1c equilibrium - solution of calcite with CO2	p. 101
Example 1d: Modeling uncertainties - Ljungskile	p. 103
Introductory example for sorption	p. 107
Introductory examples for kinetics	p. 114
Defining reaction rates	p. 115
Basic within Phreeqc	p. 117
Introductory example for isotope fractionation	p. 122
Introductory example for reactive mass transport	p. 126
Simple 1D transport: Column experiment	p. 126
1D transport, dilution, and surface complexation in an abandoned uranium mine	p. 130
3D transport with Phast	p. 134
Exercises	p. 141
Equilibrium reactions	p. 143
Groundwater - Lithosphere	p. 143
Standard output well analysis	p. 143
Equilibrium reaction - solubility of gypsum	p. 144
Disequilibrium reaction - solubility of gypsum	p. 144
Temperature dependency of gypsum solubility in well water	p. 144
Temperature dependency of gypsum solubility in pure water	p. 144
Temperature-and P(CO2)-dependent calcite solubility	p. 144
Calcite precipitation and dolomite dissolution	p. 145
Calcite solubility in an open and a closed system	p. 145
Pyrite weathering	p. 145
Atmosphere - Groundwater - Lithosphere	p. 146
Precipitation under the influence of soil CO2	p. 146
Buffering systems in the soil	p. 147
Mineral precipitates at hot sulfur springs	p. 147
Formation of stalactites in karst caves	p. 148
Evaporation	p. 149
Groundwater	p. 150
The pE-pH diagram for the system iron	p. 150
The Fe pE-p-H diagram considering carbon and sulfur	p. 152
The pH dependency of uranium species	p. 152
Origin of groundwater	p. 153
Pumping of fossil groundwater in arid regions	p. 155
Salt water/fresh water interface	p. 156
Anthropogenic use of groundwater	p. 157
Sampling: Ca titration with Edta	p. 157
Carbonic acid aggressiveness	p. 157
Water treatment by aeration - well water	p. 158
Water treatment by areation - sulfur spring	p. 158
Mixing of waters	p. 159
Rehabilitation of groundwater	p. 159
Reduction of nitrate with methanol	p. 159
Fe(0) barriers	p. 160
Increase in pH through a calcite barrier	p. 160
Reaction kientics	p. 160
Pyrite weathering	p. 160
Quartz-feldspar-dissolution	p. 161
Degradation of organic matter within the aquifer on reduction of redox-sensitive elements (Fe, As, U, Cu, Mn, S)	p. 162
Degradation of tritium in the unsaturated zone	p. 163
Reactive transport	p. 166
Lysimeter	p. 166
Karst spring discharge	p. 167
Karstification (corrosion along a karst fracture)	p. 168
The pH increase of an acid mine water	p. 169
In-situ leaching	p. 170
3D Transport - Uranium and arsenic contamination plume	p. 171
Solutions	p. 173
Equilibrium reactions	p. 173
Groundwater - Lithosphere	p. 173
Standard output well analysis	p. 173
Equilibrium reaction - solubility of gypsum	p. 175
Disequilibrium reaction - solubility of gypsum	p. 175
Temperature dependency of gypsum solubility in well water	p. 176
Temperature dependency of gypsum solubility in pure water	p. 177
Temperature- and P(CO2)-dependent calcite solubility	p. 177
Calcite precipitation and dolomite dissolution	p. 178
Comparison of the calcite solubility in an open and a closed system	p. 179
Pyrite weathering	p. 179
Atmosphere - Groundwater - Lithosphere	p. 181
Precipitation under the influence of soil CO2	p. 181
Buffering systems in the soil	p. 181
Mineral precipitations at hot sulfur springs	p. 182
Formation of stalactites in karst caves	p. 183
Evaporation	p. 183
Groundwater	p. 184
The pE-pH diagram for the system iron	p. 184
The Fe pE-pH diagram considering carbon and sulfur	p. 186
The pH dependency of uranium species	p. 187
Origin of groundwater	p. 188
Pumping of fossil groundwater in arid regions	p. 188
Salt water/fresh water interface	p. 189
Anthropogenic use of groundwater	p. 190
Sampling: Ca titration with Edta	p. 190
Carbonic acid aggressiveness	p. 191
Water treatment by aeration - well water	p. 191
Water treatment by aeration - sulfur spring	p. 191
Mixing of waters	p. 193
Rehabilitation of groundwater	p. 194
Reduction of nitrate with methanol	p. 194
Fe(0) barriers	p. 195
Increase in pH through a calcite barrier	p. 196
Reaction kinetics	p. 197
Pyrite weathering	p. 197
Quartz-feldspar-dissolution	p. 199
Degradation of organic matter within the aquifer on reduction of redox-sensitive elements (Fe, As, U, Cu, Mn, S)	p. 201
Degradation of tritium in the unsaturated zone	p. 203
Reactive transport	p. 205
Lysimeter	p. 205
Karst spring discharge	p. 205
Karstification (corrosion along a karst fracture)	p. 207
The pH increase of an acid mine water	p. 208
In-situ leaching	p. 210
3D Transport - Uranium and arsenic contamination plume	p. 212
References	p. 215
Index	p. 221
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