Geochemical Equilibrium Modeling in Soils and Sediments
- 1st Edition - March 1, 2026
- Latest edition
- Author: Arthur Paul Schwab
- Language: English
Geochemical Equilibrium Modeling in Soils and Sediments provides a systematic examination of the application of thermodynamic principles to chemical reactions of elements in soils.… Read more
Geochemical Equilibrium Modeling in Soils and Sediments provides a systematic examination of the application of thermodynamic principles to chemical reactions of elements in soils. Classical thermodynamic concepts are introduced, providing a theoretical foundation. Equilibrium reactions are then discussed element-by-element in order of decreasing average abundance in the solid phase of soils and sediments. Solid phase transitions, dissolution, volatilization, and aqueous speciation are investigated in detail, with each chapter giving readers greater depth of understanding of these complex systems.
The book represents a modernization of the approach to geochemical modeling, updating thermodynamic data and focusing on reactions that are known to occur at the solid-solution interface in soil and sediment environments. Readers are shown how these developments are integrated into geochemical modeling and how to interpret geochemical modeling results. The tools in this book will further allow readers to understand the interactions among elements, predict solubility as the physical environment changes, and give them the means to anticipate chemical and biological lability in response to perturbations.
The book represents a modernization of the approach to geochemical modeling, updating thermodynamic data and focusing on reactions that are known to occur at the solid-solution interface in soil and sediment environments. Readers are shown how these developments are integrated into geochemical modeling and how to interpret geochemical modeling results. The tools in this book will further allow readers to understand the interactions among elements, predict solubility as the physical environment changes, and give them the means to anticipate chemical and biological lability in response to perturbations.
- Discusses chemical equilibrium concepts applied to soils and sediments to explain trends in mineral transformation, aqueous transformations, and retention of contaminants in soils
- Systematically organizes elements in order of decreasing total concentrations, providing a logical approach to determining solubility controls
- Explains trends in mineral transformation, aqueous transformations, and in the retention of contaminants in soils
Soil scientists, environmental scientists, and sediment geochemists. Typical job titles would include Soil Chemist, Environmental Scientist, and Sediment Geochemist
1. Introduction
a. The dynamic nature of sediments and soils
b. A brief history of applying equilibrium concepts to soils
c. Overview of geochemical modeling
d. The structure of this textbook
e. Average elemental composition of soils and sediments
f. Problems
g. References
2. Theoretical development of chemical equilibrium concepts
a. Thermodynamic development
b. The equilibrium constant
c. Ionic strength and activity coefficients
d. Oxidation/reduction reactions
e. Measurement of pH and Eh
f. Problems
g. References
3. Geochemical models and modeling
a. Overview of types of models available
b. Model components needed for application to soils and sediments
c. Structure of the model d. Input requirements
e. Output structure
f. Limitations of equilibrium modeling i. Primary vs secondary minerals ii. The importance of dissolution/precipitation kinetics iii. Non-equilibrium 1. Oxy-anions 2. Some redox transitions
g. Visual MINTEQ: brief tutorial h. Problems i. References
4. Aluminum
a. Table of equilibrium constants: solids, solution species
b. Solubility of aluminum oxides, hydroxides, sulfates i. Primary minerals: theoretical but unattainable equilibrium
c. Solution complexes of Al3+: hydrolysis, fluorides, sulfates, chlorides, others
d. Estimating Al3+ activity from solubility data i. Hand calculations ii. MINTEQ modeling
e. Published examples f. Redox reactions of Al in soil and sediments
g. Problems
h. References
5. Silica
a. Table of equilibrium constants: solids, solution species
b. Forms of silica in soils and sediments: crystalline, amorphous, nanocrystalline
c. Solubility of silicon oxides d. Stability diagrams for silicates
e. Solution species of Si
f. Published examples
g. Problems
h. References
6. Aluminosilicate minerals
a. Table of equilibrium constants: solids, solution species
b. Primary vs secondary minerals; dissolution/precipitation kinetics
c. Brief summary of types of aluminosilicate minerals i. Conventions in writing unit cell formulae
d. Stability diagrams for aluminosilicates
e. Unique issues and challenges for chemical equilibria of aluminosilicates
f. Published examples
g. Problems
h. References
7. Carbon dioxide and carbonate equilibria
a. CO2 and carbonate equilibria in pure aqueous systems
b. Carbonates in soils and sediments
c. Published examples
d. Problems e. References
8. Calcium
a. Table of equilibrium constants: solids, solution species
b. Calcium silicates and aluminosilicates
c. Carbonates, sulfates, others
d. Stability diagrams for calcium minerals
e. Solution complexes
f. The phase rule i. CO2-H2O pure system equilibria ii. CaO-CO2-H2O pure system equilibria iii. H2SO4-CaO-CO2-H2O pure system equilibria
g. Published examples; apparent calcite nonequilibrium
h. Problems i. References
9. Magnesium
a. Table of equilibrium constants: solids, solution species
b. Magnesium silicates and aluminosilicates
c. Carbonates, sulfates, others
d. Stability diagrams for magnesium minerals
e. Solution complexes f. Published examples
g. Problems
h. References
10. Sodium and Potassium
a. Table of equilibrium constants: solids, solution species
b. Sodium and potassium solid phases
c. Stability diagrams for Na and K minerals
d. Solution complexes
e. Published examples
f. Problems
g. References
11. Iron
a. Table of equilibrium constants: solids, solution species, redox species
b. The critical role of oxidation reduction potentials in Fe chemistry in soils, sediments, and water
c. Ferric, ferrous, and mixed solid phases
d. Stability diagrams for Fe(III), Fe(II), and mixed oxide minerals e. Solution complexes
f. Published examples; the complex world of Fe in the environment
g. Problems
h. References
12. Manganese
a. Table of equilibrium constants: solids, solution species, redox species
b. The critical role of oxidation reduction potentials in Mn chemistry in soils, sediments, and water
c. Manganic, manganous, and mixed solid phases
d. Stability diagrams for manganese minerals
e. Solution complexes
f. Published examples; the unique chemistry of Mn in natural systems
g. Problems h. References
13. Phosphate
a. Table of equilibrium constants: solids, solution species
b. Solution chemistry of orthophosphate
c. Solubility of Fe phosphates
d. Solubility of Al phosphates
e. Effect of redox on the solubility of Fe phosphates
f. Solubility of Ca phosphates
g. Solubility of Mn phosphates
h. Stability diagrams for phosphates
i. Published examples i. Evidence for amorphous Al phosphate ii. Evidence for the presence of Mn(II)phosphate and its amorphous analog iii. Ca phosphate solubility
j. Problems
k. References
14. Zinc
a. Table of equilibrium constants: solids, solution species
b. Zinc solid phases
c. Stability diagrams for zinc minerals
d. Solution complexes
e. Published examples; “soil-Zn”
f. Problems
g. References
15. Copper
a. Table of equilibrium constants: solids, solution species
b. Copper solid phases
c. Stability diagrams for copper minerals
d. Solution complexes
e. Published examples; criteria for possible formation of solid phases
f. Problems
g. References
16. Nitrogen
a. Table of equilibrium constants: solids, solution species
b. Oxidation states of nitrogen
c. Challenges in applying equilibrium to gaseous nitrogen compounds i. Theoretical equilibrium between atmospheric N2 and O2
d. Redox equilibria for gaseous nitrogen species
e. Redox equilibria for soluble nitrogen species
f. Stability diagrams for nitrogen species
g. Published examples; nitrogen transformations in soil, water, atmosphere
h. Problems i. References
17. Sulfur
a. Table of equilibrium constants: solids, solution species
b. Overview of the complexity of sulfur in solid phase and solution
c. Effect of redox on sulfur solution species
d. Sulfate solids
e. Sulfide solid phases
f. Effect of redox on solubilities i. Sulfide solids ii. Metal solubilities
g. Stability diagrams for sulfur-based minerals
h. Solution species, complexes
i. Published examples; sulfur transformations in soil, water, atmosphere
j. Problems
k. References
18. Lead
a. Table of equilibrium constants: solids, solution species
b. Lead solid phases
c. Stability diagrams for Pb minerals
d. Solution complexes
e. Published examples; the immobility of Pb
f. Problems
g. References
19. Cadmium
a. Table of equilibrium constants: solids, solution species
b. Cadmium solid phases
c. Stability diagrams for Cd minerals
d. Solution complexes
e. Published examples; the challenges of traces metals
f. Problems
g. References
20. Arsenic
a. Table of equilibrium constants: solids, solution species
b. Arsenic solid phases
c. Role of redox in As transitions
d. Stability diagrams for As minerals
e. Solution complexes
f. Published examples; interactions between As and phosphate
g. Problems
h. References
21. Strontium
a. Table of equilibrium constants: solids, solution species
b. Strontium solid phases
c. Stability diagrams for Sr minerals
d. Solution complexes
e. Published examples; environmental significance of Sr
f. Problems
g. References
22. Plutonium
a. Table of equilibrium constants: solids, solution species
b. Plutonium solid phases
c. Pu redox reactions
d. Stability diagrams for Pu minerals
e. Solution complexes
f. Published examples; Pu and other radionuclides
g. Problems
h. References
23. Natural Organic ligands
a. Background
b. Occurrence
c. Table of equilibrium constants: acidity, complexation
d. Acid/base chemistry
e. Redox relationships
f. Ligand complexation
g. Problems h. References
24. Chelate equilibria
a. Occurrence of chelates in soils i. Natural ii. Synthetic
b. Potential importance of chelates in the chemistry of soils and sediments
c. Table of selected equilibrium constants for selected metals
d. Applications of geochemical modeling of chelate equilibria
e. Published examples
f. Problems
g. References
a. The dynamic nature of sediments and soils
b. A brief history of applying equilibrium concepts to soils
c. Overview of geochemical modeling
d. The structure of this textbook
e. Average elemental composition of soils and sediments
f. Problems
g. References
2. Theoretical development of chemical equilibrium concepts
a. Thermodynamic development
b. The equilibrium constant
c. Ionic strength and activity coefficients
d. Oxidation/reduction reactions
e. Measurement of pH and Eh
f. Problems
g. References
3. Geochemical models and modeling
a. Overview of types of models available
b. Model components needed for application to soils and sediments
c. Structure of the model d. Input requirements
e. Output structure
f. Limitations of equilibrium modeling i. Primary vs secondary minerals ii. The importance of dissolution/precipitation kinetics iii. Non-equilibrium 1. Oxy-anions 2. Some redox transitions
g. Visual MINTEQ: brief tutorial h. Problems i. References
4. Aluminum
a. Table of equilibrium constants: solids, solution species
b. Solubility of aluminum oxides, hydroxides, sulfates i. Primary minerals: theoretical but unattainable equilibrium
c. Solution complexes of Al3+: hydrolysis, fluorides, sulfates, chlorides, others
d. Estimating Al3+ activity from solubility data i. Hand calculations ii. MINTEQ modeling
e. Published examples f. Redox reactions of Al in soil and sediments
g. Problems
h. References
5. Silica
a. Table of equilibrium constants: solids, solution species
b. Forms of silica in soils and sediments: crystalline, amorphous, nanocrystalline
c. Solubility of silicon oxides d. Stability diagrams for silicates
e. Solution species of Si
f. Published examples
g. Problems
h. References
6. Aluminosilicate minerals
a. Table of equilibrium constants: solids, solution species
b. Primary vs secondary minerals; dissolution/precipitation kinetics
c. Brief summary of types of aluminosilicate minerals i. Conventions in writing unit cell formulae
d. Stability diagrams for aluminosilicates
e. Unique issues and challenges for chemical equilibria of aluminosilicates
f. Published examples
g. Problems
h. References
7. Carbon dioxide and carbonate equilibria
a. CO2 and carbonate equilibria in pure aqueous systems
b. Carbonates in soils and sediments
c. Published examples
d. Problems e. References
8. Calcium
a. Table of equilibrium constants: solids, solution species
b. Calcium silicates and aluminosilicates
c. Carbonates, sulfates, others
d. Stability diagrams for calcium minerals
e. Solution complexes
f. The phase rule i. CO2-H2O pure system equilibria ii. CaO-CO2-H2O pure system equilibria iii. H2SO4-CaO-CO2-H2O pure system equilibria
g. Published examples; apparent calcite nonequilibrium
h. Problems i. References
9. Magnesium
a. Table of equilibrium constants: solids, solution species
b. Magnesium silicates and aluminosilicates
c. Carbonates, sulfates, others
d. Stability diagrams for magnesium minerals
e. Solution complexes f. Published examples
g. Problems
h. References
10. Sodium and Potassium
a. Table of equilibrium constants: solids, solution species
b. Sodium and potassium solid phases
c. Stability diagrams for Na and K minerals
d. Solution complexes
e. Published examples
f. Problems
g. References
11. Iron
a. Table of equilibrium constants: solids, solution species, redox species
b. The critical role of oxidation reduction potentials in Fe chemistry in soils, sediments, and water
c. Ferric, ferrous, and mixed solid phases
d. Stability diagrams for Fe(III), Fe(II), and mixed oxide minerals e. Solution complexes
f. Published examples; the complex world of Fe in the environment
g. Problems
h. References
12. Manganese
a. Table of equilibrium constants: solids, solution species, redox species
b. The critical role of oxidation reduction potentials in Mn chemistry in soils, sediments, and water
c. Manganic, manganous, and mixed solid phases
d. Stability diagrams for manganese minerals
e. Solution complexes
f. Published examples; the unique chemistry of Mn in natural systems
g. Problems h. References
13. Phosphate
a. Table of equilibrium constants: solids, solution species
b. Solution chemistry of orthophosphate
c. Solubility of Fe phosphates
d. Solubility of Al phosphates
e. Effect of redox on the solubility of Fe phosphates
f. Solubility of Ca phosphates
g. Solubility of Mn phosphates
h. Stability diagrams for phosphates
i. Published examples i. Evidence for amorphous Al phosphate ii. Evidence for the presence of Mn(II)phosphate and its amorphous analog iii. Ca phosphate solubility
j. Problems
k. References
14. Zinc
a. Table of equilibrium constants: solids, solution species
b. Zinc solid phases
c. Stability diagrams for zinc minerals
d. Solution complexes
e. Published examples; “soil-Zn”
f. Problems
g. References
15. Copper
a. Table of equilibrium constants: solids, solution species
b. Copper solid phases
c. Stability diagrams for copper minerals
d. Solution complexes
e. Published examples; criteria for possible formation of solid phases
f. Problems
g. References
16. Nitrogen
a. Table of equilibrium constants: solids, solution species
b. Oxidation states of nitrogen
c. Challenges in applying equilibrium to gaseous nitrogen compounds i. Theoretical equilibrium between atmospheric N2 and O2
d. Redox equilibria for gaseous nitrogen species
e. Redox equilibria for soluble nitrogen species
f. Stability diagrams for nitrogen species
g. Published examples; nitrogen transformations in soil, water, atmosphere
h. Problems i. References
17. Sulfur
a. Table of equilibrium constants: solids, solution species
b. Overview of the complexity of sulfur in solid phase and solution
c. Effect of redox on sulfur solution species
d. Sulfate solids
e. Sulfide solid phases
f. Effect of redox on solubilities i. Sulfide solids ii. Metal solubilities
g. Stability diagrams for sulfur-based minerals
h. Solution species, complexes
i. Published examples; sulfur transformations in soil, water, atmosphere
j. Problems
k. References
18. Lead
a. Table of equilibrium constants: solids, solution species
b. Lead solid phases
c. Stability diagrams for Pb minerals
d. Solution complexes
e. Published examples; the immobility of Pb
f. Problems
g. References
19. Cadmium
a. Table of equilibrium constants: solids, solution species
b. Cadmium solid phases
c. Stability diagrams for Cd minerals
d. Solution complexes
e. Published examples; the challenges of traces metals
f. Problems
g. References
20. Arsenic
a. Table of equilibrium constants: solids, solution species
b. Arsenic solid phases
c. Role of redox in As transitions
d. Stability diagrams for As minerals
e. Solution complexes
f. Published examples; interactions between As and phosphate
g. Problems
h. References
21. Strontium
a. Table of equilibrium constants: solids, solution species
b. Strontium solid phases
c. Stability diagrams for Sr minerals
d. Solution complexes
e. Published examples; environmental significance of Sr
f. Problems
g. References
22. Plutonium
a. Table of equilibrium constants: solids, solution species
b. Plutonium solid phases
c. Pu redox reactions
d. Stability diagrams for Pu minerals
e. Solution complexes
f. Published examples; Pu and other radionuclides
g. Problems
h. References
23. Natural Organic ligands
a. Background
b. Occurrence
c. Table of equilibrium constants: acidity, complexation
d. Acid/base chemistry
e. Redox relationships
f. Ligand complexation
g. Problems h. References
24. Chelate equilibria
a. Occurrence of chelates in soils i. Natural ii. Synthetic
b. Potential importance of chelates in the chemistry of soils and sediments
c. Table of selected equilibrium constants for selected metals
d. Applications of geochemical modeling of chelate equilibria
e. Published examples
f. Problems
g. References
- Edition: 1
- Latest edition
- Published: March 1, 2026
- Language: English
AS
Arthur Paul Schwab
Paul Schwab is a soil physical chemist with 40 years of experience in research and teaching. His career has focused on the environmental applications of soil chemistry to a broad spectrum of issues including heavy metals, contaminant organics, fertilizers, and pesticides in soils and sediments. He has over 130 total peer-reviewed publications, 13,000 citations of his work, authored/edited two books, and received numerous awards for research. He taught soil chemistry for more than 35 years. The application of chemical equilibrium has been key to his studies, playing a role in his work starting with his graduate career (1976) through the present day.
Affiliations and expertise
Texas A&M University, TX, USA