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Environmental and Low Temperature Geochemistry, 2nd Edition




Environmental and Low Temperature Geochemistry, 2nd Edition

Peter Ryan

ISBN: 978-1-119-56858-2 October 2019 Wiley-Blackwell 424 Pages



Environmental and Low-Temperature Geochemistry presents conceptual and quantitative principles of geochemistry in order to foster understanding of natural processes at and near the earth’s surface, as well as anthropogenic impacts and remediation strategies. It provides the reader with principles that allow prediction of concentration, speciation, mobility and reactivity of elements and compounds in soils, waters, sediments and air, drawing attention to both thermodynamic and kinetic controls. The scope includes atmosphere, terrestrial waters, marine waters, soils, sediments and rocks in the shallow crust; the temporal scale is present to Precambrian, and the spatial scale is nanometers to local, regional and global.

This second edition of Environmental and Low-Temperature Geochemistry provides the most up-to-date status of the carbon cycle and global warming, including carbon sources, sinks, fluxes and consequences, as well as emerging evidence for (and effects of) ocean acidification. Understanding environmental problems like this requires knowledge based in fundamental principles of equilibrium, kinetics, basic laws of chemistry and physics, empirical evidence, examples from the geological record, and identification of system fluxes and reservoirs that allow us to conceptualize and understand. This edition aims to do that with clear explanations of fundamental principles of geochemistry as well as information and approaches that provide the student or researcher with knowledge to address pressing questions in environmental and geological sciences.

New content in this edition includes:

  • Focus Boxes – one every two or three pages – providing case study examples (e.g. methyl isocyanate in Bhopal, origins and health effects of asbestiform minerals), concise explanations of fundamental concepts (e.g. balancing chemical equations, isotopic fractionation, using the Keq to predict reactivity), and useful information (e.g. units of concentration, titrating to determine alkalinity, measuring redox potential of natural waters);
  • Sections on emerging contaminants for which knowledge is rapidly increasing (e.g. perfluorinated compounds, pharmaceuticals and other domestic and industrial chemicals);
  • Greater attention to interrelationships of inorganic, organic and biotic phases and processes;
  • Descriptions, theoretical frameworks and examples of emerging methodologies in geochemistry research, e.g. clumped C-O isotopes to assess seawater temperature over geological time, metal stable isotopes to assess source and transport processes, X-ray absorption spectroscopy to study oxidation state and valence configuration of atoms and molecules;
  • Additional end-of-chapter problems, including more quantitatively based questions.
  • Two detailed case studies that examine fate and transport of organic contaminants (VOCs, PFCs), with data and interpretations presented separately. These examples consider the chemical and mineralogical composition of rocks, soils and waters in the affected system; microbial influence on the decomposition of organic compounds; the effect of reduction-oxidation on transport of Fe, As and Mn; stable isotopes and synthetic compounds as tracers of flow; geological factors that influence flow; and implications for remediation.

The interdisciplinary approach and range of topics – including environmental contamination of air, water and soil as well as the processes that affect both natural and anthropogenic systems – make it well-suited for environmental geochemistry courses at universities as well as liberal arts colleges.

Chapter 1: Background and Basic Chemical Principles: Elements, Ions, Bonding, Reactions

1.1 An Overview of Environmental Geochemistry — History, Scope, Questions, Approaches, Challenges for the Future

1.2 The Naturally Occurring Elements — Origins and Abundances

1.2.1 Origin of the Light Elements H and He (and Li)

1.2.2 Formation of Heavier Elements

1.2.3 Formation of Planets and Compositional Differentiation

1.3 Atoms, Isotopes and Valence Electrons

1.3.1 Atoms: Protons, Neutrons, Electrons, Isotopes

1.3.2 Electrons and Bonding

1.4 Measuring Concentrations

1.4.1 Mass-based Concentrations

1.4.2 Molar Concentrations

1.4.3 Concentrations of Gases

1.4.4. Notes on Precision and Accuracy, Significant Figures and Scientific Notation

1.5 Periodic Table

1.5.1. Predicting Behavior of Elements Using the Periodic Table

1.5.2. The Earth Scientist’s Periodic Table

1.6 Ions, Molecules, Valence, Bonding, Chemical Reactions

1.6.1 Ionic bonding

1.6.2. Determining Ionic Bond Strength

1.6.3. Covalent Bonding

1.6.4. Electronegativity and Predicting Bond Type

1.6.5. Metallic Bonds, Hydrogen Bonds and van der Waals Forces

1.7 Acid-Base Equilibria, pH, K Values

1.7.1 Definitions of Acids and Bases

1.7.2 The Law of Mass Action and Quantifying Acid Dissociation

1.8 Fundamentals of Redox Chemistry

1.8.1. Defining Oxidation and Reduction

1.8.2 Redox Reactions

1.9 Chemical Reactions

1.10 Equilibrium, Thermodynamics and Driving Forces for Reactions: Systems, Gibbs Energies, Enthalpy and Heat Capacity, Entropy, Volume

1.10.1 Pyrite Oxidation as an Introductory Example

1.10.2 Systems, Species, Phases and Components

1.10.3 First Law of Thermodynamics

1.10.4 Second Law of Thermodynamics

1.10.5 Enthalpy

1.10.6 Heat Capacity

1.10.7 Gibbs Free Energy and Predicting Stability

1.10.8 The Van’t Hoff equation: Relating Gibbs Free Energy to the Equilibrium Constant (Keq)

1.11 Kinetics and Reaction Rates

1.11.1. Factors Controlling Reaction Rate

1.11.2 Reaction Rate, Reaction Order Zero-Order Reactions First-Order Reactions Second-Order Reactions

1.11.3 Temperature and the Arrhenius Equation

Review questions


Chapter 2: Surficial and Environmental Mineralogy

2.1 Introduction to Minerals and Unit Cells

2.2 Ion Coordination, Pauling’s Rules and Ionic Substitution

2.2.1 Coordination and Radius Ratio

2.2.2 Bond Strength Considerations

2.2.3 Pauling and Goldschmidt Rules of Ionic Solids Rule 1: The Coordination Principle Rule 2: The Principle of Local Charge Balance Rule 3: Sharing of Polyhedral Edges and Faces Rule 4: Valency and Sharing of Polyhedral Components Rule 5: The Principle of Parsimony:

2.3 Silicates

2.3.1 Nesosilicates

2.3.2 Inosilicates

2.3.3 Phyllosilicates The 2:1 Phyllosilicates The 1:1 Phyllosilicates

2.3.4 Tectosilicates

2.4 Clay Minerals (1:1 and 2:1 Minerals, Interstratified Clays)

2.4.1 Smectite Smectites with tetrahedrally-derived layer charge Smectites with octahedrally-derived layer charge

2.4.2 Vermiculite

2.4.3 Illite

2.4.4 Chlorite and Berthierine

2.4.5. Kaolin Group (Kaolinite and Halloysite)

2.4.6 Interstratified Clay Minerals

2.4.7 Trace Metals and Metalloids in Clay Minerals

2.5 Crystal Chemistry of Adsorption and Cation Exchange

2.5.1 Cation Exchange Mechanisms by which Cations are Attracted to Surfaces Particle Attributes that Influence Ion Exchange Point of Zero Charge and Isoelectric Point Double-Layer Complexes Units of Concentration and Measurement of CEC

2.6 Low-Temperature Non-Silicate Minerals: Carbonates, Oxides and Hydroxides, Sulfides, Sulfates, Salts

2.6.1 Carbonates

2.6.2 Oxides and Hydroxides

2.6.3 Sulfides and Sulfates

2.7 Mineral Growth and Dissolution

2.8 Biomineralization

Review questions


Chapter 3: Organic Compounds in the Environment

3.1 Introduction to Organic Chemistry: Chains and Rings, Single, Double, and Triple Bonds, Functional Groups, Classes of Organic Compounds, Organic Nomenclature

3.1.1 Definition of Organic Compounds

3.1.2 Hybridization of Carbon Atoms in Organic Compounds

3.1.3 Alkanes

3.1.4 Alkenes

3.1.5 Functional groups

3.1.6 Aromatic Hydrocarbons and Related Compounds

3.1.7 Nitrogen, Phosphorus and Sulfur in Organic Compounds

3.1.8 Pharmaceutical Compounds

3.1.9 Emerging Contaminants – PFCs

3.2 Natural Organic Compounds at the Earth Surface

3.2.1 Humic and Fulvic Material

3.2.2 Origins and Compositions of Fossil Fuels

3.3 Fate and Transport of Organic Pollutants, Controls on Bioavailability, Behavior of DNAPLS and LNAPLS, Biodegradation, Remediation

3.3.1 Solid-Liquid-Gas Phase Considerations

3.3.2 Solubility Considerations

3.3.3 Interactions of Organic Compounds and Organisms

3.3.4 Adsorption of Organic Compounds

3.3.5 Non-aqueous phase liquids (NAPLs) in the Environment

3.3.6 Biodegradation

3.3.7 Remediation


Review questions


Chapter 4: Aqueous Systems and Water Chemistry

4.1 Introduction to the Geochemistry of Natural Waters

4.1.1 Geochemistry and the Hydrologic Cycle Evaporation and Precipitation Infiltration, Soils, Chemical Weathering Surface Water and Groundwater Graphical Analysis of Climate and Surface Water Composition

4.2 The Structure of Water — Implications of Geometry and Polarity

4.3 Dissolved versus Particulate, Solutions and Suspensions

4.3.1 Dissolved Constituents and the Nature of Solutions

4.3.2 Particulate (Suspended) Fraction

4.3.3 Immiscible liquids

4.3.4 Dissolved vs. Particulate vs. Colloidal

4.4 Speciation: Simple Ions, Polyatomic Ions and Aqueous Complexes

4.5 Controls on the Solubility of Inorganic Elements and Ions

4.5.1 Role of Temperature

4.5.2 Residence Time

4.5.3 The Ratio of Ionic Charge: Ionic Radius and it Effect on Solubility

4.5.4 Reduction-Oxidation Reactions Half-cell Reactions Redox Reactions in the Environment

4.5.5 Acid-Base Considerations and pH

4.5.6 Ligands and elemental mobility

4.6 Ion activities, ionic strength, TDS

4.6.1 Ion Activity Coefficients

4.6.2 Ion Activity Product

4.6.3 Ionic Strength

4.6.4 Total dissolved solids

4.7 Solubility Products, Saturation

4.8 Co-precipitation

4.9 Behavior of selected elements in aqueous systems

4.9.1 Examples of Heavy Metals and Metalloids Heavy metals

4.9.2 Eh–pH diagrams

Case Study of Arsenic in Aquifer of Bengal Fan (g50 million people affected by redox)

4.9.3 Silicon in solutions

4.10 Eh-pH Diagrams

4.10.1 Principles of Eh-pH

4.10.2 Eh-pH Diagrams for Cu, Pb, As, U, Fe, Al

4.11 Silicon in Solution

4.12 Effect of Adsorption and Ion Exchange on Water Chemistry

4.12.1 Ionic Potential, Hydration Radius and Adsorption

4.12.2 Law of Mass Action and Adsorption

4.12.3 Adsorption Edges

4.12.4 Adsorption Isotherms

4.13 Other Graphical Representations of Aqueous Systems: Piper and Stiff Diagrams

4.14 Summary

Review questions


Chapter 5: Carbonate Geochemistry and the Carbon Cycle

5.1 Inorganic Carbon in the Atmosphere and Hydrosphere

5.1.1. Atmospheric CO2, carbonate species and the pH of rain

5.1.2 Speciation in the carbonate system as a function of pH

5.1.3 Alkalinity

5.1.4 Carbonate Solubility and Saturation

5.1.5 The effect of CO2 partial pressure on stability of carbonate minerals

5.1.6 The effect of mineral composition on stability of carbonate minerals

5.2 The Carbon Cycle

5.2.1 Oxidation States of Carbon

5.2.2 Global-scale Reservoirs and Fluxes of Carbon

5.2.3 Processes that Transfer Carbon into the Crust Carbonate Rocks Fixation of Organic Carbon into Organisms Formation of Hydrocarbons Formation of Coal

5.2.4 Rates of Organic Carbon Flux to and from the Crust

5.2.5 The Ocean Reservoir Fixation of C into Oceans Ocean Acidification Long-term Viability of Oceans as C Sink Methane Hydrates

5.2.6 Carbon in Cold Region Soils

5.2.7 The Atmospheric Reservoir Changes to Atmospheric Carbon over Geological Time Feedback Loops Anthropogenic C and the Atmosphere

5.2.8 Carbon Sequestration

Review questions


Chapter 6: Biogeochemical Systems and Cycles (N, P, S)

6.1 Systems and Elemental Cycles

6.1.1 Reservoirs, Fluxes and Systems

6.1.2 The Concept of Steady State vs. Dynamic Equilibrium

6.2 Elemental Cycles

6.2.1 The Nitrogen Cycle Nitrogen Oxidation States, Nitrogen Species Processes Operating within the Nitrogen Cycle Global Scale Reservoirs and Fluxes of Nitrogen Human Perturbation of the Nitrogen Cycle and Resulting Environmental Impacts

6.2.2 The Phosphorus Cycle P cycling in Soils The Global Phosphorus Cycle Phosphorus and Eutrophication

6.2.3 Comparison of N and P

6.2.4 The Sulfur Cycle Sulfur Oxidation States, Sulfur Species The Global S Cycle The Marine S Cycle Sulfur, Soils and Biota Sulfur and the Atmosphere Sulfur and River Flux

6.2.5 Integrating the C, N, P and S Cycles

Review questions


Chapter 7: The Global Atmosphere: Composition, Evolution and Anthropogenic Change

7.1 Atmospheric Structure, Circulation and Composition

7.1.1 Structure and Layering of the Atmosphere

7.1.2 Geological Record of Atmospheric Composition

7.1.3 Climate Proxies

7.1.4 Orbital Control on C

7.1.5 Composition of the Current Atmosphere

7.1.6 Air Circulation

7.2 Evaporation, Distillation, Co2 Dissolution and the Composition of Natural Precipitation

7.3 The Electromagnetic Spectrum, Greenhouse Gases and Climate

7.3.1 Electromagnetic Spectrum

7.3.2 Re-radiation from Earth’s Surface

7.3.3. Greenhouse Effect and Heat Trapping

7.4. Greenhouse Gases: Structures, Sources, Sinks and Effects on Climate

7.4.1 Molecular Structures and Vibrations of Greenhouse Gases

7.4.2 Greenhouse Gases, Radiative Forcing, GWPs

7.4.3 Global Warming

Review questions


Chapter 8: Air Quality: Urban and Regional Pollutants

8.1 Oxygen and Its Impact on Atmospheric Chemistry

8.2 Free Radicals

8.3 Sulfur Dioxide

8.4 Nitrogen Oxides

8.5 Carbon Monoxide

8.6 Particulate Matter

8.7 Lead (Pb)

8.8 Hydrocarbons and Air Quality: Tropospheric Ozone and Photochemical Smog

8.9 Stratospheric Ozone Chemistry

8.10 Sulfur and Nitrogen Gases and Acid Deposition

8.11 Organochlorine Pesticides, Mercury and Other Trace Constituents in the Atmosphere

8.11.1 Pesticides in Air

8.11.2 Mercury in Air

8.11.3 Arsenic, Cadmium and Nickel in Air

Review questions


Chapter 9: Chemical Weathering, Soils and Hydrology

9.1 Chemical Weathering of Primary Minerals in Soils

9.1.1. Thermodynamic vs. Kinetic Considerations

9.1.2 Predicting Weathering Rates: Goldich Stability Sequence

9.1.3 Laboratory Determinations of Primary Mineral Weathering Rates

9.1.4 Chemical Weathering Reactions Hydrolysis Dissolution of Ionic Solids Reduction-Oxidation Hydration

9.2 Products and Consequences of Chemical Weathering

9.2.1 Congruous vs. Incongruous Weathering: Dissolved vs. Solid Products

9.2.2 Geochemical Quantification of Elemental Mobility in Soil

9.2.3 Quantifying Chemical Weathering: CIA

9.2.4 Secondary Minerals: Controls on Formation, Mineral Stability Diagrams Factors Controlling Soil Mineralogy Mineral Stability Diagrams

9.3 Soil Profiles, Nomenclature, Soil-Forming Factors

9.3.1 The Concept of the Soil Profile

9.3.2 Soil-forming Factors Climate Organisms Relief (Topography) Parent Material Time Anthropogenic Factors

9.3.3 Soil Classification — Soil Orders and Geochemical Controls

9.4 Soils and the Geochemistry of Paleoclimate Analysis

9.5. Effects of Acid Deposition on Soils and Aquatic Ecosystems

9.5.1 Increased solubility of Al in Acidic Soil Solution

9.5.2 Displacement of Adsorbed Nutrient Cations

9.5.3 Leaching of Base Cations Enhanced by Increased NO3 and SO4

9.5.4 Decrease of Soil Buffering Capacity and Base Saturation

9.5.5. Acid Deposition and Heavy Metals

9.6 Soils and Plant Nutrients

9.7 Saline and Sodic Soils

9.8 Toxic Metals and Metalloids

9.9 Organic Soil Pollutants and Remediation (Fuels, Insecticides, Solvents)

Review questions


Chapter 10: Stable isotope geochemistry

10.1 Stable Isotopes – Mass Differences and the Concept of Fractionation

10.2 Delta (δ) Notation

10.3 Fractionation: Vibrational Frequencies, Mass and Temperature Dependence

10.3.1. Stable Isotopes and Chemical Bond Strength

10.3.2 Temperature-Dependent Stable Isotope Fractionation

10.3.3 Equilibrium and Non-Equilibrium Isotope Fractionation Equilibrium Isotope Fractionation Non-Equilibrium Isotope Fractionation

10.4. δ18O and δD

10.4.1 Rayleigh Distillation in the Hydrologic Cycle

10.4.2 The Meteoric Water Line

10.4.3 Regional-Scale to Global-Scale Variations in Precipitation

10.4.3 Temperature Dependence of δ18O in Precipitation

10.4.4 Paleotemperature Analysis Using Oxygen and Hydrogen Isotopes

10.4.5 Oxygen and Hydrogen Isotopes as Tracers in Soils and Groundwater

10.4.6 Application of Oxygen and Hydrogen Isotopes to Paleosol Climate Records

10.5 δ15N

10.6 δ13C

10.6.1 Carbon Isotope Analysis of Paleoenvironment

10.6.2 Carbon Isotopes in Hydrology and Chemical Weathering

10.7 δ34S

10.7.1 Fractionation of Sulfur Isotopes

10.7.2 Tracking Acid Deposition, Sulfate Reduction, and Seawater over Geologic Time

10.8 Non-Traditional Stable Isotopes

10.8.1 δ65/63Cu

10.8.2 δ56/54Fe

10.8.3 δ202/198Hg

10.8.4δ26Mg and δ44/42Ca

10.8.1 δ37/35Cl


Review questions


Chapter 11: Radioactive and Radiogenic Isotope Geochemistry

11.1 Radioactive Decay

11.1.1 Mechanisms and Products of Radioactive Decay

11.1.2 Half-lives, Decay Rates and Decay Constants

11.1.3 Uranium and Thorium Decay Series

11.2 Radionuclide Tracers in Environmental Geochemistry

11.2.1 206Pb/207Pb

11.2.2 87Sr/86Sr

11.3 Radionuclides as Environmental Contaminants

11.3.1 Controls on U, Th and their Decay Products

11.3.2 Uranium Ores, Refining and Nuclear Wastes

11.3.3 High-Level Radioactive Wastes: Geological Disposal and Considerations

11.4 Geochronology

11.4.1 14C, Cosmogenic Radionuclides and Earth-Surface Dating Techniques 14C (Radiocarbon) Cosmogenic 10Be, 26Al and 36Cl Dating Groundwater with 14C and 36Cl Exposure Age Analysis

11.5 Radioactive Decay Methods of Dating Sediments and Minerals

11.5.1 210Pb

11.5.2 K-Ar

11.5.3 Ar-Ar

11.5.4 Rb-Sr

11.5.5 U-Th-Pb

11.5.6 234U/238U and 234U Disequilibrium

Review Questions


Appendix I: Case Study on the Relationship among Volatile Organic Compounds (VOCs), Microbial Activity, Redox Reactions, Remediation and Arsenic Mobility in Groundwater

I.1 Site Information, Contaminant Delineation

I.2 Remediation Efforts

I.3 Sources of PCE and AS

I.4 Mobilization of Arsenic


Appendix II: Case Study of PFOA Migration in a Fractured Rock Aquifer: Using Geochemistry to Decipher Causes of Heterogeneity

II.1 Geologic Framework

II.2 Inorganic Chemistry of Groundwater

II.3 Stable Isotope Compositions of Groundwater

II.4 Groundwater Age-Dating

II.5 Conceptual Model for the Groundwater System


Appendix III: Instrumental Analysis

III.1 Analysis of Minerals and Crystal Chemistry

III.1.1 Electron Microscopy (SEM, TEM and many other acronyms)


III.1.2.1 Bragg’s Law

III.1.2.2 Mineral Identification by XRD


III.1.4 X-ray absorption spectroscopy (XAS) techniques (EXAFS, XANES)

III.2 Chemical Analysis of Rocks and Sediments: XRF

III.3 Elements or Compounds in Solution

III.3.1 Elements in Solution by ICP-AES, ICP-MS, AAS

III.3.2 Chromatography

III.4 Isotopic Analysis: Mass Spectrometry


Appendix IV Table of Thermodynamic Data of Selected Species at 1 ATM and 25oC