Environmental Soil & Water Chemistry (CRSS 4670/6670 Spring 2003)

Instructor: Kang Xia

Class period: MWF 10:10 am - 11:00 am, Room 3203

Office hours: Wednesday 1:30 pm - 4:00 pm

Required Textbook: "Environmental Soil and Water Chemistry: Principles and Applications", 1998, V. P. Evangelou, John Wiley & Sons, Inc.

Reference Textbooks*:

• "General chemistry" Kenneth W. Whitten, Raymond E. Davis, M. Larry Peck, 1996 (Location: Science 3rd floor; Call #: QD31.2 .W528 1996)
• "Environmental Chemistry of Soils" M. B. McBride, 1994. (Location: Science 4th floor; Call #: S592.5 .M39 1994)
• "Soil Chemistry" H. L. Bohn, B. L. McNeal, G. A. O’Connor, 1985. (Location: Science 4th floor; Call #: S592.5 .B63 1985)

The reference textbooks are reserved at the Science Library

Course Outline

Chapter 1. The Soil-Water System

1.1. Formation of elements and their distribution in soil-water system

• Elemental abundance in water, soil, earth, and the solar system
• Basic Nuclear Chemistry
• Origin and formation of the elements

1.2. Formation of rocks / minerals

• Formation of earth crust and igneous rocks
• Formation of sedimentary and metamorphic rocks

 1.3. Interrelationship between soil and water  

• Weathering processes
• Element cycling
• Soil composition
• Water composition

Chapter 2. Soil Minerals

2.1 Pauling's rules

2.2 Primary soil minerals

 2.3 Secondary soil minerals

• Clay minerals
• Clay swelling and shrinking properties
• Oxide minerals (oxides, hydroxides, and oxyhydroxides)
• Carbonate and sulfate minerals

Chapter 3. Mineral Solubility

3.1 Mineral dissolution reactions

• Solubility of elements
• Primary mineral dissolution reactions

3.2 Mineral weathering

• Major chemical mechanisms in mineral weathering
• Secondary mineral formation processes
• Factors determining mineral weathering rates
• Jackson-Sherman weathering stages
• Soil development and soil pH

 3.3 Stability (solubility) diagrams of secondary minerals

• Steps of constructing stability diagrams
• Stability diagram of gibbsite-kaolinite-montmorillonite-silica system
• Application of stability diagrams

Chapter 4. Soil Organic Matter

 4.1 Chemical composition of soil organic matter

• Fractionation of soil humic substances
• Composition of humic substances

4.2 Chemistry of soil organic matter

• pH-dependent charge of organic matter
• Complexation with metal ions
• Reactions with organic molecules

Chapter 5. Water Chemistry

5.1 Chemical composition of soil solution, surface water, and groundwater

5.2 Properties of water

• Physical states and properties of water
• Acidity, alkalinity, and conductivity
• Environmental water buffers
• Open and closed water systems

 5.3 Predicting speciation

• Speciation diagram of weak acids and bases
• Calculations of species distribution in water
• Activity coefficients of ions in water

5.4. Availability and mobility of inorganic elements  

• Potential reactions of a free cation in water
• Speciation and mobility and availability
• Controlling processes¾
• Important environmental relevant inorganic elements in soil-water system

Chapter 6. Redox Reactions

6.1 Basic electrochemistry Concepts

6.2 Redox limits and reactions in soil-water system

• The range of pe in soil-water system
• Use of Eh-pH (pe-pH) diagrams
• Important redox couples in soil-water system
• Redox reactions at mineral surfaces and with soil organic matter

6.3 Redox reaction sequence in anaerobic and aerobic soils

 6.4 Redox potential measurement in soils

Chapter 7. Mineral Surface Chemistry

7.1 Mineral particle surfaces

• Surface area
• Surface charge and structural charge
• Point of Zero Net Charge (PZNC)

7.2 Ion exchange between mineral particle surfaces and water

• Cation exchange
• Anion exchange
• Diffuse double-layer theory

7.3 Chemisorption and Precipitation on soil mineral surfaces

• Sorption of cations
• Sorption of anions
• Sorption isotherms

 Chapter 8. Soil Acidity, Alkalinity, and Salinity

 8.1 Active and reserve soil acidity

• Soil pH measurement
• Active, reserve, and total soil acidity
• Aluminum chemistry: aluminum hydrolysis & aluminum speciation
• Processes promoting soil acidity
• Neutralization of soil acidity

 8.2 Soil alkalinity and salinity

• Sources and processes promoting salinity and alkalinity
• Measurements of salinity and alkalinity
• Effect of salts on soils and plants
• Reduction of soil alkalinity and salinity

Chapter 9. Chemistry of Organic Chemicals in the Soil-Water System

9.1 Basic chemical and physical properties of pesticides and other organic pollutants

• Makeup of organic compounds and their classification based on polarity
• Organic solvent-water partitioning: the octanol-water partition constant (K_ow)
• Air-water partitioning: the Henryês Law constant (K_H)
• Effect of salt on K_ow and K_H

 9.2 Sorption and desorption of organic chemicals in the soil-water system

• Sorption mechanisms
• Factors controlling sorption mechanisms
• Sorption of ionic organic chemicals
• Sorption of moderately polar nonionic organic chemicals
• Sorption of weakly polar and nonpolar nonionic organic
• Sorption isotherms

 9.3 Transformation of organic chemicals in the soil-water system

• Abiotic transformation
• Biotic transformation
• Kinetics of transformation