THE GEOCHEMISTRY OF NATURAL WATERS

1. 1 THE GEOCHEMISTRY OF NATURAL WATERS CHEMICAL PRINCIPLES CHAPTER 1b - Kehew (2001)

2. 2 LEARNING OBJECTIVES Review basic fundamentals of chemistry. Understand commonly used concentration units and unit conversions. Learn to calculate and understand the significance of water hardness and charge-balance error. Be introduced to some common ways of graphically displaying natural water compositions. Some of the material in this presentation is a review of very basic chemical fundamentals that most of you should have learned in Introductory College Chemistry courses. This includes the nature and structure of atoms and ions, ionic vs. covalent bonding, how to determine the oxidation states of elements in compounds, the structure of water, the nature and consequences of hydrogen bonding, and the hydration of aqueous ions. If any of these subjects do not sound familiar, please take the time to carefully review the slides and notes on these subjects in this Powerpoint presentation. You will be expected to have some basic understanding of these fundamental subjects when we discuss more advanced topics later in the course. If the review in this presentation is not sufficient for you, you should consult Chapters 5, 6, and 7 in the book Faure G. (1998) Principles and Applications of Geochemistry, 2nd ed., Prentice Hall, Upper Saddle River, New Jersey. Most of the material on concentration units and interconversions should also be review for most of you, although some points may be new. Finally, the remaining material in this presentation, e.g., the discussion of water hardness, charge-balance error, Stiff plots and Piper diagrams, may be new to most of you, but are relatively simple concepts that we introduce now as preliminary warm-ups for things to come. Some of the material in this presentation is a review of very basic chemical fundamentals that most of you should have learned in Introductory College Chemistry courses. This includes the nature and structure of atoms and ions, ionic vs. covalent bonding, how to determine the oxidation states of elements in compounds, the structure of water, the nature and consequences of hydrogen bonding, and the hydration of aqueous ions. If any of these subjects do not sound familiar, please take the time to carefully review the slides and notes on these subjects in this Powerpoint presentation. You will be expected to have some basic understanding of these fundamental subjects when we discuss more advanced topics later in the course. If the review in this presentation is not sufficient for you, you should consult Chapters 5, 6, and 7 in the book Faure G. (1998) Principles and Applications of Geochemistry, 2nd ed., Prentice Hall, Upper Saddle River, New Jersey. Most of the material on concentration units and interconversions should also be review for most of you, although some points may be new. Finally, the remaining material in this presentation, e.g., the discussion of water hardness, charge-balance error, Stiff plots and Piper diagrams, may be new to most of you, but are relatively simple concepts that we introduce now as preliminary warm-ups for things to come.

3. 3 CONCENTRATION UNITS - I Mass concentrations Water analyses are most commonly expressed in terms of the mass contained in a liter of solution (mg L-1, µg L-1, ng L-1) Closely related to mg L-1 is parts per million (ppm) or mg kg-1 These two units are related through the density of the solution (?) or mass per unit volume.