​​​OMG 214 Introduction to Environmental Geochemistry

Dr. Susanne Fietz

Course Synopsis

214 geochem.png

The purpose of this course is to introduce students to the complexity of geochemical processes at Earth surface and to application of geochemical principles to the natural environment. In this class, we study the geochemistry of the atmosphere, hydrosphere and sedimentary environment taking into account the microbial impact. Human effect, including contamination and pollution, on all spheres is also discussed. Students will review basic concepts of (geo)chemistry, and apply these concepts to understand natural geochemical cycles, environmental problems and remediation strategies.

1)     Chemical quantities

    • Outcome: students at ease with basic terminology, calculations and conversions in chemistry 

2)     Atomic and molecular structure

    • Outcome: understanding the role of atomic and molecular structure for geochemical processes 

3)     Acid base equilibria in soils and water

    • pH, alkalinity, buffer capacity
    • Carbonate chemistry
    • Acid Mine Drainage & Natural Neutralization Potential
    • Outcome: understanding the role of acid-base equilibria in the natural and industrial systems 

4)     Thermodynamics

    • Kinetic and Potential energy
    • Enthalpy, Entropy, Gibbs Free Energy
    • Outcome: understand the flow of energy in chemical reactions 

5)     Solubility and saturation

    • Equilibrium chemistry; Calculating solubility and saturation
    • Outcome: enabling students to predict potential for and amounts of dissolution 

6)     Kinetics

    • Reaction rates: 0 order, 1st order, 2nd order
    • Role of kinetic rates in dissolution and precipitation
    • Outcome: understanding difference between drivers (thermodin.) and rate (kinetics) of reactions in aqueous and atmospheric geochemistry 

7)     Redox chemistry

    • Energy yield and electromotive force; Nernst Equation
    • Calculations and drawing related to Eh-pH diagrams & Interpretation
    • Sequences of electron acceptors; Energy yield and role of microbes
    • Biogeochemical cycles and human impact
    • Outcome: understanding the meaning of oxidation numbers in predicting reactions; understanding the link between electron transfer and energy; understanding the tight links between the biosphere and geosphere 

8)     Chemical Weathering

    • Impact of weathering on the environment, i.e. on geomorphology, water chemistry, atmospheric gases
    • Impact of weathering on soil properties; Cation Exchange Capacity and contaminant retention
    • Calculations and drawing related to Stability Diagrams & Interpretation
    • Outcome: understanding the role of soils and climate for weathering & the role of weathering for soils and climate; understanding the potential risk of weathering for contamination and potential use of weathering compounds in clean up processes; students at ease with common graphical illustrations 

9)     Contaminants

    • Overview of most common organic and inorganic contaminants in our surroundings
    • Persistence and mobility & fate and transport in the environment
    • Understanding remediation strategies; sorption, volatilisation/sparging, biodegradation
    • Two global threats in the environment: arsenic and mercury
    • Science for Policy Makers
    • Outcome: understanding modern threats and basic science behind remediation strategies; students at ease with calculations of transport and degradation; understanding the purpose and value of policies 

10) Atmosphere: greenhouse gases and climate change

    • Structure of atmosphere and average atmospheric composition
    • Earth's Energy Budget
    • Radiation, wavelengths, photon absorption, vibrational frequency
    • CO2 and the greenhouse effect; Understanding Climate Change debates; Science for Policy
    • Outcome: understanding the basics of the greenhouse gas effect, awareness of the current rate and extent of CO2 in the atmosphere and climate change 

11) Atmosphere: air pollution

    • Air pollutants: sources, fate and effects
    • Rainwater composition, sources of chemical species, pH
    • Science for Policy Makers
    • Outcome: understanding the link between geosphere and atmosphere; understanding the impact of human activity on the atmosphere 

12) Freshwater geochemistry

    • Processes that determine chemical composition: sources of major elements, chemical and biological removal of elements
    • Stiff and Piper diagrams, water classification
    • Contamination
    • Outcome: students familiar with basic water chemistry determinations as well as common graphical illustrations 

13) Isotopes

    • Stable isotopes; fractionation, delta notation, fractionation factor
    • Radioisotopes; decay, alpha –beta – gamma  radiations, half life time; risks associated with radiation; Science for Policy
    • Application of isotopes in environmental geochemistry: Dating, GW flow, Environmental forensics, Climate Change
    • Outcome: students familiar with the use of isotopic composition of elements to study earth's climate, geosphere, and to track the fate of contaminants; students at ease with calculations of isotope enrichment and decay in the environment 

14) Marine geochemistry: water column

    • surface currents, upwelling, thermohaline circulation
    • chemical composition; sources and sinks of chemical species
    • carbonate chemistry and seawater buffering, ocean acidification
    • Science for Policy
    • Outcome: understanding the complexity of the ocean water masses and the role for chemical composition; understanding the tight link between ocean, atmosphere, and biosphere; understanding the relevance of the Blue Economy and modern threats to the marine ecosystem 

15) Marine geochemistry: sediments

    • Controls on sinking of particles
    • Marine sediments; classification, origin, processes, distribution
    • Science for Policy and Industry
    • Outcome: understanding the basics of the formation of the marine sediment

Course Outcomes

At the end of this course, the student should be able to:

  • work confidently with different chemical units.
  • Ability to interpret environmental geochemical data sets.
    define key concepts of geochemistry, especially of the energy flow, i.e. thermodynamics.
  • conduct basic calculations related to environmental geochemistry.
  • draw and interpret common graphs that facilitate the representation of geochemical data.
  • understand the natural chemical processes/reactions in the environment and the link between the geo-, hydro, atmos- and biospheres.

    understand the role of anthropogenic perturbations and project the consequences of human activities.

·       propose solutions to real world environmental problems.


Study Materials and Textbook Recommendations

"Environmental and Low Temperature Geochemistry" by Peter Ryan, ISBN: 978-1-4051-8612-4, Wiley-Blackwell.

"Principles of Environmental Geochemistry" by G. Nelson Eby 

Additional material will occasionally be provided in class and/or posted on SUNLearn.