Environmental Chemistry in the Freshman Laboratory:

A Modular Approach


Each semester approximately 70 of the 800-1200 students who take Freshman Chemistry at UC Berkeley sign up for special lab sections focusing on environmental chemistry. Both the content and the methodology of these sections differ from the standard chemistry lab curriculum. Five modules, ranging in length from 2-5 weeks, have been developed so far. This program was funded by the National Science Foundation, the Dreyfus Foundation, the Perkin-Elmer Corporation, and the Hewlett-Packard Corporation.

Three articles have been published on this work:

  • "Determination of Polychlorinated Biphenyls (PCBs) in River Sediments: An Undergraduate Laboratory Experiment in Environmental Chemistry Using Capillary Gas Chromatography with Electron Capture Detection" S.E. Kegley, K.J. Hansen, and K.L. Cunningham, Journal of Chemical Education, 1996, v. 73, 558-562.

  • "Environmental Chemistry in the General Chemistry Laboratory, Part I: A Context-Based Approach to Teaching Chemistry" S.E.Kegley, A.M. Stacy, and M.K. Carroll The Chemical Educator,1996, Vol.1, No. 4.

  • "Environmental Chemistry in the General Chemistry Laboratory, Part II: Evaluation of An Alternative Curriculum" S.E.Kegley, A.M. Stacy, and J.P. Gutwill The Chemical Educator,1996, Vol.1, No. 4.

    Take a look at the UC Berkeley Environmental Chemistry web site.

    Modules:


    Lead in the Environment/ Pesticides in Produce/ Strawberry Creek Water Quality

    Brief Description of Modules Developed

    1. THE CHEMISTRY OF WATER (Now available from University Science Books)
      A study of water chemistry and the chemist's role in assuring safe drinking water supplies. Students travel to a local body of water, sample the water, and bring it back to the lab for extensive testing, measuring pH, alkalinity, conductivity, dissolved oxygen, calcium, sodium, magnesium, chloride, fluoride, nitrate, phosphate, and sulfate. The laboratory manual includes both instrumental methods and wet methods of analysis for a variety of common constituents in natural waters. Check out the Strawberry Creek Water Quality page to see the UC Berkeley student data from Strawberry Creek on the UC Berkeley campus.
      • CHEMICAL PRINCIPLES: pH, alkalinity, ion chromatography, conductivity, atomic absorption spectrophotometry, Beer's law, standard curves, titration curves, statistical analysis of data.
      • INTERDISCIPLINARY ASPECTS: Geology, Biology, Public Health
    2. PESTICIDES IN FRUITS AND VEGETABLES (Now available from University Science Books)
      Students analyze produce from the grocery store to test for organochlorine pesticide residues. Issues related to risk assessment and the laws regulating pesticides in the food supply are debated by the students. Check out the Pesticide module page to see the links to articles used in the debate.
      • CHEMICAL PRINCIPLES: structure/solubility relationships, extraction techniques, gas chromatography, electron capture detection.
      • INTERDISCIPLINARY ASPECTS: Biology, Toxicology, Public Health, Law and Policy.

    Other Modules Developed for the Class 

    1. LEAD IN THE ENVIRONMENT
      Students travel to nearby city parks to sample soils for lead. Samples are acid digested and analyzed for lead content by atomic absorption spectrophotometry (flame or furnace will work), with a focus on the chemistry of lead. This module has been incorporated into all of the regular freshman chemistry lab sections at UC Berkeley. The secret? An autosampler for our graphite furnace AA. Check out the Lead in the Environment page to see the UC Berkeley student data from soil near the Golden Gate Bridge in San Francisco.
      • CHEMICAL PRINCIPLES: Equilibrium, redox chemistry, preparation of standards, atomic absorption spectrophotometry, Beer's law, standard curves, soil pH.
      • INTERDISCIPLINARY ASPECTS: Geology, Toxicology, Public Health
    2. HAIR DYES AND HEALTH EFFECTS

      Students analyze permanent hair dyes to determine the dose of p-phenylenediamine received by the average hair dye consumer over a lifetime of hair dye use. Issues related to risk assessment are addressed.

      • CHEMICAL PRINCIPLES: structure/solubility relationships, acid/base properties of organic compounds, extraction techniques, gas chromatography, flame ionization detection.
      • INTERDISCIPLINARY ASPECTS: Biology, Toxicology, Public Health, Law and Policy.
    3. IS IT SAFE TO EAT THE FISH IN THE SAN FRANCISCO BAY?
      Students travel to local fishing piers to sample sediments. These samples are brought back to lab for extraction of PCBs and analysis of the extracts by gas chromatography. Issues related to bioaccumulation and biodegradation, as well as environmental racism are addressed.
      • CHEMICAL PRINCIPLES: structure/solubility relationships, extraction techniques, gas chromatography, electron capture detection.
      • INTERDISCIPLINARY ASPECTS: Biology, Toxicology, Public Health, Law and Policy.

    Teaching Methodology

    During the labs, the students are encouraged to make as many of the decisions as possible. The students decide:

      • Where to sample
      • What procedures to use
      • How to organize their time to accomplish a set of tasks

    In addition to the chemistry,

      1. Collaborative learning and decision making are emphasized, and time is allowed to repeat suspicious measurements. Besides teamwork and discovery learning, the course also emphasizes critical thinking and role playing, as students debate and discuss environmental issues related to their lab work.
      2. Students develop their compositional skills by writing site reports, in which they make a recommendation based on the data they've collected. Because there are no established right answers, students have a chance to make a real contribution, and this knowledge inspires them to work hard and to strive for accuracy.
      3. This course also serves to interface UC Berkeley to the community at large, since the results the students obtain are sent to the appropriate city and county officials.

    Updated 10/7/99.