Assessing Exposure to Toxic Chemicals: General Chemistry Applied to Human and Environmental Health

Timothy E. Elgren, Professor of Chemistry
Myriam L. Cotten, Associate Professor of Chemistry
Charles J. Borton, Chemistry Laboratory Instructor
Gregory S. Rahn, Chemical Instrumentation Specialist

Department of Chemistry, Hamilton College, Clinton, NY 13323

A one-semester Advanced General Chemistry course with a laboratory component has been developed that explores exposure to toxic chemicals. Through readings and guest lectures, students are introduced to health risks associated with chemical exposure to carcinogens and endocrine disruptors and sources of exposure. A set of laboratory projects were employed to provide students with a fundamental background in polymer chemistry, analytical methodologies and strategies for chemical separations. These projects led to an analytical assessment of our limits of chemical detection of bisphenol A (BPA) and a number of halogenated flame retardants (HFR). BPA is a component of many hard plastics (polycarbonates) and included in many of the resins that coat the inside of aluminum cans. Chemical flame retardants have become ubiquitously incorporated into foams used for carpet backing and furniture. Many are the same compounds previously banned from use as flame retardants in children's pajamas due to their known toxicity. Students were asked to craft a five-week project in which they probed the leaching of BPA from plastics or the presence of HFR in foam. All students presented posters at a public poster session to educate our campus on the nature of these toxic compounds and potential exposures. Some examples of student projects are listed below:

"Fire Retardants in Baby Products"
"Effect of EtOH on Leaching of BPA"
"The Effect of Phosphate, Amino Acids, and pH on the Leaching of BPA"
"Assessing Exposure to BPA from Polycarbonate Cups"
"Plastic Lining in Aluminum Cans Leach BPA"
"Baby Bottles and BPA"

Through lectures, investigative laboratory experiences, and non-technical reading assignments, we have tried to introduce current issues of general public interest that are chemical in nature. The strategy is to build context and interest before exploring the chemical principles in greater depth.

Small class sections allow for extended discussions. Each section met three times per week (MWF) for an hour. An additional one-hour class period was scheduled weekly (Mondays at noon) for both sections to meet together. This time was used for speakers, discussions, laboratory instruction, and exam review.

The progression of laboratory experiences was designed to 1) demonstrate that plastics are not inert materials, 2) introduce analytical methodologies including assessment of limits of detection, 3) introduce separation methods that can be used to extract toxic chemicals from polymers, and 4) provide basic training on instruments to be used for analytical determinations. This progression prepares students with little laboratory experience for the open-ended research question that they are asked to propose which must focus on some aspect of detecting bisphenol-A or halogenated flame retardants.