Fall 1999
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The chemistry laboratory class was over and the 60 students headed out the door with a valuable hands-on lesson learned. But their teacher, University of Oregon chemistry instructor Deborah Exton, was troubled by what was left behind: the results of the students' experiments, including hazardous material destined for a landfill in a certified chemical waste disposal site.
Compounding the problem, these students represented only a fraction of the 500 enrolled in General Chemistry that term who, together, produced about 80 gallons of hazardous waste material from this one experiment.
"The large number of students taking General Chemistry can create a colossal amount of waste," Exton observes.
Even so, she is adamant about the importance of students doing hands-on chemistry -- so much so that her labs are designed to enable students to perform experiments individually rather than working with lab partners.
"The hands-on experience is so valuable that I insist on it. But the waste bothered me, and I began to wonder if there might not be a more environmentally benign way to teach chemistry," she says.
That was five years ago. Since then Exton has completely revamped the way freshman chemistry laboratory courses are taught at the UO. With the assistance of laboratory preparation assistant Lynn Woolfe, she has adapted old experiments and exercises or created new ones. Now 23 out of 28 experiments that first-year chemists conduct are "green." Exton refers to these as "down-the-drain labs" where experimental residue is so harmless it can literally be poured down the drain or handled with a minimal amount of waste disposal effort.
Exton says that this approach sits well with UO students, who she describes as generally quite environmentally concerned.
How does "green chemistry" work? The student experiment that spurred Exton's thinking five years ago teaches a central technique of chemical analysis. In the past, students analyzed a liquid containing heavy metals that can be damaging to the environment and toxic to humans.
"But the point of the experiment was not the heavy metals, it was the analysis," Exton explains. "It occurred to me that many compounds would work, including environmentally benign compounds such as the red dye #40 in Kool-Aid. So why not substitute?"
And that's just what she and UO instructor Chris Grant did.
Other universities have addressed the problem of waste from chemistry labs in a variety of ways. Some have switched over to what is sometimes called "microscale chemistry," where reduced quantities of all compounds used in an experiment are shrunk by, for example, ninety percent. Smaller quantities result in proportionately less waste.
"That is a nice idea," Exton says, " but it has a big drawback. Microscale training is probably not going to be applicable in real-world working situations. In other words, it provides students with a less useful education as compared to what we offer with our green labs."
Some institutions have taken another approach by conducting virtual labs in cyberspace. While these labs create zero hazardous materials and allow students to perform procedures that might otherwise be too dangerous, they too are not without problems.
"When students only have exposure to computer simulations instead of real laboratories, they miss out on a hugely important part of chemistry," Exton says. "With green chemistry, our students work in a real lab and gain hands-on experience that is vital to truly understanding chemistry, which, we must remember, is an experimental science."
Exton observes that students respond much more positively when presented with practical applications.
"My goal is to continue developing experiments that more fully engage students by integrating the laboratory with the outside world," she says.