Two teens in finals of science competition
By Christopher Snowbeck, Pittsburgh Post-Gazette
November 20, 2004
As Sara Bacvinskas learned about the hepatitis A outbreak at the Beaver Valley Mall Chi-Chi’s restaurant last year, she kept wondering how it could have happened.
David Chancellor wondered, too, although his curiosity was piqued, in part, because his mom was busy investigating the outbreak as a public health physician with the state Department of Health.
Earlier this year, the high school students met by chance in a lab at the University of Pittsburgh and went on to collaborate on a science project regarding the outbreak. This weekend, they’re presenting their findings at the regional finals of the Siemens Westinghouse Competition in Math, Science & Technology at Carnegie Mellon University.
The project by Bacvinskas and Chancellor on how green onions can become contaminated with hepatitis A virus was among 1,037 entries reviewed for the sixth annual national competition. Just 54 projects advanced to regional finals — 11 in the Middle States regional being judged here.

“When they came to me and explained the project, I was amazed — it was so interesting,” said Fernando de Miguel, an assistant professor of urology at the Pitt medical school, who served as a mentor for Bacvinskas and Chancellor.
Two projects — one produced by a team, and one by an individual — will be chosen in this regional to advance to the national finals in Washington, D.C. Winners this weekend receive $3,000 scholarships, and a chance at the grand prize of a $100,000 scholarship.
For making it this far, Bacvinskas and Chancellor, both 16, have already won $1,000 scholarships for themselves, and $2,000 awards for their respective schools — Brashear High School and Winchester Thurston School.
But as Bacvinskas and Chancellor repeated yesterday while standing in front of a poster describing their project: “It’s not about the money.”
Local residents know full well the significance of the project by Bacvinskas and Chancellor, called “Dirt in ‘Clean’ Green Onions: Implications for Transmission of Hepatitis A.”
The largest hepatitis A outbreak of its kind occurred when 660 Chi-Chi’s patrons were sickened and four died after consuming contaminated green onions. Public health investigators determined that restaurant workers did not cause the contamination, and the Food and Drug Administration blocked imports from Mexican farms that had supplied green onions to Chi-Chi’s and other restaurants that suffered hepatitis A outbreaks last year.
But how were the scallions contaminated?
Bacvinskas, of the South Side, and Chancellor, of Squirrel Hill, designed a project to address that question and to determine whether contaminants in scallions could be washed away.
In Chancellor’s back yard, the students grew green onions in 20 pots between June 1 and Aug. 24.
At different points during the project, they treated either the soil or the growing plants with three different biomarkers that simulated hepatitis A virus particles.
Once the scallions were harvested, Bacvinskas and Chancellor used UV-light, microscopes and molecular testing to see if contaminants remained despite the fact that the green onions had been washed and were visibly dirt-free. Evidence of all three biomarkers persisted inside the scallions’ layers.
“The results of our study demonstrate that if fresh produce is contaminated with [hepatitis A virus] during the growing process, there are no washing methods that can ensure all the virus is removed,” the students wrote in their contest entry. “Therefore, to prevent future [hepatitis A] food-borne outbreaks, we recommend careful adherence to FDA guidelines in the growth and processing of green onions.”
The research is impressive in part because it addresses a question of such social importance, de Miguel said. But the students also had to perform some sophisticated lab work — namely, reverse transcription-polymerase chain reaction — to test their hypothesis.
What’s more, the students are continuing their work by studying whether green onions grown hydroponically — without soil — can become contaminated with virus taken up solely through the root system. That could help shed light on one of the big mysteries in the hepatitis outbreak: Did the green onions become contaminated as a result of water problems, or was contamination introduced through fecal matter left in the fields?
It’s too early to say if Bacvinskas and Chancellor will go on to careers in research, but de Miguel said their work so far merits praise.
“I was impressed by their performance — how focused they were in the lab,” he said. “It wasn’t playing, ‘I’m killing my time here.’ They were here doing research.”
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(Christopher Snowbeck can be reached at csnowbeck@post-gazette.comor 412 263-2625.)