Eyeglasses not only improve our vision, but, according to a Union research professor, they also may help us monitor our exposure to radon, a cancer-causing gas that is blamed for 15,000 deaths a year.
Robert Fleischer has discovered that many eyeglass lenses make perfect “personal radon dosimeters.” Most lenses these days are made of a particular plastic CR-39 (also known as allyl-diglycol carbonate) that is damaged by the alpha particles of radon; the damage can bee seen after chemical etching. Since many people wear their eyeglasses throughout waking hours, and leave them close at hand while sleeping, eyeglass exposure gives a direct and complete picture of personal radon exposure.
Fleischer, a former General Electric Co. scientist now working in the College's Geology Department, says his discovery was “an accidental recognition that this stuff [plastic lenses] has information on it that we can pull out.”
At GE, Fleischer's research concentrated on determining astronauts' exposure to radiation as evidenced by etching tracks in their helmets, used during the missions of Apollo 8 and 12. But when he learned of the contents of plastic eyeglass lenses, he recognized a remarkable similarity to case of those astronaut helmets. Having spent much of his professional career tracing the “etchings” made by radon alpha particles, he hypothesized that he would find similar results from etching in eyeglass lenses. In 1987, he wrote a paper titled “Serendipitous Dosiometry: An Opportunity and an Opportunity Lost” for the journal Health Physics, hoping that another researcher might make use of his ideas.
But no one did, so last year, Fleischer finally decided to embark on his own study, seeking assistance from geology students Stephen Hadley '00 and Nicholas Meyer '00. They gathered discarded eyeglasses from a local optician, who provided information about when each pair was made, and were able to measure the eyeglasses' wearer's exposure to radon over the life of the glasses.
Fleischer says that his method of using eyeglasses to measure radon exposure is a significant improvement over the commonly-used radon detectors in basements. “The tendency to measure basements is an unwise decision by the EPA [Environmental Protection Agency] — most people don't live in their basements,” he says. “What matters most are the numbers on the first and second floors.” In addition, Fleischer's method allows for measurements in a wearer's home and work environment, thus measuring the actual average exposure throughout the day.
The next step in Fleischer's research is to compare the radon exposure findings from analyzing eyeglass lenses to findings from the stationary radon detectors traditionally used in homes. He expects to find that the readings are very close, but since most people do not spend all of their time in their homes, Fleischer anticipates that discrepancies between two findings might indicate when the major source of radon is outside of the home.
Fleischer, Hadley, and Meyer delivered their paper last spring at the meeting of the American Geological Association and published their findings in the September 2000 issue of Health Physics. Fleischer also has presented the findings at the International Radiation Protection Association in Hiroshima, Japan. Since returning from Japan, Fleischer is expanding his research in fission tracking to examine the evidence of radiation in glass from near to “ground zero” of the hydrogen bomb blast in Hiroshima.
A call for glasses
If you wear eyeglasses during most of your waking hours, and if the lenses are made of plastic CR-39 (the most common plastic lens), Professor Bob Fleischer would like to use your glasses to measure your exposure to radon.
Working with a team of Union students, Fleischer will monitor your exposure to radon based on the “alpha tracking” in your old glasses as well as with small detectors designed to measure radon at different levels of your home. Fleischer is looking for alumni willing to participate in this study of how much of a hazard environmental radon is and how best to assess a person's exposure to this primary form of indoor radioactivity. Because Fleischer or one of his students will be personally conferring with you on useful, unobtrusive locations for detectors in your home, only participants within a 30-minute drive of Union College are currently acceptable. At no cost, Fleischer will supply you with the results of his research.
To learn more or to sign up, please call Fleischer at (518) 388-6985 or e-mail fleishr@union.edu.