MUSCATINE — New research by the University of Iowa shows that PCBs — a class of chemicals known to cause cancer in humans — are present in older school buildings. The study, published Wednesday, surveyed six schools in Iowa and Indiana, including two in Columbus Junction.

It is the largest survey of PCBs in schools to date.

“This is the first time we’ve been able to pinpoint the source of PCBs inside schools,” said Keri Hornbuckle, professor of civil and environmental engineering at the UI College of Engineering. “This study shows that the indoor air is contaminated, and that the contamination is due to materials that remain in use in the school buildings.”

PCBs are from a family of man-made organic chemicals, known as chlorinated hydrocarbons, that were frequently used in construction of industrial buildings, including public schools from the 1950s to 1970s. Their toxic qualities were discovered later, prompting the Environmental Protection Agency to ban them in 1979. PCBs are still present in the environment, particularly in old chalking and fluorescent light ballasts.

School districts are not required to measure the levels of PCBs in their buildings, but the EPA has established guidelines for acceptable levels. When researchers collected indoor and outdoor air samples at the six schools, they found evidence of PCBs inside each of the schools, all at levels the EPA deemed acceptable.

Much is still unknown about PCBs, and the EPA’s acceptable levels are under some debate, said Rachel Marek, UI College of Engineering assistant research scientist and lead author of the study.

“We don’t know precisely what level is safe for kids to breathe,” she said. “The EPA level is under discussion among all of us that are studying PCBs in the air and PCBs in schools. We know PCBs are toxic, we know that they are carcinogens and endocrine disruptors, which means they affect hormones, we know they are neurotoxins. So any level of PCBs in schools is of some concern.”

The only way to know if PCBs are present in a building, Marek said, is to test for it. Removing sources of PCBs can be sometimes funded by grants. If, for example, the PCBs come from outdated light fixtures, school districts can apply for grants to replace the ballasts with energy-efficient fixtures.

But it begins with taking PCB measurements in the school.

“This is something that can be done in every school around the country,” she said.

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