New research from the University of Iowa shows that polychlorinated biphenyls (PCBs), chemicals known to cause cancer in humans, are present in older schools and that the source of the PCBs is most likely outdated building materials, such as window caulking and light ballasts.
[Photo: Dr. Peter Thorne]
The multi-year study by the Iowa Superfund Research Program, based in the University of Iowa College of Public Health, is the largest yet to examine airborne PCBs in schools. It shows that though the presence of PCBs can vary from school to school and even classroom to classroom, children’s exposure rates are roughly the same in rural and urban areas. It also shows that exposure to PCBs by inhalation may be equal to or higher than exposure through diet, a finding that surprised researchers.
PCBs are man-made chemical compounds that were used in industrial and commercial applications from 1929 to 1979, when they were banned. However, PCBs are still present in the environment, especially in areas with high concentrations of heavy industry and in buildings constructed in the ’50s, ’60s, and ’70s, when PCBs were used in various building materials. Many public schools were built with PCB-laced materials, and public health experts estimate that as many as 25,920 schools nationwide still have window caulking that contains the chemical compounds.
Researchers collected indoor and outdoor air samples at six schools in Iowa and Indiana from 2012 to 2015. And though none of the schools had PCB levels high enough to meet federal standards for immediate remediation, researchers say the study is important because it shows that reduction of airborne PCBs in schools could be accomplished by removing old caulk around windows and modernizing light fixtures.
“Our nation’s schools must provide a safe and healthy environment for growing and learning,” says Dr. Peter S. Thorne, professor and head of occupational and environmental health in the UI College of Public Health and principal investigator of the study. “In addition to protecting children from risks such as asthma and obesity, schools need to be free of elevated exposures to persistent pollutants, including lead and PCBs.”
The study, published in Environmental Science & Technology, comes at a time of increasing concern over PCBs in schools. In 2014, a school in Lexington, Massachusetts, was shuttered after high levels of PCBs were found inside the building. New York City officials recently completed a multi-year program to replace PCB-laden light ballasts in more than 800 schools. And last year, parents in Malibu, California, won a publicized court battle to remove PCBs in schools.
“Due to the presence of PCBs in the environment, humans are easily exposed to them,” says Dr. Rachel F. Marek, assistant research scientist at the UI College of Engineering and lead author of the study. “Exposure of school-aged children to PCBs is of particular concern because these are compounds we know impair memory and learning and cause cancer in humans.”
Schools are not required to measure PCBs; however, the United States Environmental Protection Agency provides guidelines for acceptable PCB levels. UI researchers studied PCB levels in four urban schools in East Chicago, Indiana, and two rural schools in Columbus Junction, Iowa. PCB levels inside the schools were below the current EPA action level of 500 nanograms per cubic meter, with a maximum reading of 194 ng/m. The highest PCB levels were reported at two schools in East Chicago. Both were built before the PCB ban in 1979.
“This is the first time we’ve been able to pinpoint the source of PCBs inside schools,” says Dr. Keri C. Hornbuckle, professor of civil and environmental engineering at the UI College of Engineering and project leader for the Iowa Superfund Research Program. “This study shows that the indoor air is contaminated, and that contamination is due to materials that remain in use in the school buildings.”
UI researchers are planning their next PCB project, one that will measure PCB levels in different rooms in the same pre-1979 building. They also plan to offer free indoor PCB testing to schools.Tags: Iowa