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Keri Hornbuckle discusses airborne PCBs in Keystone Science Lecture

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Approaches for studying airborne exposure to polychlorinated biphenyls (PCBs) — and helping communities reduce such exposure — were discussed by Iowa Superfund Research Program (ISRP) Director Keri Hornbuckle, Ph.D., during her Feb. 4 Keystone Science Lecture. The NIEHS-funded program is housed at the University of Iowa.

PCBs are a large group of chemicals that persist in the environment. They have been associated with conditions such as diabetes, liver toxicity, skin ailments, and immune, neurological, and respiratory issues. The substances can be found in products ranging from adhesives and paints to insulation and electrical equipment. Although the chemicals were banned in the U.S. in 1979, potentially harmful exposure to PCBs is an ongoing concern, according to Hornbuckle.

Potentially dangerous byproducts

A group of 209 PCB mixtures known as Aroclors were produced by the company Monsanto in the middle of the 20th century for use in electrical transformers, fluorescent light ballasts, hydraulic fluid additives, building materials, and flame retardants. Sale of Aroclors was banned by the U.S. Environmental Protection Agency in 1975. However, non-Aroclor PCBs continue to be manufactured, largely as byproducts of certain industrial processes, noted Hornbuckle.

She explained that exposures are ubiquitous in the U.S. because of how the substances vaporize into the air, especially on hot days. Although it has been assumed that exposure comes primarily through diet because of how PCBs bioaccumulate in fish and other animals, it is now known that inhalation is another important route of exposure. Hornbuckle, who leads the ISRP Analytical Core, discussed how research methods optimized for assessment of the chemicals have provided new insights about sources of airborne PCBs, exposures, and potential for remediation.

Quantifying exposure

Hornbuckle’s team developed a set of sampling and analytical methods to provide the highest quality PCB data. For example, they use an instrumental method for detection and quantification of the chemicals that uses triple quadrupole mass spectrometry. The approach allows scientists to measure PCBs with a level of accuracy and precision comparable to that provided by high-resolution mass spectrometry but at lower cost.

According to Hornbuckle, the method enables her team to better understand sources of airborne PCB exposure. She noted that the scientists study the release of the substances in cities, rural areas, and school classrooms.

Beginning in 2009, ISRP Project 4 began sampling for airborne PCBs in Chicago, and researchers discovered the prevalence of airborne non-Aroclor PCBs. The scientists determined that past systems for measuring the chemicals had been developed using Monsanto mixtures, which meant that modern PCBs produced as byproducts of manufacturing had gone unnoticed.

Interestingly, one driver of PCBs being emitted into the air involves the heat of the day, not proximity to manufacturing sites.

“The variability of PCBs across the city of Chicago is mostly driven by temperature,” Hornbuckle explained. “The hotter it is, the more they’re released into the air.”

Another surprising finding is that living in rural areas does not equate to lower levels of PCB exposure. In addition, some children experience the highest levels of PCBs in their classrooms.

Reducing health risks

“Many American schools were built in the middle part of the last century, and PCBs were widely added to building materials because they do make resilient materials that don’t need replacement — think lighting, window caulking, masonry joints, paint, and carpets,” Hornbuckle said.

Mitigating the risk of exposure in schools is challenging, she noted. There is no federal program to remove PCB contamination once it is discovered, and schools with resources to address the problem are likely in high-income areas. Because expensive remediation — removal of the substances — is often not feasible in low-income districts, more vulnerable populations can experience the most exposures.

Hornbuckle suggested that school districts can target the worst exposure areas by testing for PCBs on a room-by-room basis.

She said that the state of Vermont is undertaking such a campaign in its schools — combing for sources of PCB exposure, room by room. And a side benefit of many schools around the country updating their ventilation and air filtration systems to slow the spread of COVID-19 is that these measures lower exposure to PCBs as well.

“When you’re trying to determine toxicological risk and opportunities for remediation, some level of focus is needed,” Hornbuckle said. “It’s important to create a strategy for remediation that is cost-effective and that allows for [exposure] measurement when you’re done.”

During a lively Q&A discussion, NIEHS and National Toxicology Program Director Rick Woychik, Ph.D., noted that he grew up in northeastern Wisconsin on the Fox River, which became contaminated with PCBs.

“It is rather sobering to realize just how contaminated that area was,” he said, adding that in many places, PCBs are just one set of chemicals to which people are exposed.

“A major research challenge is to better understand how all of these exposures can influence health and disease,” noted Woychik.

Citations:
Jahnke JC, Martinez A, Hornbuckle KC. 2022. Distinguishing Aroclor and non-Aroclor sources to Chicago air. Sci Total Environ; doi:10.1016/j.scitotenv.2022.153263 [Online 20 January 2022].

Bannavti MK, Jahnke JC, Marek RF, Just CL, Hornbuckle KC. 2021. Room-to-room variability of airborne polychlorinated biphenyls in schools and the application of air sampling for targeted source evaluation. Environ Sci Technol 55(14):9460–9468.

By Kelley Christensen. Kelley Christensen is a contract writer and editor for the NIEHS Office of Communications and Public Liaison.

This article was originally published in Environmental Factor, published by the National Institute for Environmental Health Sciences.

Dr. Field recognized as National Radon Hero

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The Conference of Radiation Control Program Directors (CRCPD) has selected Bill Field, University of Iowa professor emeritus of occupational and environmental health and member of the EHSRC, to receive the organization’s 2022 Radon Hero Award. The award recognizes an individual who has demonstrated leadership in reducing the health effects of radon exposure, the second leading cause of lung cancer in the United States. The award is based on the recipient’s contributions to this effort, the breadth and scope of their services, and sustained commitment to mitigating radon risk.  He was previously awarded Honorary Membership to CRCPD in 2010.

Official presentation of the CRCPD Radon Hero Award will occur during the organization’s annual radon meeting in October 2022.

Field is recognized as one of the foremost authorities on radon, not only for his research into the radioactive gas, but because of his advocacy and outreach efforts. He helped identify radon as the leading environmental cause of cancer deaths in the United States, and remains dedicated to educating the public about the health risks of radon and ways to reduce exposure in homes, schools and at work.

 

This post was originally posted on the UI College of Public Health website. 

N95s, KN95s best mask for protecting against COVID-19 on campus, experts say

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This story was published in the Daily Iowan on February 6, 2022 by Kate Perez and features EHSRC Member Dr. Patrick O’Shuaghnessy, who is the Director of the Exposure Science Facility.
University of Iowa health experts say that the best mask to wear to protect yourself is an N95 mask. The recently distributed KN95s provide the second-best protection, and the worst are the blue surgical masks, according to Center for Disease Control and Prevention guidance.

University of Iowa health experts recommend the UI community to wear KN95 masks instead of surgical masks to offer better protection against COVID-19.

Patrick O’Shaughnessy, director of graduate studies in the UI College of Public Health Department of Occupational and Environmental Health, said N95 masks are most effective because of the tight seal formed to the face while wearing them, while the surgical masks are least effective.

“[N95 masks are] definitely the best protection. The surgical masks they’ve been passing out give the least protection,” he said. “They were designed for source control. They’re designed to protect others from you. They’re designed to catch your output from your mouth, the droplets coming out as you talk, to prevent the transmission that way.”

When the masks are looser, like the surgical ones, O’Shaughnessy said more leakage occurs out of the mask’s sides.

O’Shaughnessy said it is better to wear a KN95 mask from the university than a surgical one, as surgical masks are not supposed to be used as the main way of combating COVID-19.

“They were never designed to be a complete protection for the person wearing them,” O’Shaughnessy said. “That’s where it’s really important for the whole campus community together to be wearing the [KN95] masks.”

The UI announced on Jan. 12 that it would stock each university building health station with KN95 masks, an upgrade from the blue surgical masks given out during the first semester.

O’Shaughnessy said he ranks the KN95 masks that the UI are giving out somewhere in the middle of the other two types of masks, as they can form a tighter seal to the mouth than the surgical masks.

“Especially with the nose metal piece there, you get a better seal around your nose with the KN95,” O’Shaughnessy said. “They filter very similarly to the N95s. It really just comes down to the construction of the mask and how well it fits against your face.”

In an email to The Daily Iowan, Jeneane Beck, assistant vice president for external relations, wrote that the UI follows the Centers for Disease Control and Prevention guidelines when evaluating masks.

Lately, counterfeit masks have been spreading throughout the country, with the CDC reporting that about 60 percent of KN95 respirators the National Institute for Occupational Safety and Health evaluated during the pandemic in 2020 and 2021 did not meet their requirements.

Deborah Zumbach, associate vice president and director of parking and transportation and business services at the UI, wrote in a statement to the DI that the university requests authenticity documentation before making purchases, including the distributed masks.

“The university is fortunate to have an experienced team making regular purchases for a large academic medical center,” Zumbach wrote. “This results in business relationships with a variety of reliable vendors and suppliers in the United States. When making any purchase, the team requests all available documentation regarding a product’s efficacy and authenticity.”

The KN95 masks that are being distributed are from the company Dayhelp. The Dayhelp website states that the masks are FDA Registered Class 1. However, the company is not listed on the CDC website as a NIOSH-approved manufacturer of N95 respirators.

According to the CDC, surgical masks are loose-fitting, disposable, and create a physical barrier between the nose and the mouth of the wearer. These masks, however, may not provide as much protection compared to a KN95 mask.

“While a surgical mask may be effective in blocking splashes and large-particle droplets, it does not filter or block very small particles in the air that may be transmitted by coughs, sneezes, or certain medical procedures,” the CDC website states. “Surgical masks also do not provide complete protection from germs and other contaminants because of the loose fit.”

Dan Diekema, professor of internal medicine and associate hospital epidemiologist, said in a recent post on the UI Hospitals and Clinics’ website that he recommends people wear a medical-grade mask, whether it is a surgical, KN95, or N95 mask.

“We also consider unfitted N95s and KN95s to be equivalent to a medical-grade mask because they fit snugly against the face, allowing for fewer particles to break through,” Diekema said. “The most important thing is the fit to the face to protect the person wearing the mask, as well as others.”