Emission characterization and criteria for remediation of airborne Polychlorinated Biphenyls in a school and a university building
Creators: name: Bannavti, Moala Keshei
Publisher: name: University of Iowa
Year: 2025
Subjects: subject: emissions
subject: polychlorinated biphenyls
subject: remediation
subject: School
subject: public abstract
subject: Analytical Chemistry
subject: FOS: Chemical sciences
subject: Gas Chromatography
subject: Mass Spectrometry

description: Polychlorinated biphenyls (PCBs) are a group of 209 human-made persistent organic pollutants. Inhaled exposure to PCBs has been linked to cancer, hormone disfunction, and cognitive learning disorders regardless of age or sex. PCB mixtures were intentionally produced in the United States as Aroclors by Monsanto from the 1930s to late 1970s when it was outlawed by the Toxic Substance Control Act (TSCA). Increased usage of PCBs in building materials directly coincides with the rise of public construction from the 1950s to 1980. An estimated 55,000 US public and private schools are contaminated with Aroclor PCBs. Additionally, schools may be contaminated with modern PCBs that are inadvertently manufactured in colorant production processes. These colorants are added to inks, paints, and other brightly colored items used in schools. PCB remediation in schools is often expensive and is not airborne-focused, despite evidence that inhalation is an equal or greater exposure route than diet. The work of this thesis is to understand the emission characterization of airborne PCBs indoors and diverse stakeholder perspectives on remediation in hopes of improving its cost efficiency and equity. This work seeks to observe if a room can serve as a PCB micro-environment within a building, and furthermore, if materials within a room can dictate the magnitude and distribution patterns of PCB congeners. I conducted three major studies to meet these goals.
description: First, I examined the differences in airborne PCB concentration and congener distribution from room-to-room in a school building. I deployed polyurethane foam passive air samplers (PUF-PAS) in nine rooms and one outdoor location (n = 3 each) in Columbus Secondary School. Airborne PCB concentrations varied significantly from room-to-room (1.5 – 36 ng m-3). Rooms constructed or renovated before the TSCA (1977), had higher concentrations than those built after. Cosine theta analysis, positive matrix factorization and principal component analysis were used to observe differences in PCB congener distribution which also varied from room-to-room (cosine theta &gt; 0.9). Most room air profiles were dominated by a mixture of Aroclor 1254 and 1016. Nevertheless, in the practice gym non-Aroclor PCBs were a significant source (~30%). Second, I identified airborne PCB emissions from commonly used, large surface area, indoor materials. I sampled emissions directly, using polyurethane foam passive emissions samplers (PUF-PES) in the University of Iowa’s Institute of Rural Environmental Health office building. Measurements were taken before and after removing surface PCBs via hexane wiping the flooring (tile with carpet overlay) and wood panel walling from two rooms, and hallway tile outside those rooms. Surface PCB removal significantly reduces emissions across all measured materials (p-value = 1.2 x 10-4). The difference before and after wiping the flooring (n=6) averaged 6,187 ng m-2d-1, wood panel (n=6) averaged 3,832 ng m-2d-1, and tile (n=3) averaged 11,841 ng m-2d-1. These results indicate a removable PCB surface layer is a distinct emissions source. Most of the 209 PCB congeners were significantly reduced by hexane wiping (59%). Using a mass balance simulation, I found emissions from flooring and walling fully accounted for the mass of PCBs in the room air.
description: Finally, I investigated which forms of science communication aid stakeholders in making decisions about PCB remediation of school air in the United States. I conducted a comprehensive review of studies specific to airborne PCB remediation in schools. Nine academic publications met the inclusion criteria. The review uncovered the need for all stakeholder groups to further investigate the influence of cost, legal regulation, and effectiveness of remediation practices on the state airborne PCB contamination in schools. To advance the exploration of these themes I held interviews with US Environmental Protection Agency personnel, engineering consultants, and a parent-teacher community group leader. Stakeholders use various forms of science communication to make decisions on airborne PCB remediation in schools including rigorous peer-reviewed journal articles and easily digestible, short presentations.
description: Throughout my dissertation work I participated in community-centered report back such as specialized lectures and a press release. The research presented in this dissertation advances stakeholder understanding of the sources and distribution of PCBs in schools and the predictive relationship between material emissions and air concentration indoors.