Year: 2022
Type: dissertation
Abstract: PCBs are a group of industrial chemicals consisting of 209 different congeners, each with varying numbers and positions of chlorine atoms on a biphenyl backbone. Their physical and chemical properties make them very useful in many applications, including transformers, capacitors, building materials, plastics, and carbonless copy paper. The total worldwide production of PCBs may be as high as 2 million tons, much of which has become environmentally available. The manufacture of PCBs was banned in the United States in 1979 and globally in 2001 due to recognition of their impacts on human health. However, due to their stable properties, they are highly persistent in the environment and contamination remains in many areas. Additionally, new PCB contamination is being added to the environment due to certain PCBs being created as a byproduct of other industrial processes, including paint pigment manufacture. While the environmental concentrations for many PCBs that had been used in the now banned commercial mixtures have been decreasing, PCBs created as a by-product have shown an increase in environmental concentration. The impacts to human health of PCBs have been well studied, however, much of this previous research has been on commercial mixtures or 7 indicator congeners, meaning that there are over 200 other congeners with less known about them. Hence, less is known about toxicities on an individual congener scale for a majority. Health impacts currently associated with PCBs include metabolic syndrome, endocrine disruption, neurological disorders, immune disorders, and cancer. The Airborne Exposures to Semi-Volatile Organic Pollutants (AESOP) study has been studying the exposure to PCBs in two communities, East Chicago, IN and Columbus Junction, IA since 2008. The study has gathered data on all PCB congeners in indoor and outdoor air, blood, and food. Health data was not gathered about the participants in the past, so a health survey was created and sent to all previous members of the cohort and previously collected data on hormone levels, medication use, and blood PCB concentration was analyzed to determine health status and the association between health, hormones, and PCBs. We hypothesized that the health of the AESOP cohort is worse than that of the general population and that PCB exposure has an impact on hormone levels. Health outcomes in the AESOP cohort indicates similarities to and differences from the national adult population, as well as differences between the two communities. These differences are more pronounced for mental health, prediabetes, and gestational diabetes. Hormone levels within the AESOP population were determined to be within the reference range, with the exception of T4, where levels in AESOP participants trend low. Lastly, all hormones analyzed were associated with different individual PCB congeners, some of which have not been previously reported. This study provides new evidence for the endocrine disrupting effects of PCBs on a congener specific level.
DOI: 10.17077/etd.006415
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4292801204