Date on Master's Thesis/Doctoral Dissertation

5-2017

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Epidemiology and Population Health

Degree Program

Public Health Sciences with a specialization in Epidemiology, PhD

Committee Chair

Zierold, Kristina

Committee Co-Chair (if applicable)

Brock, Guy

Committee Member

Brock, Guy

Committee Member

Sears, Lonnie

Committee Member

Baumgartner, Kathy

Committee Member

Polivka, Barbara

Author's Keywords

pediatric anxiety and depression; metal exposure; coal ash; fly ash; southwest Louisville; copper

Abstract

Background: In the last several decades, the use of coal has become more prevalent in turn increasing the amount of coal ash being produced. Coal ash, the by-product of coal combustion, is composed of small particles that contain essential elements, hazardous metals, polycyclic aromatic hydrocarbons, and radioactive material. While a small proportion of coal ash is reused, the majority gets discarded in open-air landfills and ash ponds. Fly ash, the major component of coal ash, can become emitted into the air and potentially contribute to the air pollution and metal exposure in the surrounding community. Few studies, particularly in the United States, have investigated the relationship between coal ash and adverse health effects in children. Furthermore, because children are still developing both physically and neurologically they are more susceptible to the potential harms of coal ash and more vulnerable to the excess exposure of heavy metals and essential elements found in coal ash. The United States Environmental Protection Agency estimates that 1.5 million children are exposed to coal ash. Though the mechanisms are still unclear, metal exposure has been linked to mood disorders, such as anxiety and depression. The goal of this study was to examine the relationship between PM10, fly ash, and metal exposure and anxiety and/or depression problems in children aged 6-14 years, living near two coal ash storage facilities, and who were recruited in the first 16 months of an ongoing study. Methods: To determine anxiety and depression, the Child Behavior Checklist (CBCL) was completed for children residing in neighborhoods surrounding two large coal ash storage facilities. In-home air samples were collected and analyzed with Proton-Induced X-ray Emission (PIXE) and Scanning Electron Microscopy (SEM) to assess PM10, fly ash, and home environmental metal exposure. Toenail and fingernail samples were collected and analyzed with PIXE to assess metal body burden exposure. Logistic regression models, adjusting for potential covariates, were used to assess the relationship between in-home PM10, fly ash, metal exposure, and metal body burden and three primary outcomes determined from the CBCL: anxiety problems, withdrawn/depressed problems, and anxious/depressed problems. Results: High copper body burden was significantly associated with anxiety problems (AOR=10.3, 95% CI: 1.53-69.3, p-value=0.02), withdrawn/depressed problems (AOR=21.7, 95% CI: 1.96-240, p-value=0.01), and anxious/depressed problems (AOR=52.1, 95% CI: 2.96-919, p-value=0.01). Presence of manganese in the body was significantly associated with anxiety problems (AOR=9.03, 95% CI: 1.40-58.4, p-value=0.02) and anxious/depressed problems (AOR=8.72, 95% CI: 1.39-54.7, p-value=0.02). High filter metal score was significantly associated with withdrawn/depressed problems (AOR=0.14, 95% CI: 0.03-0.80, p-value=0.03). Conclusions: The results of this study use preliminary data from the overarching and ongoing study and should therefore by interpreted with caution. Findings are based on the recruited population from September 2015 through January 2017. These findings suggest that more studies are needed to comprehensively examine the relationship between PM10, fly ash, and metal exposure, in the home environment and metal body burden, and pediatric anxiety and/or depression problems, particularly in regards to exposure that may be from coal ash.

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