Date of Award

3-2023

Document Type

Thesis

Degree Name

Master of Science in Industrial Hygiene

Department

Department of Systems Engineering and Management

First Advisor

Jeremy M. Slagley, PhD

Abstract

In the course of maintaining a safe, mission-ready aircraft fleet and operational runways, United States Airmen experience a range of occupational risks. These risks include inhalable hazards generated from oft-used maintenance practices, such as blasting which emits silica from the media abrasives as well as contaminants from the exterior coatings. Additional inhalation hazards range from engine and fuel emissions, chemical agents, radiation, and explosives, to naturally occurring and human-manufactured biopathogens. Of notable concern are emissions in forward-deployment areas, including urban pollution, particulates released from runway construction and maintenance activities, and combustion from burn pits containing hazardous and unknown combinations of toxicants. The focus of this study is to examine the effects of mixtures of selected, commonly occurring “benchmark” emissions; specifically, mixtures of respirable-size silicon dioxide (SiO2), cadmium oxide (CdO), and chromium oxide (Cr2O3) particulates. Each of the study particulates, individually, are known inhalation hazards and potentially carcinogenic. Less is known about how mixtures of these particulates affect human lung cells. This study, which employed In vitro methodology using adenocarcinomic human alveolar basal epithelial cells (A549), focused on assessing and characterizing the critical energy and zeta potential of the non-metal SiO2 with the metallic particulates, CdO and Cr2O3, and how these mixtures affect human lung cells. MTT and LDH assays were used to assess the viability of A549 cells following exposure to the benchmark particulates and their mixtures. Cytokine-pro-inflammatory markers were used to measure inflammatory response in the lung cells. MTT assays suggested particle mixtures had an additive toxicity effect on cell viability. LDH assays showed no effects, which appears to be caused by particle interference. None of the study particles individually, or in combination, had an effect on the pro-inflammatory markers. The research is relevant because of the pervasive exposure of Airmen to the study particulates and varied particulate mixtures, along with the yet unknown, and potentially harmful, effects of these exposures. Further research is needed to bolster the scant knowledge of the effects of these particulate mixtures.

AFIT Designator

AFIT-ENV-MS-23-M-216

Comments

Plain-text title form: Effects of Occupationally Military-Relevant Particle Mixtures (SiO2, CdO, Cr2O3) on A549 Human Pulmonary Epithelial Cells

A 12-month embargo was observed for posting this thesis on AFIT Scholar. Approved for public release. PA case number on file.

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