Publication Date

2024

Document Type

Dissertation/Thesis

First Advisor

Samonds, Karen E.

Degree Name

Ph.D. (Doctor of Philosophy)

Legacy Department

Department of Biological Sciences

Abstract

Microplastics (plastic pieces less than 5 mm) have emerged as a pervasive form of pollution acknowledged as a universal threat to both environmental and human health. Their small size and widespread distribution pose significant risks to marine life, terrestrial ecosystems, and ultimately human health. Microplastics have been reported in food and drink items designated for human consumption, in cosmetics and consumer goods designed for human use, and within the air we breathe, each providing an entry route for microplastics to enter the human body. Recently, microplastic particles have been detected in a variety of human tissue samples (e.g., lung tissue). However, details pertaining to the mechanisms of microplastic entry remain limited. It is also unclear how the physical and chemical properties may influence the likelihood of particle entry and accumulation in our body systems. Studies reporting microplastics within human tissue samples used different methods of sample collection, preparation, and analysis, making it difficult to compare results. Moreover, none of these studies have reported a recovery rate to establish the accuracy of the results, leaving critical knowledge gaps in this field of research. The work in this dissertation is focused on advancing our understanding of microplastics and their interaction within the human respiratory system. This dissertation presents a method of sample collection of human respiratory tissues designed and validated to mitigate potential plastic contamination while collecting cadaveric tissue samples. Additionally, as spectroscopic analysis is commonly used to detect microplastics in human tissues, a digestion protocol was assessed using a recovery study. The recovery study was conducted using formalin-fixed cadaveric lung tissue spiked with polystyrene microbeads. A recovery rate of 63.58% was achieved after conducting an enzymatic and oxidative digestion. Furthermore, this work investigated microplastic inhalation by comparing particles in nasal mucosa and lung tissue samples from cadaveric subjects using µFTIR-spectroscopy. Microplastics were found in all samples, with polyester being the most abundant polymer type. This study provides insights into microplastic deposition and accumulation in human tissues and underscores the need for further research on microplastic impacts on human health.

Extent

130 pages

Language

en

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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