Year: 2026
Type: dissertation
Abstract: Nanoplastics (NPs) (1-1000 nm), are unintentionally produced nanoscale objects derived by fragmentation or degradation of microplastics (MPs) (> 5 mm) in the environment. Their environmental prevalence is currently poorly understood, and it is only recently that their potential impact has become apparent. As a result, the need for identification, quantification, and toxicity analysis of these emerging contaminants, is now recognized. Unlike non-weathered engineered nanomaterials (ENMs) whose biodistribution, bioaccumulation, bioactivity, and toxicity are dictated by their physiochemical properties, fragmented nanoplastics offer a non-uniform size and shape distribution at the nanoscale. This difference warrants investigation of how that diversity in properties, along with their polymeric nature influences their biological and environmental toxicity and fate. The increased use and persistence of plastics through everyday consumer products has drastically increased exposure rates through inhalation, ingestion, and dermal contact, thus general adverse effects (oxidative stress, inflammatory response, neurotoxicity) need to be considered. Nanoplastics are found throughout aquatic environments, and, similarly to ENMs can also act as carriers for chemicals, pollutants, and micro-organisms. Several toxicity studies have shown that nanoplastics and microplastics are ingested by aquatic species and have been found to bioaccumulate within the liver, kidney, gut, and the brain. However, unlike ENMs, there are significantly fewer studies and even less is known about how weathered and environmentally relevant nanoplastics and microplastics may affect biological endpoints in humans. Notably, (nano)plastics show great compositional diversity, which contributes to the uncertainty of their impact, commonly observed plastics are polyethylene (PE), polypropylene (PP), polystyrene (PS), poly-vinyl-chloride (PVC), polyamide (PA), and polyethylene terephthalate (PET). There is a lack of literature regarding the mechanisms that induce fragmentation within the environment. A large portion of biological and toxicity studies have used non-weathered commercially available engineered nanoplastics, while these are excellent reference materials for initial characterization and control groups, they do not accurately represent the nanoplastics present in the environment. This research aims to provide clarity regarding the effects of UV exposure and mechanical abrasion as mechanisms of action for the degradation of PET MPs, toxicity associated with exposure to engineered and weathered environmentally relevant PET MPs/NPs within MCF-7 cells, and quantifying phthalate exposure via leachate from recycled single-use consumer PET bottles as well as the risk associated with that exposure.
Author: Kasuske, Zachery Augustus
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7171271950