Finding Fingerprints: A Novel Analytical Approach to Identifying Nanoplastics by Assessing Spatiotemporal Deformation Characteristics with Scanning Electron Microscopy

Jared Stine
Event Speaker
Jared Stine
Environmental Engineering Ph.D. student (Advisor, Stacey Harper)
Event Type
CBEE Seminar
Date
Event Location
Kelley 1001 and Zoom
Event Description

With annual plastic production exceeding 335 million metric tons worldwide, plastic waste continues to accumulate in the environment where it degrades into smaller plastic particles over time. Due to their size, nanoscale plastic particles (nanoplastics) may exist in quantities several orders of magnitude greater than those found for microplastics, yet their collective mass remains well under the limits of detection for most standard analytical methods. The goal of this research is to adapt existing tools to address the analytical challenges posed by nanoplastics identification. Given the unique thermodynamic properties of anthropogenic polymers, we hypothesized that nanoplastics could be differentiated by polymer type using spatiotemporal deformation data collected with scanning electron microscopy (SEM). We selected polyvinyl chloride (PVC), polyethylene terephthalate (PET), and high-density polyethylene (HDPE) to capture a range of thermodynamic properties and molecular structure encompassed by commercially available plastics. Pristine samples of each polymer type were chosen and individually milled to generate micro- and nanoscale particles for SEM analysis. These polymers were compared against proxy materials representing common environmental media, including algae (Raphidocelis subcapitata), kaolinite clay, and nanocellulose. Samples for SEM analysis were prepared uncoated to enable observation of polymer deformation under set electron beam parameters. For each sample type, five particles approximately 1 µm in diameter were selected and videos of particle deformation between 30 and 60 seconds in length were recorded and studied. Data was also collected in blinded samples prepared with mixtures of the aforementioned materials to test the viability of this methodology for identifying plastic particles near the nanoscale. Based on evidence collected, degradation patterns between plastic particles and particles present in common environmental media show significant differences. A computer vision algorithm is currently in development and being tested against manual measurements to further improve the usefulness of this methodology.

Speaker Biography

I am an elder PhD candidate in environmental engineering here at Oregon State. I earned my Bachelor's degree in Civil Engineering from Cal Poly, San Luis Obispo in 2015. After graduating, I spent four years working as a consultant designing transportation infrastructure and assessing the environmental impacts of various land development projects. I became a licensed Professional Engineer in Oregon back in 2020 shortly after moving here. Having earned a toxicology minor and completed the Graduate Certificate in College and University Teaching, my primary interests are on the human elements in engineering. Coming into my graduate studies, I wanted to better understand how humans interact with their environment and how anthropogenic contaminants can affect our health. By focusing part of my studies on teaching, I also aspire to effectively communicate science to others. My research projects involve looking at novel methods to potentially characterize environmental nanoplastics, studying nanoplastic toxicity, and understanding the various physicochemical processes influencing nanoplastic bioavailability in the human gastrointestinal tract. Outside of research, I enjoy cooking, playing DnD, making music with friends, and not talking about work.