Date of Award
Doctor of Philosophy (PhD)
Civil and Environmental Engineering
Freshwater, Human perception, Lakes, Methodology, Microplastic, Sampling
Plastic pollution is a global problem impacting every environmental compartment, from the air in Mount Everest to urban freshwater supplies. The scope and magnitude of the plastic problem requires an interdisciplinary approach that addresses human and environmental dimensions. I look to inform circular economy approaches through three phases of research: 1) individual waste generation and perceptions of waste and plastic issues; 2) methods and quality control evaluation for quantification of freshwater microplastics; and 3) temporal and spatial variation in plastic particle dynamics over a 3-year period in an urban lake compared with a rural lake in Central New York. In phase 1 (Chapter 2), I consider the non-perishable waste generation and environmental perceptions of participants in a social media campaign, Futuristic February. Participants in this campaign were directed to collect their non-perishable waste in February 2020. The aim of this work was to evaluate general perceptions of the survey participants on common areas of misinformation regarding waste and plastics, as well as to obtain general information regarding individual waste generation. Participant’s perceptions of plastic and waste issues were compared to popular search results on Google and Google Scholar in a mini-review. Participants were most uncertain on topics related to bioplastics and biodegradable plastics. The majority of participants (86%) agreed that there were trash islands in the ocean gyres. The mini-review results showed that uncertainty differed by group (Google, Google Scholar, and participants) and topic, rather than any consistent pattern among participants and search platform. In Phase 2 (Chapter 3) I focus on quantifying environmental impacts of plastic pollution in temperate freshwaters. Methods for collection and quantification of plastic particles in the environment are non-standardized and often incomparable across studies. In this chapter I consider the use of point sampling (grab, bucket, and pump methods) and areal sampling (net) methods for microplastic sampling in fresh surface waters. I used a strict quality control correction using a limit of detection (LOD) and limit of quantification (LOQ) approach to account for background contamination. Point sampling methods were less likely to exceed the LOD compared to net sampling, though results differed depending on the location chosen for sampling and if visible floatable plastic pollution was present. Net sampling likely underrepresented smaller particles but collected a higher diversity with respect to color and morphology and exceeded the LOD in every sample, providing a more reliable method for monitoring microplastics. Lastly, in Phase 3 (Chapter 4) I applied the refined net method identified in Phase 2 to monitor both urban and rural lake surface waters for microplastics in central New York over a 3-year period (2019-2021). The goals of this monitoring campaign were to: identify patterns with respect to source and location, and discuss potential impacts of seasonal stratification on microplastic circulation in dimictic lakes. Plastic particle concentrations were higher in Onondaga Lake (urban) compared to Skaneateles Lake (rural), likely owing to higher potential inputs for plastic pollution from CSOs, urban runoff, and wastewater effluent inputs. The shorter residence time and smaller number of large inflows impacted by urbanization to Onondaga Lake resulted in a higher temporal variation. Chemical characterization of particles revealed patterns of particle types that can further inform sources and losses of particles for improved regional floatables management. Lastly, I offer areas for future research and priority policy action based on these three phases of work in Chapter 5.
Markley, Laura Audrey Thomasina, "A Multi-Disciplinary Approach to Plastic Pollution from Environmental Sampling to Surveying: Quality Assurance, Freshwater Contamination, and Popular Opinions" (2023). Dissertations - ALL. 1715.