Abstract

Microplastic (MP) pollution is one of the most significant environmental issues of the modern era, driven by the persistence of plastic and its rapid accumulation in aquatic environments. MPs (5 mm -1 µm) are now pervasive across global ecosystems, including the Laurentian Great Lakes, which receives an estimated 11,000 tons of plastic debris annually. Despite their prevalence, critical gaps remain in understanding MP input sources, polymer composition, morphological diversity, and spatial and temporal distribution. This study addresses those gaps by quantifying and characterizing the spatial, temporal, and compositional variability of MPs in the nearshore region of Lake Ontario’s Rochester Embayment across water, sediment, fish fillet, and fish gastrointestinal tract. Results demonstrate MP contamination across all sites and environmental matrices (water column: 0.07-0.82 particles L-1, sediment: 10-383 particles kg-1, fish fillet: 0-0.52 particles g-1, gastrointestinal tract: 0-1.97 particles g-1). Polyethylene terephthalate fibers dominated all matrices, suggesting synthetic textile shedding and wastewater derived inputs as primary sources. Spatially, elevated concentrations were observed at a high use public recreational beach adjacent to the mouth of the Genesee River and an exposed lakeshore pier in a suburb east of the City of Rochester. Temporal trends showed higher summer concentrations followed by declines in fall and winter, reflecting seasonal variability in inputs and hydrodynamic processes. The occurrence of similar polymer types and morphologies across matrices, coupled with widespread detection across sites, suggests ongoing transport of MPs through the water column, deposition into sediments, and biological exposure and uptake by fish. This highlights a strong connectivity among abiotic and biotic compartments. Sediments functioned as a dynamic temporary sink for MPs, while fish fillets revealed a direct pathway for human exposure. Together, these findings demonstrate that MP contamination in the Rochester Embayment is ubiquitous and generally similar in composition across matrices. This suggests that input, transport, and biological uptake link water, sediment, and organisms. This connectivity underscores the continual input of MP to the system and for potential human exposure through freshwater food webs. Continued monitoring and targeted source reduction efforts are critical to address MP pollution in Great Lakes ecosystems.

Publication Date

6-15-2025

Document Type

Thesis

Student Type

Graduate

Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences

College

Golisano Institute for Sustainability

Advisor

Christy Tyler

Advisor/Committee Member

Matthew Hoffman

Advisor/Committee Member

Nathan Eddingsaas

Comments

This thesis has been embargoed. The full-text will be available on or around 8/9/2027.

Campus

RIT – Main Campus

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