200-3 Following the Flow: Temporal and Spatial Dynamics of Microplastics from the Neuse River to the Atlantic Ocean in Coastal North Carolina

Session: Microplastics in the Environment

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Abstract:

Microplastics, defined as synthetic plastic fragments less than 5.0 mm in diameter, are ubiquitous in aquatic environments. However, their environmental and health impacts remain poorly understood. These particles are prevalent in both marine and freshwater systems, yet the mechanisms and rates of their transport are largely unknown. This study collected water samples in July 2023, 2024, and 2025 along a transect from the Neuse River to the Atlantic Ocean in coastal North Carolina to investigate microplastic migration and temporal changes in abundance. Sampling sites included the Neuse River, Adam’s Creek, Harlowe Creek, Calico Bay, Morehead City, Bogue Sound, Atlantic Beach, and Cape Lookout.

Microplastic extraction followed NOAA protocols using wet sieving, wet peroxide oxidation, and density separation. We extended filtration beyond the conventional 300 µm to 30 µm to capture smaller microplastics. Each sample was analyzed microscopically for microplastic categorization and quantification, with dual verification by independent counters for accuracy.

This study examines variations in microplastic presence across different years, locations, sizes, and types. A significant finding is that the majority of microplastics are smaller than 300 µm, indicating that previous studies may have underestimated their prevalence in the environment.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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