7-20 Preliminary Analysis of the Spatial Distribution of Microplastics Along the Cuyahoga River, Ohio.

Session: Undergraduate Research, Part I (Posters)

Presenting Author:

Authors:

Abstract:

Due to their prevalence in modern society, plastics are nearly ubiquitous throughout our world, and when left in the natural environment, they degrade into microplastics. Microplastics are particles that range in diameter from 5 millimeters down to nanometers, and they pose many potential environmental and health risks due to their small size and ease of ingestion. While the study of microplastics in the environment has become more common over the past ten years, microplastic concentrations remain unexplored in many regions throughout the country. Here we present a method for separating microplastics from organic matter and clastic sediment as well as preliminary measurements of microplastic concentrations in the Cuyahoga River as it flows through Northeast, Ohio. We test the hypothesis that microplastic concentrations increase near urban areas with higher population densities.  As an initial investigation, we sampled five locations along the Cuyahoga River, collecting sediment both suspended in the water column and deposited on the riverbanks. Sample locations were selected at varied distances from population centers and upstream and downstream from important small tributaries, allowing for an examination of spatial correlation between microplastic concentrations and proximity to population centers. We sieve and analyze each phi size separately to investigate the correlation between particle size and microplastic concentration. Next, we digest organic material using hydrogen peroxide (H₂O₂, 35%). Then, microplastics are separated from the clastic sediments through heavy liquid separation using a saturated NaCl solution. Following separation, we quantify the microplastic abundance using an optical microscope and classify types of polymers within the microplastic sample using spectral analysis techniques such as FTIR. These preliminary results show how microplastics are distributed throughout a portion of the Cuyahoga River watershed, and we begin to investigate the partitioning of microplastics between active transport and deposition. The methods described here can also be applied to other rivers to investigate their microplastic content, and this study can inform future work that examines the correlation between high concentrations of microplastics and health effects on humans and animals.

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.