Publication Date

2024

Document Type

Dissertation/Thesis

First Advisor

Brown, Megan R.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Earth, Atmosphere, and Environment (EAE)

Abstract

Microplastics (MPs) in agriculture have been well-documented. Agrochemicals, organic fertilizers, and farming equipment all contribute plastic to agricultural soils, groundwater, and surface water and are utilized in different capacities throughout the year. It is unknown how the specific utilization of these products affects the concentration of MPs being input into the environment. Previous research has been primarily related to detection and transport of MPs in soils, groundwater, and surface water. I am unaware of any studies that have taken into consideration farming practices and seasons, and how they may affect any fluctuations in MP concentrations. Water samples (20 L) were taken from seven locations along and near Kilbuck Creek, a river in Northern Illinois running primarily through agricultural land and were collected five times throughout the year during different agricultural activities or farming seasons. Samples were separated by density and MPs were counted using an AmScope Stereo microscope 45X. The overall average concentration of MPs decreased downstream from 21.9 MP/L near the head waters, to 15.1 MP/L at the last sampling location, close to the confluence with the Kishwaukee River. Seasonally, concentrations started high in March (18.6 MP/L), dipped in May (12.2 MP/L) and then increased in July (17.9 MP/L) and decreased slightly through September (15.8 MP/L) and December (13.4 MP/L). Individually, the creek sites follow the same trends with a few exceptions. There were similarities in the MP density distribution within each sampling as well. MPs with a density of ≥1.8 g/cm3 were found in the greatest amounts throughout the year; MPs with a density of ≤1.2 g/cm3 were the second most abundant. Fibers accounted for 72.5% of all MPs collected, and fragments accounted for 24.7%. Shape distribution throughout the seasons follows the overall concentration trend. Precipitation is often a driving factor for MP transport, but no correlation was found in this study. However, there is not enough evidence to definitively attribute these trends to farming practices or seasons. Future research that can reduce the limitations found in this study could better assess any correlation between MP concentrations and farming seasons.

Extent

72 pages

Language

en

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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