Date of Award


Document Type


Degree Name

Master of Science (MS)


School of Biological Sciences

First Advisor

William Perry


Microplastic accumulation is one of the greatest changes to every ecosystem on Earth. Microplastics, < 5 mm in diameter, are an emerging contaminant of concern and are found across every habitat. Microplastics are directly released into the environment from industrial and personal care products or are a result of degradation and fragmentation of larger plastic debris. Microplastic contamination in the natural environment can have negative chemical and ecological effects on aquatic biota and humans. Rivers are an important transport pathway of microplastics from terrestrial to marine ecosystems. There is very little data on the abundance of microplastics in freshwater. To better understand the magnitude of microplastic contamination in freshwater, the concentration of microplastic in agricultural drainage tile outlets and stream waters in McLean County, Illinois during Spring and Summer (high and low flow periods) were measured. Grab samples were collected from five tile and four stream sites across 4 watersheds. Microplastic concentrations at each site were compared using ArcGIS. Microplastics are present in both agricultural drainage tile outlets and agricultural streams during Spring and Summer with approximately 80% of the microplastic particles being fibers. We did find a significant difference in microplastic concentrations between Spring and Summer but no significant difference between tile and stream sites within seasons. Our results suggest tile outlets and the tiles themselves may be a significant source of microplastics to streams and may lead to substantial inputs to downstream systems like drinking water reservoirs. KEYWORDS: microplastic; contaminant; rivers; freshwater; agricultural drainage tile; drinking water reservoirs


Imported from McGinnis_ilstu_0092N_12056.pdf


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