Loyola University Chicago

Department of Biology

Loren Hou Project Description

Title: Microplastic in Aquatic Food Webs: Museum Specimens and Ingestion Experiments Reveal Controls on Microplastic Ingestion by Freshwater Fish


Plastic is pervasive in modern economies and ecosystems. Early research suggests freshwater fish commonly ingest microplastic (particles < 5 mm), which may influence fish digestive tissues, but no studies have examined historical patterns in microplastic consumption or rates of microplastic retention in fish. We measured microplastic in digestive tissue of specimens collected and preserved over the last century (Field Museum, Chicago). We selected Micropterus salmoides (largemouth bass), Notropis stramineus (sand shiner), Ictalurus punctatus (channel catfish), and Neogobius melanostomus (round goby) because each was well represented in the museum collection, with specimens from urban rivers. Specimens from 1900-2018 showed increases in microplastic concentration from the 1950's to present. In a second project, we collected round gobies from Lake Michigan in Chicago to conduct feeding experiments to measure microplastic ingestion and retention rates. The majority of microplastic was excreted within 72 hours of ingestion. Results will aid in understanding ecological interactions of microplastic and freshwater fish, informing further work on the movement of microplastic in aquatic food webs.


This research was funded by the National Science Foundation and the Graduate School of Loyola University Chicago. Thank you to my thesis advisor, Timothy Hoellein, and committee members Rachel McNeish, Martin Berg, and John Kelly for their guidance. A big thank you to Jacob Ahn, Armand Cann, Amy Fetters, Fatima Ghulam, and the Hoellein Lab at Loyola University Chicago for their assistance in the field and laboratory. Thank you to Caleb McMahon, Susan Mochel, Kevin Swagel, Chelsea Rochman, and Keenan Munno for their collaboration and support. Finally, thank you to my family and friends for motivating me and giving me strength to push through this thesis writing journey.


Loren Hou was born and raised in Chicago, Illinois. She attended Loyola University Chicago from August 2014 – December 2016 and earned a Bachelor of Science degree in Biology. She also worked in Tham Hoang’s Aquatic Ecotoxicology lab at Loyola, to investigate the effects of metal mixtures on Daphnia magna mortality and reproduction. During her time at Loyola as a graduate student, Loren was a teaching assistant for introductory ecology courses.

Committee Members:

Dr. Timothy Hoellein

Dr. Martin Berg

Dr. John Kelly

Rachel McNeish, Ph.D.