Date of Award

5-2019

Culminating Project Type

Thesis

Degree Name

Biological Sciences - Cell and Molecular: M.S.

Department

Biology

College

College of Science and Engineering

First Advisor

Heiko L. Schoenfuss

Second Advisor

Satomi Kohno

Third Advisor

Nathan Bruender

Fourth Advisor

Edward Perkins

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Keywords and Subject Headings

Complex mixtures, Fathead minnow, Contaminant of Emerging Concern, Short-term exposure

Abstract

Aquatic species are exposed to a diverse class of contaminants of emerging concerns (CECs) throughout different life stages. In this study, the effects of CECs in increasing complexity on three life stages of fathead minnows (Pimephales promelas) were assessed using existing Great Lakes tributaries’ chemical occurrence and concentration data. Fathead minnows were exposed to either a water solvent control, or the following chemicals: 4-nonylphenol (surfactant), 5-methyl-1H-benzotriazole (corrosion inhibitor, anti-freezing agent), atrazine (herbicide), bisphenol-a (plasticizer), desvenlafaxine (antidepressant), fexofenadine (allergy medication), estrone (hormonal medication), metformin (antidiabetic medication), metolachlor (herbicide), N,N-diethyl-m-toluamide (insect repellent), sulfamethoxazole (antibiotic), tris(2-butoxyethyl) phosphate (flame retardant), fluoranthene (byproduct of organic raw material pyrolysis), imidacloprid (insecticide), triclosan (antibacterial), ibuprofen (anti-inflammatory medication), 17-beta estradiol (hormonal medication), 2,4,6-trinitrotoluene (energetic), 2,4-dinitroanisole (energetic), 2,6-diamino-3,5-dinitropyrazine-1-oxide (energetic), 2,4,6-trinitro-3-bromoanisole (energetic). All chemicals were used in exposures singly and in mixtures of different complexity. Concentration series for the exposures was centered on medium concentration which contained the highest environmentally measured concentrations while low exposure used 1/10th, ultra-low 1/100th and the high exposure was set to 10x the medium exposure concentration. Adult and larval exposures were conducted simultaneously, while embryonic exposures were conducted at a later time using the same exposure waters. The apical endpoints for the study were survival, overall health, and several reproductive behaviors for adult fathead minnows. Survival, and feeding efficiency data were collected for larval fathead minnows. Lastly, time-to-hatch, and developmental abnormality for fathead minnow embryos were also recorded. Results suggest that the 96 hours CEC exposures affect different apical endpoints depending on the exposed life stage. As the complexity of the chemical exposure increased, alterations in endpoints such as courtship behavior in adult fathead minnows became more frequent. Medium and high concentrations elicited the greatest effects. In both single chemical and mixture exposures, concentration-dependent responses were not observed. This study highlights the need for complementary studies at different exposure time points as well as in vivo studies to identify potential “biological fingerprints” of single chemical effects in complex mixtures.

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