Date of Award

7-19-2018

Degree Type

Thesis

Degree Name

M.Sc.

Department

Great Lakes Institute for Environmental Research

First Advisor

Kenneth G Drouillard

Keywords

Accumulation, Fish, Microplastic, PCBs, POPs, Toxicology

Rights

CC-BY-NC-ND

Abstract

Microplastic are ubiquitous in aquatic habitats and commonly found in the gut contents of fish yet relatively little is known about the retention of microplastic particles by fish. Microplastics also contribute to an anthropogenic organic phase in the environment capable of absorbing hydrophobic organic compounds including persistent organic pollutants (POPs). Relatively little is known about the potential interactions between microplastics and persistent organic pollutant (POP) exposures to fish. In order to determine how microplastic particles affect the accumulation of POPs in fish, I first determined the gut retention of two types of microplastic particles (microbeads and microfibers) in goldfish. Although a small number of microplastic particles were retained in fish GI-tracts after 6 days (0-3 particles/50), the retention of microplastics was generally similar to the retention of bulk digesta contents. According to a breakpoint regression model fitted to digesta contents and microplastic particles, the 50% and 90% evacuation times were 10 h and 33.4 h, respectively. The results of this study indicate that neither microbeads nor microfibers are likely to accumulate within the gut contents of fish over successive meals. In Chapter 3 of this thesis, I applied a duel-tracer design to quantify polychlorinated biphenyl (PCB) dietary assimilation efficiencies (AE) in goldfish to compare microplastic-associated PCB AEs with diet matrix-associated PCB AEs. Microplastic-associated PCBs showed a 13.36% (12.27-14.49%) assimilation efficiency in goldfish while food matrix-associated PCBs showed 51.64% (48.97-54.32%) assimilation efficiency; which is 3.9 fold higher than measured for microplastic-associated PCBs. The joint findings from this thesis indicate that microplastic particles, and POPs associated with them, are unlikely to significantly enhance POPs bioaccumulation by fish.

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