Defense Date

8-29-2019

Document Type

Capstone

Degree Name

M.S. Coastal Zone Management

First Advisor

Dorothy Ellen Renegar

Second Advisor

Bernhard Riegl

Abstract

Marine plastics are a global issue which has garnered significant support for mitigation efforts in recent history. Research on the prevalence of plastic polymers in the marine environment has also come to the forefront of the scientific community, however studies on the toxicological impacts of their presence remains to be a little studied matter to date. In this study an intensive critical review of existing data was conducted to compile profiles (including: stability ranks, sorption capacities, organic and inorganic toxic constituent concentrations, bioaccumulations scores per constituent, biomagnification scores per constituent, and totaled threat scores out of five) for the three most common plastic polymers present in the Southwestern Atlantic region. These three polymer types were assigned total toxicity threat scores based upon the sum toxicity of their organic and inorganic constituents. Basic trophic structure level rankings were generated for the six most commercially significant fishery species in the Southwest Atlantic were generated and the toxicological effects of the three polymers of interest on each species were calculated.

It was determined that biomagnification scores are significantly affected by trophic level rank, indicating that higher trophic level organisms experience significantly higher rates of biomagnification of toxic plastic constituents. No significant effect of polymer stability was observed on threat score. Toxicological effects and Minimal Risk Levels (MRL) at which those effects are seen were compiled for each constituent, with the majority of constituents being reported as present in concentrations higher than the listed MRL before the processes of bioaccumulation and biomagnification took place. Exposure to carcinogenic/toxic concentrations of toxic substances associated with marine plastics is significant in species that occupy higher trophic level positions, putting a major resource (commercial fisheries) at risk as well as that risk being extended to human health via the consumption of commercially significant fishery species.

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