Date of Award

May 2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Environmental Health Sciences

First Advisor

Todd R Miller

Committee Members

Kurt Svoboda, Christopher Quinn, Michael Laiosa, Hongbo Ma

Abstract

Environmental contaminants are increasingly detected in surface water, soil, and sediment. There is a concern that environmental contaminants, such as cyanpeptides and antimicrobials pose potential harm to environmental and public health. It is important that scientists evaluate the potential impacts that cyanopeptides and antimicrobials may have on the environment and public health in order to guide stakeholders in determining appropriate policies and regulations. Here we investigated the toxicological effects of two types of commonly detected environmental contaminants, antimicrobials (triclosan and triclocarban) and cyanopeptides (anabaenopeptins and cyanopeptolins), using the model organism Caenorhabditis elegans (C. elegans). Chapter 1 introduces the model organism C. elegans and proposes the use of this nematode model for environmental toxicology studies. Acute lethality and sublethal toxicity of cyanopeptides (anabaenopeptins and cyanopeptolins) and antimicrobials (triclosan and triclocarban) are identified using C. elegans in Chapters 2 and 3. The examined toxicity endpoints included reproduction, hatching time, growth rate, lifespan, age-related vulval integrity, germline toxicity, and stress response. In Chapter 4, we examined the potential mechanism of toxicity of the antimicrobials, triclosan and triclocarban. In Chapter 5, we identify the toxicological effects of degradation products produced by triclosan and triclocarban after these chemicals enter the environment. The research presented here demonstrates that cyanopeptides (anabaenoptpins and cyanopeptolins) and antimicrobials (triclosan and triclocarban) pose potential harm to the environment and establishes endpoints for future toxicological studies in the model organism C. elegans. These findings will provide insight into the toxicological effects and mechanism(s) of toxicity that will add to our knowledge of the effects of these environmental contaminants, as well as provide scientific evidence to policy-makers and regulatory agencies for the creation and amendment of environmental regulation policies.

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