Access Type

Open Access Thesis

Date of Award

January 2017

Degree Type

Thesis

Degree Name

M.S.

Department

Pharmaceutical Sciences

First Advisor

David K. Pitts

Abstract

The limit of the availability of water is based on two factors, scarcity and quality. Conserving and protecting our water resources one of the most critical issues facing humanity as we struggle to deal with contaminated lakes and rivers and climate change. The main aim of this study is to examine toxicity of known water contaminants on aquatic model organisms and be able to develop methodology that will enable the characterization of endocrine disrupting potential of water samples with unknown contaminants. Both the category of water contaminants known as pharmaceuticals, personal care products that are known as PPCPs and other non-PPCP contaminants such as pesticides, plasticizers, flame retardants, combustion products, and herbicides are being detected in surface water and ground water. Some of the main sources of these contaminants are agricultural runoff, industrial sources and wastewater effluent. These compounds can be found in very low concentrations and may alter the physiological processes and have long term developmental impacts when animals are exposed. This exposure can alter the endocrine system, and may also be associated with other toxic properties (e.g., neurotoxic). The contaminants found to alter endocrine function have become known as endocrine disrupting chemicals. There is evidence of EDC activity on wildlife and increasing concern about EDC effects on humans. Some of the best evidence to date for EDC activity suggests that there is significant estrogenic and ant-androgenic activity in some of our surface water, especially downstream from wastewater effluent outflows.

This study is part of a large EDC project that focuses on the behavioral effects of EDCs as one part of a triad of behavioral assays to characterize estrogenic and anti-androgenic activity in water. The overall goal for the EDC project is to develop a mathematical model for estimating the estrogenicity and anti-androgenic properties of contaminants contributing to EDC – like activity in water. The hypothesis is that known or suspected EDCs have detectable behavioral effects, and that the characterization of these behavioral effects in combination with developmental and gene expression data will provide a mathematical model that enables the identification of chemicals contributing to the estrogenicity or ant-androgenic qualities of contaminated water. Two model organisms, Daphnia pulex and Danio rerio, used to evaluate the sub-lethal effects of the chemicals known or suspected to be EDCs. The behavioral assay evaluated the swimming behavior of these aquatic animals using a novel optical tracking system and measured the maximum distance travelled (mm) and mean change in angle (degrees) over a 24-hour period of exposure. This series of experiments has demonstrated significant concentration-dependent differences in responses across the series of chemicals, between species for a given chemical (chlorpyrifos, atrazine), and similarities in response to a chemical by both species (dieldrin).

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