Date of Award

Spring 2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Forestry and Natural Resources

First Advisor

Maria S. Sepulveda

Committee Member 1

Reuben R. Goforth

Committee Member 2

Linda S. Lee

Abstract

In recent years, the presence of pharmaceuticals and personal care products (PPCPs) in aquatic systems has led to research on their fate and effects. PPCPs have been found in mixture in wastewater effluents, surface, ground, and drinking water at low concentrations from areas of intense urbanization. Although adverse effects to human health from the current environmental concentrations are unlikely, the impacts to ecological receptors are not clear. We performed field and laboratory studies to quantify and evaluate effects of PPCPs on fish. First, a field study was conducted at the Baca National Wildlife Refuge, Colorado (2010-2012) because a portion of the Refuge receives discharges of treated water from the Aspen Wastewater Treatment Plant (WWTP). Water and fish samples were used to quantify the presence of PPCPs in surface and wastewater effluents, and to determine the potential impact of PPCPs in fish communities (using histology and gene expression analysis). We focused on fathead minnows ( Pimephales promelas ) since they have been the subject of relevant ecotoxicological research and are a good sentinel species. A total of 120 analytes were quantified using a combination of grab samples and polar organic chemical integrative samplers (POCIS). Although no PPCPs were detected from the grab samples, POCIS allowed for the detection of PPCPs in all our fish sites. High concentrations of N,N-Diethyl-meta-toluamide (DEET) and thirteen pharmaceuticals (triclocarban, triclosan, gemfibrozil, ibuprofen, progesterone, diphenhydramine, atenolol, caffeine, trimethoprim, levorphanol, cannabidiol, tetrahydrocannabinol (THC), and naproxen) were detected in all fish sites, including the reference site. Cellular changes in gonads and livers and significant changes in gene expression (steroidogenic acute regulatory protein, star and androgen receptor, ar ) were observed from female and male fathead minnows sampled from creeks contaminated with PPCPs. However, because we could not identify a clean reference site, we cannot affirm these changes are due to PPCP exposure. We conclude that POCIS is a sensitive method for the detection and quantification of PPCPs in small streams. Additional studies at the Refuge are needed to better understand the ecological impacts of PPCPs.

Next, we conducted a laboratory study using the same PPCPs found in our field study and exposed adult fathead minnows for 48 hr to the highest environmental concentration of each chemical. Our goal was to evaluate molecular changes of a suite of genes known to respond after exposure to chemicals affecting lipid metabolism, and the endocrine and nervous systems. Fish were exposed to triclocarban (1.4 μg/L), DEET (0.6 μg/L) or to a PPCP mixture consisting of: atenolol (1.5 μg/L), caffeine (0.25 μg/L), diphenhydramine (0.1 μg/L), gemfibrozil (1.5 μg/L), ibuprofen (0.4 μg/L), naproxen (1.6 μg/L), triclosan (2.3 μg/L), progesterone (0.2 μg/L), triclocarban (1.4 μg/L), and DEET (0.6 μg/L). Vitellogenin ( vtg ) was up-regulated in livers of females and males exposed to triclocarban. Also, an up-regulation of hepatic lipoprotein (lpl ) and a down-regulation of ar and star were observed in testes. The group treated with DEET only showed a significant decrease in ar in females. In contrast, the PPCP mixture down-regulated vtg in females and males, and expression of estrogen receptor alpha (erα ), star, and thyroid hormone receptor alpha 1 (thra1 ) in testes. Our results show the molecular `estrogenic' effects of triclocarban are eliminated (males) or reversed (females) when dosed in conjunction with several other PPCPs, once again showing that results from single exposures could be vastly different from those observed with mixtures.

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