Pharmacology, Toxicology and Environmental Health Commons^™

Evaluating Soil Health Changes Following Cover Crop And No-Till Integration Into A Soybean (Glycine Max) Cropping System In The Mississippi Alluvial Valley, Alexandra Gwin Firth

Theses and Dissertations

The transition of natural landscapes to intensive agricultural uses has resulted in severe loss of soil organic carbon (SOC), increased CO₂ emissions, river depletion, and groundwater overdraft. Despite negative documented effects of agricultural land use (i.e., soil erosion, nutrient runoff) on critical natural resources (i.e., water, soil), food production must increase to meet the demands of a rising human population. Given the environmental and agricultural productivity concerns of intensely managed soils, it is critical to implement conservation practices that mitigate the negative effects of crop production and enhance environmental integrity. In the Mississippi Alluvial Valley (MAV) region of Mississippi, USA, …

Removal Of Arsenic (Iii) And Arsenic (V) From Aqueous Solution Via Common Sunflower Helianthus Annuus By Phytoremediation, Irving A. Vazquez Hurtado

Theses and Dissertations

Phytoremediation provides a cost-effective, non-invasive technique to remove contaminants from the soil and groundwater. Sunflowers are fast growing and have a showed effective at removing various pollutants from soil, including lead and other heavy metals. Health issues related to arsenic are mainly attributed to exposure of arsenite, whereas arsenate is much less toxic. The common sunflower Helianthus annuus was the species used to remove both arsenic (III) and As(V) ions from hydroponics solutions. In the present study sunflower seeds were germinated for a week, placed under the sun for a day and subsequently placed in a nutrient solution to aid …

Behavioral Screening And Chiral Bioanalysis Of Emerging Stimulant-Type Drugs In Rats, Tyson R. Baird

Theses and Dissertations

The epidemic of drug use in the United States and elsewhere in the world has resulted in tragic loss of life and substantial economic costs. Novel psychoactive substances (NPS) are one of the contributors to this problem, and the lack of information about many of these drugs compounds their risk. This dissertation proposes a strategy to use intracranial self-stimulation (ICSS) as a behavioral screening tool to assess emerging drugs of abuse for their abuse potential in order to generate a proactive threat assessment. A series of stimulant-type drugs including methcathinone, α-pyrrolidinohexanophenone (α-PHP), cocaine, and the phenyltropane analogs of cocaine WIN35428 …

Biochar Applications To The Remediation Of Lead And Polychlorinated Biphenyl Contaminated Water, Victory Itua Igberase

Theses and Dissertations

This study investigated the performance of biochar materials as adsorbents to remove Pb and polychlorinated biphenyl (PCB) in aqueous solutions. Batch adsorption and column experiment packed with biochar and geomaterials (pumice) in 1:1 volume ratio was evaluated to address the efficacy of biochar in removing Pb while only batch adsorption was employed for PCB removal with biochar materials. Overall, PT biochars performed the best (42–53 mg g−1) followed by BE biochars (10–32 mg g−1) and AB biochars (17–27 mg g−1) while high temperature biochars were favored in terms of maximum Pb adsorption capacity. Column Pb breakthrough showed similar results, with …

Health Goals For Perfluorinated Alkyl Substances (Pfas): A Review Of Branched Isomers, The Role Of Industrial Sources, And The Implications Of Pfas In Biosolids On End-Of-Life Disposal Methods, Katarina Schulz

Theses and Dissertations

Per- and polyfluorinated alkyl substances, or PFAS, have been used for over half a century, but have become an emerging contaminant of significant concern due to their newly found widespread occurrence and recalcitrance in the environment, their tendency to bioaccumulate, and the health effects now associated with a very low level of exposure. Many gaps in knowledge remain about the fate of these chemicals in the environment and the extent of their impacts on biota. This thesis aims to fill some of the recognized gaps in knowledge: differences between linear and branched isomers of PFAS, predicting the presence of PFAS …

Nebulizer-Based Systems To Improve Pharmaceutical Aerosol Delivery To The Lungs, Benjamin M. Spence

Theses and Dissertations

Combining vibrating mesh nebulizers with additional new technologies leads to substantial improvements in pharmaceutical aerosol delivery to the lungs across therapeutic administration methods. In this dissertation, streamlined components, aerosol administration synchronization, and/or Excipient Enhanced Growth (EEG) technologies were utilized to develop and test several novel devices and aerosol delivery systems. The first focus of this work was to improve the poor delivery efficiency, e.g., 3.6% of nominal dose (Dugernier et al. 2017), of aerosolized medication administration to adult human subjects concurrent with high flow nasal cannula (HFNC) therapy, a form of continuous-flow non-invasive ventilation (NIV). The developed Low-Volume Mixer-Heater (LVMH) …

An Investigation Into The Trophic Magnification Of Polychlorinated Biphenyls In The Lake Michigan Food Web, Philip Hurst

Theses and Dissertations

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants known to contribute to several adverse health conditions in humans including cancers and a suite of liver diseases. While there exist 209 unique PCB congeners, the World Health Organization has identified 12 that pose the greatest health risk to humans due to these congeners’ functional similarity to dioxins, another notoriously toxic class of contaminants. Along with methylmercury, PCBs are the primary drivers behind fish consumption advisories in the Great Lakes. These guidelines are informed primarily by surveys of contaminants in freshwater biota. However, the proliferation of invasive species, such as …

Analysis Of Organochlorine Pesticides Levels In Irrigation Water From Various Water Sources Across Egypt, Omar Tarek Khairy

Theses and Dissertations

Organochlorine pesticides are extensively used in agriculture to cope with the world’s increasing population and demands for nutrition. This class of pesticides poses a serious risk to human health upon chronic exposure to elevated levels. Determination of organochlorine pesticides levels in water has been extensively covered in literature in Egypt and other parts of the world. The need for up-to date data and statistical information regarding the levels of organochlorine pesticides in water is ever increasing. These compounds, although a lot have been prohibited from use decades ago, can still be detected in trace levels in water due to their …

Quantifying The Variability In Heavy Metal Concentrations In Produce Grown In Metals-Rich Soil, Harris Lowell Byers

Theses and Dissertations

Childhood Pb exposure is associated with a multitude of poor health outcomes. In food-insecure areas, growing fresh produce in residential backyard gardens is one option for parents; however, commonly grown crops are known to accumulate Pb in consumable tissues when grown in metals-rich soils. A variety of produce representing a continuum of consumable tissues were grown in soils collected from two residential vegetable gardens, a former metal foundry, and commercial topsoil purchased from a local hardware store. The concentrations of heavy metals in crop tissues were measured with custom wavelength dispersive X-ray Fluorescence (WD-XRF) spectroscopy and portable energy dispersive X-ray …

5-Ht2b Receptor-Mediated Cardiac Valvulopathy, Pallavi Nistala

Theses and Dissertations

5-HT_2B receptor agonism causes cardiac valvulopathy, a condition characterized by thickening of the heart valves and as a result, regurgitation of blood within the heart. The anti-obesity drug fenfluramine, which was originally prescribed as an anorectic, was withdrawn from the market due to causing cardiac valvulopathy. Fenfluramine, after metabolism by N-dealkylation, produces the metabolite norfenfluramine, which acts as a more potent valvulopathogen. The same was seen with MDMA (ecstasy), a popular drug of abuse, which is metabolized by N-dealkylation to produce MDA, a more potent valvulopathogen. Glennon and co-workers. studied a series of 2,5-dimethoxy-4- substituted phenylisopropylamines (DOX type) hallucinogens …

Increasing Marine Debris Awareness Through Public Education And Analyzing Fish For Microplastic And Pollutant Contamination, Stephanie R. Dubois

Theses and Dissertations

Marine debris is any persistent solid material that is manmade and then disposed of into the world’s oceans. Outreach and education was used in combination with biological research using an indicator fish species to raise awareness about the impacts of marine debris and encourage change in behavior to reduce marine debris. Pre and post surveys were administered during marine debris education tours for K-12 students at the Coastal Studies Lab on South Padre Island, Texas to determine change in knowledge and behavior regarding marine debris. Pinfish were collected from Laguna Madre and stomachs and livers removed for microplastics content and …

Development Of Cellular High Throughput Assays To Determine The Electrophysiological Profile Of Gaba(A) Receptor Modulators For Neurology And Immunology, Nina Yina Yuan

Theses and Dissertations

Gamma (γ) -aminobutyric acid (GABA) is the major inhibitory neurotransmitter found in

the mammalian central nervous system. Its effect stems from its ability to cause the opening of ion channels which causes an influx of negatively charged chloride ions or an efflux of positively charged potassium ions. This hyperpolarization of the neuron lowers the threshold for neuronal firing. This has an overall inhibitory effect on neurotransmission, decreasing the excitability of the neuron and diminishing the likelihood of a successful action potential occurring. There are two classes of GABA receptor: ligand-gated GABAA receptor (GABAAR) and metabotropic GABAB receptor (GABABR). The GABAAR …

Iodine-131: Measurement And Application Of A Novel Tracer In Lake Michigan, Michael Patrick Montenero

Theses and Dissertations

Iodine-131 is a short-lived (half-life=8.0233 days), gamma emitting, radiopharmaceutical that, when excreted by patients, enters aquatic systems via sewage effluent discharged from water reclamation facilities (WRFs). Here, I report on 131I activities in the nearshore of southwest Lake Michigan in the vicinity of Milwaukee, Wisconsin. This is the first report on 131I activity in any of the Great Lakes of North America.

The flux of 131I from Milwaukee’s two WRFs was monitored from July 2013 to December 2014. Mean discharge of 131I from the Jones Island WRF was (0.664 ± 0.012)×108 Bq d-1 (mean effluent 131I activity: ~0.25 Bq L-1; …

The Identification And Quantification Of Sewage Contamination In The Milwaukee Estuary, Hayley Templar

Theses and Dissertations

Sewage contamination from failing infrastructure and sewer overflows is a major environmental and human health concern in waterways, especially in urban communities bordering the Great Lakes such as Milwaukee, Wisconsin. Culture-based fecal indicator bacteria, such as Escherichia coli, enterococci, and fecal coliforms are traditionally used to indicate the presence of a human health risk due to fecal contamination. These indicators, however, fail to distinguish between sources of fecal contamination (human vs. non-human). Two human-specific fecal indicators, human Bacteroides and human Lachnospiraceae, were used to identify and quantify sewage contamination in the Milwaukee estuary, which discharges to Lake Michigan, as well …

Female Reproductive Impacts Of Dietary Methylmercury In Yellow Perch (Perca Flavescens) And Zebrafish (Danio Rerio), Abigail Rachael Debofsky

Theses and Dissertations

This study sought to evaluate the effects of dietary MeHg exposure on female teleost reproduction and phenotypically-anchor gene dysregulation in adult yellow perch (Perca flavescens) and zebrafish (Danio rerio) in order to establish relevant biomarkers relating exposure and subsequent reproductive effects. Yellow perch were used in the study for their socioeconomic importance within the Great Lakes basin, and their significance to the food web. Utilization of zebrafish allowed for a detailed analysis of the molecular effects of MeHg and established its relevance as a model for other fish species. MeHg exposures at environmentally relevant levels were done in zebrafish for …

Development Of Non-Traditional Platinum Anticancer Agents: Trans-Platinum Planar Amine Compounds And Polynuclear Platinum Compounds, Daniel E. Lee

Theses and Dissertations

Development of Non-Traditional Platinum Anticancer Agents: trans-Platinum Planar Amine Compounds and Polynuclear Platinum Compounds

By Daniel E. Lee, Ph.D.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2015

Major Director: Nicholas P Farrell, Ph.D., Professor, Department of Chemistry

Platinum anticancer compounds with cis geometry, similar to cisplatin, have been explored to circumvent the cisplatin resistance; however, they were not considered broadly active in cisplatin cells due to exhibiting similar or same cell death mechanism as cisplatin. Platinum compounds with trans geometry were less studied …

Decision-Support Tool For Residential Pesticides In The South Carolina Coastal Zone, Lisa Claire Wickliffe

Theses and Dissertations

The Environmental Protection Agency (EPA) is charged with ensuring pesticides do not pose unreasonable adverse risks to the public and to the environment. This is a daunting task with over one billion pounds of pesticides used across the nation each year. The U.S. EPA estimates approximately 75% of all pesticide usage in the U.S. are agricultural while 25% is for home, garden, industrial, commercial, and government applications. One area of application of concern to public health and the environment regarding misuse of pesticides is in residential settings. In these instances, individuals may not have any knowledge of identifying whether they …

Estimation Of Aerosolized Antibiotic Resistant Bacteria Concentrations From Wastewater Treatment Facilities Using Spatially-Based Dispersion Modeling, Renee Nichole Dickman

Theses and Dissertations

Pathogenic bacteria can develop resistance to antibiotics to which they were previously sensitive, resulting in increased morbidity and mortality worldwide [1]. The increase in drug resistance in bacteria is an emerging public health concern. The activated sludge tanks of wastewater treatment plants are known sources of antibiotic resistant bacteria. These resistant bacteria can become aerosolized and disperse downwind. Using previously sampled aerosol concentrations and meteorological data, a Gaussian dispersion model was developed to estimate the concentration downwind from a selected wastewater treatment facility. The emission rate was calculated to be 7,941 CFU/m²/sec ± 2,149 CFU/m²/sec. This value was used in …

In Vitro Toxicity Of Silver Nanoparticles In Human Lung Epithelial Cells, Christina R. Kearns

Theses and Dissertations

Nanotechnology is quickly becoming incorporated into everyday products and uses. Silver nanoparticles, specifically, are being used in commercial products, to include aerosols. The purpose of this research was to determine whether silver nanoparticles are toxic to human lung epithelial cells. Different types (coated vs. uncoated), concentrations (10, 50, 100, and 200 µg/mL) and sizes (coated 5 and 80nm, uncoated 10 and 80nm) of silver nanoparticles were used during this study. Toxicity measurements were completed through in vitro techniques. Another study was also completed on toxicity mechanisms by measuring the reactive oxygen species (ROS) generated. Results showed that silver nanoparticles induce …

Deterministic Intracellular Modeling, Jacqueline B. Young

Theses and Dissertations

The United States Air Force is interested in the potential side effects at the cellular level from exposure to mission-essential chemicals. Presently, Air Force toxicology studies are conducted to help shed light in identifying potential hazards to workers. However, it takes a considerable amount of money, resources, and time to obtain and analyze experimental results from toxicology studies. The necessity for innovative methods that enable researchers to more effectively generate and analyze data is apparent.

Stochastic Intra-Cellular Modeling, Thomas E. Hopkins

Theses and Dissertations

Air Force personnel may sometimes come into contact with potentially harmful chemicals while performing their duties. Of course the Air Force desires to keep any potential health risks to its members to a minimum. To this end the Air Force would like to identify which chemicals are toxic, their level of toxicity, and the processes by which these chemicals disrupt normal biological activities at the cellular level. The development of mathematical models can be of great benefit to toxicity studies. Because real world systems involve randomness, that is noise, and the desire is to create mathematical models to represent those …

Chromate Dissociation From Primer Paint In Simulated Lung Fluid, Tiffany J. R. Morgan

Theses and Dissertations

OSHA has proposed a new strontium chromate exposure standard that would potentially cause Air Force paint facilities to be in violation of the proposed standard if adopted. This proposed reduction make the continued use of chromate containing primer paints very difficult. There is currently no acceptable replacements for chromate containing primer paints on AF aircraft. This study suggests that paint particles with chromate bound in primer paint may be unavailable for bodily absorption if inhaled and a reduced standard for painting applications may be unnecessary. Primer paint overspray was collected into simulated lung fluid (SLF) and allowed 6 hr, 24 …

Modeling Chemical Absorption Through Membranes, Jeffrey M. Hemmes

Theses and Dissertations

Understanding the processes involved in dermal penetration of chemicals and drugs is important to both toxicologists and pharmacologists. Researchers developing new drugs are interested in enhancing the penetration of chemicals through the skin, while environmental professionals are interested in limiting such penetration. For both types of applications, predictive biologically-based mathematical models can be very useful in understanding the processes involved, particularly when such models are based on physiological and biochemical parameters which can be measured experimentally. In this thesis we study two existing physiologically-based pharmacokinetic (PBPK) models that predict concentrations of neat and aqueous dibromomethane (DBM) absorbed into and through …

Effects Of Ammonium Perchlorate On The Thyroid Hormone Levels Of The Sprague-Dawley Rat, James H. King Jr.

Theses and Dissertations

The purpose of this research was to determine the threshold dose for ammonium perchlorate (AP) in the Sprague-Dawley rat. No dose response data exist for AP and the EPA has studied literature on the subject of perchlorates to determine a provisional reference dose. The Perchiorate Group, a consortium of DoD and industry representatives, believes this provisional reference dose is too conservative. This experiment was executed to provide dose response data on which to base a more accurate reference dose. The study consisted of eight groups of 12 Sprague-Dawley rats, six male and six female, which were exposed to incremental doses …

Physiologically-Based Pharmacokinetic Modeling Of Skin Absorption Using Dermal Subcompartments, Richard L. Bookout Jr.

Theses and Dissertations

Dermal penetration of chemicals and drugs is important to both toxicologists and pharmacologists. Drug developers try to enhance and environmental professionals try to limit penetration of chemicals through the skin. Both can use predictive biologically-based mathematical models to assist in understanding the processes involved. When these models are based on physiological and biochemical parameters which can be measured in the laboratory, they can be extremely useful. Appropriately validated models based on first principles can be predictive of human exposures when the processes involved are adequately understood. In this thesis we develop four new physiologically-based pharmacokinetic (PBPK) models to predict blood …