Browsing by Author "Klein, David M."
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Item Analysis of Indoor Radon in Texas and Depleted Uranium in Hawai'i(2019-05-08) Lim, Lucy; Klein, David M.; Hetherington, Callum; Anderson, Todd A.; Cao, GuofengThis dissertation is composed of three studies related to mass spectrometry and environmental uranium. Each study was written as separate chapters, formatted as manuscripts submitted for publication to three different peer review journals. Chapter I is a review of Fourier Transform Mass Spectrometry. Chapter II discusses the investigation of potential depleted uranium (DU) release from radiation control/impact areas on three U.S. Army bases in Hawai’i. Chapter III is the updated Environmental Protection Agency (EPA) Indoor Radon Map of Texas. Each chapter has an abstract, introduction, analytical methods, results, discussion, conclusions, and references section. Each will have an appendix of tables and figures.Item Anti-fouling in wastewater reuse treatment systems and modeling contaminants of emerging concern leaching potential(2016-05) Monaco, Paula Ann; Morse, Audra N.; Klein, David M.; Reid, Ted W.; Uddameri, VenkateshReverse osmosis (RO) has become prominent for non-potable wastewater reuse systems; however, operational problems such as fouling due to biological attachment and chemical scaling limit reverse osmosis performance. Fouling potentially leads to increased operational energy needs, costs and biological clogs in reuse treatment (RO) and distribution systems. Research objectives aimed to address fouling issues in reuse systems during experiments studying the use of a co-polymerized feed spacer material covalently binding organo-selenium for its anti-fouling potential. The efficacy of selenium doped feed spacer was tested versus real municipal and industrial wastewater sources and varying wastewater solids concentrations during bench-scale experiments. Additionally, a stainless steel water distribution system equipped with a permanent, selenium catalytic biofilm inhibition agent, to improve a systems performance by reducing the frequency of shutting down to clear biological clogs was studied. Modification to the surface of stainless steel piping through covalent binding of organo-selenium compounds was shown to inhibit average biomass concentration (µm3/µm2) and biofilm thickness (µm) attached to stainless steel piping. An additional research objective was to develop screening tool framework and decision support system to understand fate and occurrence of contaminants of emerging concern (CEC) such as personal care products and pharmaceuticals (PPCPs) discharged from passive treatment facilities effluent. The convective-dispersive solute transport model served as a screening tool to better understand leaching potential of PPCPs and exposure to aquifers resulting in the classification and ranking of PPCPs based on their ability to leach, adsorb and degrade.Item Arsenic fed piglets: Assessing arsenic levels in decomposing pig tissues and soil samples(2017-05) Brown, Courtney L.; Prada, Paola A.; Klein, David M.; Sperry, KathyThis research developed an instrumental method by which arsenic levels can be successfully detected in decomposing pig tissue. An essential goal of a forensic toxicologist is the analysis of biological matrices for the presence of drugs, metals, and other toxins, as they are important for investigations associated with the potential use of these materials acutely prior to homicidal-death. Currently, there are several methods available for the assessment of heavy metals such as arsenic in human tissue collected during a typical autopsy (Formicki et al., 2010). However, when one considers examining decomposing tissues these tests are limited in their ability to detect heavy metals like arsenic. An experiment has been conducted that potentially allows one to detect arsenic levels in decomposing pig tissue (skin, muscle and bone) as well as from surrounding soil. The purpose of the experiment is to set minimal ranges of arsenic levels in these tissues. The experiment begins with the feeding of arsenic (in the form of potassium arsenate) to 4 piglets; the feeding of arsenic was at sub-lethal concentrations over a 3 day period. The piglets received a total of 2.8 mg/kg amount of arsenic. On the fourth day, the pigs were euthanized. An additional piglet was used as a control animal, it was not fed arsenic. After euthanizing them, all 5 piglets were set out for surface decomposition. Results demonstrated that arsenic concentrations can be identified in skin, muscle, bone, and soil after a three month decomposition period. Furthermore, multi-factor analysis of variance yielded significant effects for the response of arsenic concentration with respect to the decomposition time (p =0.0198) and type of bio-specimen (p = 0.0300) in relation to measured concentration values. There was no observed significant difference across all piglets tested. Arsenic concentrations were much higher in the soil samples collected from underneath the cadaveric area of each piglet, with a peak concentration detected at day 18 of decomposition. Little data specific to how arsenic redistributes postmortem is available, hence the work presented helps in the forensic assessment of acute-toxic antemortem dosages specific to death events.Item Arsenic in muskmelon (Cucumis melo) plants and wine in West Texas(2016-08-11) Hettick, Bryan Edward; Klein, David M.; Cañas-Carrell, Jaclyn E.; Martin, KirtArsenic is currently a topic of relevance in both the fields of toxicology and human health. The overall goal of this thesis was to explore the potential interaction between arsenic with wine and muskmelon plants in West Texas and assess the potential hazard they pose for human consumption. This process began with a thorough review of the scientific literature on the chemical properties of arsenic and the known ways in which it interacts with biological systems. Two experimental studies were then conducted to help establish a better understanding of the element on West Texas. The first of these explored the effects of arsenic on muskmelon plants grown in the area that were exposed to the element through irrigation water. The second study analyzed the arsenic content of a selection of wine samples provided by a local winery. Both the muskmelon fruit and the wine were compared to drinking water in terms of total arsenic exposure. The results of this research indicate that arsenic can be found in all parts of the muskmelon plant and the concentration of arsenic in wine from the area exceeds the acceptable regulatory limit established for water. However both the muskmelon fruit and wine would contribute less arsenic to overall exposure for humans than what is acceptable for drinking water at recommended rates of consumption. Therefore we concluded that neither muskmelon fruit nor wine pose an immediate threat of arsenic exposure for humans.Item Biophysical Modeling to Improve Analytical Methodology in Environmental Toxicology(2017-09-13) Oates, R.P., III; Klein, David M.; Cañas-Carrell, Jaclyn E.; Anderson, Todd A.; Morse, Audra N.Proper conceptual understanding of biophysical interactions with emerging contaminants is required for modern toxicology, as its scope continues to broaden alongside technological innovations that present challenges to environmental health. This dissertation is designed to address several areas of concern on a conceptual and non-hypothetical basis: ototoxicity associated with earbud technologies, per capita chemical efflux as a function of human population density, and methods to increase accuracy in quantitation of environmental contaminants throughout the field of toxicology. Principles at the interface of acoustics, physics, and organic chemistry were applied to further elucidate biophysical mechanisms associated with toxicity on a conceptual basis. It was determined that: special relativity can be applied to calculate pressures from earbud speakers to monitor sound exposure, biophysical viscosity is a factor that can be used to link fugacity with epidemiology through chemical potentials of contaminants, and primary standards from analytical chemistry can be used to normalize pollutant concentrations reported from methods that utilize mass spectrometry more accurately. This dissertation is written under the premise that if we can accurately model fundamental physical processes that monitor environmental health, then it is possible to extend stewardship as a mode of human health.Item Determination of carbon-based nanomaterial distribution, toxicity, and trophic transfer in aquatic environments(2016-08) Cano, Amanda Marie; Cañas-Carrell, Jaclyn E.; Green, Micah J.; Klein, David M.; Maul, Jonathan D.; Saed, MohammedNanotechnology is an emerging field with applications across many industries. Carbon-based nanomaterials (CNMs) such as multi-wall carbon nanotubes (MWCNTs), graphene (G), and graphene oxide (GO) are engineered nanomaterials used in environmental, medical, technological, and agricultural applications. Some of these practices include direct application to the terrestrial and aquatic environment, which can pose risk to environmental and human health. Studies have shown potential for accumulation and toxicity in aquatic organisms when exposed to CNMs. Furthermore, it is uncertain how CNMs interact with contaminants in the aquatic environment as CNM concentration, colloidal stability, and size effect bioavailability and fate in the environment. Research from this dissertation will investigate adsorption, bioaccumulation, toxicity, and trophic transfer of CNMs in the aquatic environment. Adsorption of Cu2+ ions onto MWCNTs, G, and sodium dodecylbenzene sulfonate (SDBS) was measured in moderately hard or hard freshwater. Higher adsorption capacities were seen in CNMs in moderately hard freshwater. In solutions of high ionic strength CNM adsorption capacities decreased. Bioaccumulation was seen in D. magna exposed to MWCNTs of varying outer diameters (O.D., 8-15 nm or 20-30 nm) in moderately hard or hard freshwater using a microwave-induced heating method. Highest MWCNT concentrations were seen in D. magna exposed in hard freshwater, however there was no significant difference between O.D. sizes in bioaccumulation. Generation of reactive oxygen species (ROS) was observed in D. magna exposed to CNMs in moderately hard freshwater after 12 h and an overall decrease in swimming velocity was seen in all CNM treatments. Trophic transfer was observed between D. magna and Pimephales promelas (fathead minnow, FHM) exposed to MWCNTs with varying O.D.s without and in the presence of Cu2+ ions. MWCNT concentrations were quantified using a microwave-induced heating method. Trophic transfer was observed for both MWCNT sizes. Higher concentrations of MWCNTs (20-30 nm O.D.) were seen in FHM in the presence of Cu2+ ions. A similar trend was seen in Cu2+ ions accumulated in FHM, indicating complexation or adsorption of Cu2+ onto MWCNTs. This research will aid in ecological risk assessment and future nanomaterial regulation.Item The recovery of DNA in indoor and outdoor area environments(2014-05) Favorite, Paris; Klein, David M.; Sperry, Kathy; Fedler, Clifford B.After attending this presentation, attendees will have an understanding of how scientific techniques such as polymerase chain reaction (PCR) are used in detecting the presence of pig (Sus scrofa) DNA collected from intestines of maggots. The focus of the study is to analyze samples collected from the intestines of early in-star maggots used to identify the presence of pig (Sus scrofa) DNA in decomposed remains placed in an open air environment and in an enclosed environment. We hypothesize that the amount of DNA recovered will vary significantly between the two environments. This study, involves two female pigs that are being used as an animal model for human victims, suspects, or third party suspects for forensic investigations. Deoxyribonucleic acid sequence data was obtained from the intestines of maggots that fed on pig remains. Deoxyribonucleic acid has become standard in forensic science to analyze biological samples from decomposed remains. In addition, DNA serves as an essential tool for the identification of humans. This presentation will affect the forensic community by identifying how environmental factors can influence postmortem changes and affect the presence of DNA on remains. In order to further explore the effects of indoor and outdoor areas the decomposition and insect colonization of pig carcasses were observed over a 14-day period in a semi-arid environment located at Research Site located in Lubbock, Texas. Two juvenile female pig carcasses weighing approximately 15 kg was placed at Site; one was placed inside a wooden house and the other placed outdoors in a field. Observations and sample collection from the pig carcasses were conducted daily. Blowfly (Calliphoridae) larvae (maggots) were collected in late summer and the intestines of the insects were analyzed to determine the amount of DNA present. The characteristics of a semi-arid environment are such that developmental growth of maggots may be impeded, consequently having a possible influence on the amount of DNA recovered. Maggots were collected and preserved in 15 mL falcon tubes filled with 5-10 mL of 70% ethanol. All larvae samples collected were be placed in a freezer at 40 C to improve preservation of the DNA in maggots and stored until ready for extraction. Following DNA extraction polymerase chain reaction assay was used to identify the presence of DNA recovered from the maggot’s intestines. This procedure identifies and purifies the DNA recovered from samples and can be used as evidence to solve criminal cases such as homicide, sexual assault, and negligence. Gene sequences were amplified by PCR, sequenced, and analyzed by capillary electrophoresis. The expected findings of this study determined that arid environments can affect the amount and recovery of DNA. Therefore, these results determined that environmental factors can show differences in decomposition patterns that can influence the recovery of DNA in remains.Item Toxicity Testing and Hormone Analyses for Cetacean Health Assessments(2017-12-14) Hayden, Mary J; Godard-Codding, Céline; Fair, Patricia; Klein, David M.; Singh, Kamaleshwar P.Currently, there is a severe need for health and toxicology information with regards to wild cetacean populations. They prove challenging to monitor, and data on population dynamics, health information, and relative fitness is difficult to obtain for free-ranging populations of cetaceans. 16 cetacean species are classified as endangered by the Marine Mammal Protection Act, and all marine mammals face a multitude of environmental and anthropogenic stressors. Due to their protection status as well as logistics and ethical concerns, traditional in vivo toxicity testing is not possible in cetaceans. Health information, such as reproductive rates, stress, and fitness, as well as an understanding of contaminant toxicity is critical when developing a scientific-based management and conservation plan for these populations. Here we describe the method development and optimization to conduct cetacean health assessments by analyzing blubber steroid hormones. We also describe and report on the development and optimization of an organotypic culture model to conduct cetacean toxicity testing. Two methodologies were used to measure steroid hormones in cetacean blubber samples: an enzyme-linked immunosorbent assay (ELISA) and liquid chromatography tandem-mass spectrometry (LC-MS/MS). ELISAs are commonly employed for steroid hormone measurement from the blubber matrix, and optimizations were needed to conduct hormone analysis in the blubber using LC-MS/MS. Analysis of blubber hormones using LC-MS/MS was possible through the incorporation of gel permeation chromatography for lipid removal from sample extract. Both methodologies were successful in determination of pregnancy from blubber progesterone analysis using minimal tissue (50 mg wet weight). Progesterone concentrations of pregnant female cetaceans were within the range of concentrations reported in the literature for other pregnant cetaceans. LC-MS/MS was also able to generate data on three additional steroid hormones from the same extract: testosterone, estradiol, and cortisol. These preliminary method optimizations for LCMS/MS provide significant advancements to the field of cetacean endocrinology and the ability to generate health assessments for wild cetaceans. Organotypic culture of cetacean skin and blubber was assessed for its use in cetacean toxicity testing. Skin and blubber were precision cut and cultured and/or exposed to common marine contaminants for up to 72 hours. Viability of non-dosed tissue was assessed through establishing fibroblast cell culture, assessing intracellular potassium of tissue, and measuring lactate dehydrogenase (LDH) activity in culture media. Non-dosed tissues were viable for up to 72 hours in culture. Intracellular potassium analysis of dosed tissue showed that tissues were viable upon exposure in culture for up to 72 hours. Expression of two biomarkers of exposure, cytochrome P4501A1 (CYP1A1) and cytochrome P4501B1 (CYP1B1), was analyzed by quantitative PCR which detected induction of CYP1A1 in tissues exposed to benzo(a)pyrene for 24 and 48 hours. CYP1A1 downregulation was detected in tissues exposed to chemical dispersant and crude oil for 24 hours. This research demonstrates the applicability of cetacean skin and blubber organotypic culture as a viable, non-lethal, minimally-invasive methodology for cetacean toxicity testing.Item Toxicokinetics and Sources of Lead in American Woodcock (Scolopax minor)(2017-12-11) French, Amanda Dawn; Klein, David M.; Cañas-Carrell, Jaclyn E.; Conway, Warren C.; Barnes, Melanie A. W.This dissertation is composed of multipled studies related to the bioaccessibility and availability of Pb shot to American woodcock (Scolopax minor). Each chapter (I – V) consists of an abstract, introduction, methods, results, discussion, conclusion, references, and tables and fitures section. Chapters I and II have been published in peer review journals, while Chapters III-V are formatted as manuscripts that will be sumitted for publication. Chapter I is a published literature review that contains information on current studies on Pb in American woodcock in addition to the effects, abosroption and sources of Pb in previous American woodcock studies. Chapter II is a published methods manuscript that discusses the method development for a small mass acid digestion technique. Chapter III discusses the bioaccessibility of Pb and Sb from Pb shot and the feasibility of using Sb as a trace-metal marker of Pb shot exposure. Chapter IV presents exposure levels and sources of Pb in woodcock as determined by the analysis of lead, antimony, and lead isotope ratios in feathers and bones. Chapter V is a geospatial analysis of the Pb concentrations found in woodcock feathers and bones. Conclusions and regulatory implications from all previous chapters (I-V) are presented in Chapter VI.