Browsing by Author "Klein, David"
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Item Determination of Several Elements in Chelonia mydas and Pterodroma hypoleuca from Hawaii(2019-04-25) Shaw, Katherine Rosellyn; Klein, David; Cañas-Carrell, Jaclyn E.; Anderson, Todd A.Elemental contaminants are present in the food chain through natural or anthropogenic sources. Larger doses, longer durations of exposure and frequent exposure will increase the risk of elemental toxicity. Animals such as sea turtles and seabirds are often used as bioindicators of environmental contaminants because they are long lived and near the top of their food chains. Beast feathers of Bonin petrel (Pterodroma hypoleuca) have a quick turnover and represent shorter-term exposure, while wing feathers are grown over longer periods and represent longer-term accumulation. Whole blood from Hawaiian green sea turtles (Chelonia mydas) was used to evaluate recent exposure while keratinized scute was used to represent long term contamination. Chapter I is a literature review that contains information on the uses of lead isotope ratios and their disadvantages. It also discusses alternatives to lead isotope ratios. Chapter II compares elemental concentrations in wild Hawaiian green sea turtles to captive Hawaiian green sea turtles at Sea Life Park Hawaii to determine if captive sea turtles could be used as a baseline to better understand concentrations in wild sea turtles. Chapter III discusses the concentrations of lead and arsenic in green sea turtles of Kailua Bay that have been exposed to lead shot from a historic skeet shooting range. Chapter IV presents contaminant levels in two feather types from Bonin petrels in the Northwestern Hawaiian Islands and compares the results to a study conducted approximately 15 years prior to determine how concentrations have changed over time. Chapter V is a risk assessment to determine the risk of lead exposure to sea turtle.Item Distribution of Particulate Matter and Affiliated Chemicals Emitted from Beef Cattle Feedyards(2017-05) Smith, Philip; Ghosh, Souparno; Klein, David; Mayer, GregoryWithin the west Texas region, beef cattle feedyards are a source of particulate matter (PM). This PM is comprised mostly of manure, and has previously been implicated as a mechanism of transport for manure-affiliated chemicals off of feedyards into the surrounding environment. Manure-affiliated chemicals include veterinary pharmaceuticals, administered to cattle for growth promotion and maintenance of health, that may have deleterious effects following exposure in non-target organisms. Previous research has documented steroids and antibiotics in feedyard-emitted PM; this dissertation provides the first quantitation of the beta agonist ractopamine in feedyard-emitted PM. Quantitation of these chemicals in PM has, to this point, been conducted within or adjacent to feedyard boundaries, which provides limited information with regards to fate in the environment. This dissertation examined the persistence of veterinary pharmaceuticals and elevated PM concentrations up to 5 km downwind of feedyards. Dramatic reductions in PM concentration and a corresponding reduction in pharmaceutical concentration (per m3 air) were observed in the first km downwind of feedyards; no reduction, however, was observed in pharmaceutical concentrations per g PM at any distance. To examine the transport of feedyard-emitted PM on a regional scale, dust storm samples in Lubbock, TX and a variety of source samples from the west Texas region were characterized based on both concentrations of trace elements and microbial community. Results indicate a difference in composition for dust storms on different dates, which entered Lubbock from different directions, including an increase in microbes associated with cattle operations in a storm that passed through a region with a high concentration of feedyards and dairies prior to reaching Lubbock. Overall, this research begins to address the data gaps that exist regarding the transport of feedyard PM and affiliated chemicals after they exit feedyard boundaries.Item Exploring the Scope of Landowner Water Rights for Domestic and Livestock Purposes(Texas Tech Journal of Texas Administrative Law, 2006) Klein, David; Smith, RobinThis article examines the present scope of a Texas landowner’s domestic and livestock rights in light of the current versions of Chapter 11 of the Texas Water Code and Chapters 295 and 297 of the Texas Administrative Code. It begins by analyzing the history of a landowner’s domestic and livestock water rights and the history of water rights through different sovereignties, beginning with the Spanish regime up to Texas’s Adjudication Act in 1967. It addresses current statutory law, regulatory provisions, case law of the Texas Courts, and issues that have arisen at the Texas Commission on Environmental Quality. Lastly, it covers potential impacts on domestic and livestock water rights in the future based upon the past and present states of water law as well as other water issues confronting the State of Texas today.Item Neonicotinoids in the aquatic environment(2018-12) McManus, Michelle Marie; Cañas-Carrell, Jaclyn E.; Anderson, Todd; Crago, Jordan; Klein, DavidNeonicotinoids are an important class of systemic insecticides in agricultural and household use. Neonicotinoids, such as imidaclorprid (IMI), clothianidin (CLO), thiamethoxam (TMX), and acetamiprid (ACE), are used to control sap feeding insects and underground grubs. Nicotinic acetylcholine receptor (nAChR) agonism is the primary mode of action. Surface water contamination by neonicotinoids is common and photodegradation proceeds quickly in water. The impact of water constituents on the analysis and photodegradation of neonicotinoids is relatively unknown. Studies have shown neurobehavioral impacts of IMI and TMX on larval zebrafish, but it is uncertain how photoproducts or clothianidin exposure may alter neurodevelopment. This dissertation research includes analytical method optimization for the extraction of neonicotinoids from soil, sediment, and water; the direct and indirect photolysis of imidacloprid; and the neurotoxicological effects of neonicotinoids and associated photoproducts in zebrafish. Several potential causes of neonicotinoid underestimation in surface water were assessed including analyte stability, SPE extraction materials, and the influence of dissolved organic carbon (DOC) and pH on extraction efficiency. The best extraction results were obtained when samples were extracted using 30 µm particle size HLB and analyte retention by C18 sorbent was particularly affected by DOC content. Analyte stability was determined to not be of concern if samples are stored at or below 20 °C. The use of matrix-matched standards to reduce matrix induced ionization issues without the addition of further cleanup steps in the LC-MS/MS determination of neonicotinoid pesticides was assessed for sediment and soil. Recovery of analytes was within limits set by the EU commission guidance document on pesticide residues or all analytes; the highest recovery was from sediment followed by laboratory sand and agricultural soil. The impact of several aquatic constituents on the degradation rate of imidacloprid (IMI) were independently determined under natural sunlight. Dissolved iron and DOC decreased the rate of IMI degradation and nitrate had no effect. There was no change in degradation rate of imidacloprid in natural water compared to the light control. The neurobehavioral changes from exposure of embryo-larval zebrafish to IMI and desnitro-imidacloprid (DNIMI) photoproduct were observed. The DNIMI photoproduct and clothianidin (CLO) had the most significant impacts on gene expression of the acetylcholine receptor α7 subunit and dopaminergic pathway genes. This research will aid in the accurate environmental monitoring of neonicotinoids in surface water and ecological risk assessment of neonicotinoids.