Browsing by Author "Smith, Philip N."
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Item Accumulation and effects of HMX in the green anole (Anolis carolinensis)(2007-08) Jones, Lindsey E.; McMurry, Scott T.; Lovern, Matthew; Cobb, George P.; Smith, Philip N.; Anderson, Todd A.The use and subsequent environmental contamination of energetic compounds is an ever increasing international concern. Perhaps one of the greatest lapses in knowledge, and therefore threats to the natural environment, of these compounds is their toxicity to reptiles, particularly with respect to reproduction. To that end, a three-part study was conducted in an effort to define the role of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, High Melting Explosive), one of the top four explosive compounds of the twentieth century, in the reproductive toxicology of the green anole (Anolis carolinensis), a common reptilian model species. First, the acute oral toxicity (LD50) was measured in adult anoles using the up-and-down method described by the Organization for Economic Co-Operation and Development and United States Environmental Protection Agency. Then, part two of the study used artificially contaminated nesting media to assess accumulation of HMX into eggs at different combinations of incubation time and concentration. Also, initial growth parameters were measured for all hatchlings. The third part of the study was designed to assess HMX transfer from the diet of adults to eggs. In addition to assessing accumulation, hatching rates of eggs, growth rate of hatchlings, and signs of toxicity and abnormal reproductive function in adults were monitored. HMX was not acutely toxic to adult anoles and the LD50 was estimated at greater than 2,000 mg HMX/kg body weight. A dose-dependent accumulation of HMX into the egg was observed, though no significant developmental differences were observed among treatment groups. Exposed adults also exhibited dose-dependent accumulation of HMX, as well as treatment-related food aversion. From these studies it can be concluded that HMX readily accumulates in reptiles both directly (via ingestion of contaminated prey and/or contact with contaminated soil) and indirectly (via maternal transfer). Further study to determine the effect of HMX over two breeding seasons may be warranted.Item Acute, sub-acute, and sub-chronic effects of polcyclic aromatic hydrocarbons in northern bobwhite quail (colinus virginianus)(2007-12) Beall, Blake Nelson; Smith, Philip N.; Godard-Codding, Céline; Cobb, George P.Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants of aquatic and terrestrial ecosystems. PAHs are known to induce biochemical alterations in exposed animals. The cytochrome P450 enzyme system is known to be a significant Phase I metabolic pathway for the breakdown of PAHs that enter animal systems. Little is known about the effects of PAHs in Northern bobwhite quail (Colinus virginianus) and other terrestrial avifauna. The objectives of this study were to 1) determine if benz[a]anthracene, pyrene, and naphthalene exposure are acutely toxic in quail, and 2) determine if sub-acute exposure to benz[a]anthracene in quail would render mortality and produce alterations in enzyme activity, and 3) determine if sub-chronic exposure to benz[a]anthracene in quail would produce alterations in enzyme activity. Quail, acutely dosed with benz[a]anthracene, pyrene, and naphthalene experienced no mortality at the limit dose of 2000 mg/kg bodyweight. Additionally, there were no alterations in animal behavior. Sub-acute exposure of quail to benz[a]anthracene did not produce mortality. Quail were exposed to benz[a]anthracene at concentrations of 0, 0.1, 1, 10, 100, and 1000 mg/kg feed for 5 days. Alterations in cytochrome P450 1A and P450 2B were observed. An increasing trend in mean ethoxyresorufin-O-deethylase (EROD) activity in the liver was observed as exposure level increased. Pentoxyresorufin-O-deethylase (PROD) activity in the liver in exposed animals was significantly different when compared to the control. EROD activity in the kidney in the sub-acute study was observed to be significant when the interaction between exposure group and time was considered. Sub-chronic exposure of quail to benz[a]anthracene produced alterations in cytochrome P450 1A and P450 2B. Quail were exposed to benz[a]anthracene at concentrations of 0, 0.1, 1, and 10 mg/kg feed for 1, 3, 9, 30, and 60 days. EROD activity in the liver was observed to be significant when the interaction between exposure group and time was considered. An increasing trend in mean EROD and PROD activity in the liver and kidney was observed as exposure concentration increased. This study indicates that benz[a]anthracene, pyrene, and naphthalene are not acutely toxic in exposed quail, and benz[a]anthracene exposure affects enzyme activity in quail exposed sub-acutely and sub-chronically. Overall, this study provides evidence that metabolic alterations are experienced by Northern bobwhite quail exposed to PAHs.Item Agkistrodon piscivorus leucostoma (Western Cottonmouth). Diet.(Society for the Study of Amphibians and Reptiles, 2006) Rainwater, Thomas R.; Anderson, Todd A.; Platt, Steven G.; Smith, Philip N.Cottonmouths are opportunistic predators and scavengers that consume a variety of vertebrate prey (Gloyd and Conant 1990. Snakes of the Agkistrodon Complex: A Monographic Review. SSAR. Oxford, Ohio. 614 pp, and references therein). Watersnakes (Nerodia spp.) are considered a common component of the cottonmouth diet, but few studies have reported which species of Nerodia are consumed (Burkett 1966. Univ. Kansas Publ. Mus. Nat. Hist. 17:435-491; Gloyd and Conant, op. cit.). Here, we report Agkistrodon piscivorus leucostoma attempting to prey upon Nerodia erythrogaster flavigaster.Item An investigation into the toxicity, bioconcentration, and risk of perfluoroalkyl substances in aquatic taxa(2017-05) Olson, Adric D.; Anderson, Todd A.; Salice, Christopher J.; Smith, Philip N.; Maul, Jonathan D.Perfluorinated compounds (PFASs) such as perfluorooctane sulfonate (PFOS) and pefluorohexane sulfonate (PFHxS) are surfactants that were discovered to be persistent and potentially toxic in the environment and to humans. They were used in Aqueous Film Forming Foams (AFFFs) and in some household products due to their flame-retardant nature. As part of AFFF formulations they were used to fight fires, but the large volume required and their mobility as a liquid led them to be detected in a large number of waterways and animal tissues. They were voluntarily phased out by the manufacturer between 2000 and 2002 over concerns about their persistence and health effects. These same concerns have led to them being listed as a contaminant of emerging concern by the U.S. Environmental Protection Agency (US EPA) and the Organisation for Economic Co-operation and Development (OECD). This project presents work with PFOS, and to a lesser extent PFHxS, on a variety of aquatic taxa, spanning a large section of the food web. Initially, my work involved figuring out an experimental setup to use with these chemicals, as they have been shown to sorb to glass. In the second chapter, I report a study using the Western mosquitofish (Gambusia affinis) in the laboratory, field collection of other fish species, and a literature review to develop a physiologically based pharmacokinetic (PBPK) model to predict the uptake of and depuration of PFOS into and out of several fish tissues. In that chapter, I also developed a spatially-explicit bioconcentration model that can be used to simulate the variability inherent in environmental exposures. Then, I present the result of toxicity tests over both an acute and sub-chronic exposure period with a snail, the great pond snail (Lymnaea stagnalis), and an insect, the yellow fever mosquito (Aedes aegypti). These tests are crucial for improving scientific understanding for a variety of reasons: acute toxicity tests are generally used by risk assessors to estimate the risk due to a chemical while chronic tests more closely approximate the environmentally relevant exposure length, due to the persistence of the chemicals. I found that none of the species evaluated exhibited toxic effects at environmentally relevant concentrations of PFOS. However, different life stages of L. stagnalis were affected differently by exposure. Further, I discovered that combining PFOS and PFHxS into a mixture increased the toxicity to A. aegypti in a manner greater than would be predicted by additivity. Finally, I present an analysis of the PFOS burdens of a marine invertebrate, the Eastern oyster (Crassostrea virginica), collected along the Texas coastline. The amount of PFOS found in these samples suggest that the phase-out of PFASs has been successful in decreasing environmental concentrations found worldwide. These results provide further insight for the scientific community about the behavior of PFOS and may allow risk managers to make more informed decisions relating to PFASs.Item Antibiotics, Bacteria, and Antibiotic Resistance Genes: Aerial Transport from Cattle Feed Yards via Particulate Matter(2015) McEachran, Andrew D.; Blackwell, Brett R.; Hanson, J. Delton; Wooten, Kimberly J.; Mayer, Gregory D.; Cox, Stephen B.; Smith, Philip N.Background: Emergence and spread of antibiotic resistance has become a global health threat and is often linked with overuse and misuse of clinical and veterinary chemotherapeutic agents. Modern industrial-scale animal feeding operations rely extensively on veterinary pharmaceuticals, including antibiotics, to augment animal growth. Following excretion, antibiotics are transported through the environment via runoff, leaching, and land application of manure; however, airborne transport from feed yards has not been characterized. Objectives: The goal of this study was to determine the extent to which antibiotics, antibiotic resistance genes (ARG), and ruminant-associated microbes are aerially dispersed via particulate matter (PM) derived from large-scale beef cattle feed yards. Methods: PM was collected downwind and upwind of 10 beef cattle feed yards. After extraction from PM, five veterinary antibiotics were quantified via high-performance liquid chromatography with tandem mass spectrometry, ARG were quantified via targeted quantitative polymerase chain reaction, and microbial community diversity was analyzed via 16S rRNA amplification and sequencing. Results: Airborne PM derived from feed yards facilitated dispersal of several veterinary antibiotics, as well as microbial communities containing ARG. Concentrations of several antibiotics in airborne PM immediately downwind of feed yards ranged from 0.5 to 4.6 μg/g of PM. Microbial communities of PM collected downwind of feed yards were enriched with ruminant-associated taxa and were distinct when compared to upwind PM assemblages. Furthermore, genes encoding resistance to tetracycline antibiotics were significantly more abundant in PM collected downwind of feed yards as compared to upwind. Conclusions: Wind-dispersed PM from feed yards harbors antibiotics, bacteria, and ARGs.Item Effects of agrochemical mixtures detected on wildflowers near beef cattle feed yards on Painted Lady Butterflies (Vanessa cardui)(2018-08) Peterson, Eric M.; Smith, Philip N.; Anderson, Todd A.; Longing, ScottInsect pollinator populations are declining across the United States. Potential causes of observed declines in insect pollinators include, but are not limited to, reduced wildflower availability, monoculture agriculture, parasites, diseases, malnutrition, and pesticides. Pollinators are likely exposed to pesticides used on row crop agriculture and agrochemicals used at livestock production facilities, specifically beef cattle feed yards. To characterize potential pollinator exposure to pesticides and agrochemicals, wildflowers were collected within one kilometer of feed yards and row crop fields. Wildflowers were analyzed for veterinary pharmaceuticals used on feed yards to promote cattle growth, insecticides used to control feed yard pests, and pesticides commonly used in regional row crop agriculture. To further understand potential impacts of pollinator exposure to these unique agrochemical mixtures, a model butterfly species, the painted lady butterfly (Vanessa cardui), was used for toxicity testing. All wildflower samples collected near beef cattle feed yards contained the insecticide moxidectin, which was observed to be extremely toxic to V. cardui larvae (lethal dose in which 50% died (LD50) = 1.7 ± 0.2 ng/g). No other agrochemical identified on wildflowers occurring near feed yards produced any significant effects when V. cardui larvae were exposed within environmentally relevant ranges. Since 82% of wildflowers contained moxidectin plus either a veterinary pharmaceutical or row crop pesticide, a mixture toxicity experiment was conducted. The determined lethal dose in which 15% of larvae died (LD15) of moxidectin was administered with varying concentrations of the other agrochemicals. While no mixture induced any significant effect in this limited trial, we cannot conclude that moxidectin will not potentiate toxicity of other chemicals as has been reported in the literature. This preliminary study has identified the presence of previously unknown agrochemical mixtures emanating from feed yards and row crops in the Southern High Plains (SHP) on wildflowers and underscored the potential for adverse effects on pollinating insects.Item Effects of fullerenes and functionalized fullerenes on Daphnia magna: Behavioral responses and interactions of functionalized fullerene with hydrophobic organic contaminants(2010-05) Brausch, Kathryn Ann; Maul, Jonathan D.; Anderson, Todd A.; Smith, Philip N.Nanotechnology is a growing industry that utilizes nano-sized materials. In recent years, manufactured nanoparticles have been introduced into many consumer products as a result of unique properties related to their size. Due to the wide range of potential uses, it is likely that carbon nanomaterials will be found in the aquatic environment. However, the environmental risks of nanotechnology in aquatic systems are relatively unknown. This research evaluates potential effects of fullerenes (C60) and functionalized fullerenes ((1,2-methanofullerene C60)-61-carboxylic acid) (fC60) on the aquatic invertebrate Daphnia magna. One proposed use of carbon nanomaterials, especially functionalized nanomaterials, is in agricultural production as smart delivery systems and nanosensors. Due to this proposed use, the potential exists for fullerene and agricultural chemicals to co-occur as contaminants in the aquatic environment. The potential interaction effects of fC60 and the hydrophobic pesticides bifenthrin, a pyrethroid insecticide, and tribufos, an organophosphate cotton defoliant, were investigated. Observed endpoints included D. magna 48-h survival, 70-d reproduction (bifenthrin), 21-d reproduction (tribufos), and 5 and 10-d growth. Both mixtures and pesticides alone reduced D. magna survival and reproduction (p < 0.05). Forty-eight h LC50values were 0.86 (0.70 – 1.06) for bifenthrin only and 0.22 (0.18 – 0.25) for bifenthrin–fC60 mixtures. IC50 values for reduced number of days surviving and reduced reproduction were 0.55 (0.36 – 0.80) and 0.49 (0.28 – 0.72) μg/L for bifenthrin only and 0.39 (0.16 – 0.53) and 0.77 (0.31 – 0.94) μg/L for bifenthrin–fC60 mixtures. For tribufos experiments, forty-eight h LC50values were 6.63 (5.50 – 8.01) for tribufos only and 9.17 (8.03 – 10.49) for tribufos–fC60 mixtures. IC50 values for reduced number of days surviving and reduced reproduction were 9.89 (8.15 – 10.70) and 5.79 (4.48 – 7.60) μg/L for tribufos only and 8.17 (5.97 – 9.30) and 6.59 (5.29 – 8.12) for tribufos mixtures with fC60. No growth effects were observed. These results suggest that although fC60 had an effect on bifenthrin acute toxicity, they had little effect on pesticide chronic toxicity. In addition to potential interaction effects, changes in D. magna behavior in response to fullerene exposure have been reported. Behavioral endpoints are important because changes in behavior can influence Daphnia spp. predator avoidance behaviors, alter predator-prey interactions, increase predation of Daphnia spp., and potentially affect Daphnia populations. This is important to consider because Daphnia spp. serve as an important food source for fish. To evaluate potential changes in D. magna behavior, several responses were measured and included: phototactic behavior, swimming velocity, vertical variance, net angle, sinuosity, average angle, curvature coefficient, modal angle upward, and modal angle downward, were evaluated. C60 affected phototactic behavior over time with organisms being found lower in the exposure chamber when in the absence of food and higher in the exposure chamber when in the presence of food (p < 0.05). Additionally, exposed D. magna were higher in the exposure chamber when in the presence of predator kairomones than control organisms (p < 0.05). Additionally, a 38.8% reduction in swimming velocity was observed in organisms exposed to 545.4 μg/L C60 (p < 0.05). No other components of D. magna swimming behavior were affected and functionalized fullerenes did not affect any of the observed endpoints. This research adds to the knowledge of fullerene effects on aquatic invertebrates and is important in evaluating the risks of nanotechnology to aquatic ecosystems.Item Exploration into the developmental toxicity of organophosphate insecticides in zebrafish (Danio rerio)(2019-08) Schmitt, Cassandra Denee; Crago, Jordan; Smith, Philip N.; Mayer, Gregory D.Organophosphates (OP) are a class of compounds utilized as insecticides for agricultural application in the United States. Effective at controlling such insect populations as mites, aphids, and caterpillars, OPs have greatly contributed to increased crop productions since their early 20th century development. OPs are toxic to many non-target organisms through their primary mechanism of action as acetylcholinesterase (AChE) inhibitors. Precipitation often facilitates the distribution of OPs which contaminates surface waters. These insecticides are inadvertently introduced to aquatic ecosystems, recreational areas, and freshwater sources. Zebrafish (ZF) are a useful for investigations into the potential adverse effects of OP exposure, because they are a complimentary vertebrate model for the study of human health. The neurobehavioral and molecular alterations in embryo-larval ZF post exposure to OPs are well documented, but few studies observe the comparative effects across multiple compounds or generations. This thesis research comprises the comparative analyses of four predominant OPs (diazinon, dichlorvos, methyl-parathion, and dichlorvos) and a transgenerational examination of the OP metabolite chlorpyrifos-oxon developmental exposure in wild-type ZF. Investigations included a combination of neurobehavioral, biochemical, molecular, and epigenetic endpoints to assess both cholinergic and noncholinergic effects. This research contributes to previously limited data on the comparative and long-term effects of prenatal OP exposure in controlled laboratory conditions.Item Exposure and effects of polychlorinated biphenyls and metals in raccoons and selected rodents at the Paducah Gaseous Diffusion Plant in Western Kentucky(Texas Tech University, 2000-05) Smith, Philip N.The Paducah Gaseous Diffusion Plant in Western Kentucky is an industrial facility built in the 1950s to enrich raw uranium for fuels and bomb materials. Polychlorinated biphenyls, metals, and other contaminants have been released into the environment through various industrial processes over the past fifty years, and are thought to have moved into the surrounding areas through erosion and run-off. Contaminant concentrations in tissues of wildlife species were measured to monitor the amounts and spatial distribution of contaminants at this site. A residue study using white-footed mice (Peromyscus leucopus) and rice rats (Oryzomys palustris) as indicator species documented the movement of contaminants into the lowest levels of the terrestrial food web and identified highly contaminated areas. Rice rats were the best biomonitors for PCB contamination and white-footed mice the best indicators of metal contamination at this site. Results of the rodent study raised questions about the potential bioaccumulation of contaminants into higher trophic-level organisms inhabiting the areas surrounding the plant. Raccoons (Procyon lotor) were chosen to assess distribution of contamination on a larger scale and to evaluate the potential for bioaccumulation of contaminants in upper trophic-level organisms. Raccoons were captured, radio-collared, and tracked to determine spatial utilization of potentially contaminated areas. Concentrations of PCBs and metals were determined in raccoon tissues. Physiological biomarkers of exposure, including a variety of cytochrome P450 measurements, porphyrins, and other physiological markers were measured to evaluate adverse responses to contaminant exposure.Item Maternal transfer and tissue distribution of HMX in quail eggs(2007-05) Liu, Jun; Cobb, George P.; Smith, Philip N.; Anderson, Todd A.An efficient sample extraction and cleanup method was developed for determination of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in eggs. The procedure included solvent extraction of HMX from eggs followed by cleanup using florisil and styrene-divinyl benzene (SDB) cartridges. Chromatographic separation was achieved on a reverse phase (RP) C18 column, with a mobile phase containing 60% methanol + 40% 1.0 mM acetic acid aqueous solution. Overall recoveries from eggs containing 10, 50, 250 and 1000 ng/g of HMX were 84.0%, 88.0%, 90.6% and 87.4%. A method detection limit (MDL) of 0.15 ng/g was achieved. Then we evaluated the use of the gas exchange rate as an indicator of chemical stress in avian embryos/eggs. Northern bobwhite quail (Colinus virginianus) were exposed to HMX via feed at concentrations of 0, 12.5, 50.0, and 125.0 mg/kg. Metabolic rates (oxygen consumptions) of incubated quail eggs were then measured via respirometry to examine potential effects of HMX exposure. Metabolic rate was examined on 5, 9, and 21 days of incubation. Next, concentrations of HMX in eggs were determined by liquid chromatography-mass spectrometry. Concentrations of HMX in eggs from the four dose groups were significantly different. Mean (¡À SE) concentrations of HMX in quail eggs were 1025 ¡À 77, 3610 ¡À 143 and 7021 ¡À 300 ng/g in the low, medium and high dose groups respectively. A significant difference in oxygen consumption rates was observed among eggs at the three developmental stages (pItem Potential sources of exposure to endocrine-disrupting chemicals among companion canines(2012-12) Wooten, Kimberly; Smith, Philip N.; Anderson, Todd A.; Mayer, Gregory D.Effects of environmental chemicals on companion animals are considerably understudied as compared to humans, even though they often occupy similar environs and are exposed via similar routes. Companion canines display chewing and mouthing behaviors that likely contribute to chemical exposures. These behaviors are similar to those exhibited by children. Concern over chemical exposure among children has led to regulations for endocrine disrupting chemicals including phthalates and bisphenol A (BPA), but similar regulations do not apply to pet products. The goal of this study was to examine the potential of pet toys and training devices (bumpers) to leach phthalates and BPA into canine saliva. Effects of aging and chewing were evaluated with bumpers to determine if usage conditions would affect chemical leaching. Concentrations of six phthalates and BPA were determined in leachates via LC-MS/MS. In vitro transcriptional activation assays were used to assess potential for pet toy and bumper leachates to induce anti-androgenic and estrogenic activity. Bumpers leached high concentrations di-2-ethylhexyl phthalate and BPA, and aging and chewing increased leaching of most congeners as compared to new bumpers. Bumper leachates induced anti-androgenic and estrogenic activity in vitro. Pet toys leached comparatively lower concentrations of phthalates and BPA, but did leach diethyl phthalate in higher concentrations than bumpers. Pet toy leachates induced estrogenic, but not anti-androgenic, activity in vitro. Overall, results confirm that pet toys and bumpers are sources of exposure to phthalates and BPA in companion canines.Item The development and application of preconcentration/preelution ion chromatography methods for the detection of trace perchlorate in difficult matrices(2005-08) Cañas-Carrell, Jaclyn E.; Anderson, Todd A.; Smith, Philip N.; Tian, Kang; Hooper, Michael J.Perchlorate originates as a contaminant in the environment from the use of solid salts in the manufacture of solid rocket fuels and munitions. As a result of perchlorate occurrence and persistence, there has been much debate over what level of perchlorate is safe for daily consumption and USEPA recently set a reference dose for perchlorate. Ion chromatography (IC) is one of the most widely used methods for perchlorate determination because of its availability. However, analysis of biological samples by IC is often difficult because matrix components often interfere with low level detection. A preconcentration/ preelution ion chromatography method (PC/PE) was developed in our laboratory to address such interferences in high salinity samples and was proposed to have potential application for other matrices. In this study, the ability of the method to remove interferences and lower sample background was determined for gastrointestinal tract, kidney, liver, zebrafish, quail egg, lettuce, milk, urine, citrus, and soil matrices. The PC/PE method was applicable to the analysis of kidney, liver, zebrafish, quail egg, lettuce, and urine samples. Operating conditions were optimized for each matrix and there appeared to be no significant effect of prewash solution concentration on background. The range of optimal wash volumes, regardless of matrix, was shorter with a 15 mM NaOH prewash solution than a 10 mM solution. Optimal injection durations varied with matrix type, but recoveries were excellent for most matrices at injection periods greater than 60s. The method was capable of reducing background when compared to EPA Method 314.0 which resulted in detection limits, with the exception of zebrafish and urine, that were 2-fold lower those achieved by common IC. PC/PE was applicable to the remaining matrices, but poor recovery in the cleanup process hindered further investigation of the gastrointestinal tract and citrus matrices. Previously published methods for milk were determined to be better than the methodology developed here. Finally, there was no difference in soil background when analyzed by PC/PE compared to EPA Method 314.0. Therefore, an extraction method for perchlorate from soil with analysis by EPA Method 314.0 is presented here.Item Toxic responses of blue orchard mason bees (Osmia lignaria) following contact exposure to neonicotinoids, macrocyclic lactones, and pyrethroids(2021) Peterson, Eric M.; Green, Frank B.; Smith, Philip N.Analysis of particulate matter originating from beef cattle feed yards on the High Plains of the United States has revealed occurrence of multiple pesticides believed to potentially impact non-Apis pollinators. Among these pesticides are those that are highly toxic to Apis mellifera (honey bees). However, little non-Apis bee species toxicity data exist; especially pertaining to beef cattle feed yard-derived pesticides. Therefore, we conducted a series of 96-h contact toxicity tests with blue orchard mason bees (Osmia lignaria) using three neonicotinoids, two pyrethroids, and two macrocyclic lactones. Neonicotinoids (thiamethoxam, imidacloprid, and clothianidin) were most toxic with LD50 values ranging from 2.88 to 26.35 ng/bee, respectively. Macrocyclic lactones (abamectin and ivermectin) were also highly toxic to O. lignaria with LD50 estimates of 5.51–32.86 ng/bee. Pyrethroids (permethrin and bifenthrin) were relatively less toxic with LD50 values greater than 33 ng/bee. Sensitivity ratios for each pesticide were calculated to relate O. lignaria LD50 values to existing honey bee toxicity data. All three neonicotinoids were more toxic to O. lignaria than A. mellifera, but pyrethroids and abamectin were relatively less toxic. Additionally, three of seven pesticides (43%) resulted in significantly different mass normalized LD50 values for male and female O. lignaria. These results indicate that non-Apis pollinators may be highly susceptible to pesticides originating from beef cattle feed yards, necessitating consideration of more stringent regulatory protections than those based on A. mellifera pesticide sensitivity.Item Transfer of phthalates from c-polyvinyl chloride and cross-linked polyethylene pipe (PEX-b) into drinking water(IWA Publishing, 2017) Faust, Derek R.; Wooten, Kimberly J.; Smith, Philip N.Several different materials have been used for production of domestic water pipes throughout history. In recent years, the use of cross-linked polyethylene (PEX) pipe has increased dramatically, yet the potential for leaching of phthalates, which are endocrine disrupting compounds associated with adverse reproductive effects in humans, has not been examined. In this study, the potential of chlorinated polyvinyl chloride (cPVC) and red, blue, and heat PEX piping to leach phthalates into static hot and cold water after 2, 8, and 48 hours was evaluated. Concentrations of six phthalates, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzyl-butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di(n-octyl) phthalate (DNOP), were determined by gas chromatography-mass spectrometry. Pipe type (F3,71 = 15.6, P = 0.001) contributed significantly to phthalate concentrations in water, while temperature (F4,71 = 1.74, P = 0.106) and time (F4,71 = 1.02, P = 0.427) were not significant factors. Significantly higher concentrations of DEP, DBP, and BBP were observed in cPVC pipe (Item Viable antimicrobial resistant bacteria are transported from cattle feed yards via aerosolized particulate matter(Avens Publishing Group, 2018) Thompson, Kelsey N.; Wooten, Kimberly J.; Hensley, Loren L.; Smith, Philip N.; Mayer, Gregory D.Increased awareness of consequences associated with Antimicrobial Resistant Bacteria (ARB) has given rise to considerable research on how and where resistance to antimicrobial agents occurs. A recent investigation that utilized DNA sequencing-based technologies to characterize bacterial communities suggests that ARBs are generated on cattle feed yards and dispersed into the environment via wind-blown Particulate Matter (PM). Despite compelling evidence that bacterial DNA was prominent in fugitive PM, it remained unclear whether the bacterial DNA was derived from viable microorganisms. Thus, the narrow focus of this investigation was to determine whether bacteria associated with airborne PM emanating from cattle feed yards are viable, and if so, whether any cultivable bacteria were resistant to antibiotics. Numerous viable aerobic, microaerophilic, and anaerobic bacteria were successfully cultured from aerosolized, feed yardderived PM. Several cultured isolates were resistant to an assortment of antibiotics. This confirms that viable antimicrobial resistant bacteria do indeed travel on airborne PM emanating from cattle feed yards.