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Solvent Effects and Bioconcentration Patterns of Antimicrobial Compounds in Wetland Plants

Description: This study looked at effects of organic solvents dimethylsulfoxide, dimethylformamide and acetone at 0.01%, 0.05% and 0.1% concentration on germination and seedling development wetland plants. Even at 0.01% level, all solvents affected some aspect of seed germination or seedling growth. Acetone at 0.01% was least toxic. Root morphological characteristics were most sensitive compared to shoot morphological characteristics. This study also looked at bioconcentration patterns of antimicrobial compounds triclosan, triclocarban and methyl-triclosan in wetland plants exposed to Denton Municipal Waste Water Treatment Plant effluent. Bioconcentration patterns of antimicrobial compounds varied among species within groups as well as within organs of species. The highest triclocarban, triclosan and methyltriclosan concentration were in shoot of N. guadalupensis, root of N. lutea and in shoots of P. nodous respectively.
Date: May 2011
Creator: Adhikari, Sajag
Partner: UNT Libraries

Response of Freshwater and Saltwater Toxicity Test Species to Calcium and Salinity Concentrations Encountered in Toxicity Tests

Description: The responses of freshwater (Daphnia magna. Pimephales promelas) and saltwater (Mysidopsis bahia. Cyprinodon variegatus) toxicity test species to elevated calcium concentrations and changing salinity conditions were investigated. The use of salinity as a criterion for selection between saltwater and freshwater test species was investigated by conducting both calcium and salinity toxicity tests. Salinity was determined to be an inappropriate criterion under conditions encountered in this study.
Date: 1989
Creator: Price, Edmund E., 1954-
Partner: UNT Libraries

The Toxicity of Fluorine

Description: The following report discusses the toxicity of fluorine as described in literature on fluorine intoxication and case studies of Roholm's experimental observations.
Date: 1943
Creator: Ferry, J. L.
Partner: UNT Libraries Government Documents Department

The Effects of Neonicotinoid Exposure on Embryonic Development and Organ Mass in Northern Bobwhite Quail

Description: Since their emergence in the early 1990s, neonicotinoid use has increased exponentially to make them the world's most prevalent insecticides. Although there is considerable research concerning the lethality of neonicotinoids, their sub-lethal and developmental effects are still being explored, especially with regards to non-mammalian species. The goal of this research was to investigate the effects of the neonicotinoid imidacloprid on the morphological and physiological development of northern bobwhite quail (Colinus virginianus). Bobwhite eggs (n = 650) were injected with imidacloprid concentrations of 0 (sham), 10, 50, 100 and 150 grams per kilogram of egg mass, which was administered at day 0 (pre-incubation), 3, 6, 9, or 12 of growth. Embryos were dissected on day 19 when they were weighed, staged, and examined for any overt structural deformities. Embryonic heart, liver, lungs and kidneys were also weighed and preserved for future use. Treated embryos exhibited increased frequency of severely deformed beaks and legs, as well as larger hearts and smaller lungs at the higher dosing concentrations. Some impacts are more pronounced in specific dosing periods, implying that there may be critical windows of development when embryos are highly susceptible to neonicotinoid exposure. This investigation suggests that imidacloprid could play a significant role in chick survival and declining quail populations in treated regions of the country.
Date: May 2016
Creator: Gobeli, Amanda
Partner: UNT Libraries

Evaluating the Role of UV Exposure and Recovery Regimes in PAH Photo-Induced Toxicity

Description: Polyaromatic hydrocarbons (PAHs) are contaminants synthesized through incomplete combustion of carbon based substances. PAHs are known to be photodynamic and toxicity increases exponentially when in contact with ultraviolet radiation (UV). The effect of UV absent recovery periods and potential for latent toxicity during photo-induced toxicity are previously unknown and are not included within the toxicity model. Results of equal interval tests further support the current reciprocity model as a good indicator of PAH photo-induced toxicity. Interval test results also indicate a possible presence of time-dependent toxicity and recovery thresholds and should be included into toxicity risk assessments. Moreover, results of latent effects assays show that latent mortality is a significant response to PAH photo-induced toxicity and should be included into toxicity risk assessments. The present research demonstrates that UV exposure time rate is a significant driving force of PAH photo-induced toxicity.
Date: August 2017
Creator: Gnau, Jennifer Leigh
Partner: UNT Libraries

Two Year Feeding Test

Description: The following report presents the results of the second year of the two-year feeding tests of uranium compounds to 50 male and 50 female rats.
Date: 1949
Creator: Maynard, Elliott A.; Downs, William L. & Hodge, Harold C.
Partner: UNT Libraries Government Documents Department

Molecular Characterization of a Novel Heavy Metal Uptake Transporter from Higher Plants and its Potential for Use in Phytoremediation - Final Report

Description: Heavy metal toxicity poses major environmental and health problems, and heavy metals are more difficult to remediate than chemical contaminants, which can be degraded by microorganisms. Cadmium and arsenic, for example, are non-essential heavy metals which are toxic to living cells at very low concentrations. Cd 2+ ions displace Ca2+ or Zn2+ in proteins and can cause oxidative stress, while arsenic also causes oxidative stress damage and is a well known carcinogen.
Date: October 1, 2000
Creator: Schroeder, J.
Partner: UNT Libraries Government Documents Department

The Effects of Glyphosate Based Herbicides on Chick Embryo Development

Description: Glyphosate based herbicides are among the most widely used herbicides in the world. The purpose of this study was to determine developmental toxicity of glyphosate, the active ingredient in the common herbicide Roundup, on developing chicken embryos. Few studies have examined toxic effects of glyphosate alone versus the full compound formulations of Roundup, which include adjuvants and surfactants. Adjutants and surfactants are added to aid in solubility and absorption of glyphosate. In this study chicken embryos were exposed at the air cell on embryonic day 6 to 19.8 or 9.9 mg / Kg egg mass of glyphosate in Roundup or glyphosate only. Chickens treated with 19.8 and 9.9 mg / Kg glyphosate in Roundup showed significant reduction in survivability compared to glyphosate alone treatments and controls. On embryonic day 18, embryos were sacrificed for evaluation of developmental toxicity using wet embryo mass, dry embryo mass, and yolk mass as indicators. Morphology measurements were taken on liver mass, heart mass, tibiotarsus length and beak length. Embryos treated with 19.8 mg / Kg glyphosate and 9.9 mg / Kg glyphosate in Roundup showed significant reductions in wet and dry embryo mass and yolk mass. Tibiotarsus length in 9.9 mg / Kg glyphosate in Roundup treatments were significantly reduced compared to 9.9 mg / Kg glyphosate treatments. Beak length was significantly reduced in 9.9 mg /Kg glyphosate in Roundup treatments compared to all other groups.
Date: August 2013
Creator: Winnick, Blake Edward
Partner: UNT Libraries

Pathologies in earthworms: sublethal biomarkers of xenobiotic toxicity

Description: This research is part of an overall program to develop and use a suite of acute and sublethal toxicity biomarkers, and testing protocols for use in assaying potential effects of complex mixtures of xenobiotics such as found in soils containing agricultural biocides and petrochemical wastes dredged sediments, and hazardous waste sites (HWS). The purpose of this study was to evaluate four biomarkers of sublethal pathology that could be used in an integrative model of multiple toxicity endpoints with the earthworm Lumbricus terrestris.
Date: May 1991
Creator: Cikutovic Salas, Marcos A.
Partner: UNT Libraries

Toxicity Studies of Aquatic Actinomycetes

Description: Since Actinomycetes have been isolated from finished public drinking water, it is believed that the organisms are unaffected by the chlorination and flocculation of water treatment plants and pass as spores through the filters into the general distribution system. For this reason it was deemed imperative to study the toxic effects of these organisms.
Date: August 1952
Creator: Fair, Helena Juengermann
Partner: UNT Libraries

Modeling the Effects of Chronic Toxicity of Pharmaceutical Chemicals on the Life History Strategies of Ceriodaphnia Dubia: a Multigenerational Study

Description: Trace quantities of pharmaceuticals (including carbamazepine and sertraline) are continuously discharged into the environment, which causes concern among scientists and regulators regarding their potential long-term impacts on aquatic ecosystems. These compounds and their metabolites are continuously interacting with the orgranisms in various life stages, and may differentially influence development of embryo, larvae, juvenile, and adult stages. To fully understand the potential ecological risks of two candidate pharmaceutical chemicals (carbamazepine (CBZ) and sertraline (SERT)) exposure on survival, growth and reproduction of Ceriodaphnia dubia in three sucessive generations under static renewal toxicity test, a multigenerational approach was taken. Results indicate that SERT exposure showed higher sensitivity to chronic exposure to C. dubia growth and reproduction than CBZ exposure. The lowest concentration to affect fecundity and growth was at 50 µg L-1 SERT in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8 µg L-1. The effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2 µg SERT L-1, respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to SERT leads to effects that occur at concentrations an order of magnitude higher than predicted environmental concentrations indicating potential transgenerationals effects. Additionally, a process-based dynamic energy budget (DEB) model is implemented to predict the simulated effects of chronic toxicity of SERT and CBZ to C. dubia individual behavior at laboratory condition. The model‘s output indicates the ecotoxicological mode of action of SERT exposure, which acts on feeding or assimilation with an effect that rapidly saturates at higher concentrations. Offspring size decreases with the toxic effects on feeding, and offspring number is thus less affected than total investment in reproduction. Consequently, CBZ affects direclty in reproduction which are captured by DEBtox ...
Date: December 2013
Creator: Lamichhane, Kiran
Partner: UNT Libraries

Potential Toxicity and Underlying Mechanisms Associated with Pulmonary Exposure to Iron Oxide Nanoparticles: Conflicting Literature and Unclear Risk

Description: This review article will focus on known risks following iron oxide nanoparticles (IONPs) exposure supported by human, animal, and cell culture-based studies, the potential challenges intrinsic to IONPs toxicity assessment, and how these may contribute to the poorly characterized IONPs toxicity profile.
Date: September 7, 2017
Creator: Kornberg, Tiffany G.; Stueckle, Todd A.; Antonini, James M.; Rojanasakul, Liying W.; Castranova, Vincent; Yang, Yong et al.
Partner: UNT College of Engineering

Glucose or Altered Ceramide Biosynthesis Mediate Oxygen Deprivation Sensitivity Through Novel Pathways Revealed by Transcriptome Analysis in Caenorhabditis elegans

Description: This article discusses how RNA-sequencing analysis was performed to assess how a glucose-supplemented diet and/or a hyl-2 mutation altered the transcriptome.
Date: August 5, 2016
Creator: Ladage, Mary L.; King, Skylar D.; Burks, David J.; Quan, Daniel L.; Garcia, Anastacia M.; Azad, Rajeev K. et al.
Partner: UNT College of Arts and Sciences

THE METABOLSIM AND TOXICITY OF RADIUM-223 IN RATS

Description: This report covers studies of the excretion and retention of 'tracer' and toxic doses of the 11.2-day Ra{sup 223} isotope, its acute toxicity (organ weight changes, gross and microscopic pathology, and Fe{sup 59} utilization by the bone marrow), and long-term histopathological changes and alterations in the hemogram.
Date: February 21, 1958
Creator: Durbin, Patricia; Durbin, Patricia W.; Asling, C. Willet.; Jeung, Nylan; Williams, Marilyn H.; Post, James. et al.
Partner: UNT Libraries Government Documents Department

Responses of Pristina leidyi Smith 1896 (Naididae: Oligochaeta) to Cadmium, Vanadium, and Some Environmental Factors

Description: Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and direct body contact with aquatic sediments. Chronic testing with oligochaetes has historically focused on tubificids with test lengths of one year or more to encompass several generations. Most naidid oligochaetes have generation times of three to seven days and could provide chronic information in a matter of weeks. The cosmopolitan distributed naidid, Pristina leidyi, was evaluated for use as a toxicity test organism. Results of research conducted includes culture methods, effects of temperature on reproduction, growth rates in a reference sediment, acute toxicity tests, and chronic toxicity tests.
Date: May 1990
Creator: Smith, David P. (David Paul), 1956-
Partner: UNT Libraries

Final Report - Phase II - Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions: An Integrated Laboratory and Field Study

Description: Our understanding of subsurface microbiology is hindered by the inaccessibility of this environment, particularly when the hydrogeologic medium is contaminated with toxic substances. Past research in our labs indicated that the composition of the growth medium (e.g., bicarbonate complexation of U(VI)) and the underlying mineral phase (e.g., hematite) significantly affects the rate and extent of U(VI) reduction and immobilization through a variety of effects. Our research was aimed at elucidating those effects to a much greater extent, while exploring the potential for U(IV) reoxidation and subsequent re-mobilization, which also appears to depend on the mineral phases present in the system. The project reported on here was an extension ($20,575) of the prior (much larger) project. This report is focused only on the work completed during the extension period. Further information on the larger impacts of our research, including 28 publications, can be found in the final report for the following projects: 1) Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions: An Integrated Laboratory and Field Study Grant # DE-FG03-01ER63270, and 2) Acceptable Endpoints for Metals and Radionuclides: Quantifying the Stability of Uranium and Lead Immobilized Under Sulfate Reducing Conditions Grant # DE-FG03-98ER62630/A001 In this Phase II project, the toxic effects of uranium(VI) were studied using Desulfovibrio desulfuricans G20 in a medium containing bicarbonate or 1, 4-piperazinediethane sulfonic acid disodium salt monohydrate (PIPES) buffer (each at 30 mM, pH 7). The toxicity of uranium(VI) was dependent on the medium buffer and was observed in terms of longer lag times and in some cases, no measurable growth. The minimum inhibiting concentration (MIC) was 140 M U(VI) in PIPES buffered medium. This is 36 times lower than previously reported for D. desulfuricans. These results suggest that U(VI) toxicity and the detoxification mechanisms of G20 depend greatly on the chemical forms of U(VI) present ...
Date: September 28, 2006
Creator: Peyton, Brent & Sani, Rajesh
Partner: UNT Libraries Government Documents Department

Toxicity Bioassays for Ecological Risk Assessment in Arid and Semiarid Ecosystems. Reviews Environmental Contamination and Toxicology 168:43-98.

Description: This paper discusses current limitations for performing ecological risk assessments in dry environments (i.e., ecosystems that are characteristic of many DOE Facilities) and presents novel approaches to addressing ecological risk in such systems.
Date: February 2001
Creator: Markwiese, J. T.; Ryti, R. T.; Hooten, M. M.; Michael, D. I. & Hlohowskyj, I.
Partner: UNT Libraries Government Documents Department

Report of Flood, Oil Sheen, and fish Kill Incidents on East Fork Poplar Creek at the Oak Ridge Y-12 Plant

Description: Water quality and plant opemtion irriiormation provided by the Y-12 Plant strongly suggest that a dechlorinating agent, applied to the raw water released below the North-South Pipes was responsible for the toxicity resulting in the fish kill of July 24. Dissolved oxygen (DO) measurements in upper EFPC indicai e that low oxygen levels (3-5 ppm) occurred for a period of up to 30 min. This slug of low DO water traveling down EFPC to the lake could easily explain the massive fish kill and the resulting observations. Dissolved oxygen levels of 5.2 ppm or lower are documented as causing problems for warmwater fish species (Heath 1995). The presence of other stressors, including a range of petrochemicals, tends to lower resistance to low oxygen conditions. Given the sequence of events in upper EFPC in the few days prior to July 24, where extremely high flows were followed by inputs of a wide range of low concentrations of oils, the sensitivity to low DO conditions might be heightened. The possible toxic impact of ::he oils and other contaminants reaching EFPC as a result of the heavy rainfidl on July 22 doesn't appear significant enough to be the sole cause of the kill on July 24. Even during the height of the kill, a large school of fish remained immediately downstream of the North-South Pipes. If the toxicity of waters flowing through this outlet were the primary cause of the kill, then it would be expected that this school of fish would not have been present immediately below the pipes. Any impact of waters entering from other sources, such as pumping of basements WOUIC1 have produced a staggered pattern of mortality, with fishing dying in different localities at different times and rates. Further, it would be expected that the morta.lhy observed would have ...
Date: September 1, 1997
Creator: Skaggs, B.E.
Partner: UNT Libraries Government Documents Department

Cytotoxicity and Functional Toxicity of Mefloquine and the Search for Protective Compounds

Description: Mefloquine hydrochloride is an antimalarial agent that has been used for the past 40 years. Numerous reports of neurological side effects have recently led the FDA to issue a strong warning regarding long-term neurological effects. This warning lead to the U.S. Army’s Special Forces and other components to discontinue its use in July of 2013. Despite reported adverse side effects, mefloquine remains in circulation and is recommended to travelers going to specific Asian countries. Mefloquine has been used as a treatment for those already infected with the malaria parasite (blood concentrations ranging from 2.1 to 23 µM), and as prophylaxis (blood concentrations averaging 3.8 µM) (Dow 2003). The purpose of this study was to quantify Mefloquine’s toxicity using spontaneously active nerve cell networks growing on microelectrode arrays in vitro and to identify compounds that alleviate or reduce toxic effects. The current literature on mefloquine toxicity is lacking electrophysiological data. These data will contribute to research on the mechanism of adverse side effects associated with mefloquine use. Sequential titration experiments were performed by adding increasing concentrations of mefloquine solution to cultured neurons. Network responses were quantified and reversibility was examined. In each network, activity decreases were normalized as a percent of reference activity yielding a mean IC50 value of 5.97 ± 0.44 (SD) µM (n=6). After total activity loss, no activity was recovered with two successive medium changes. To test for network response desensitization resulting from sequential applications over 5-6 hr periods, one-point titrations at varying concentrations were conducted with fresh networks. These experiments yielded a single concentration response curve with an IC50 value of 2.97 µM. This represents a statistically significant shift (p < 0.0001) to lower concentrations of mefloquine, demonstrating that sequential applications result in network desensitization. After mefloquine exposures, cells were evaluated for irreversible cytotoxic damage. Over a ...
Date: May 2015
Creator: Holmes, Katelyn
Partner: UNT Libraries