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Articles 1 - 23 of 23
Full-Text Articles in Physical Sciences and Mathematics
Mercury Reduces Avian Reproductive Success Through Direct Embryotoxicity Rather Than Altered Parental Behavior, Stephanie Yen Chin
Mercury Reduces Avian Reproductive Success Through Direct Embryotoxicity Rather Than Altered Parental Behavior, Stephanie Yen Chin
Dissertations, Theses, and Masters Projects
No abstract provided.
Methylmercury Exposure Affects Risk-Taking Behaviors In Zebra Finches: Tradeoffs Between Eating And Being Eaten, Megan Elizabeth Kobiela
Methylmercury Exposure Affects Risk-Taking Behaviors In Zebra Finches: Tradeoffs Between Eating And Being Eaten, Megan Elizabeth Kobiela
Dissertations, Theses, and Masters Projects
No abstract provided.
Sublethal Effects Of Methylmercury On Flight Performance And Molt In European Starlings (Sturnus Vulgaris), Jenna Rae Carlson
Sublethal Effects Of Methylmercury On Flight Performance And Molt In European Starlings (Sturnus Vulgaris), Jenna Rae Carlson
Dissertations, Theses, and Masters Projects
No abstract provided.
Sublethal Effects Of Methylmercury On The Songbird Immune Response: An Experimental Study, Catherine Ann Lewis
Sublethal Effects Of Methylmercury On The Songbird Immune Response: An Experimental Study, Catherine Ann Lewis
Dissertations, Theses, and Masters Projects
No abstract provided.
Effects Of Dietary Mercury Exposure On Spatial Memory Of Zebra Finches, Taeniopygia Guttata, Amanda Mae Bessler
Effects Of Dietary Mercury Exposure On Spatial Memory Of Zebra Finches, Taeniopygia Guttata, Amanda Mae Bessler
Dissertations, Theses, and Masters Projects
No abstract provided.
Toxicology Of Decabromodiphenyl Ether In Avian Embryos: Disposition Of The Flame Retardant Bde-209 In Yolk-Injected Chicken Embryos (Gallus Gallus), Samantha D. Sifleet
Toxicology Of Decabromodiphenyl Ether In Avian Embryos: Disposition Of The Flame Retardant Bde-209 In Yolk-Injected Chicken Embryos (Gallus Gallus), Samantha D. Sifleet
Dissertations, Theses, and Masters Projects
Polybrominated diphenyl ethers (PBDEs) are flame retardant chemicals of toxicological concern present in humans, wildlife, and the environment. Deca-BDE is the highest production product due to historical use patterns and recent regulatory limitations on the other two commercial formulations (Penta-BDE and Octa-BDE) in the U.S and Europe. The EU banned Deca-BDE starting July 1, 2008. However, it remains in usage in North America and elsewhere in the world. BDE-209 is the dominant congener in all Deca- BDE commercial products. BDE-209 has been reported to under go metabolic debromination to lesser brominated and more toxic and bioaccumulative congeners. However, insufficient data …
Application Of Survival Analysis Methods To Pulsed Exposures: Exposure Duration, Latent Mortality, Recovery Time, And The Underlying Theory Of Survival Distribution Models, Yuan Zhao
Dissertations, Theses, and Masters Projects
Ecotoxicologists adopted median lethal concentration (LC50) methods from mammalian toxicology. This conventional LC50 approach has shortcomings. Fixing the exposure duration and selecting the 50% mortality level result in loss of ecologically relevant information generated at all other times. It also ignores latent mortality that can manifest after exposure ends. as a result, it cannot adequately predict pulsed exposure effects in which concentration, duration, and frequency of pulses change through time. The underlying theory of the dose-response models used to calculate LC50 values, stochastic versus individual effective dose (IED) theory, has not been tested rigorously either. In this study, the effects …
Predicting Metal Interactions With A Novel Quantitative Ion Character -Activity Relationship (Qicar) Approach, David R. Ownby
Predicting Metal Interactions With A Novel Quantitative Ion Character -Activity Relationship (Qicar) Approach, David R. Ownby
Dissertations, Theses, and Masters Projects
Environmental toxicologists adopted QSARs from pharmacology fairly early on to predict organic contaminant toxicity. In contrast, models relating metal ion characteristics to their bioactivity remain poorly explored and underutillized. Quantitative Ion Character-Activity Relationships (QICARs) have recently been developed to predict metal toxicity. The QICAR approach based on metal-ligand binding tendencies has been applied to a wide range of effects, species, and media on a single metal basis. In previous single metal studies, a softness parameter and the ; log of KOH ; were the ion qualities with the highest predictive value for toxicity. Here, QICAR modeling was brought a step …
Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin
Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin
Dissertations, Theses, and Masters Projects
The interactive effects of humic acids (HAs) and salinity on the bioavailability and toxicity of the pesticides chlorpyrifos and 4,4'-dichlorodiphenyltrichloroethane (DDT) were investigated. The effects of various HAs on the toxicity of chlorpyrifos were initially assessed with the chronic MicrotoxRTM test. Environmentally relevant concentrations of Aldrich, Peat, Leonardite and Suwannee River HAs had no significant effect on the toxicity of either chlorpyrifos or copper (Cu), the test's positive control. as reductions in contaminant toxicity had previously been reported for some contaminants by HAs, it appeared that salinity might be a mitigating factor. Thus salinity effects were further investigated with Aldrich …
Heat Shock Protein (Hsp70) Response In The Eastern Oyster, Crassostrea Virginica, Exposed To Various Contaminants (Pahs, Pcbs And Cadmium), Luis A. Cruz Rodriguez
Heat Shock Protein (Hsp70) Response In The Eastern Oyster, Crassostrea Virginica, Exposed To Various Contaminants (Pahs, Pcbs And Cadmium), Luis A. Cruz Rodriguez
Dissertations, Theses, and Masters Projects
The stress protein response has been proposed as a general indicator of exposure to stress as their expression might integrate overall biological impact and interactions among multiple stressors. as a marker of contaminant effects, a major advantage is the premise of higher sensitivity over other indices such as condition index, scope for growth and survival. Laboratory exposure to suspended field contaminated sediments (SFCS) elicited a stress protein response (HSP70) in the eastern oyster, ( Crassostrea virginica). The stress response probably resulted from the combined effect of various contaminants including PAHs, metals and PCBs. Exposure to 1--2g suspended clay particles spiked …
Effects Of Polychlorinated Biphenyl Exposure On Development And Sexual Differentiation In Ranid Tadpoles, Mary J. Rybitski
Effects Of Polychlorinated Biphenyl Exposure On Development And Sexual Differentiation In Ranid Tadpoles, Mary J. Rybitski
Dissertations, Theses, and Masters Projects
The effects of AroclorRTM1242 exposure on developing amphibians were examined by exposing southern leopard frogs, Rana sphenocephala, to a contaminated diet throughout the larval period. Treatment groups consisted of an untreated control, a solvent control, 17beta-estradiol, and three PCB doses (10, 100, and 1000 mug/g). PCB accumulation and biotransformation were examined. Effects of PCB exposure on metamorphosis and sexual differentiation were assessed. PCB accumulation was not statistically different between the egg masses. Levels of PCBs in the tissues differed in a dose related manner. Within treatments, body weight appeared to be the major factor correlated with PCB concentration. Congener patterns …
Interactive Effects Of Cadmium And Benzo(A)Pyrene In Mummichog (Fundulus Heteroclitus), Peter Van Den Hurk
Interactive Effects Of Cadmium And Benzo(A)Pyrene In Mummichog (Fundulus Heteroclitus), Peter Van Den Hurk
Dissertations, Theses, and Masters Projects
When animals are exposed to mixtures of environmental pollutants, it is generally assumed that the toxic effects of the individual components are additive. However, examples of synergistic and antagonistic effects have been described. to study the mechanisms of interaction between a metal and a polycyclic aromatic hydrocarbon, mummichog (Fundulus heteroclitus) were injected with combinations of cadmium (Cd) and benzo (a) pyrene (BP). Measured effect parameters were: mortality, BP-metabolite production in isolated hepatocytes and microsomes, hepatic induction of CYP1A (the BP metabolizing enzyme) and metallothionein (the Cd binding protein), and biliary excretion of BP-metabolites. The mortality data demonstrated that both synergistic …
Expression Of The Xenobiotic Transporter P-Glycoprotein In The Mummichog (Fundulus Heteroclitus), Peter S. Cooper
Expression Of The Xenobiotic Transporter P-Glycoprotein In The Mummichog (Fundulus Heteroclitus), Peter S. Cooper
Dissertations, Theses, and Masters Projects
The mammalian mdr1 P-glycoprotein (Pgp) has been implicated in xenobiotic resistance of drug-resistant cell lines and tumors, and may function in excretion or exclusion of toxic xenobiotics at several sites within the body. Pgp gene family members are expressed in excretory epithelia of several aquatic taxa and may contribute to the survival of pollution-tolerant aquatic animals in contaminated environments. For this reason the expression of Pgp family members was investigated in the livers and liver tumors of creosote-resistant mummichog (Fundulus heteroclitus) inhabiting a creosote-contaminated site (Atlantic Wood) in the Elizabeth River, Virginia. Expression of members of the Pgp gene family …
Demersal Predator Exposure To Toxic Organic Contaminants: Direct Effects Of Macrofauna In Trophic Transfer, Patrick Winfield Lay
Demersal Predator Exposure To Toxic Organic Contaminants: Direct Effects Of Macrofauna In Trophic Transfer, Patrick Winfield Lay
Dissertations, Theses, and Masters Projects
The bioaccumulation and metabolism of organic contaminants (PAH, PCB) by three estuarine polychaetes, Nereis succinea (Frey and Leuckart 1847), Paraprionospio pinnata (Ehlers 1901) and Polydora ligni (Webster 1879), and by the fish predator, spot (Leiostomus xanthurus Lacepede 1802), were examined in laboratory experiments. Variations in trophic transfer of these contaminants resulting from differences in prey and contaminant type were also investigated. Toxicokinetic modeling reveals that metabolism of organic contaminants by invertebrate species result in variations in uptake, metabolism and elimination rate constants. Incorporation of prey metabolism potential in kinetic models increases the latter's predictability of biota-sediment accumulation factors (BSAFs), or …
Comparative Toxicity Of Creosote And Creosote Contaminated Sediments, Padma T. Venkatraman
Comparative Toxicity Of Creosote And Creosote Contaminated Sediments, Padma T. Venkatraman
Dissertations, Theses, and Masters Projects
No abstract provided.
Toxicity Resistance In Mummichog (Fundulus Heteroclitus) From A Chemically Contaminated Environment, Cynthia A. H. Williams
Toxicity Resistance In Mummichog (Fundulus Heteroclitus) From A Chemically Contaminated Environment, Cynthia A. H. Williams
Dissertations, Theses, and Masters Projects
No abstract provided.
Investigations Into Cataract Formation In Sciaenid Fish Species From The Elizabeth River, Chesapeake Bay, Virginia, Christopher D. Williams
Investigations Into Cataract Formation In Sciaenid Fish Species From The Elizabeth River, Chesapeake Bay, Virginia, Christopher D. Williams
Dissertations, Theses, and Masters Projects
Cataract formation in the Elizabeth River (ER) has been reported since 1986. Previous studies have concentrated on describing cataract as a function of exposure to polluted sediments, especially polycyclic aromatic hydrocarbons (PAH). These studies, however, have not examined what processes might be involved in fish cataractogenesis. The overall objective of this research was to identify important processes associated with the early development of cataract in feral fish populations. Field studies were used to systematically examine cataract development. Cataract in sciaenids was not associated with previously described cataractogenic factors, but could be linked to contaminated sediments of the ER. Cataract was …
Effects Of Methyl Parathion On The Cellular Immune Responses In Giant Black Tiger Shrimp, Penaeus Monodon, Nantarika. Bodhipaksha
Effects Of Methyl Parathion On The Cellular Immune Responses In Giant Black Tiger Shrimp, Penaeus Monodon, Nantarika. Bodhipaksha
Dissertations, Theses, and Masters Projects
The effects of an organophosphorus pesticide, methyl parathion, on cellular immune defense mechanisms of the giant black tiger shrimp (Penaeus monodon) were studied. Animals were exposed for 96 hours at concentrations equal to, above and below the LC&\sb{lcub}50{rcub}& (3 ppb). Phagocytes were obtained from the heart and circulating hemolymph. Cellular immune responses, including chemotaxis, phagocytosis and the respiratory burst were examined. Chemotactic activity was determined by means of a modified Boyden double chamber technique. There was a dose-dependent decrease in the chemotactic activities of both circulating hemocytes and cardiac phagocytes. Phagocytic activity (percent phagocytosis) was examined by the microscopic enumeration …
Monooxygenase Induction And Lethality As Endpoints In Aquatic Toxicology, Daniel W. Sved
Monooxygenase Induction And Lethality As Endpoints In Aquatic Toxicology, Daniel W. Sved
Dissertations, Theses, and Masters Projects
Spot, Leiostomus xanthurus, were exposed to suspended sediments (&\approx&20 mg/L) contaminated with polycyclic aromatic hydrocarbons (PAH) in a laboratory flow-through system to evaluate the applicability of hepatic ethoxyresorufin O-deethylase (EROD) induction as an indicator of PAH exposure. PAH sources tested were coal-tar creosote (CTC), a low molecular weight fraction of creosote (LMWF), and a high molecular weight fraction of creosote (HMWF). A standard 96-h acute toxicity test was conducted to ensure that PAH concentrations tested in induction studies were sub-acutely toxic. The 96-h LC50 for spot was 1740 &\mu&g PAH/L (95% confidence interval = 1480-2060 &\mu&g PAH/L). The lowest concentration …
Evaluation Of Carbon-14 Uptake Algal Toxicity Assay And Its Application In Field Assessment Of Tributyltin Chloride And Chlorinated Sewage Toxicities, Soon Lin Ho
Dissertations, Theses, and Masters Projects
No abstract provided.
Uptake, Distribution, Metabolism And Clearance Of Kepone By Channel Catfish (Ictalurus Punctatus), Peter A. Vanveld
Uptake, Distribution, Metabolism And Clearance Of Kepone By Channel Catfish (Ictalurus Punctatus), Peter A. Vanveld
Dissertations, Theses, and Masters Projects
No abstract provided.
Effects Of Ingestion Of Kepone Contaminated Food By Juvenile Blue Crabs (Callinectes Sapidus Rathbun), Daniel J. Fisher
Effects Of Ingestion Of Kepone Contaminated Food By Juvenile Blue Crabs (Callinectes Sapidus Rathbun), Daniel J. Fisher
Dissertations, Theses, and Masters Projects
No abstract provided.
Acute Toxicity Of No 6 Fuel Oil To Intertidal Organisms In The Lower York River, Virginia, Jeffrey L. Hyland
Acute Toxicity Of No 6 Fuel Oil To Intertidal Organisms In The Lower York River, Virginia, Jeffrey L. Hyland
Dissertations, Theses, and Masters Projects
No abstract provided.