Toxicology Commons^™

The Sublethal Physiological Effects Of Exposure To Copper And Silver Mixtures On Rainbow Trout (Oncorhynchus Mykiss), Wesley Truong

Theses and Dissertations (Comprehensive)

The mechanisms behind metal-metal interactions in freshwater environments are currently not well understood. Freshwater environments consist of many different types of metals, from those naturally present such as copper (Cu) and those that originate from anthropogenic sources like silver (Ag). Both Cu and Ag use apical sodium (Na⁺) channels for uptake into the gills of freshwater fish. In the gills, the mechanisms of Cu²⁺ and Ag⁺ toxicity appear to be similar to one another, which is by inhibiting Na⁺ /potassium (K⁺)- adenosine triphosphatase (NKA) and carbonic anhydrase (CA). Inhibition of NKA and CA …

Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, Ricky W. Lewis

Theses and Dissertations--Plant and Soil Sciences

Engineered nanomaterials (ENMs) have become ubiquitous in consumer products and industrial applications, and consequently the environment. Much of the environmentally released ENMs are expected to enter terrestrial ecosystems via land application of nano-enriched biosolids to agricultural fields. Among the organisms most likely to encounter nano-enriched biosolids are the key soil bacteria known as plant growth promoting rhizobacteria (PGPR). I reviewed what is known concerning the toxicological effects of ENMs to PGPR and observed the need for high-throughput methods to evaluate lethal and sublethal toxic responses of aerobic microbes. I addressed this issue by developing high-throughput microplate assays which allowed me …

The Effects Of Manufactured Nanomaterial Transformations On Bioavailability, Toxicity And Transcriptomic Responses Of Caenorhabditis Elegans, Daniel L. Starnes

Theses and Dissertations--Plant and Soil Sciences

In recent decades, there has been a rapid expansion in the use of manufactured nanoparticles (MNPs). Experimental evidence and material flow models predict that MNPs enter wastewater treatment plants and partition to sewage sludge and majority of that sludge is land applied as biosolids. During wastewater treatment and after land application, MNPs undergo biogeochemical transformations (aging). The primary transformation process for silver MNPs (Ag-MNPs) is sulfidation, while zinc oxide MNPs (ZnO-MNPs) most likely undergo phosphatation and sulfidation. Our overall goal was to assess bioavailability and toxicogenomic impacts of both pristine, defined as-synthesized, and aged Ag- and ZnO-MNPs, as well as …

Validation Of Type 2 Diabetes Risk Variants Identified By Genome-Wide Association Studies In Northern Han Chinese, Ping Rao, Yong Zhou, Siqi Ge, Anxin Wang, Xinwei Yu, Mohamed Ali Alzain, Andrea K. Veronica, Jing Qiu, Manshu Song, Jie Zhang, Hao Wang, Honghong Fang, Qing Gao, Youxin Wang, Wei Wang

Research outputs 2014 to 2021

Background:

More than 60 genetic susceptibility loci associated with type 2 diabetes mellitus (T2DM) have been established in populations of Asian and European ancestry. Given ethnic differences and environmental factors, validation of the effects of genetic risk variants with reported associations identified by Genome-Wide Association Studies (GWASs) is essential. The study aims at evaluating the associations of T2DM with 29 single nucleotide polymorphisms (SNPs) from 19 candidate genes derived from GWASs in a northern Han Chinese population.

Method:

In this case-control study, 461 T2DM-diagnosed patients and 434 controls were recruited at the Jidong oil field hospital (Hebei, China) from January …

The Role Of Oxidative Stress In The Mechanisms Of Ammonia-Induced Brain Swelling And Tolerance In The Goldfish (Carassius Auratus), David F. Jones Lisser Mr.

Theses and Dissertations (Comprehensive)

Toxic build-ups of ammonia can cause potentially fatal brain swelling in mammals, but such swelling is reversible in the anoxia- and ammonia-tolerant goldfish (Carassius auratus). The mechanisms of ammonia-induced brain swelling and tolerance remain elusive, but several studies have suggested a role for reactive oxygen species (ROS), which may damage proteins and lipids in the plasma membrane of astrocytes in the brain. As a result, osmotic gradients across cell membranes may be altered leading to water uptake by astrocytes and swelling. While a role for ROS has been proposed in mammals, no studies have addressed this question in …

Nickel And Copper Mixture Toxicity To Daphnia In Soft Water, Prachi Deshpande

Theses and Dissertations (Comprehensive)

Industrially important metals, such as Cu and Ni, sometimes are present at elevated concentrations in lakes, including those in the Sudbury, ON region. Although they are essential metals, their divalent-cation state (Cu²⁺ and Ni²⁺) can be toxic at high concentrations in the water. The free-ion toxicity of each of these metals has been studied in isolation, but rarely as a mixture. The economic importance of Cu²⁺ and Ni²⁺ makes them essential to study in the context of mixture toxicity. The objectives were to: (1) determine Cu and Ni mixture toxicity to Daphnia through acute LC50 …

Do Toxicity Modifying Factors Influence Acute Or Chronic Toxicity Of Thulium To Hyalella Azteca?, Alexandria H. Loveridge

Theses and Dissertations (Comprehensive)

The industrial demand for rare earth elements (REEs) is growing and as a result, environmental exposure is a concern. Very little is understood about the toxicity of REEs in aquatic environments. The objective of this research is to evaluate the acute and chronic toxicity of Tm and to also understand the toxicity modifying influence of dissolved organic matter (DOM) and cationic competition (Ca2+, Mg2+ and Na+). Furthermore, the aim of this study was to determine linkages between Tm bioaccumulation, growth and survival during chronic exposures. Standard methods (Environment Canada) were followed for both 96h acute and 14d chronic tests, in …

Bioactivity/Cytotoxicity Of Micro-/Nano-Materials And Novel Development Of Fiber-Optic Probes For Single Cell Monitoring, Qingbo Yang

Doctoral Dissertations

"Manufactured nano-/micro-materials (MNMs) have been widely used and their interactions with niche biological environment are highly concerned for both of their biohazardous and bioactive effects, whereas no available comprehensive evaluations or regulations have been provided yet. This dissertation thus focuses on three major aspects: 1) fundamental toxicity understandings of a typical MNMs (zinc oxide nanoparticles), 2) bioactivity evaluations of representative bioactive MNMs, and 3) development of novel micro-probes for high spatial resolution monitoring. Firstly, the NP's concentration, irradiation, hydrodynamic size, and the localized pH, ionic strength, NP zeta-potential as well as dissolved oxygen levels were found correlated with the production …

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

The Smell Of Hopelessness, Juline Cariba Rachel Party

Capstones

Rafts of sargassum seaweed kilometers wide have been invading the Caribbean for more than five years, but 2015 was the worst. Tons of seaweed stretch from Texas south to Trinidad and Tobago, with the Lesser Antilles suffering the most damage. Residents near beaches are exposed to an insidious and pernicious danger, scientists say, from fumes that smell like rotten eggs, emitted by the decaying algae. The odor also drives tourists away from beaches and restaurants, and the tourism economy is collapsing.Amid the algae crisis, an elderly woman, Virginie Mark, is trying to survive. She struggles with her health, finances and …

Lead Exposure In Children Through Water And Soil, Sravya Maru

Environmental Management & Risk Assessment (PH 560)

Lead is a metal which has the ability to spread in the earth’s crust and has corrosive property. It is a naturally occurring metal which is soft in nature. Lead exposure in children is through various pathways and the major concentrated sources are the soil and drinking water. Children are most susceptible to lead exposure is due to their growing/developing bodies which are very sensitive to lead. Lead poisoning in children is a preventable environmental disease affecting many children around the world. This paper discusses how soil and water plays a major role in lead exposure to children’s routine life. …

Mechanisms And Intervention Strategies For Alcohol And Hiv-Antiretroviral Therapy-Induced Liver Injury., Hridgandh Donde

Electronic Theses and Dissertations

Chronic alcohol consumption is a leading cause of liver disease and liver-related death worldwide. Alcoholic liver disease includes, hepatic steatosis, steatohepatitis and ultimately fibrosis and cirrhosis. Emerging evidence has established the important role of the “gut-liver” axis in the development of alcoholic liver disease (ALD). Our recent work indicated that chronic alcohol induced perturbations in the gut microbiome and consequent changes in fatty acids have a major impact on the development of intestinal barrier dysfunction and ALD. The aim of this study was to investigate whether treatment with tributyrin - a butyrate prodrug results in protection against ALD in terms …

Comparative Aquatic Toxicity Of A Commercial Naphthenic Acid And Processes For Mitigating Risks, Ciera Kinley

All Theses

Comparative toxicity data can inform predictions of relative risk, and can be used to implement strategies for altering exposures to mitigate risk. Naphthenic acids (NAs) are a complex group of carboxylic acids that naturally occur in petroleum sources and energy-derived process waters (e.g. refinery effluents and oil sands process affected waters). These compounds are relatively persistent in water and can be a source of toxicity to aquatic organisms. In the first experiment of this thesis, responses of sentinel aquatic organisms to 7-d exposures of commercial (Fluka) NAs were measured (in terms of acute toxicity) to discern relative sensitivities. In terms …

Use Of Spirometry For Medical Clearance And Surveillance In Occupations Requiring Respirator Use, Ushang Prakshbhai Desai

USF Tampa Graduate Theses and Dissertations

Medical certification of workers for respirator use is an important activity of occupational medicine health professionals. Spirometry is a diagnostic tool to evaluate respiratory distress/insufficiency that may affect respirator use. In this study, we analyzed the pulmonary function data of 337 workers from different occupations which required medical evaluation to wear a respirator. The American Thoracic Society and National Fire Protection Association criteria were used to evaluate employees. Of 337 workers who were cleared for respiratory use on the basis of medical questionnaires for respirator compliance, 14 (4.15%) failed to pass respirator compliance on the basis of NFPA criteria and …

Elucidation Of The Role Of Poly(Adp-Ribose) Polymerase In Drug-Induced Toxicity, Kambria Haire

USF Tampa Graduate Theses and Dissertations

Drug toxicity may cause liver injury, resulting in damage to cells and tissues. This damage can lead to cytotoxic events that may result in an activation of poly (ADP-ribose) polymerase (PARP). A study was conducted to determine if cocaine and acetaminophen toxicity lead to DNA damage and to the activation of the repair protein, PARP in the liver using the hepatotoxicants: cocaine and acetaminophen (APAP).

A dose-response analysis for cocaine concluded that a dose as low as 20 mg/kg resulted in elevated ALT levels. A higher dose of 60 mg/kg was tested for analyses but resulted in severe hemorrhaging. The …

Mercury Emissions From Coal-Fired Powerplants, Divya Gade

Environmental Management & Risk Assessment (PH 560)

Mercury is a neurotoxic heavy metal that pose a risk to the public as well as the environmental health. It is a naturally occurring element that is released into the environment from the natural or anthropogenic emissions. Among the anthropogenic emissions, coal-fired powerplants account for approximately 50 percent of the emissions because of the lack of regulations for the emissions from these facilities. The other larger sources of mercury emissions such as municipal waste combustors and medical waste incinerators are subjected to the stringent regulations thereby minimizing their total contribution. Mercury is a natural component of coal and is released …

Relationship Between Emissions Of Human Activities And Ozone Layer Depletion, Umer Murtaza

Environmental Management & Risk Assessment (PH 560)

Ozone depletion always holds an importance being a protective shield to humans and environment as well. Human activities and man-made substances are playing major role to this depletion which is increasing day by day. In this paper influence of man-made substances on ozone depletion and consequences of this depletion have been discussed. Role of chlorofluorocarbons as depleting agents is more comparatively other substances. Due to ozone depletion life on earth is affecting which are resulting different consequences like skin cancer, eye diseases and destruction of crops and aquatic life. EPA has worked a lot to save the ozone and many …

An Investigation Of The Effect Of Malathion On Adaptive Plasticity Of Pseudacris Sierra, Michael Jonathan Maples

Master's Theses

This thesis is composed of two chapters. Chapter one reviews what is known about adaptive plasticity in response to predators, describes the physiological systems involved in such plasticity, and outlines the evolutionary consequences of adaptive plasticity. Chapter two describes a scientific experiment that investigates how malathion may impact adaptive plasticity in the Sierran Treefrog, Pseudacris sierra. Anuran tadpoles suffer high mortality rates due to predation. In response to strong selective forces relating to these high predation rates, tadpoles evolved the ability to adaptively respond to predators through morphological and behavioral plasticity. The morphological and behavioral responses are varied and depend …

Removal Of Heavy Metal Ions From Aqueous Solution Using Rice Husks-Based Adsorbents, Fanuel J Ligate, James E.G Mdoe

Tanzania Journal of Science

This study reports on the preparation and characterization of rice husks-based adsorbents and their application in the removal of heavy metal ions from aqueous solution. Three different adsorbents were developed: rice husks ash (RHA), rice husks ash-derived silica (RHS) and triaminopropyl-silica hybrid (TSH-R). The prepared materials were characterized by acid titration, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) spectroscopy and nitrogen physisorption analysis. Results from the ATR-FTIR analysis indicated that pure silica was obtained from RHA and that after surface modification the triaminopropyl group was successfully attached onto the silica framework with a …

Assessment Of Heavy Metal Concentration In Water Around The Proposed Mkuju River Uranium Project In Tanzania, Firmi P. Banzi, Peter K. Msaki, Najat K. Mohammed

Tanzania Journal of Science

Effective verification for compliance with water quality standards in uranium mining in Tanzania requires data sensitive to monitor heavy metal concentration in water around the Mkuju River Uranium Project before mining commences. The area susceptible for pollution by the project was estimated using AERMOD dispersion model and found to cover about 1300 km2. Thirty one surface and groundwater samples were collected and analysed for heavy metals and physicochemical properties using ICP-MS and standards techniques, respectively. The physicochemical properties for water samples analysed ranges from 5.7 to 7.8 for pH, 2.8 to 80.2 mg/L for TDS and 15 to 534.5 mS/cm …