Chemistry Commons^™

Northern Fur Ssal Vibrissae Organochlorine Contaminant Concentrations, Dimitri Giarikos, Amy Hirons, Courtney White

SECLER Data

The eastern Pacific stock of northern fur seals (Callorhinus ursinus) on the Pribilof Islands has experienced population declines since 1980. The decline may be due to anthropogenic persistent organic pollutants (POPs) which bioaccumulate, are toxic, and persistent. This study conducted a comparison of 21 organochlorine (OC) and 39 polybrominated diphenyl ether (PBDE) analyte concentrations utilizing archived vibrissae (whiskers) from individual fur seals sampled in 1993 (n=30) and 2013 (n=41). The PBDEs had values five times greater than the legacy status OCs. There were no significant mean concentration differences between 1993 and 2013 for total organochlorines (ΣOCs), or total …

Northern Fur Seal Vibrissae Polybrominateddiphenylether Concentrations, Dimitri Giarikos, Amy Hirons, Courtney White

SECLER Data

The eastern Pacific stock of northern fur seals (Callorhinus ursinus) on the Pribilof Islands has experienced population declines since 1980. The decline may be due to anthropogenic persistent organic pollutants (POPs) which bioaccumulate, are toxic, and persistent. This study conducted a comparison of 21 organochlorine (OC) and 39 polybrominated diphenyl ether (PBDE) analyte concentrations utilizing archived vibrissae (whiskers) from individual fur seals sampled in 1993 (n=30) and 2013 (n=41). The PBDEs had values five times greater than the legacy status OCs. There were no significant mean concentration differences between 1993 and 2013 for total organochlorines (ΣOCs), or total …

Development Of A Flow Cytometry Method For The Identification And Enumeration Of Enterococcus Faecalis, Riza Magbitang

Master's Theses

A multi-color flow cytometry method coupled with fluorescent staining was developed to detect and quantify E. faecalis concentrations in coastal waters as an alternative to the traditional membrane filtration method. The developed method was used to characterize E. faecalis during batch growth and yielded consistent results across the various physiological states of the cells. Additionally, the application of propidium iodide (i.e., a viability stain), afforded the method the ability to differentiate between cells with intact and compromised cell membranes, which raises the potential of quantifying cells that are in viable-but-non-culturable (VBNC) state. Initial field test using natural seawater samples spiked …

Design Of Engineered Nanomaterials For Pfas Adsorption And Catalytic Degradation From Relevant Environmental Conditions, Sheng Yin

Open Access Theses & Dissertations

Poly- and per-fluoroalkyl substances (PFAS) are a class of artificially made chemicals whose carbon chains are fully or partially fluorinated. Due to their persistent and pervasive distribution and their adverse effects on human health, the removal of PFAS from the environment has been the focus of current research. This project explores the use of engineered nanomaterials for the effective removal of PFAS through various adsorption and catalytic degradation methods. First, a comprehensive review of recent studies highlights the significant potential of various nanomaterials, including carbon-based, non-metal, single-metal, and multi-metal nanomaterials, for PFAS remediation. These materials are evaluated for their performance, …

Assessing The Reactivity Of Amino Acids To Chlorination Using Capillary Electrophoresis, Pedro De Allende

Electronic Theses, Projects, and Dissertations

Amino acids (AA) are ubiquitous in wastewater systems. One of the most popular wastewater treatments is chlorination which is effective at eradicating bacteria and overall treating the wastewater, but it can also produce disinfection by-products (DBPs). Certain DBPs have been classified as Class B Carcinogens to humans and are therefore highly regulated and monitored. Past studies have shown that natural organic matter (NOM), specifically amino acids, can be precursors to DBPs if chlorinated to the correct dose. This thesis project explored AA chlorination's mechanism(s) to understand further which products arise. In particular, the investigation detailed which steps of the mechanism …

Chemical Recycling Of Bio-Based Polyurethane Foams: Evaluating Bio-Based Glycols In Comparison To Petroleum-Based Glycols, Anirudh Thorbole Mr.

Electronic Theses & Dissertations

The paradigm shift towards bio-based polyurethane foams (bio-PUF) has significantly increased post-consumer waste. To address this issue, this research represents a novel approach to enhance sustainable development in the recycling industry by replacing traditional petroleum-based glycols with sustainable bio-based alternatives. This study explores the glycolysis of bio-PUF using bio-based SG-522 glycol and polyethylene glycol (PEG) for comparison. The findings from this research as outlined, reveal no significant differences in depolymerization time between the two glycols, achieving proper depolymerization and high recovery yields of over 95% after solvent purification. Comprehensive FT-IR and NMR analyses confirmed the successful degradation of bio-PUF and …

Chemical And Morphological Characterization Of Airborne Particulate Matter At The Jackpile-Paguate Mine, Pueblo Of Laguna, New Mexico: Implications For Potential Metals Exposure, Andreanna C. Roros

Earth and Planetary Sciences ETDs

The inhalation of windblown particulate matter (PM) derived from abandoned uranium mines (AUMs) is a potential environmental health risk to Native American communities that live in proximity to these sites. However, the aeolian transport of metal-bearing PM from AUMs, as a potential exposure pathway, has not been investigated in any detail. In this study, we sampled airborne particulate matter within the Jackpile Mine located on the lands of the Pueblo of Laguna, New Mexico using passive sampling methods to understand the characteristics of dust within the mine site. The objective was to determine the elemental concentrations, mineralogy, and morphology of …

Heavy Metals Implications To Sediment Microbiome And Coral Response To Arsenic Dosing, Dimitrios G. Giarikos, Amy Hirons, Jose V. Lopez, Abigail Renegar, Jason Gershman

SECLER Data

No abstract provided.

Herbicides, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Herbicides play a vital role in integrated weed management programs. Knowledge of the mechanisms and activity of herbicides will improve the impact and sustainability of herbicides as a weed management tactic. This fact sheet is a guide to the types of herbicides available and when and how they should be used.

Positron Emission Tomography In Oncology And Environmental Science, Samantha Delaney

Dissertations, Theses, and Capstone Projects

The last half century has played witness to the onset of molecular imaging for the clinical assessment of physiological targets. While several medical imaging modalities allow for the visualization of the functional and anatomical properties of humans and living systems, few offer accurate quantitation and the ability to detect biochemical processes with low-administered drug mass doses. This limits how physicians and scientists may diagnose and treat medical issues, such as cancer, disease, and foreign agents.

A promising alternative to extant invasive procedures and suboptimal imaging modalities to assess the nature of a biological environment is the use of positron emission …

A Molecular Dynamics Study On The Destruction Mechanism Of Per And Polyfluoroalkyl Substances Due To Ultrasound Technology, Bruno Bezerra De Souza

Dissertations

Per- and polyfluoroalkyl substances (PFAS) are a group of stable synthetic chemicals that are highly persistent and harmful pollutants to the environment and human health. PFAS have caused a strong public and regulatory response due to their ubiquitous presence in the environment and toxicity to humans. The application of ultrasound is one of the most effective treatment technologies for the mineralization of PFAS in contaminated water. However, this technology is treated as a black box causing the inability to be optimized. Therefore, there is a pressing need to investigate the intricate dynamics of PFAS degradation under ultrasound to unlock its …

Du Undergraduate Showcase Abstracts: Research, Scholarship, And Creative Works, August Alexander, Kevin Summers, E. Paige Lloyd, Alyssa Aragon, Lauren Wols, Erica Larson, Colton Arciniaga, Lily Baeza, Ellie Barnett-Cashman, Sidney Barbier, Maverick Bartholomew, Ryan Bell, Trevor Briggs, Amanda Brown, Cory Marchi, Maddy Pontius, Jennifer Gallagher, Claire Kwok, Channing Bullock, Alex Mccollister, Kim Gorgens, Daniela Chavez, Yamilet Espinoza Nuñez, Giovanni Valladares Giron, William Christensen, Olivia Kachulis, Daniel Cierasynski, Brandon Cohen, Spenser Dobbs, Lindsay Goolsby, Noah Craver, Nyah Cubbison, Liam Doherty, Nicole Doris, Yan Qin, Alexander Nguyen, Lily Harmon, Shubh Todi, Naichen Zhao, Noah Fagello, Stacia Fritz, Paola Gascot-Chinea, Alex Volkova, Janelyn Geronimo, Elsie Harrington, Shane Simmons, Clarice Hise, Laura Moreno Palmer, Henry Xu, Yesu Leela Pasupula, Emily Fisher, Zachary Hogan, Colin Kleckner, Alyssa Knaus, Erin Kubat, Sam Werkema, Katie Lamberton, Lilliya Larson, Allie Leary, Vanessa Leon-Gamez, James H. Gallagher, E. Dale Broder, Robin M. Tinghitella, Emma Loeber, Alina Mali, Ixchel Marquez, Lauren Mcgrath, Ella Matthews, Grace Naegelen, Audrey Ng, Megan Lucyshyn, Rachel Brough, Alexandra Norman, Joe Ontiveros Rodriguez, Ben Dossett, Ori Miller, Janamejay Sharma, Christopher Reardon, Vincent Pandey, Regan Parish, Ren Pratt, Alisha Pravasi, Sanchari Das, Cari Reichel, Emma Robson, Victoria Rockwell, Jayce Rumsey, Steven Said, Norah Schroder, Alaina Smith, Shannon Murphy, Shujan A. Sharafeldeen, Stanley M. Kanai, James T. Nichols, David E. Clouthier, Macalia R. Augustus, Daniel Silva Rios, Scott Simpson, Anna Sparling, Chase Spurbeck, Kimberly Chiew, Christine Stadnik-Poteroba, Jacqueline Stephenson, Evelyn Stovin, Mia Supan, Lauren Tapper, Will Thrush, Anna Vogt, Michaela Walheim, Jon Weber, Hunter Whitehouse, Kansas Wood, Hayley Sayre, Lydia Mccann, Maread Mclaughlin, Kelly Krumrie, Olivia Wuttke

DU Undergraduate Research Journal Archive

Abstracts from the DU Undergraduate Research Showcase.

Releases Of Hazardous Materials And Waste From Transportation Incidents In The Us: An Analysis To Increase Environmental Resiliency, Elizabeth Irene Tautges

Master's Projects and Capstones

Excessive amounts of hazardous materials and waste are released into the environment from transportation incidents. The United States federal government has regulations on the movement of hazardous material and waste during transportation, but preventing environmental releases is not a major priority. Multiple external factors influence the release of hazardous material and waste into the environment. Transportation incidents can be prevented by modifying the information collected in emergency reports, adjusting transportation patterns and conditions, and expressing negative environmental impacts, preparing responder efforts to communicate effectively. The components of previous hazardous materials and waste releases emphasize the needed improvements for increasing environmental …

Method Validation Of Metals In Environmental Soil Samples, Sofia Deangelis, Nana Nguyen

Student Research Symposium

Vehicles are a major source of metal accumulation in terrestrial environments. Green infrastructure, such as bioswales, has been implemented as a way to mitigate this damage. However, there is a limited understanding of the processes that occur in these bioswales as few go back after implementation to identify areas in the bioswale with accumulation of pollutants. Inductively coupled mass spectrometry (ICP-MS) has the potential to be used in this type of study due to the machine’s high sensitivity and selectivity. However complications can arise while using the ICP-MS to characterize complex environmental samples. This study seeks to optimize microwave assisted …

Multiscale Variability Of Heavy Metals In A Western U.S. Snowpack, Kelsey Hefner

Student Research Symposium

Natural and anthropogenically sourced particulates are deposited from the atmosphere to landscapes via dry and wet deposition, making frozen winter snowpack a natural archive of atmospheric elemental composition. Wildfires in the Western United States are increasing in extent, duration, and severity, especially in alpine regions. Severe fires remove forest canopy and can impact how atmospheric elements are dispersed and stored across snow-dominated watersheds. We evaluated Al, V, Cr, Mn, Ni, Cu, As, Zn, Se, Mo, Cd, and Pb concentrations in 394 winter snow core samples. We collected samples in 2019 and 2020 from a chronosequence of eight forests that burned …

Investigating The Impact Of Secondary Activation Time On The Adsorption Properties Of Activated Biochar For Arsenic Removal From Wastewater, Achyuth Bharadwaj Rayarao

Graduate Theses and Dissertations (2019 - present)

Biochar, a naturally occurring and renewable carbon material, becomes porous through activation. Activated biochar is an ideal candidate for use as an adsorbent. The objective of this study is to investigate whether activated biochar derived from Colorado soft pine serves as a better adsorbent and demonstrates enhanced adsorption capabilities after undergoing secondary physical activation at various activation times. The effect of secondary action time on physical adsorption properties drawn from the analysis of isotherm plots, surface areas and pore size patterns were examined by using a physisorption analyzer. Chemical structures were identified using both ultimate and proximate analyses, while porosity …

Enabling More Efficient Solar Thermal Energy Production And Storage, Allan Wilson

Poster Presentations

Concentrated Solar Power (CSP) stores & transfers energy using a Thermal Energy Storage Fluid (EIA AEO 2022)

Boron-Doped Diamond As A Resilient Electrode Material In Molten Salts, Hannah Katherine Patenaude

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molten salt chemistry has a range of applications within nuclear technology, including for the Molten Salt Reactors (MSRs) and pyroprocessing to recover valuable actinides for energy and national security needs. However, the high-temperature, corrosive nature of molten salts makes them particularly challenging to deploy on an industrial scale and study in benchtop measurements. Material accountability and corrosion monitoring of MSR fuels are essential components to the successful deployment of MSRs, and electroanalytical techniques like cyclic voltammetry (CV) and spectroelectrochemistry (SEC) can provide a wealth of information to describe salt systems in situ. To perform such measurements, it is imperative to …

Modification, Transport, And Sources Of Hydrocarbon Oxidation Products From Groundwater At Crude Oil And Diesel Spill Sites In Minnesota: Unveiling Common “Theems” Via Spectroscopy & Chromatography, Eduardo E. Turcios Valle

LSU New Orleans Theses and Dissertations

In this thesis, petroleum-contaminated groundwater from three spill-affected Minnesota sites—two contaminated with crude oil; one with diesel—is investigated to elucidate whether differences in degradation products from different parent oils exist. After spill events, parent molecules from the leaked oil seep underground and undergo microbial degradation over time, transforming into hydrocarbon oxidation products (HOPs), water-soluble contaminants that infiltrate groundwater aquifers, flowing into nearby environments and towns while exhibiting environmental persistence, toxicity to aquatic biota, and potential risks to humans that become exposed. Spectroscopic and chromatographic study of the structural themes and spatial distributions of HOPs reveals preferential degradation of aliphatic (biolabile) …

Chemical Composition, Fate, And Toxicity Of Dissolved Hydrocarbon Oxidation Products In High Latitude Aquatic Environments, Maxwell Louis Harsha

LSU New Orleans Theses and Dissertations

Oil spilled in aquatic environments undergoes abiotic and biotic oxidation processes that produce hydrocarbon oxidation products (HOPs). HOPs rapidly diffuse in the water column, persisting and readily bioavailable to aquatic organisms. Characterizing HOPs is challenging because most of the mixture resides in the unresolved complex mixture (UCM). Understanding of the formation, fate, and toxicity of HOPs in high latitude environments remains limited. This research addresses these gaps through a comprehensive experimental approach, utilizing various analytical techniques including nonvolatile dissolved organic carbon (NVDOC) analysis, ultrahigh-resolution mass spectrometry, tandem mass spectrometry, inductively coupled plasma mass spectrometry, and fluorescence excitation-emission matrix spectroscopy. Additionally, …

Conversion Of Microcrystalline Cellulose To Hexane Using Hydrogenated Metal Oxides At Low Temperature And Pressure, Mubarak Osman

Electronic Theses and Dissertations

Increasing global energy demand and environmental concerns have fueled the exploration of sustainable and efficient methods for renewable fuel production. The conversion of cellulosic waste to hydrocarbon fuels using hydrogenated metal oxides presents a novel and eco-friendly approach to sustainably address energy demand. In this study, hydrogenated metal oxides were used as catalysts in a relatively low-temperature and atmospheric-pressure environment to facilitate the conversion of cellulosic waste into hydrocarbon fuels. Hydrogenated metal oxides have been introduced as potential hydrogen transfer catalysts. The expected result is the selective conversion of cellulose to hexane at relatively low temperatures, which significantly reduces energy …

Examination Of The Effects Of Ultraviolet Radiation On The Toxicity Of An Array Of Pesticides, Polyaromatic Hydrocarbons, And Pharmaceuticals Via In-Vitro Bioassays, Jessica R. Stephens

LSU Master's Theses

Chemicals are often released via anthropogenic means both intentionally and unintentionally into aquatic environments. The chemical fate of these compounds can vary greatly depending on numerous factors that can include but are not limited to salinity, pH, dissolved oxygen, and exposure to ultraviolet radiation. The goal of this study was to investigate the effect of UV radiation on the level of toxicity of different chemicals over time. Chemicals were selected based on previous studies of the toxicity of both parent and metabolites formed as a result of photolysis. Anthracene, phenanthrene, anthraquinone, dicloran, chlorothalonil, hydroxy chlorothalonil, benzobicyclon hydrolysate, and sertraline were …

Applied Depositional Geosystems Of The Coos Bay Basin, Oregon: Organic Geochemistry, Maturation, Paleoenvironmental Reconstruction And Biostratigraphy Of The Coaledo Delta During The Middle Eocene Climatic Optimum (Meco), Allison K. Barbato

LSU Doctoral Dissertations

The Coos Bay Basin on the southwestern coast of Oregon is a forearc basin that contains exceptionally preserved Eocene to Miocene, tidal to wave-dominated, shallow deltaic to deep marine sediments of the Coaledo Delta. Coastal depositional environments are known to host source, reservoir, and seal rocks. Climate, topographic relief, and geographical position all play an important role in regional vegetation development and oceanic setting. This study assesses 84 outcrop and 12 core samples from Coos Bay for their organic geochemical characteristics and microfossil assemblage to provide source rock characterization information, organofacies descriptions, environmental reconstructions, and age control.

Results indicate the …

Investigating Ocean Carbonate System Changes Across Latitudes In The North Atlantic Basin With A Time-Series Mooring System, Anna Trujillo

Independent Study Project (ISP) Collection

The world ocean, specifically the Arctic, serves as one of the greatest mitigators for anthropogenic carbon dioxide release, making the study of high latitude ocean carbonate chemistry an increasingly important topic. While much work has been done concerning the science of acidification and future model projections, analyzing data to detect decadal anthropogenic trends and effects is also highly important. Aiming to add to this data pool, this study investigated the ocean carbonate system at three North Atlantic mooring locations at polar, subtropical, and tropical latitudes from 2013 - 2021. Time series datasets of the pH and pCO₂ of surface water …

Exploring Cation Exchange: Unveiling Its Significance In Biochar And Bioenergetics Applications, Gyanendra Kharel

Chemistry & Biochemistry Theses & Dissertations

Cation exchange, a cornerstone of soil chemistry and nutrient cycling, is a fundamental chemical process that occurs in soils, sediments, membranes, and other solid materials. It involves the interchange of positively charged ions, or cations, between a solid matrix and a surrounding solution. This process is crucial in various natural and engineered systems, leading to a range of applications across different fields.

This dissertation presents an extensive investigation into the applications of cation exchange in the fields of biochar and bioenergetics, encompassing three distinct aims. The first aim concentrates on the surface oxygenation of biochar through ozonization, aiming to achieve …

Advanced Oxidation Of Methyl Tert Butyl Ether With Ultraviolet Light Emitting Diodes, Aaron R. Neal

Theses and Dissertations

Methyl Tert-Butyl Ether (MTBE) is a volatile, soluble, organic compound introduced to gasoline within the United States as a fuel oxygenator in 1979. MTBE is a common groundwater pollutant due to its high water solubility and resistance to bio-degradation; it commonly infiltrates groundwater sources via leaking underground storage tanks or fuel spills. This research employed ultraviolet light emitting diodes (UV-LEDs) and hydrogen peroxide (H₂O₂) induced advanced oxidation process (AOP) to treat MTBE contaminated water at the bench scale. Using four H₂O₂:MTBE molar peroxide ratios (100:1, 200:1, 400:1, 500:1), MTBE degradation was induced …

Thin-Film Nanocomposite Membranes With Alumina Nanoparticles For Textile Wastewater Treatment Applications, Amr Mohamed Tayel

Theses and Dissertations

Thin-film nanocomposite (TFN) membranes are gaining great interest in industrial wastewater treatment due to their superior performance, especially for higher water flux and pollutants’ rejection, as well as improved chemical, thermal and mechanical stabilities, compared to other types of membranes. The performance of TFN membranes can be enhanced using different types of nanofillers, among which ceramic nanomaterials, such as Al2O3, offer a promising potential for applications involving treatment of industrial wastewater such as textile effluents, and this is due to their stability, hydrophilicity, and relative low cost. The study of the TFN membrane properties and structure allows the optimization and …

Impact Of Solar Radiation On Perchlorate Formation In The Atmosphere: Evidence From Ice Core Measurements, Bishnu Kunwar

Electronic Theses and Dissertations

Perchlorate, which derives from both anthropogenic and natural sources in the current environment, poses a substantial health hazard to humans as it competes with iodine uptake in the thyroid gland. Consequently, there has been considerable concern about minimizing human exposure to environmental perchlorate by restricting its release from man-made sources. However, the absence of a clear understanding regarding the respective contributions of man-made and natural sources has hindered widespread regulation efforts. A 300-year (1700–2007) Summit, Greenland ice core record from a previous study showed relatively stable perchlorate concentrations in Greenland snow prior to 1980, with some elevated perchlorate levels associated …

Plasmid-Borne Biosynthetic Gene Clusters Within A Permanently Stratified Marine Water Column, Paraskevi Mara, David Geller-Mcgrath, Elizabeth A. Suter, Gordon T. Taylor, Maria G. Pachiadaki, Virginia P. Edgcomb

BCES: Faculty Publications

Plasmids are mobile genetic elements known to carry secondary metabolic genes that affect the fitness and survival of microbes in the environment. Well-studied cases of plasmidencoded secondary metabolic genes in marine habitats include toxin/antitoxin and antibiotic biosynthesis/resistance genes. Here, we examine metagenome-assembled genomes (MAGs) from the permanently-stratified water column of the Cariaco Basin for integrated plasmids that encode biosynthetic gene clusters of secondary metabolites (smBGCs). We identify 16 plasmid-borne smBGCs in MAGs associated primarily with Planctomycetota and Pseudomonadota that encode terpenesynthesizing genes, and genes for production of ribosomal and non-ribosomal peptides. These identified genes encode for secondary metabolites that are …

Wildfire Effects On The Fate Of Deposited Nitrogen In A Boreal Larch Forest, Weili Liu, Jiaxing Zu, B. Liu, Lin Qi, Wei Huang, Yunting Fang, Jian Yang

Earth and Environmental Sciences Faculty Publications

The effects of nitrogen (N) deposition on forests largely depend on the ecosystem N status and the fates of deposited N. Boreal forests are typically N-limited ecosystems and are considered to be more efficient in retaining deposited N relative to temper- ate and tropical forests. As a primary disturbance in boreal forests, wildfires may alleviate N limitation in the burned ecosystem and increase mineralization, resulting in the altered outcomes of the N deposition.