Open Access. Powered by Scholars. Published by Universities.®

Environmental Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

Environmental Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 301 - 330 of 482

Full-Text Articles in Environmental Chemistry

The Level Of Polyaromatic Hydrocarbon Contamination On The Kalamazoo River Shoreline Remains High Following The 2010 Enbridge Oil Spill, Wisam Abdulabbas Flayyih Al Isawi Apr 2016

The Level Of Polyaromatic Hydrocarbon Contamination On The Kalamazoo River Shoreline Remains High Following The 2010 Enbridge Oil Spill, Wisam Abdulabbas Flayyih Al Isawi

Research and Creative Activities Poster Day

  • One of the nation’s worst inland oil spills occurred near Marshall in Michigan in 2010.
  • The recent Enbridge Line 6B rupture released over three million liters of diluted bitumen crude oil into the environment.
  • The spilled oil entered the Talmadge Creek and flowed into the Kalamazoo River, a Lake Michigan tributary.
  • Polycyclic Aromatic Hydrocarbons (PAHs) together with other pollutants were released into the environment.
  • PAHs represents significant threats to aquatic organisms due to their carcinogenic and mutagenic properties and their persistence in the environment.
  • Five years following the oil spill accident, the levels and identities of PAHs were investigated in …


Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, Ruixin Zhou, Marcelo I. Guzman Apr 2016

Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The reductive tricarboxylic acid (rTCA) cycle is an important central biosynthetic pathway that fixes CO2 into carboxylic acids. Among the five reductive steps in the rTCA cycle, the two-electron reduction of fumarate to succinate proceeds nonenzymatically on the surface of photoexcited sphalerite (ZnS) colloids suspended in water. This model reaction is chosen to systematically study the surface photoprocess occurring on ZnS in the presence of [Na2S] (1–10 mM) hole scavenger at 15 °C. Experiments at variable pH (5–10) indicate that monodissociated fumaric acid is the primary electron acceptor forming the monoprotic form of succinic acid. The following …


One Year Later: The Politics And Stories Of Post-Earthquake Nepal, Boyer Andrew Apr 2016

One Year Later: The Politics And Stories Of Post-Earthquake Nepal, Boyer Andrew

Independent Study Project (ISP) Collection

A 7.8 magnitude earthquake struck Nepal on April 25th, 2015. This was followed by a second major earthquake of magnitude 7.3 on May 12th , 2015. These disasters took the lives of thousands of Nepali people, destroyed hundreds of thousands of structures, and displaced an estimated two million people. Immediately following the disaster, there was an outpouring of humanitarian aid from around the world. This lead to a conference where $4.1 billion USD of reconstruction funds were pledged to Nepal by international donors. Five months later, a new constitution passed into law and an informal blockade of …


Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown Mar 2016

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …


Methane Emissions As Energy Reservoir: Context, Scope, Causes And Mitigation Strategies, Xiaoli Chai, David J. Tonjes, Devinder Mahajan Jan 2016

Methane Emissions As Energy Reservoir: Context, Scope, Causes And Mitigation Strategies, Xiaoli Chai, David J. Tonjes, Devinder Mahajan

Technology & Society Faculty Publications

Methane (CH4) is now considered a bridge fuel between present fossil (carbon) economy and desired renewables and this energy molecule is projected to play an important role in the global energy mix well beyond 2035. The atmospheric warming potential of CH4 is 28-36 times, when averaged over a 100-year period, that of carbon dioxide (CO2) and this necessitates a close scrutiny of global CH4 emissions inventory. As the second most abundant greenhouse gas (GHG), the annual global CH4 emissions were 645 million metric tons (MMT), accounting for 14.3% of the global anthropogenic GHG emissions. Of this, five key anthropogenic sources: …


An Ecotoxicological Survey Of Tributaries Of The Selenge River, Mongolia, August 2010, Viktor T. Komov, Ch. Javzan, William G. Brumbaugh Jan 2016

An Ecotoxicological Survey Of Tributaries Of The Selenge River, Mongolia, August 2010, Viktor T. Komov, Ch. Javzan, William G. Brumbaugh

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The biodiversity of the Selenga river basin and the receiving waters of the lake Baikal, are among the greatest in the world with over 1,700 known endemic species of plants and animals. Mining activities along the Selenga river and its tributaries pose a major threat of chemical contamination, potentially reducing habitat quality and suitability for aquatic species. Moreover, the Selenga river serves as a major water source for the lake Baikal. Little information exists on the chemical contaminant concentrations in the Selenga river basin. Thus, the objectives of our study were to evaluate the concentrations of metals in soil, sediment, …


The Role Of Microbial Exopolymers In Determining The Fate Of Oil And Chemical Dispersants In The Ocean, Antonietta Quigg, Uta Passow, Wei-Chun Chin, Chen Xu, Shawn Doyle, Laura Bretherton, Manoj Kamalanathan, Alicia K. Williams, Jason B. Sylvan, Zoe V. Finkel, Anthony H. Knap, Kathleen A. Schwehr, Saijin Zhang, Luni Sun, Terry L. Wade, Wassim Obeid, Patrick G. Hatcher, Peter H. Santschi Jan 2016

The Role Of Microbial Exopolymers In Determining The Fate Of Oil And Chemical Dispersants In The Ocean, Antonietta Quigg, Uta Passow, Wei-Chun Chin, Chen Xu, Shawn Doyle, Laura Bretherton, Manoj Kamalanathan, Alicia K. Williams, Jason B. Sylvan, Zoe V. Finkel, Anthony H. Knap, Kathleen A. Schwehr, Saijin Zhang, Luni Sun, Terry L. Wade, Wassim Obeid, Patrick G. Hatcher, Peter H. Santschi

Chemistry & Biochemistry Faculty Publications

The production of extracellular polymeric substances (EPS) by planktonic microbes can influence the fate of oil and chemical dispersants in the ocean through emulsification, degradation, dispersion, aggregation, and/or sedimentation. In turn, microbial community structure and function, including the production and character of EPS, is influenced by the concentration and chemical composition of oil and chemical dispersants. For example, the production of marine oil snow and its sedimentation and flocculent accumulation to the seafloor were observed on an expansive scale after the Deepwater Horizon oil spill in the Northern Gulf of Mexico in 2010, but little is known about the underlying …


Adsorption Of Antibiotics By Vermiculite, Mosa J. Ferdous Jan 2016

Adsorption Of Antibiotics By Vermiculite, Mosa J. Ferdous

Dissertations and Theses

The occurrence of residual antibiotics in the environment has been a worldwide issue and warrants the development of inexpensive yet effective methods for antibiotics removal from contaminated water. In this thesis work, the adsorption of four antibiotics, namely chlorotetracycline (CTC), oxytetracycline (OTC), ofloxacin (OFL), and enrofloxacin (ENR), onto natural vermiculite has been studied using batch (static) and column (dynamic) adsorption techniques. The Langmuir and Freundlich isotherm models were initially used to explain the adsorption processes. The separation factor (RL) values derived from the Langmuir model and the 1/n values derived from Freundlich model in the present investigation were less than …


Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan Jan 2016

Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan

Doctoral Dissertations

"As the rapid growing of nanotechnology, the release of engineered nanoparticles (ENPs) into the environment is inevitable. After entering the real environment, ENPs tend to react with different components of the ecosystem (e.g. water, soil, air, plants) and make their characterization difficult. Analyzing ENPs in these complex matrices still remains as a grand challenge. ENPs characterization is normally the first step of risk assessment. Current analytical techniques have shown some limitations in revealing the unique characteristics of ENPs in complex matrices and reliable analytical techniques are in urgent need. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an emerging …


Systematic Postsynthetic Modification Of Nanoporous Organic Frameworks And Their Performance Evaluation For Selective Co2 Capture, Timur Islamoglu Jan 2016

Systematic Postsynthetic Modification Of Nanoporous Organic Frameworks And Their Performance Evaluation For Selective Co2 Capture, Timur Islamoglu

Theses and Dissertations

Porous organic polymers (POPs) with high physicochemical stability have attracted significant attention from the scientific community as promising platforms for small gas separation adsorbents. Although POPs have amorphous morphology in general, with the help of organic chemistry toolbox, ultrahigh surface area materials can be synthesized. In particular, nitrogen-rich POPs have been studied intensively due to their enhanced framework-CO2 interactions. Postsynthetic modification (PSM) of POPs has been instrumental for incorporating different functional groups into the pores of POPs which would increase the CO2 capture properties. We have shown that functionalizing the surface of POPs with nitro and amine groups …


Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq Jan 2016

Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq

Theses and Dissertations (Comprehensive)

Numerous studies have been conducted on the removal of inorganic phosphorus (P) from wastewater, but a push towards lower effluent targets necessitates the additional removal of organic phosphorus as well. This study tested the ability of manganese oxide nanoparticles and iron oxide as potential catalysts for conversion of organic P into more readily removable inorganic forms, as well as the role of iron(III) chloride as coagulant to subsequently allow P to be removed by solids/liquid separation. Removals of 99-101% were obtained for model compounds at pH 5-7, 0.05-0.5 M H2O2, and Fe:P molar ratio of 5:1. …


Photooxidation Reactions Of Small-Chain Methyl Esters, Aerosol Photoelectron Spectroscopy, And The Photodissociation Of Ethylenediamine, Giel Muller Dec 2015

Photooxidation Reactions Of Small-Chain Methyl Esters, Aerosol Photoelectron Spectroscopy, And The Photodissociation Of Ethylenediamine, Giel Muller

Master's Theses

Research conducted at the University of San Francisco is presented within this masters thesis, including the Cl-initiated photooxidation reactions of methyl propanoate, methyl butanoate, and methyl valerate (pentanoate), the aerosol photoelectron spectroscopy of isoprene and gamma-valerolactone, and the TPEPICO investigation of ethylenediamine. Experiments were conducted at the Lawrence Berkeley National Lab Advanced Light Source (ALS), the National Synchrotron Radiation Research Center in Hsinchu City (NSRRC), and the University of Stockton in California, respectively.


Evaluation Of Veterinary Pharmaceuticals And Iodine For Use As A Groundwater Tracer In Hydrologic Investigation Of Contamination Related To Dairy Cattle Operations, Larry Boot Pierce, Honglin Shi Oct 2015

Evaluation Of Veterinary Pharmaceuticals And Iodine For Use As A Groundwater Tracer In Hydrologic Investigation Of Contamination Related To Dairy Cattle Operations, Larry Boot Pierce, Honglin Shi

Sinkhole Conference 2015

Standard groundwater tracers such as Rhodamine WT, Fluorescein, Eosin and Tinopal CBX effectively provide a snapshot of hydrological conditions over a brief period of time and in a tightly controlled setting. However, in complex environmental situations with multiple potential sources, groundwater hydrologists are often seeking groundwater tracers that have extended longevity in the natural environment and the ability to directly pinpoint source locations. After reviewing operations of the nearby dairy it was determined that emerging contaminants, specifically two bovine veterinary pharmaceuticals (antibiotics), cephapirin sodium (CEPNa) and cephapirin benzathine (CEPB), and a sanitation agent, elemental Iodine (I) may have potential as …


Using Nitrate, Chloride, Sodium, And Sulfate To Calculate Groundwater Age, Kimm Crawford, Terry Lee Oct 2015

Using Nitrate, Chloride, Sodium, And Sulfate To Calculate Groundwater Age, Kimm Crawford, Terry Lee

Sinkhole Conference 2015

Regression analysis is used to identify monotonic trends to assign water age using ion data from two large well water databases from southeast Minnesota (SE MN). Nitrate (NO3-N), chloride (Cl), sodium (Na), and sulfate (SO4) ions in the commonly used aquifers in SE MN can be used as groundwater tracers since they are either entirely or partly anthropogenic in their sources, their loading occurs on a regional scale, and they are almost entirely conserved. Ion concentrations over time are used to establish six trend patterns. Two patterns are unchanging (background and stable above background), and four are changing (linear up, …


Influence Of Ph And Bulk Density On Carbon Dioxide Efflux In Three Urban Wetland Types, Christopher Chappell, Andra Johnson Sep 2015

Influence Of Ph And Bulk Density On Carbon Dioxide Efflux In Three Urban Wetland Types, Christopher Chappell, Andra Johnson

Professional Agricultural Workers Journal

Abstract

The aim of this study was to understand soil carbon dioxide (CO2) efflux of three different urban wetlands and how pH and bulk density relate to soil CO2 efflux of each wetland. The three wetlands were bottomland, upland, and shrub/scrub. The study was conducted over a twenty week period using the Li-Cor 8100 “closed chamber” method to measure soil CO2 efflux. The findings show that the bottomland wetland efflux was significantly higher than the shrub/scrub and upland wetland. The pH of shrub/scrub was significantly higher than the upland. The bulk density of the bottomland was …


Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman Sep 2015

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O3(g) by catechol γO3 = (7.49 ± 0.35) × 10–6 occurs for …


Evaluating Sub-Lethal Effects Of Orchard-Applied Pyrethroids Using Video-Tracking Software To Quantify Honey Bee Behaviors, Erin M. Ingram, Julie Augustin, Marion D. Ellis, Blair Siegfried Sep 2015

Evaluating Sub-Lethal Effects Of Orchard-Applied Pyrethroids Using Video-Tracking Software To Quantify Honey Bee Behaviors, Erin M. Ingram, Julie Augustin, Marion D. Ellis, Blair Siegfried

Department of Entomology: Faculty Publications

Managed honey bee, Apis mellifera L., colonies are contracted to pollinate fruit and nut orchards improving crop quality and yield. Colonies placed in orchards are potentially exposed to pyrethroid insecticides used for broad-spectrum pest control. Pyrethroids have been reported to pose minimal risk to bees due to their low application rates in the field and putative repellent properties. This repellency is believed to alter foraging behavior with the benefit of preventing bees from encountering a lethal dose in the field. However, sub-lethal exposure to pyrethroids may adversely impact bee behavior potentially resulting in social dysfunction or disruption of foraging.

This …


Synthesis Of Palladium And Palladium-Copper Nanostructures As Electrocatalysts, Haibin Wu Jul 2015

Synthesis Of Palladium And Palladium-Copper Nanostructures As Electrocatalysts, Haibin Wu

Graduate Theses and Dissertations

Pd and its alloys are alternatives of Pt as promising catalysts and electrocatalysts for many reactions. Size controlled synthesis of nanoparticles remains a major research subject, since smaller size particles show better catalytic performance. In this work, we developed a modified chemical wet method to prepare Pd and Pd-Cu nanostructures with uniform small size. Different sizes and shapes of Pd nanostructures were successfully synthesized by using the two reducing agents (i.e., L-ascorbyl-6-palmitate or phenylphosphinic acid). The reducing agents play a role to control the final morphologies and sizes of particles. The use of L-ascorbyl-6-palmitate favors to form irregular branch shapes …


Nutrient Addition Effects On Tropical Dry Forests: A Mini-Review From Microbial To Ecosystem Scales, Jennifer S. Powers, Kristen K. Becklund, Maria G. Gei, Siddharth B. Iyengar, Rebecca Meyer, Christine S. O'Connell, Erik M. Schilling, Christina M. Smith, Bonnie G. Waring, Leland K. Werden Jun 2015

Nutrient Addition Effects On Tropical Dry Forests: A Mini-Review From Microbial To Ecosystem Scales, Jennifer S. Powers, Kristen K. Becklund, Maria G. Gei, Siddharth B. Iyengar, Rebecca Meyer, Christine S. O'Connell, Erik M. Schilling, Christina M. Smith, Bonnie G. Waring, Leland K. Werden

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here, we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales …


Evaluation Of The Feasibility Of Struvite Precipitation From Domestic Wastewater As An Alternative Phosphorus Fertilizer Resource, Amanda R. Bird May 2015

Evaluation Of The Feasibility Of Struvite Precipitation From Domestic Wastewater As An Alternative Phosphorus Fertilizer Resource, Amanda R. Bird

Master's Projects and Capstones

Finite phosphate rock ore reserves are estimated to be exhausted in 100 to 150 years. Phosphate rock ore is the single global source material for phosphorus fertilizer production. Once these reserves are gone, agricultural production will be negatively impacted. There are currently no alternative phosphorus resources. However, phosphorus concentrations present in human excrement traveling through domestic wastewater treatment facilities is being disposed of directly to the environment, often resulting in pollution problems. Recovering phosphorus from wastewater with struvite precipitation systems at wastewater treatment plants can alleviate future phosphorus scarcities. Evaluation of phosphorus recovery through struvite precipitation at wastewater treatment plants …


Blue Carbon In Freshwater / Brackish Marshes On The Barrier Islands Of Virginia Aboveground Net Primary Productivity And Carbon Pools, Emily Caitlin Adams Apr 2015

Blue Carbon In Freshwater / Brackish Marshes On The Barrier Islands Of Virginia Aboveground Net Primary Productivity And Carbon Pools, Emily Caitlin Adams

Biological Sciences Theses & Dissertations

"Blue carbon" is a relatively new concept describing carbon distributed tidally and sequestered via net production within coastal ecosystems, including seagrass beds, mangrove forests, and salt-water marshes. These systems sequester carbon at least 10 times faster than terrestrial systems. Fresh to brackish wetlands that receive irregular tidal influence due to overwash and storm events have not been typically studied as blue carbon systems. My objective was to quantify carbon pools within four interdunal fresh to brackish marshes on Hog Island, Virginia to determine their blue carbon potential. Marshes 1 and 2 were farthest from the ocean, below and above a …


Blue Carbon In Coastal Freshwater/Brackish Marshes On The Barrier Islands Of Virginia: Belowground Carbon Dynamics, Nathan M. Sedghi Apr 2015

Blue Carbon In Coastal Freshwater/Brackish Marshes On The Barrier Islands Of Virginia: Belowground Carbon Dynamics, Nathan M. Sedghi

Biological Sciences Theses & Dissertations

Some coastal ecosystems sequester substantially more carbon (blue carbon) than land locked systems due to high net primary production and deposition associated with oceanic influences. Most blue carbon research has focused on mangroves, seagrass beds, and salt marshes. Studies on blue carbon potential of coastal freshwater marshes are less common. Barrier islands frequently flood, with seawater reaching interior ecosystems. I examined brackish/freshwater marshes on Virginia barrier islands for possible roles as blue carbon systems. I studied four interior marshes on Hog Island, which varied in proximity to a direct overwash path and protection by a trail berm that divides northern …


Comparing Three Methods For Estimating Ozone Depleting Substance Substitute Greenhouse Gases: Case Study Of The New York City Region, Wallace A. Murray Iii Jan 2015

Comparing Three Methods For Estimating Ozone Depleting Substance Substitute Greenhouse Gases: Case Study Of The New York City Region, Wallace A. Murray Iii

Theses and Dissertations

This thesis evaluates the United States Environmental Protection Agency (EPA) method for estimating emissions from one source, Ozone Depleting Substances Substitutes (ODS substitutes) by comparing results for the New York City Metropolitan Statistical Area (NYC-MSA) with results from two other methodologies. The EPA’s method utilizes population data and GDP data to estimate and geographically allocate emissions, with little regard for the geographies of industrial activity. The two alternative methods use data for industrial employment and activity to provide results for comparison and perhaps a more accurate accounting and allocation of emissions throughout the NYC-MSA.


Pyrolysis-Gc-Ms For The Rapid Environmental Forensic Screening Of Contaminated Brownfield Soil, Azucena Lara-Gonzalo, Michael A. Kruge, I Lores, B Gutiérrez, José Luis Gallego Jan 2015

Pyrolysis-Gc-Ms For The Rapid Environmental Forensic Screening Of Contaminated Brownfield Soil, Azucena Lara-Gonzalo, Michael A. Kruge, I Lores, B Gutiérrez, José Luis Gallego

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

An abandoned chemical plant in Asturias (Spain) was studied using a multi-faceted molecular fingerprinting approach, demonstrating that it is possible to: (1) carefully unravel tangled evidence resulting from multiple pollution sources, and (2) recognize major contaminants largely ignored by conventional analyses. This methodology employed a battery of GC-MS analyses of liquid chromatographic fractions of soil extracts, plus the pyrolysis products of the soil extract's asphaltene fraction and the whole soil itself. In this example, coal tar distillation and the subsequent production of naphthalene, phenols and polymer resins are responsible for most of the soil contamination. Styrene, naphthalene, indene, and their …


Analytical Pyrolysis Principles And Applications To Environmental Science, Michael A. Kruge Jan 2015

Analytical Pyrolysis Principles And Applications To Environmental Science, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Over the past half century, analytical pyrolysis has proven itself to be an effective means for the semiquantitative characterization of complex macromolecular organic substances. It has been demonstrated that instruments such as Py-FID, Py-MS, and in particular, Py-GC/MS can provide valuable geochemical insights when applied to a wide variety of problems in environmental science. The more widespread use of analytical pyrolysis methods in the evaluation of environmental pollution is recommended, because of their relatively low cost and information-rich results.

Pyrolysis is the heating of organic substances in an inert, oxygen-free atmosphere, thereby avoiding combustion. When performed on a large scale, …


Magnetic Mineral Diagenesis In The River‐Dominated Inner Shelf Of The East China Sea, China, Can Ge, Weiguo Zhang, Chenyin Dong, Yan Dong, Jinyan Liu, Nguyen Thi Thu Hien, Huan Feng, Lizhong Yu Jan 2015

Magnetic Mineral Diagenesis In The River‐Dominated Inner Shelf Of The East China Sea, China, Can Ge, Weiguo Zhang, Chenyin Dong, Yan Dong, Jinyan Liu, Nguyen Thi Thu Hien, Huan Feng, Lizhong Yu

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The inner shelf of the East China Sea is a river-dominated margin characterized by fine-grained mud deposits and a rapid sedimentation rate. Three short sediment cores (similar to 2.7m in length) were examined to characterize spatial variations in magnetic mineral diagenesis. The sediment cores were analyzed for sedimentation rates, magnetic properties, particle size distribution, organic carbon, and total sulfur content. The two more proximal cores with higher sedimentation rates (similar to 2.2cm/yr and similar to 0.96cm/yr) do not exhibit obvious effects of reductive dissolution of magnetite with increasing depth, which is consistent with their lower total sulfur content. The offshore …


Derivatization And Separation Of Natural Estrogens (Estrone, 17Β-Estradiol, And Estriol) Using Gas Chromatography With Flame Ionization Detection (Gc-Fid), Dena L. Guptill Jan 2015

Derivatization And Separation Of Natural Estrogens (Estrone, 17Β-Estradiol, And Estriol) Using Gas Chromatography With Flame Ionization Detection (Gc-Fid), Dena L. Guptill

Masters Theses

A major cause of concern for estrogens found in the environment is that even at very low concentrations (10-100 ng/L) they can have a negative effect on aquatic ecosystems by disrupting endocrine systems. Due to the increasing importance of monitoring the levels of estrogens in the environment, a detection method was developed to identify and quantify three natural estrogens (estrone, 17β-estradiol and estriol) using gas chromatography with flame ionization detection (GC-FID). In addition, the efficacy of two derivatizing agents, N,O-bis(trimethylsilyl) acetamide (BSTA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), was evaluated. The GC detector (FID) was most responsive with E3, followed by E1 and …


Investigation Of Natural Perchlorate Levels In Antarctic Snow In Relation To The Ozone Hole, Thomas Crawford, Alexandria Kub, Han Vid Cho Jan 2015

Investigation Of Natural Perchlorate Levels In Antarctic Snow In Relation To The Ozone Hole, Thomas Crawford, Alexandria Kub, Han Vid Cho

The Journal of Undergraduate Research

Snow samples collected from the West Antarctic Ice Sheet Divide in January 2013 were analyzed for perchlorate concentrations to determine a possible seasonal variation. These samples were dated for the years 2007 through 2012 using annual variations in sulfate concentration as determined by an ion chromatography (IC) method. Perchlorate concentrations in the samples were measured with an IC instrument paired with tandem mass spectrometry detection. The concentration data show that perchlorate reached an annual maximum concentration in the austral autumn seasons, assuming that snowfall was relatively constant throughout the course of each year. Comparison with published total column ozone density …


Selective Solid Phase Extraction Of Uranium Using An Aminophosphonic Acid Functionalized Composite Material, Ranalda Tsosie Jan 2015

Selective Solid Phase Extraction Of Uranium Using An Aminophosphonic Acid Functionalized Composite Material, Ranalda Tsosie

Graduate Student Theses, Dissertations, & Professional Papers

Uranium is an element of interest because it is an abundant source of concentrated energy. In 1948 the US offered money for uranium ore mined in the US, which created a mining boom in the southwest that included the Navajo Reservation. During the late 1960s the demand for uranium decreased and many mining operations shutdown and left behind a legacy of contamination. As a result many Navajo communities have numerous water sources that exceed established maximum contamination levels for uranium and other toxic metals. These contaminations are a direct result of abandoned Cold War uranium mines and mill waste sites …


Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman Nov 2014

Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air–water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon …