Environmental Chemistry Commons^™

A Colorimetric Sensor Array For Differentiating Emerging Material Contaminants Based On Surface Chemistry, Ifunanya Chiamaka Ede

All Master's Theses

Emerging materials contaminants, such as microplastics (MPs) and engineered nanoparticles (ENPs), are now recognized to contaminate oceans, seas, freshwater, and drinking water through many different exposure pathways. The extent of the materials' water contamination problem has only begun to be properly appreciated in the last decade. While comprehensive global data on the exact quantity of nano- and microcontaminants in drinking water is challenging to ascertain, studies have shown that microplastics and nanoparticles can now be found in drinking water sources worldwide.  Indeed, a well-publicized recent study has shown that 93% of bottled water around the world contains microplastic contamination.

Detecting …

The Surface Chemistry And Binding Interactions Of Lignin With Polymer-Encapsulated Gold Nanoparticles Acting As Model Microplastics, Oluwaseun Ayodeji Akinsola

All Master's Theses

This study investigates the surface chemistry and molecular-level interactions between lignin, a special type of natural organic matter, and polymer-capped gold nanoparticles, shedding light on the strength of adsorption between lignin and nanoscale polymer surfaces. Specifically, the study presents a variety of nanoscale polymer surfaces displaying different charged functional groups, using layer-by-layer assembly of three polyelectrolytes (polyallylamine hydrochloride (PAH)), polyacrylic acid (PAA), and poly(diallyldimethylammonium chloride (PDADMAC)) on 90 nm citrate-stabilized gold nanoparticles (AuNPs). This approach provides a library of polymer-encapsulated AuNPs for investigating the binding interactions of lignin to nanoscale polymers via spectroscopic techniques. ζ-potential, dynamic light scattering (DLS), …

Effect Of Iron On The Oxidative Capacity Of Carbonaceous Nanoparticles, Daniel Chavez

All Master's Theses

Inhalation of ambient particulate matter (PM_2.5) emitted during combustion of fuels has negative impacts on human health. Triggered in part by the generation of reactive oxygen species (ROS) that lead to oxidative stress, significant gaps exist in the understanding of the detailed chemistry of these detrimental effects. Trace metals and carbonaceous material of the nanometer-sized particles contained in PM_2.5 have been implicated as key players in causing these effects. Here, the role of Fe is investigated with carbonaceous nanoparticles (CNP) while mimicking simple cellular conditions. By adding environmentally representative and controlled concentrations of Fe(II) or Fe(III) to …

Effect Of Carbonaceous Nanoparticles On Naturally Occurring Iron Reduction By Carboxylates, Ashleen Reddy

All Master's Theses

The emission of ambient particulate matter (PM) is regulated by many institutions due to the detrimental effects on health, environment and climate; yet many underlying mechanisms of PM reactivity are still not well understood. In the current study, the effect of carbonaceous nanoparticles (CNPs), contained within ultrafine PM (particle diameter ≤ 100 nm), is investigated on naturally occurring processes that increase the abundance of bioavailable iron. Enhancing iron bioavailability (i) increases primary productivity of iron-limited microorganisms, affecting the carbon cycle and global climate, and (ii) increase toxicity of inhaled particles through the associated production of reactive oxygen species (ROS). Specifically, …

Seasonal Soil Carbon Fluxes In Transitioning Agricultural Soils In Central Washington State: Relations To Land-Use, Environmental Factors And Soil Carbon-Nitrogen Characteristics, Brandon Kautzman

All Master's Theses

Changing agricultural land-use practices to increase soil carbon sequestration contributes to climate change mitigation and improved food security by moving CO₂ from the atmosphere into soil as soil organic carbon (SOC). In 2016, a farm in Thorp, Washington, Spoon Full Farm, began converting land historically farmed using conventional methods of tillage and synthetic fertilizers to conservation farming methods with direct seeding and organic soil amendments with a goal of sequestering carbon in the soil. This project evaluates relationships of soil CO₂ respiration and net ecological exchange (NEE) with land-use types, seasonal environmental factors (air temperature, relative humidity, soil …

Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth

All Master's Theses

Fine atmospheric particulate matter (PM_2.5) emitted during the combustion of fossil and biomass fuels is known to adversely affect human health. While the underlying mechanisms are thought to be driven by the generation of reactive oxygen species (ROS), specific particle characteristics responsible for this detrimental effect are not well understood. In this research, the quantitative determination of the biologically relevant antioxidant, glutathione (GSH), was optimized for use as an indicator of oxidative stress to shed light on relevant particle characteristics. This was accomplished via fluorescent spectroscopy for GSH determination by way of reaction with o-phthalaldehyde (OPA), a …

Bioavailable Iron In Equatorial Pacific Ocean Aerosol Samples, Hsiang T Teng

All Master's Theses

Oceanic iron (Fe) fertilization experiments performed in remote regions have established that Fe additions draw carbon into the ocean, at least over the months-long time frame of the experiments. However, the mechanisms that control Fe speciation in atmospheric aerosol particles before and after deposition into the surface ocean remain largely unknown. This is in part due to the analytical challenge of quantifying Fe at environmentally significant sub-nano molar levels. The flow injection analysis method combined with the luminol chemiluminescence analytical system allows us to explore the near-real time determination of pico-molar levels of both Fe(II) and H₂O_{2 …}

Iron Sources And Dissolved-Particulate Interactions In The Seawater Of The Western Equatorial Pacific, Iron Isotope Perspectives, M. Labatut, F. Lacan, C. Pradoux, J. Chmeleff, A. Radic, J. W. Murray, F. Poitrasson, Anne M. Johansen, F. Thil

All Faculty Scholarship for the College of the Sciences

This work presents iron isotope data in the western equatorial Pacific. Marine aerosols and top core margin sediments display a slightly heavy Fe isotopic composition (δ⁵⁶Fe) of 0.33 ± 0.11‰ (2SD) and 0.14 ± 0.07‰, respectively. Samples reflecting the influence of Papua New Guinea runoff (Sepik River and Rabaul volcano water) are characterized by crustal values. In seawater, Fe is mainly supplied in the particulate form and is found with a δ⁵⁶Fe between −0.49 and 0.34 ± 0.07‰. The particulate Fe seems to be brought mainly by runoff and transported across continental shelves and slopes. …

Global Estimates Of Mineral Dust Aerosol Iron And Aluminum Solubility That Account For Particle Size Using Diffusion-Controlled And Surface-Area-Controlled Approximations, Qin Han, Charles S. Zender, J. Keith Moore, Clifton S. Buck, Ying Chen, Anne Johansen, Christopher I. Measures

All Faculty Scholarship for the College of the Sciences

Mineral aerosol deposition is recognized as the dominant source of iron to the open ocean and the solubility of iron in the dust aerosol is highly variable, with measurements ranging from 0.01–80%. Global models have difficulty capturing the observed variations in solubility, and have ignored the solubility dependence on aerosol size. We introduce two idealized physical models to estimate the size dependence of mineral aerosol solubility: a diffusion‐controlled model and a surface‐area‐controlled model. These models produce differing time‐ and space‐varying solubility maps for aerosol Fe and Al given the dust age at deposition, size‐resolved dust entrainment fields, and the aerosol …

Detection Of Radioactive Isotopes From The Fukushima Daiichi Nuclear Power Plant In The Kittitas Valley Of Washington State, Randle Affholter, Michael Braunstein, Cesar Mendoza, Anne Johansen

Student Published Works

Following the Fukushima Daiichi nuclear power plant disaster in March, 2011, various radioactive isotopes were emitted from the plant [Ewing, 2011]. We hypothesized that emissions would bind to particulate matter, which then could be dispersed by wind currents and deposited across the planet. We analyzed an aerosol sample collected with a high volume cascade impactor in the Kittitas Valley of Washington state. NaI(Tl) gamma spectrometry revealed the presence of the isotopes ¹³²Te and ¹³¹I, consistent with the type of nuclear accident at Fukushima Daiichi.

Cadmium In Kittitas County Soils, Don G. Muller

All Master's Theses

This paper deals with a survey of soil cadmium concentrations in Kittitas County, Washington, using atomic absorption spectrophotometry as the analytical method. The purpose of the survey was to establish, in an area relatively free from cadmium contamination, background levels for a wide variety of soil conditions. The results showed cadmium concentrations ranging from amounts below the detection limit in remote areas to 2.58ppm in cultivated, inhabited areas, with an overall average concentration of 0.12 ppm cadmium

The Effects Of Herbicides On Three Soil Inhabiting Blue Green Algal Species, Lee C. Darlington

All Master's Theses

The object of this study was to examine the effects of varying concentrations of 2, 4-D, Dalapon, and Tordon on the growth of several nitrogen-fixing blue-green algal species obtained from soil samples and grown under culture conditions in the laboratory.