Matching Items (8)
Filtering by
- Genre: Doctoral Dissertation
Description
Radioactive cesium (137Cs), released from nuclear power plants and nuclear accidental releases, is a problem due to difficulties regarding its removal. Efforts have been focused on removing cesium and the remediation of the contaminated environment. Traditional treatment techniques include Prussian blue and nano zero-valent ion (nZVI) and nano-Fe/Cu particles to remove Cs from water; however, they are not efficient at removing Cs when present at low concentrations of about 10 parts-per-billion (ppb), typical of concentrations found in the radioactive contaminated sites.
The objective of this study was to develop an innovative and simple method to remove Cs+ present at low concentrations by engineering a proteoliposome transporter composed of an uptake protein reconstituted into a liposome vesicle. To achieve this, the uptake protein, Kup, from E. coli, was isolated through protein extraction and purification procedures. The new and simple extraction methodology developed in this study was highly efficient and resulted in purified Kup at ~1 mg/mL. A new method was also developed to insert purified Kup protein into the bilayers of liposome vesicles. Finally, removal of CsCl (10 and 100 ppb) was demonstrated by spiking the constructed proteoliposome in lab-fortified water, followed by incubation and ultracentrifugation, and measuring Cs+ with inductively coupled plasma mass spectrometry (ICP-MS).
The ICP-MS results from testing water contaminated with 100 ppb CsCl, revealed that adding 0.1 – 8 mL of Kup proteoliposome resulted in 0.29 – 12.7% Cs removal. Addition of 0.1 – 2 mL of proteoliposome to water contaminated with 10 ppb CsCl resulted in 0.65 – 3.43% Cs removal. These removal efficiencies were greater than the control, liposome with no protein.
A linear relationship was observed between the amount of proteoliposome added to the contaminated water and removal percentage. Consequently, by adding more volumes of proteoliposome, removal can be simply improved. This suggests that with ~ 60-70 mL of proteoliposome, removal of about 90% can be achieved. The novel technique developed herein is a contribution to emerging technologies in the water and wastewater treatment industry.
The objective of this study was to develop an innovative and simple method to remove Cs+ present at low concentrations by engineering a proteoliposome transporter composed of an uptake protein reconstituted into a liposome vesicle. To achieve this, the uptake protein, Kup, from E. coli, was isolated through protein extraction and purification procedures. The new and simple extraction methodology developed in this study was highly efficient and resulted in purified Kup at ~1 mg/mL. A new method was also developed to insert purified Kup protein into the bilayers of liposome vesicles. Finally, removal of CsCl (10 and 100 ppb) was demonstrated by spiking the constructed proteoliposome in lab-fortified water, followed by incubation and ultracentrifugation, and measuring Cs+ with inductively coupled plasma mass spectrometry (ICP-MS).
The ICP-MS results from testing water contaminated with 100 ppb CsCl, revealed that adding 0.1 – 8 mL of Kup proteoliposome resulted in 0.29 – 12.7% Cs removal. Addition of 0.1 – 2 mL of proteoliposome to water contaminated with 10 ppb CsCl resulted in 0.65 – 3.43% Cs removal. These removal efficiencies were greater than the control, liposome with no protein.
A linear relationship was observed between the amount of proteoliposome added to the contaminated water and removal percentage. Consequently, by adding more volumes of proteoliposome, removal can be simply improved. This suggests that with ~ 60-70 mL of proteoliposome, removal of about 90% can be achieved. The novel technique developed herein is a contribution to emerging technologies in the water and wastewater treatment industry.
ContributorsHakim Elahi, Sepideh (Author) / Conroy-Ben, Otakuye (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Fox, Peter (Committee member) / Arizona State University (Publisher)
Created2018
Description
This dissertation critically evaluated methodologies and devices for assessing and protecting the health of human populations, with particular emphasis on groundwater remediation and the use of wastewater-based epidemiology (WBE) to inform population health. A meta-analysis and assessment of laboratory-scale treatability studies for removing chlorinated solvents from groundwater found that sediment microcosms operated as continuous-flow columns are preferable to batch bottles when seeking to emulate with high fidelity the complex conditions prevailing in the subsurface in contaminated aquifers (Chapter 2). Compared to monitoring at the field-scale, use of column microcosms also showed (i) improved chemical speciation, and (ii) qualitative predictability of field parameters (Chapter 3). Monitoring of glucocorticoid hormones in wastewater of a university campus showed (i) elevated stress levels particularly at the start of the semester, (ii) on weekdays relative to weekend days (p = 0.05) (161 ± 42 μg d-1 per person, 122 ± 54 μg d-1 per person; p ≤ 0.05), and (iii) a positive association between levels of stress hormones and nicotine (rs: 0.49) and caffeine (0.63) consumption in this student population (Chapter 4). Also, (i) alcohol consumption determined by WBE was in line with literature estimates for this young sub-population (11.3 ± 7.5 g d-1 per person vs. 10.1 ± 0.8 g d-1 per person), whereas caffeine and nicotine uses were below (114 ± 49 g d-1 per person, 178 ± 19 g d-1 per person; 627 ± 219 g d-1 per person, 927 ± 243 g d-1 per person). The introduction of a novel continuous in situ sampler to WBE brought noted benefits relative to traditional time-integrated sampling, including (i) a higher sample coverage (93% vs. 3%), (ii) an ability to captured short-term analyte pulses (e.g., heroin, fentanyl, norbuprenorphine, and methadone), and (iii) an overall higher mass capture for drugs of abuse like morphine, fentanyl, methamphetamine, amphetamine, and the opioid antagonist metabolite norbuprenorphine (p ≤ 0.01). Methods and devices developed in this work are poised to find applications in the remediation sector and in human health assessments.
ContributorsDriver, Erin Michelle (Author) / Halden, Rolf (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Kavazanjian, Edward (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2018
Description
Traditional public health strategies for assessing human behavior, exposure, and activity are considered resource-exhaustive, time-consuming, and expensive, warranting a need for alternative methods to enhance data acquisition and subsequent interventions. This dissertation critically evaluated the use of wastewater-based epidemiology (WBE) as an inclusive and non-invasive tool for conducting near real-time population health assessments. A rigorous literature review was performed to gauge the current landscape of WBE to monitor for biomarkers indicative of diet, as well as exposure to estrogen-mimicking endocrine disrupting (EED) chemicals via route of ingestion. Wastewater-derived measurements of phytoestrogens from August 2017 through July 2019 (n = 156 samples) in a small sewer catchment revealed seasonal patterns, with highest average per capita consumption rates in January through March of each year (2018: 7.0 ± 2.0 mg d-1; 2019: 8.2 ± 2.3 mg d-1) and statistically significant differences (p = 0.01) between fall and winter (3.4 ± 1.2 vs. 6.1 ± 2.9 mg d-1; p ≤ 0.01) and spring and summer (5.6 ± 2.1 vs. 3.4 ± 1.5 mg d-1; p ≤ 0.01). Additional investigations, including a human gut microbial composition analysis of community wastewater, were performed to support a methodological framework for future implementation of WBE to assess population-level dietary behavior. In response to the COVID-19 global pandemic, a high-frequency, high-resolution sample collection approach with public data sharing was implemented throughout the City of Tempe, Arizona, and analyzed for SARS-CoV-2 (E gene) from April 2020 through March 2021 (n = 1,556 samples). Results indicate early warning capability during the first wave (June 2020) compared to newly reported clinical cases (8.5 ± 2.1 days), later transitioning to a slight lagging indicator in December/January 2020-21 (-2.0 ± 1.4 days). A viral hotspot from within a larger catchment area was detected, prompting targeted interventions to successfully mitigate community spread; reinforcing the importance of sample collection within the sewer infrastructure. I conclude that by working in tandem with traditional approaches, WBE can enlighten a comprehensive understanding of population health, with methods and strategies implemented in this work recommended for future expansion to produce timely, actionable data in support of public health.
ContributorsBowes, Devin Ashley (Author) / Halden, Rolf U (Thesis advisor) / Krajmalnik-Brown, Rosa (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Varsani, Arvind (Committee member) / Whisner, Corrie (Committee member) / Arizona State University (Publisher)
Created2022
Description
This dissertation applies wastewater-based epidemiology (WBE) to aqueous process flows to gauge the public health status concerning exposure and potential abuse of pharmaceuticals, antimicrobials, and narcotics. The masses of emerging contaminants emitted into Indian aquatic and terrestrial environments were the highest for open defecation (17 ± 12 mt/d), with non-steroidal anti-inflammatory drugs dominating environmental loading (14 ± 10 mt/d), followed by antibiotics, antimicrobials, phthalates and miscellaneous pharmaceuticals (Chapter 2). Fourteen wastewater treatment plants sampled across the U.S. had a combined average mass loading of 71 ± 12 µg/d/capita for the antimicrobials triclosan and triclocarban, with paraben compounds contributing 19 ± 5 µg/d/US capita. Risk models showed unfavorable hazard quotients (HQ>1) for sensitive aquatic organisms (algae, zebra fish and rainbow trout) from predicted exposures to antimicrobials of alternative use, i.e., chlorhexidine and benzalkonium chloride (Chapter 3). Substances subject to licit and illicit use, monitored by WBE in a medium-sized southwestern U.S. city before and during COVID-19-related lockdowns, showed the highest mass loads for cocaine and its major metabolite benzoylecgonine (2,207 total), methadone and its major metabolite 2-Ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (197), parent mitragynine (60), oxycodone and its major metabolite noroxycodone (48), heroin and its major metabolite 6-acetylmorphine (45), and parent codeine (37) in mg/1,000 capita/day. Heroin use during the lockdown increased ~10-fold relative to the pre-lockdown baseline, whereas oxycodone and codeine mass loading decreased 5-fold and 2.5-fold, respectively (Chapter 4). Experiments elucidating the stability of stress hormones and their metabolites as a function of temperature and in-sewer residence time revealed a rapid degradation to completion over 24 hours at 35°C, whereas lower temperatures of 25°C and 15°C were found to allow for successful tracking of indicators of stress at the population level; statistically significant differences in stress hormone decay rates were observed due to geographic locations at 25°C (p=0.009) but not due to redox conditions in the sewer pipe (Chapter 5). This thesis demonstrated the successful application of WBE for studying population health frequently and inexpensively, with the limitation that a lack of centralized wastewater infrastructure in developing countries may create barriers for at-risk populations to access and utilize this novel technology (Chapter 6).
ContributorsKelkar, Varun Pushkaraj (Author) / Halden, Rolf U (Thesis advisor) / Hamilton, Kerry A (Committee member) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2021
Description
This dissertation focused on studying risks associated with emerging drinking water contaminants and tradeoffs related to water management interventions. The built environment impacts health, as humans on average spend ~90% of their time indoors. Federal regulations generally focus on drinking water at the water treatment plant and within the distribution system as opposed to when it enters buildings after crossing the property line. If drinking water is not properly managed in buildings, it can be a source or amplifier of microbial and chemical contaminants. Unlike regulations for chemical contaminants that are risk-based, for pathogens, regulations are either based on recommended treatment technologies or designated as zero, which is not achievable in practice. Practice-based judgments are typically made at the building level to maintain water quality. This research focuses on two drinking water opportunistic pathogens of public health concern, Legionella pneumophila and Mycobacterium avium complex (MAC). Multiple aspects of drinking water quality in two green buildings were monitored in tandem with water management interventions. Additionally, a quantitative microbial risk assessment framework was used to predict risk-based critical concentrations of MAC for drinking water-related exposures in the indoor environment corresponding to a 1 in 10,000 annual infection target risk benchmark. The overall goal of this work was to inform the development of water management plans and guidelines for buildings that will improve water quality in the built environment and promote better public health. It was determined that a whole building water softening system with ion exchange softening resin and expansion tanks were unexplored reservoirs for the colonization of L. pneumophila. Furthermore, it was observed that typical water management interventions such as flushing and thermal disinfection did not always mitigate water quality issues. Thus, there was a need to implement several atypical interventions such as equipment replacement to improve the building water quality. This work has contributed comprehensive field studies and models that have highlighted the need for additional niches, facility management challenges, and risk tradeoffs for focus in water safety plans. The work also informs additional risk-based water quality policy approaches for reducing drinking water risks.
ContributorsJoshi, Sayalee (Author) / Hamilton, Kerry A (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Conroy-Ben, Otakuye (Committee member) / Halden, Rolf (Committee member) / Arizona State University (Publisher)
Created2023
Description
This dissertation focuses on the structure-function relationships of nanomaterials (NMs) and some of their applications in environmental engineering. The aim is to investigate NMs of different surface chemistries and assess their interactions with biological models, evaluate the weathering impact and degradation parameters to improve polymer coatings, test their efficiency for contaminant removal and provide further understanding in the safe design of nanomaterials. Nanoecotoxicological risk assessment currently suffers from a lack of testing procedures adapted to nanomaterials. Graphene oxide (GO) is a carbon nanomaterial (CNM) that consists of a single layer of carbon atoms arranged in a hexagonal network. It is decorated with a high density of oxygen functional groups including epoxide and hydroxyl moieties on the basal planes and carboxylic and carbonyl groups at the edges. The changes in surface chemistry give GO unique properties that can be tailored for a function. Additionally, because of its simple synthesis and flexible chemistry, GO has been a popular building block of many composite CNMs. In environmental engineering, specifically, water treatment, GO has been studied by itself or as a composite for pollutant removal, biofouling reduction, and as an antimicrobial agent, just to name a few. Like GO, silver (Ag) is another NM widely used in water treatment for its biocidal properties. Despite the recent growth in this field, a fundamental understanding of the function-structure relationships in NMs is still progressing. Through a systematic set of experiments, the structure-properties-function and structure-properties-hazard relationships were investigated. These relationships can be used to establish guidelines to engineer “safe-by-design” functional nanomaterials, where materials are tailored to enhance their function while minimizing their inherent biological or environmental hazard.
ContributorsBarrios, Ana Cecilia (Author) / Perreault, Francois (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Conroy-Ben, Otakuye (Committee member) / Hua-Wang, Qing (Committee member) / Arizona State University (Publisher)
Created2021
Description
Pathogenic contamination is a significant factor contributing to the degradation of surface water both globally and within the United States. This leads to negative economic impacts, sickness, and, in severe cases, fatalities. As the world's population grows, pollution increases, placing more stress on water resources, particularly in arid regions. The situation is made worse by climate change. The forecasted expansion of arid and semi-arid land areas and alterations in precipitation patterns could have a significant impact on those living in poverty and dry regions. This dissertation aims to investigate previously undocumented threats to water quality through understanding pathogen drivers in arid and semi-arid environments and documenting wastewater infrastructure on Tribal lands. Specifically, I first investigated how ephemeral streams (common in arid and semiarid areas) impact the presence of pathogens in surface waters by identifying the main drivers of E. coli concentration from a series of proposed predictors. Second, I identified unknown potential sources of water quality impairments on Tribal lands, which are mainly rural and in arid or semiarid areas, focusing on wastewater infrastructure in these systems. I specifically quantified populations served by wastewater treatment plants and then used a remote sensing approach to identify possible unpermitted wastewater lagoons that often serve as the only wastewater infrastructure in some areas. The findings revealed unique insights that could help aid water management in arid and semiarid regions as well as in rural areas.
ContributorsMenchu Maldonado, Maria Elena (Author) / Muenich, Rebecca L. (Thesis advisor) / Vivoni, Enrique R. (Committee member) / Conroy-Ben, Otakuye (Committee member) / Hamilton, Kerry (Committee member) / Arizona State University (Publisher)
Created2023
Description
This dissertation encompasses the interaction of antimicrobial chemicals and emerging contaminants with multi-drug resistant (MDR) bacteria and their implications in engineered systems. The aim is to investigate the effect of combination antimicrobials on MDR bacteria E. coli, evaluate the extent of synergism and antagonism of utilizing two distinct biocidal chemicals, and evaluate the influence of endocrine-disrupting chemicals (EDCs) on protein production in response to stressors. Resistance mechanisms of bacteria such as E. coli include the use of protein systems that efflux excess nutrients or toxic compounds. These efflux proteins activate in response to environmental stressors such as contaminants and antimicrobials to varying degrees and are major contributors to antibiotic resistance in pathogenic bacteria. As is the case with engineered microbial environments, large quantities of emerging contaminants interact with bacteria, influencing antibiotic resistance and attenuation of these chemicals to an unknown degree. Interactions of antimicrobials on MDR bacteria such as E. coli have been extensively studied for pathogens, including synergistic combinations. Despite these studies in this field, a fundamental understanding of how chemicals influence antibiotic resistance in biological processes typical of engineered microbial environments is still ongoing. The impacts of EDCs on antibiotic resistance in E. coli were investigated by the characterization of synergism for antimicrobial therapies and the extrapolation of these metrics to the cycling of EDCs in engineered systems to observe the extent of antibiotic resistance proteins to the EDCs. The impact of this work provides insight into the delicate biochemistry and ongoing resistance phenomena regarding engineered systems.
ContributorsNovoa, Diego Erick (Author) / Conroy-Ben, Otakuye (Thesis advisor) / Abbazadegan, Morteza (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2022