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- Member of: ASU Electronic Theses and Dissertations
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
Description
Hydrophobic ionizable organic compounds (HIOCs) like per- and polyfluoroalkyl substances (PFAS), certain pharmaceuticals, and surfactants have been detected in groundwater, wastewater, and drinking water. Anion exchange resin treatment is an effective process for removal of anionic contaminants from water. Spent anion exchange resins are conventionally regenerated with high alcohol by volume (ABV) methanol in solution with brine. While effective for regeneration of resins saturated with inorganic anions such as sulfate, nitrate, and perchlorate, HIOCs prove more resistant to regeneration. This research investigated the efficacy of using novel cosolvent solutions with brine to regenerate resins saturated with organic carboxylate and sulfonate anions to understand the effects cosolvent properties have on regenerative ability. Experiments were conducted on six PFAS compounds to evaluate trends in regeneration for three alcohols. For all PFAS species, equivalent ABV and brine solutions showed greatest regeneration with 1-propanol over ethanol and methanol. Experiments with the pharmaceutical sodium diclofenac were conducted showing similar regeneration of 75% methanol and 25% 1-propanol for equivalent salt concentrations and higher regeneration with 1-propanol than ethanol and methanol for equivalent ABV. A series of experiments with surfactant dodecylbenzene sulfonate determined that the key parameters to determine regeneration of the resin for an alcohol cosolvent solution were cosolvent volume fraction, molar mass, Kow value, solution ionic strength, and dielectric constant. Individual assessments on the cost-effectiveness, flammability, and sustainability of cosolvent solutions point to possible future experiments and opportunities for recycled distillery waste streams as regenerative solutions for anion exchange resin.
ContributorsGraham, Cole David (Author) / Boyer, Treavor H (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Garcia Segura, Sergio (Committee member) / Arizona State University (Publisher)
Created2022
Description
Wastewater-based epidemiology (WBE) has emerged as a powerful tool for community health assessment, using wastewater-borne biological and chemical markers as analytical targets. This study investigates the critical influence of sampling frequency on the resultant estimates of opioid consumption and the prevalence of SARS-CoV-2 infections at the neighborhood level using common WBE biomarkers including fentanyl, norfentanyl, and the SARS-CoV-2 N1 gene as targets. The goal was to assess sampling methodologies that include the impact of the day of the week and of the sampling frequency. Wastewater samples were collected two or three times per week over the course of five months (n=525) and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) or reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) for target chemical or molecular indicators of interest. Results showed no statistically significant differences for days of the week (i.e., Tuesday vs. Thursday vs. Saturday) for 24-hour composite samples analyzed for fentanyl or SARS-CoV-2; however, concentrations of the human metabolite of fentanyl, norfentanyl, were statistically different between Tuesday and Saturday (p < 0.05). When data were aggregated either by Tuesday/Thursday or Tuesday/Thursday/Saturday to examine sensitivity to sampling frequency, data were not statistically different except for the Tuesday/Thursday weekly average and Saturday for norfentanyl (p < 0.05). These results highlight how sample collection and data handling methodologies can impact wastewater-derived public health assessments. Care should be taken when selecting an approach to the sampling frequency based on the public health concerns under investigation.
ContributorsAJDINI, ARIANNA (Author) / Halden, Rolf (Thesis advisor) / Driver, Erin (Committee member) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2023
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 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
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
Bisphenol-A or BPA is a common chemical pollutant that contaminates the environment, specifically water systems, due its mass production in human-made plastic
items and subsequent improper disposal. BPA is also an endocrine disruptor that has
negative health impacts on organisms exposed to them, ranging from changes in
reproduction to neural activity. In this study I researched the impact of early exposure to
weak levels of BPA on adult zebrafish (Danio rerio) social behavior. Zebrafish are highly
social creatures that rely on group living for protection and resource attainment in the
wild, meaning any alteration to how they interact with their conspecifics can be
detrimental to their survival. For one-week postfertilization, I exposed baby zebrafish to
either 0.01 mg/l BPA, 0.001 mg/l BPA, 0.1% DMSO, or water. I raised the fish to
adulthood and tested their reaction to a social stimulus. I found that early exposure to low
doses of Bisphenol-A led to an increase in zebrafish activity levels (increased distance
and time spent traveling) and a decrease in preference towards the social stimulus (more
time away from the social stimulus). Increases in activity suggest that the long-term
effects of early BPA exposure may be linked to chronic stress. However, all treatment
and control groups spent most of their time near the social stimulus when they had visual
access to it, implying a natural social drive that was not completely blocked by the
exposure to BPA. This also verifies that visual signals are highly important to social
behavior, since fish given olfactory access alone did not spend as much time in proximity
to the social stimulus. Although even short-term exposure to weak BPA has a lasting
impact on zebrafish social behavior, future studies are needed to confirm that these
persistent effects are related to stress.
ContributorsTufarelli, Alyssa (Author) / Martins, Emilia (Thesis advisor) / Suárez-Rodríguez, Monserrat (Committee member) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2022
Description
Although anion exchange resins (AERs) have been implemented for a wide range of aqueous contaminants including notorious perfluoroalkyl acids (PFAAs) that are of human health concern, the potential benefits and underlying chemistry of weak-base (WB) AERs are overlooked. To fill these key gaps in the literature, this research evaluated the removal and regeneration efficiency of WB-AER (IRA 67 and IRA 96) with strong-base (SB) AER as the baseline. Batch equilibrium tests were first conducted for the removal of nitrate, sulfate, 3-phenylpropionic acid, and six legacy PFAAs with contrasting properties at different solution pH using polyacrylic and polystyrene chloride-form AERs. In ambient (pH 7) and acidic (pH 4) solutions, the polymer composition was the controlling factor followed by the length of alkyl chain of the resin while AER basicity did not influence the selectivity for the selected contaminants. WB resin had higher capacity than SB analogs based on quantitative analysis using isotherm model parameters. Batch and column adsorption experiments showed significantly greater removal of PFAAs by polystyrene than polyacrylic AERs regardless of resin basicity, with the order of decreasing polyacrylic resin selectivity of PFOS >> PFHxS ≈ PFOA > PFBS > PFHxA ≈ PFBA. The removal performance of WB-AER was reversible, declining drastically at basic conditions and gradually regained once below the pKa of the resin due to the pH-dependent nature of amine groups. This was not the case for IRA 96 (i.e., polystyrene) which exhibited high removal of PFAAs irrelevant of pH because of the nonpolar character of polystyrene matrix. The non-hydrophobic IRA 67 (i.e., polyacrylic) had a satisfactory regeneration using non-toxic salt-only solutions comprising 1% NaOH and 0.5% NaOH + 0.5% NaCl, while IRA 96 was only amenable to brine/methanol regeneration. Important caveats on the validity of isotherm modeling in batch adsorption tests were discussed. Results for batch and column experiments using chloride-form and free-base form WB-AER, respectively, provide insights for industrial applications.
ContributorsKassar, Christian (Author) / Boyer, Treavor H. (Thesis advisor) / Westerhoff, Paul K. (Committee member) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2022
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