Matching Items (83)
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
Despite the safe and effective use of attenuated vaccines for over fifty years, measles virus (MV) remains an insidious threat to global health. Problematically, infants less than one year of age, who are the most prone to severe infection and death by measles, cannot be immunized using current MV vaccines. For this dissertation, I generated and performed preclinical evaluation of two novel MV vaccine candidates. Based on data from clinical trials that showed increasing the dosage of current MV vaccines improved antibody responses in six-month-old recipients, I hypothesized that increasing the relevant antigenic stimulus of a standard titer dose would allow safe and effective immunization at a younger age. I generated two modified MVs with increased expression of the hemagglutinin (H) protein, the most important viral antigen for inducing protective neutralizing immunity, in the background of a current vaccine-equivalent. One virus, MVvac2-H2, expressed higher levels of full-length H, resulting in a three-fold increase in H incorporation into virions, while the second, MVvac2-Hsol, expressed and secreted truncated, soluble H protein to its extracellular environment. The alteration to the virion envelope of MVvac2-H2 conferred upon that virus a measurable resistance to in vitro neutralization. In initial screening in adult mouse models of vaccination, both modified MVs proved more immunogenic than their parental strain in outbred mice, while MVvac2-H2 additionally proved more immunogenic in the gold standard MV-susceptible mouse model. Remarkably, MVvac2-H2 better induced protective immunity in the presence of low levels of artificially introduced passive immunity that mimic the passive maternal immunity that currently limits vaccination of young infants, and that strongly inhibited responses to the current vaccine-equivalent. Finally, I developed a more physiological infant-like mouse model for MV vaccine testing, in which MV-susceptible dams vaccinated with the current vaccine-equivalent transfer passive immunity to their pups. This model will allow additional preclinical evaluation of the performance of MVvac2-H2 in pups of immune dams. Altogether, in this dissertation I identify a promising candidate, MVvac2-H2, for a next generation measles vaccine.
ContributorsJulik, Emily (Author) / Reyes del Valle, Jorge (Thesis advisor) / Chang, Yung (Committee member) / Blattman, Joseph (Committee member) / Hogue, Brenda (Committee member) / Nickerson, Cheryl (Committee member) / Arizona State University (Publisher)
Created2016
Description
The influence of climate variability and reclaimed wastewater on the water supply necessitates improved understanding of the treatability of trace and bulk organic matter. Dissolved organic matter (DOM) mobilized during extreme weather events and in treated wastewater includes natural organic matter (NOM), contaminants of emerging concern (CECs), and microbial extracellular polymeric substances (EPS). The goal of my dissertation was to quantify the impacts of extreme weather events on DOM in surface water and downstream treatment processes, and to improve membrane filtration efficiency and CECs oxidation efficiency during water reclamation with ozone. Surface water quality, air quality and hydrologic flow rate data were used to quantify changes in DOM and turbidity following dust storms, flooding, or runoff from wildfire burn areas in central Arizona. The subsequent impacts to treatment processes and public perception of water quality were also discussed. Findings showed a correlation between dust storm events and change in surface water turbidity (R2=0.6), attenuation of increased DOM through reservoir systems, a 30-40% increase in organic carbon and a 120-600% increase in turbidity following severe flooding, and differing impacts of upland and lowland wildfires. The use of ozone to reduce membrane fouling caused by vesicles (a subcomponent of EPS) and oxidize CECs through increased hydroxyl radical (HO●) production was investigated. An "ozone dose threshold" was observed above which addition of hydrogen peroxide increased HO● production; indicating the presence of ambient promoters in wastewater. Ozonation of CECs in secondary effluent over titanium dioxide or activated carbon did not increase radial production. Vesicles fouled ultrafiltration membranes faster (20 times greater flux decline) than polysaccharides, fatty acids, or NOM. Based upon the estimated carbon distribution of secondary effluent, vesicles could be responsible for 20-60% of fouling during ultrafiltration and may play a vital role in other environmental processes as well. Ozone reduced vesicle-caused membrane fouling that, in conjunction with the presence of ambient promoters, helps to explain why low ozone dosages improve membrane flux during full-scale water reclamation.
ContributorsBarry, Michelle (Author) / Barry, Michelle C (Thesis advisor) / Westerhoff, Paul (Committee member) / Fox, Peter (Committee member) / Halden, Rolf (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2014
Description
Arsenic (As) and chromium (Cr) occur naturally in AZ surface and groundwaters, pose different health impacts, and exhibit different treatment efficacies. Hexavalent chromium (Cr(VI)) has newly recognized human health concerns, and State and Federal agencies are evaluating a low Cr(VI)-specific maximum contaminant level (MCL) for drinking water. Occurrence of Cr and As in municipal drinking waters and industrial cooling tower waters was quantified by grab samples and compared with sampling results obtained from a new passive sampler developed specifically for Cr(VI). Cr(VI) and As concentrations in groundwater used for cooling tower make-up water concentrations were ~3 ppb and ~4 ppb, respectively, and were concentrated significantly in blowdown water (~20 ppb and ~40 ppb). Based upon pending Cr(VI), As, and other metal regulations, these blowdown waters will need routine monitoring and treatment. Cr(VI) concentrations in a water treatment plant (WTP) raw and finished water samples varied from 0.5 and 2 ppb for grab samples collected every 4 hours for 7 consecutive days using an ISCO sampler. The development of an ion exchange (IX) based passive sampler was validated in the field at the WTP and yielded an average exposure within 1 standard deviation of ISCO sampler grab data. Sampling at both the WTP and cooling towers suggested sources of Cr(III) from treatment chemicals or wood preservatives may exist. Since both facilities use chlorine oxidants, I quantified the apparent (pH=5) second-order rate constant for aqueous chlorine (HOCl/OCl-) with Cr(III) to form Cr(VI) as 0.7 M-1s-1. Under typical conditions (2 ppb Cr(III) ; 2 mg/L Cl2) the half-life for the conversion of Cr(III) to the more toxic form Cr(VI) is 4.7 hours. The occurrence studies in AZ and CA show the Cr(VI) and As treatment of groundwaters will be required to meet stringent Cr(VI) regulations. IX technologies, both strong base anion (SBA) and weak base anion (WBA) resin types were screened (and compared) for Cr removal. The SBA IX process for As removal was optimized by utilizing a reactive iron coagulation and filtration (RCF) process to treat spent IX brine, which was then reused to for SBA resin regeneration.
ContributorsBowen, Alexandra (Author) / Paul, Westerhoff K. (Thesis advisor) / Hristovski, Kiril (Committee member) / Halden, Rolf (Committee member) / Arizona State University (Publisher)
Created2014
Description
Six high-production-volume neonicotinoids were traced through a municipal wastewater treatment plant (WWTP) and engineered wetland located downstream, in a study motivated by reports on these insecticides posing threats to non-target invertebrate species and potentially playing a role in the global honeybee colony collapse disorder. An array of automated samplers was deployed in a five-day monitoring campaign and resultant flow-weighted samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) using the isotope dilution method. Concentrations in WWTP influent and effluent were 54.7 ± 2.9 and 48.6 ± 2.7 ng/L for imidacloprid, respectively, and 3.7 ± 0.3 and 1.8 ± 0.1 ng/L for acetamiprid, respectively. A mass balance over the WWTP showed no (p=0.09, CI = 95%) removal of imidacloprid, and 56 ± 6% aqueous removal of acetamiprid. In the constructed wetland downstream, a lack of removal was noted for both imidacloprid (from 54.4 ± 3.4 ng/L to 49.9 ± 14.6 ng/L) and acetamiprid (from 2.00 ± 0.03 ng/L to 2.30 ± 0.21 ng/L). Clothianidin was detected only inconsistently in the WWTP and wetland (>2 to 288 ng/L; 60% detection frequency), whereas thiamethoxam (<10 ng/L), thiacloprid (<2 ng/L), and dinotefuran (<180 ng/L) were not detected at all. Thus, imidacloprid and acetamiprid were identified as recalcitrant sewage constituents (estimated U.S. WWTP discharge of 1920- 4780 kg/y) that persist during conventional wastewater treatment to enter U.S. surface waters at potentially harmful concentrations.
ContributorsSadaria, Akash Mahendra (Author) / Halden, Rolf (Thesis advisor) / Fox, Peter (Committee member) / Popat, Sudeep (Committee member) / Arizona State University (Publisher)
Created2015
Environmental releases of neonicotinoid and fipronil insecticides via U.S. wastewater infrastructure
Description
This dissertation is focused on environmental releases from U.S. wastewater infrastructure of recently introduced, mass-produced insecticides, namely neonicotinoids as well as fipronil and its major degradates (sulfone, sulfide, amide, and desulfinyl derivatives), jointly known as fiproles. Both groups of compounds recently have caught the attention of regulatory agencies worldwide due to their toxic effects on pollinators and on aquatic invertebrates at very low, part-per-trillion levels (Chapter 1). Mass balance studies conducted for 13 U.S. wastewater treatment plants (WWTPs) showed ubiquitous occurrence (3-666 ng/L) and persistence of neonicotinoids (Chapter 2). For the years 2001 through 2016, a longitudinal nationwide study was conducted on the occurrence of fiproles, via analysis of sludge as well as raw and treated wastewater samples. Sludge analysis revealed ubiquitous fiprole occurrence since 2001 (0.2-385 µg/kg dry weight) and a significant increase (2.4±0.3-fold; p<0.005) to elevated levels found both in 2006/7 and 2015/6. This study established a marked persistence of fiproles during both wastewater and sludge treatment, while also identifying non-agricultural uses as a major source of fiprole loading to wastewater (Chapter 3). Eight WWTPs were monitored in Northern California to assess pesticide inputs into San Francisco Bay from wastewater discharge. Per-capita-contaminant-loading calculations identified flea and tick control agents for use on pets as a previously underappreciated source term dominating the mass loading of insecticides to WWTPs in sewage and to the Bay in treated wastewater (Chapter 4). A nationwide assessment of fipronil emissions revealed that pet products, while representing only 22±7% of total fipronil usage (2011-2015), accounted for 86±5% of the mass loading to U.S. surface waters (Chapter 5). In summary, the root cause for considerable annual discharges into U.S. surface waters of the neonicotinoid imidacloprid (3,700-5,500 kg/y) and of fipronil related compounds (1,600-2,400 kg/y) is domestic rather than agricultural insecticide use. Reclaimed effluent from U.S. WWTPs contained insecticide levels that exceed toxicity benchmarks for sensitive aquatic invertebrates in 83% of cases for imidacloprid and in 67% of cases for fipronil. Recommendations are provided on how to limit toxic inputs in the future.
ContributorsSadaria, Akash Mahendra (Author) / Halden, Rolf (Thesis advisor) / Fraser, Matthew (Committee member) / Perreault, Francois (Committee member) / Mascaro, Giuseppe (Committee member) / Arizona State University (Publisher)
Created2017
Description
Many Fic domain proteins, through catalyzing post translational modifications (PTM) of protein substrates, functionally contribute to bacterial pathogenesis and the regulation of bacterial growth. Furthermore, one form of Fic-mediated regulation is the Fic toxin-antitoxin system, whereby an antitoxin interacts with and inhibits the Fic toxin. This study sought to determine the functional importance of Mycobacterium tuberculosis Fic and its putative antitoxin protein, Rv3642c. Using M. tuberculosis H37Rv genetic deletion mutants, fic and Rv3642c were demonstrated to promote intracellular survival in human THP-1 macrophage-like cells. Unlike other Fic toxins, of Fic toxin-antitoxin systems, Fic did not inhibit bacterial growth in vitro in the absence of Rv3642c. Notably, Fic demonstrated in vitro AMPylation of a THP-1 cell extract protein as shown by immunodetection. Fic also exhibited auto-AMPylation activity. Interestingly, a mutation of the conserved histidine in the Fic domain motif, a residue previously shown to be critical for AMPylation, had no effect on Fic-mediated ATP hydrolysis or AMPylation activity. Rv3642c was demonstrated to form a complex with Fic when co-expressed in Escherichia coli, indicating a toxin-antitoxin interaction. Screening M. tuberculosis protein fractions and culture filtrate with α-Fic and α-Rv3642c rabbit antisera did not detect monomers of Fic or Rv3642c, thus the cellular localization of Fic and the Rv3642c-Fic complex remains unclear. The results of this study provide insight into the function of M. tuberculosis Fic, and suggest that Fic and Rv3642c are important for M. tuberculosis survival in the intracellular macrophage environment. Furthermore, these findings challenge the current dogma that Fic domain catalysis is dependent on the conserved histidine of the Fic motif.
ContributorsLaMarca, Ryan (Author) / Haydel, Shelley (Thesis advisor) / Lake, Douglas (Committee member) / Nickerson, Cheryl (Committee member) / Arizona State University (Publisher)
Created2017
Description
Uncertainty is inherent in predictive decision-making, both with respect to forecasting plausible future conditions based on a historic record, and with respect to backcasting likely upstream states from downstream observations. In the first chapter, I evaluated the status of current water resources management policy in the United States (U.S.) with respect to its integration of projective uncertainty into state-level flooding, drought, supply and demand, and climate guidance. I found uncertainty largely absent and discussed only qualitatively rather than quantitatively. In the second chapter, I turned to uncertainty in the interpretation of downstream observations as indicators of upstream behaviors in the field of Wastewater-Based Epidemiology (WBE), which has made possible the near real-time, yet anonymous, monitoring of public health via measurements of biomarkers excreted to wastewater. I found globally, seasonality of air and soil temperature causes biomarker degradation to vary up to 13-fold over the course of a year, constituting part of the background processes WBE must address, or detrend, prior to decision-making. To determine whether the seasonal change in degradation rates was introducing previously unaccounted for uncertainty with respect to differences in observed summertime and winter-time populations, I evaluated demographic indicators recorded by the Census Bureau for correlation with their distance from all major wastewater treatment plants across the U.S. The analysis identified statistically significant correlation for household income, education attainment, unemployment, military service, and the absence of health insurance. Finally, the model was applied to a city-wide case study to test whether temperature could explain some of the trends observed in monthly observations of two opiate compounds. Modeling suggests some of the monthly changes were attributed to natural temperature fluctuation rather than to trends in the substances’ consumption, and that uncertainty regarding discharge location can dominate even relative observed differences in opiate detections. In summary, my work has found temperature an important modulator of WBE results, influencing both the type of populations observed and the likelihood of upstream behaviors disproportionally magnified or obscured, particularly for the more labile biomarkers. There exists significant potential for improving the understanding of empirical observations via numerical modeling and the application of spatial analysis tools.
ContributorsHart, Olga (Author) / Halden, Rolf (Thesis advisor) / Mascaro, Giuseppe (Committee member) / Renaut, Rosemary (Committee member) / Nelson, Keith (Committee member) / Arizona State University (Publisher)
Created2019
Description
Understanding how microorganisms adapt and respond to the microgravity environment of spaceflight is important for the function and integrity of onboard life support systems, astronaut health and mission success. Microbial contamination of spacecraft Environmental Life Support Systems (ECLSS), including the potable water system, are well documented and have caused major disruption to spaceflight missions. The potable water system on the International Space Station (ISS) uses recycled wastewater purified by multiple processes so it is safe for astronaut consumption and personal hygiene. However, despite stringent antimicrobial treatments, multiple bacterial species and biofilms have been recovered from this potable water system. This finding raises concern for crew health risks, vehicle operations and ECLSS system integrity during exploration missions. These concerns are further heightened given that 1) potential pathogens have been isolated from the ISS potable water system, 2) the immune response of astronauts is blunted during spaceflight, 3) spaceflight induces unexpected alterations in microbial responses, including growth and biofilm formation, antimicrobial resistance, stress responses, and virulence, and 4) different microbial phenotypes are often observed between reductionistic pure cultures as compared to more complex multispecies co-cultures, the latter of which are more representative of natural environmental conditions. To advance the understanding of the impact of microgravity on microbial responses that could negatively impact spacecraft ECLSS systems and crew health, this study characterized a range of phenotypic profiles in both pure and co-cultures of bacterial isolates collected from the ISS potable water system between 2009 and 2014. Microbial responses profiled included population dynamics, resistance to silver, biofilm formation, and in vitro colonization of intestinal epithelial cells. Growth characteristics and antibiotic sensitivities for bacterial strains were evaluated to develop selective and/or differential media that allow for isolation of a pure culture from co-cultures, which was critical for the success of this study. Bacterial co-culture experiments were performed using dynamic Rotating Wall Vessel (RWV) bioreactors under spaceflight analogue (Low Shear Modeled Microgravity/LSMMG) and control conditions. These experiments indicated changes in fluid shear have minimal impact on strain recovery. The antimicrobial efficacy of silver on both sessile co-cultures, grown on 316L stainless steel coupons, and planktonic co-cultures showed that silver did not uniformly reduce the recovery of all strains; however, it had a stronger antimicrobial effect on biofilm cultures than planktonic cultures. The impact of silver on the ability of RWV cultured planktonic and biofilm bacterial co-cultures to colonize human intestinal epithelial cells showed that, those strains which were impacted by silver treatment, often increased adherence to the monolayer. Results from these studies provide insight into the dynamics of polymicrobial community interactions, biofilm formation and survival mechanisms of ISS potable water isolates, with potential application for future design of ECLSS systems for sustainable human space exploration.
ContributorsKing, Olivia G (Author) / Nickerson, Cheryl (Thesis advisor) / Barrila, Jennifer (Committee member) / Ott, C (Committee member) / Yang, Jiseon (Committee member) / Arizona State University (Publisher)
Created2019
Description
Plastic pollution has become a global threat to ecosystems worldwide, with microplastics now representing contaminants reported to occur in ambient air, fresh water, seawater, soils, fauna and people. Over time, larger macro-plastics are subject to weathering and fragmentation, resulting in smaller particles, termed ‘microplastics’ (measuring < 5 mm in diameter), which have been found to pollute virtually every marine and terrestrial ecosystem on the planet. This thesis explored the transfer of plastic pollutants from consumer products into the built water environment and ultimately into global aquatic and terrestrial ecosystems.
A literature review demonstrated that municipal sewage sludge produced by wastewater treatment plants around the world contains detectable quantities of microplastics. Application of sewage sludge on land was shown to represent a mechanism for transfer of microplastics from wastewater into terrestrial environments, with some countries reporting as high as 113 ± 57 microplastic particles per gram of dry sludge.
To address the notable shortcoming of inconsistent reporting practices for microplastic pollution, this thesis introduced a novel, online calculator that converts the number of plastic particles into the unambiguous metric of mass, thereby making global studies on microplastic pollution directly comparable.
This thesis concludes with an investigation of a previously unexplored and more personal source of plastic pollution, namely the disposal of single-use contact lenses and an assessment of the magnitude of this emerging source of environmental pollution. Using an online survey aimed at quantifying trends with the disposal of lenses in the US, it was discovered that 20 ± 0.8% of contact lens wearers flushed their used lenses down the drain, amounting to 44,000 ± 1,700 kg y-1 of lens dry mass discharged into US wastewater.
From the results it is concluded that conventional and medical microplastics represent a significant global source of pollution and a long-term threat to ecosystems around the world. Recommendations are provided on how to limit the entry of medical microplastics into the built water environment to limit damage to ecosystems worldwide.
A literature review demonstrated that municipal sewage sludge produced by wastewater treatment plants around the world contains detectable quantities of microplastics. Application of sewage sludge on land was shown to represent a mechanism for transfer of microplastics from wastewater into terrestrial environments, with some countries reporting as high as 113 ± 57 microplastic particles per gram of dry sludge.
To address the notable shortcoming of inconsistent reporting practices for microplastic pollution, this thesis introduced a novel, online calculator that converts the number of plastic particles into the unambiguous metric of mass, thereby making global studies on microplastic pollution directly comparable.
This thesis concludes with an investigation of a previously unexplored and more personal source of plastic pollution, namely the disposal of single-use contact lenses and an assessment of the magnitude of this emerging source of environmental pollution. Using an online survey aimed at quantifying trends with the disposal of lenses in the US, it was discovered that 20 ± 0.8% of contact lens wearers flushed their used lenses down the drain, amounting to 44,000 ± 1,700 kg y-1 of lens dry mass discharged into US wastewater.
From the results it is concluded that conventional and medical microplastics represent a significant global source of pollution and a long-term threat to ecosystems around the world. Recommendations are provided on how to limit the entry of medical microplastics into the built water environment to limit damage to ecosystems worldwide.
ContributorsRolsky, Charles (Author) / Halden, Rolf (Thesis advisor) / Green, Matthew (Committee member) / Neuer, Susanne (Committee member) / Polidoro, Beth (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)
Created2020