Matching Items (13)

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Adult Zebrafish (Danio rerio) Exposure to Bisphenol-A (BPA) Impairs Behavioral Lateralization

Description

Cerebral lateralization describes the asymmetries between the two halves of the brain which results in side-specialized processing of certain functions. This phenomenon provides a selective advantage by promoting enhanced cognitive abilities. However, due to the plastic nature of lateralization, an

Cerebral lateralization describes the asymmetries between the two halves of the brain which results in side-specialized processing of certain functions. This phenomenon provides a selective advantage by promoting enhanced cognitive abilities. However, due to the plastic nature of lateralization, an individual’s lateralization is highly subject to change by many external factors, such as pollution, throughout its life. Additionally, lateralized regions are dependent on different contexts, so lateralized elements do not all experience the same effects. A common pollutant found worldwide is bisphenol-A (BPA), a critical component of many plastics. BPA is a known endocrine disruptor that can agonize and antagonize the functions of sex steroids. Other studies have demonstrated the importance of sex steroids in regulating the development of cerebral lateralization; BPA may similarly affect lateralization. A popular research animal for studying toxicology is the zebrafish. Its advantages include a fully sequenced genome, many human orthologs, and more importantly, expresses lateralized behaviors that are indicative of the strength of its cerebral lateralization. This experiment analyzed the effects of BPA exposure on visual lateralization of zebrafish. Given the role that sex steroids play in moderating lateralization, it was hypothesized that exposing zebrafish to BPA would diminish the strength of lateralization in the brain which would translate into reduced behavioral lateralization. To test this, one group was exposed to 0.01 mg/L BPA for one week and compared against a control group in their eye preference when approaching a visual cue. Two settings, a foraging context and a social context, were utilized to examine the scope of impairment in lateralization. The control group in both settings displayed similar strengths in behavioral lateralization with a left eye preference. However, the lateralized response faded completely with BPA treatment. This experiment demonstrates that BPA induces loss of lateralization and possesses similar impacts on mechanisms controlling investigatory behavior in these two contexts. Wild populations may encounter higher concentrations of BPA, and although there is greater variability in these exposures, this experiment proves that exposure even beyond critical periods of development can impair lateralization. Additional research will have to be conducted to identify the effects of BPA on other lateralized behaviors and sensory modalities to pinpoint the exact mechanisms through which BPA influences lateralization.

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2020-05

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Inactivation of bacteria and viruses in water using ultraviolet light and advanced oxidation processes in a bench-scale and two pilot-scale systems

Description

Adenoviruses cause gastrointestinal illnesses and have been listed on the U.S. EPA’s Contaminant Candidate Lists (CCL). They are highly resistant to ultraviolet (UV) inactivation. Advanced oxidation processes (AOPs) are known to improve inactivation of microorganisms and simultaneously oxidize organics. The

Adenoviruses cause gastrointestinal illnesses and have been listed on the U.S. EPA’s Contaminant Candidate Lists (CCL). They are highly resistant to ultraviolet (UV) inactivation. Advanced oxidation processes (AOPs) are known to improve inactivation of microorganisms and simultaneously oxidize organics. The bacteriophage P22 was selected as a surrogate for adenoviruses due to their physical and genetic similarities.

The main objective of this study was to compare the synergic disinfection potential of titanium dioxide (TiO2) or peracetic acid (PAA) with UV for viruses and bacteria in water.

Both bench-scale and pilot-scale evaluation was done. A bench-scale collimated beam was included to evaluate the inactivation of P22 and E. coli by UV with and without TiO2 or PAA. A Purifics Photo-Cat system which is an integrated UV/ceramic membrane reactor was used for the pilot-scale TiO2-UV AOP experiments. For pilot-scale PAA-UV AOP experiments, an in-line D222 UV reactor unit provided by NeoTech Aqua Solutions, Inc. was used.

TiO2 doses of 1, 10, and 40 mg/L were applied in the collimated beam and the Photo-Cat system. Higher TiO2 doses resulted in a higher inactivation in the Photo-Cat and lower inactivation in the collimated beam apparatus. Adding 40 mg/L of TiO2 in the photo-Cat system improved P22 inactivation by 25% while it slightly decreased P22 inactivation in collimated beam apparatus.

PAA doses of 0.25 or 0.5 ppm were continuously injected upstream of the UV light and a 53% or 90% increase in inactivation was observed for E. coli, respectively, as compared to UV alone. However, P22 required higher dose with PAA-UV AOP and PAA concentrations of 1 or 10 ppm resulted in an 18% and 70% increase in the inactivation respectively, as compared to UV alone. Interestingly, when the same condition was applied to water with more organics (UVT 79%), E. coli exhibited the same level of susceptibility to PAA-UV AOP while P22 inactivation decreased.

The results provide new insight on the effectiveness and applicability of adding AOP to UV for microbial inactivation in water. PAA-UV AOP can potentially enhance existing UV disinfection systems with minimal chemical addition, and a simple retrofit to existing UV units.

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Date Created
2017

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Methods and devices for evaluating environmental remediation progress and population health

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

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.

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Date Created
2018

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Engineering a proteoliposome transporter to capture radioactive cesium from water

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

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.

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Date Created
2018

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Use of granular activated carbon and carbon block filters at municipal and point of use drinking water treatment for removal of organics

Description

Activated Carbon has been used for decades to remove organics from water at large scale in municipal water treatment as well as at small scale in Point of Use (POU) and Point of Entry (POE) water treatment. This study focused

Activated Carbon has been used for decades to remove organics from water at large scale in municipal water treatment as well as at small scale in Point of Use (POU) and Point of Entry (POE) water treatment. This study focused on Granular Activated Carbon (GAC) and also activated Carbon Block (CB) were studied.

This thesis has three related elements for organics control in drinking water. First, coagulation chemistry for Alum and Aluminum Chlorohydrate (ACH) was optimized for significant organics removal to address membrane fouling issue at a local municipal water treatment plant in Arizona. Second, Rapid Small Scale Column Tests were conducted for removal of Perfluorinated compounds (PFC), PFC were present in groundwater at a local site in Arizona at trace levels with combined concentration of Perfluorooctaneoic Acid (PFOA) and Perfloorooctanesulfonic Acid (PFOS) up to 245 ng/L. Groundwater from the concerned site is used as drinking water source by a private utility. PFC Removal was evaluated for different GAC, influent concentrations and particle sizes. Third, a new testing protocol (Mini Carbon Block (MCB)) for bench scale study of POU water treatment device, specifically carbon block filter was developed and evaluated. The new bench scale decreased the hydraulic requirements by 60 times approximately, which increases the feasibility to test POU at a lab scale. It was evaluated for a common POU organic contaminant: Chloroform, and other model contaminants.

10 mg/L of ACH and 30 mg/L of Alum with pH adjustment were determined as optimal coagulant doses. Bituminous coal based GAC was almost three times better than coconut shell based GAC for removing PFC. Multiple tests with MCB suggested no short circuiting and consistent performance for methylene blue though chloroform removal tests underestimated full scale carbon block performance but all these tests creates a good theoretical and practical fundament for this new approach and provides directions for future researchers.

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2017

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Structure-Function Relationships of Nanomaterials and Their Applications For the Development of Sustainable Environmental Engineering

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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

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.

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Date Created
2021

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Low Levels of Bisphenol-A Decrease Metabolic Rate and Boldness in Zebrafish, Danio rerio

Description

Human impact alters the natural environment via multiple pathways, including contamination from pollutants. This human activity may adversely impact an organism’s ability to respond to environmental change. Using Bisphenol-A (BPA), a common environmental contaminant, I examined how exposure affected behavioral

Human impact alters the natural environment via multiple pathways, including contamination from pollutants. This human activity may adversely impact an organism’s ability to respond to environmental change. Using Bisphenol-A (BPA), a common environmental contaminant, I examined how exposure affected behavioral strategies critical for survival in a changing environment. BPA is used during plastic manufacturing, and it enters aquatic systems from wastewater streams; however, it is an endocrine-disruptor that has broad health effects from metabolism to behavior at a wide exposure range. In this study, I specifically tested whether environmentally relevant concentrations of BPA impact maximum metabolic rate and boldness in zebrafish, Danio rerio. I also examined activity level, optomotor response, body mass, and standard length to see if I can mechanistically explain any underlying changes caused by BPA. I treated groups of adult zebrafish for 7 days and exposed them to either 0.1% dimethyl sulfoxide (DMSO, control), a low environmentally relevant concentration of BPA (0.02 mg/L), or a 1-fold higher BPA concentration (0.2 mg/L). I found that the low exposure group experienced a decrease in maximum metabolic rate and the high exposure group showed a decrease in boldness. In other words, these changes in metabolism were not dosage dependent while the boldness results were dosage dependent. BPA had no effects on optomotor response, body mass, standard length or activity level. These results suggest that no level of BPA is safe, environmentally relevant concentrations are having an effect on adult organisms’ behavior and health that could affect their survival.

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2021

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Monitoring Contaminants of Emerging Concern in Global Wastewater Using Sewage Epidemiology

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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

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).

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Date Created
2021

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Novel Applications of Wastewater-based Epidemiology for Assessing Population Nutrition, Infectious Disease, and Chronic Illness

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)

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.

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Date Created
2022

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Early Exposure to Low Concentrations of Bisphenol-A can Decrease Zebrafish Social Behavior

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

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.

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Date Created
2022