Maryland Institute for Applied Environmental Health Theses and Dissertations

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    (2023) Morgado, Michele Ewing; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The number of outbreaks and sporadic illnesses associated with non-cholera Vibrio spp. contaminated seafood and coastal water sources have been increasingly reported across the United States and many other nations, and may continue to rise as a result of ocean warming, adversely impacting public health. However, there are limited data concerning the trends in virulence and antibiotic resistance of these bacterial pathogens outside of Southern U.S. waters, including critical estuarine systems such as the Chesapeake Bay. Moreover, there are few studies that have evaluated longitudinal trends in Vibrio illness (vibriosis) among water users (recreational and commercial) and shellfish consumers in more northern states such as Maryland. To address these knowledge gaps my dissertation research involved 1) a retrospective longitudinal molecular analysis, as well as antimicrobial susceptibility testing, to evaluate changes in V. vulnificus and V. parahaemolyticus antibiotic resistance patterns and virulence factors; and 2) an epidemiological study using publicly-available data to evaluate vibriosis trends. My specific aims were as follows: 1) To evaluate changes in virulence factors among V. vulnificus and V. parahaemolyticus isolates recovered from the Chesapeake Bay between 2009-2022; 2) To evaluate changes to antibiotic susceptibility among V. vulnificus and V. parahaemolyticus isolates recovered from the Chesapeake Bay between 2009-2022; and 3) To evaluate long-term trends in the incidence of severe vibriosis among water users (recreational and commercial) and shellfish consumers in Maryland between 2006-2019. Overall, my results indicate that potentially pathogenic V. vulnificus and V. parahaemolyticus occur across the Chesapeake Bay throughout every season, including at frequencies that may still lead to an increased risk of infection in the fall and possibly early winter. Moreover, the mid and lower sections of the Bay, which include many commercial and recreationally important areas, may harbor a greater risk of severe vibriosis from wound-associated water exposures, given the greater presence of V. vulnificus isolates characterized by clinically-relevant virulence factors. Interestingly, I also found that antibiotic resistance patterns among V. vulnificus and V. parahaemolyticus isolates collected from Tangier Sound in the lower Chesapeake Bay have remained relatively stable since 2009. Notwithstanding, recovered Vibrio spp. isolates exhibited varying levels of resistance and intermediate-resistance to antibiotics used to treat severe vibriosis, underscoring the need for prompt diagnosis and treatment with effective first line antibiotic agents. Finally, my epidemiological analysis revealed that long-term increases in Vibrio infections, notably V. vulnificus wound infections, are occurring in Maryland. This trend, along with increased rates in hospitalizations and average hospital durations, underscore the need to improve public awareness, water monitoring, post-harvest seafood interventions, and environmental forecasting, particularly as our climate warms and creates environmental conditions that support the growth of estuarine vibrios.
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    (2023) Snyder, Jessica A; Payne-Sturges, Devon; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    0ABSTRACT Title of thesis: EXAMINATION OF THE ASSOCIATIONS BETWEEN SELECTED PERFLUOROALKYL SUBSTANCES AND THEIR ISOMERS WITH BODY WEIGHT IN ADOLESCENTS USING NHANES 2013-2018 Jessica Snyder, Master of Science, 2023 Thesis Directed by: Professor Devon Payne-Sturges Maryland Institute for Applied Environmental Health Perfluoroalkyl substances (PFAS), a class of environmentally persistent chemicals, are suspected of having obesogenic properties, with studies thus far being inconclusive. Few past studies of PFAS toxicity have distinguished between isomer types of each PFAS group during analysis, however. In this thesis, data for non-smoking 14-19 year-olds from three cycles of the National Health and Nutrition Examination Survey was analyzed to identify potential associations in adolescents between bodyweight and two major families of PFAS: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and to additionally determine if differentiating between linear and branched isomeric groups of two major PFAS families could better elucidate any associations found. In unadjusted models, weighted linear regression of body mass index (BMI) and serum concentrations of branched, linear, and total PFAS isomer groups, all returned positive associations ranging from β (95% confidence interval) of 4.06 (3.44, 4.68) for total PFOS to 12.33 (10.39,14.28) for linear PFOA. When models were adjusted for sex, age, race/ethnic origin and income level, however, only a negative association between BMI and branched PFOS (bPFOS) was found, with β= -1.24 (-2.10, -0.39). Unadjusted weighted logistic regression models of both overweight and obese status resulted in positive associations between obesity and both branched PFOS and total PFOS with odds ratios (95% confidence intervals) of 0.45 (0.27, 0.74) and 0.86 (0.75, 0.99) respectively. After adjusting for potential confounders, the only statistically significant relationship was between branched bPFOS and obesity, with a 56% decrease in the odds of obesity for every unit increase in serum concentration of bPFOS [β =-1.06, adjusted odds ratio= 0.44 (0.26,0.76)]. There was no significant difference between the sexes in any results. The apparent protective effect that bPFOS has against obesity and elevated BMI, notable as a health outcome association in itself, also illustrates that isomeric differentiation is important in studying PFAS, as nPFOS had no statistically significant 1 association by itself while ΣPFOS, used by many studies, did. Thus, the lack of differentiation could mask which PFAS type contributes to any associations discovered.
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    (2023) Smith, Cameron Nicole; Rosenberg Goldstein, Rachel; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Even with the establishment of the Safe Drinking Water Act in 1974, private wells are still not regulated or monitored for drinking water quality or the presence of contaminants such as total coliform bacteria and Escherichia coli. The presence of microbiological contaminants in private wells poses a public health risk. With Agricultural Agents from the University of Maryland Extension, we collected 67 water samples from Maryland farms with private wells located in seven regions and 19 counties of Maryland. We evaluated water samples for total coliforms and E. coli to understand the risk of contamination for Maryland private well owners. We also analyzed the impact of well factors, location, and climate on the presence of total coliforms and E. coli in well water by analyzing participant survey responses and climate data. Our results found that 39% (26/67) of the well water samples were positive for total coliforms and 10% (7/67) were positive for E. coli. Region (p<0.01), county (p=0.03), previously testing for pH (p<0.01), and ambient temperature (p=0.05) were significant factors impacting total coliform concentration. Region (p<0.01) and precipitation in the last 24 hours of collection (p<0.01) were the only significant factors impacting E. coli concentration. These findings emphasize the importance of well water testing for private well owners.
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    Examining Consumer Product Use And Phthalate Exposure Among Vulnerable Populations
    (2023) Boyle, Meleah; Quirós-Alcalá, Lesliam; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    One in 13 Americans have asthma, and higher rates have been reported among women and Black children.1 In addition, hairdressers who are exposed to chemicals through products used on themselves and their clients frequently report respiratory symptoms and conditions.2–10 Limited studies indicate that chemicals in personal care and consumer products (PCP) may impact respiratory health.11–14 The goal of this dissertation is to describe PCP use and exposures to recognized and suspected respiratory irritants (phthalates) among vulnerable populations who may experience disparate exposures. The aims are to: 1) characterize PCP use among 110 children with asthma, 2) examine associations between PCP use and asthma morbidity among 110 children with asthma, and 3) characterize concentrations and exposure determinants to phthalate metabolites in post-shift urine samples among 23 female hairdressers and 17 female office workers. In aim 1, participants were majority Black (87%), males (56%), and aged 8-11 years (66%). Adolescents (12-17 years) and females reported more frequent use of hair, face, and body products compared to children (8-11 years) and males. Participants used chemical treatments on their hair as young as 4 years and females 11-16 years used feminine wipes, spray, and regular deodorant in the genital area. For aim 2, use of aerosol products, hair products, and nail polish were positively associated with maximal symptom days [number of aerosol products (aOR: 1.36; CI: 1.17, 1.59), hairspray (aOR: 1.63; CI: 1.14, 2.33), perfume (aOR: 1.40; CI: 1.11,1.77); shampoo (aOR: 1.34; CI: 1.05,1.73), hair sheen (aOR: 1.41; CI: 1.00, 2.00), nail polish (aOR: 2.42; CI: 1.72, 3.41)] among children with asthma. For Aim 3, the geometric mean (GM) for monoethyl phthalate (MEP) was 10 times higher among hairdressers (161.4 ng/mL) than office workers (15.3 ng/mL). Hairdressers who provided chemical services had higher GM MEP concentrations than those who did not: texturizing (200.2 vs. 115.4 ng/mL), relaxing (181.6 vs. 92.1 ng/mL), bleaching (182.3 vs. 71.6 ng/mL), hair color (171.9 vs. 83.2 ng/mL), and Brazilian blowout (181.4 vs. 134.6 ng/mL). Hairdressers who provided natural services had lower GM MEP concentrations than those who did not: twists (129.1 vs. 215.8 ng/mL), sister locs/locs (86.0 vs. 241.9 ng/mL), and afros (94.7 vs. 203.9 ng/mL). While larger studies are needed, this dissertation provides new data on PCP use and phthalate exposure among Black children and hairdressers.
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    (2022) Chattopadhyay, Suhana; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    To evaluate the adverse health effects associated with tobacco smoking, the majority of studies have largely focused on the impact of chemical constituents in tobacco products and less on the impact of microbial contaminants within these products. Similarly, the United States (U.S.) Food and Drug Administration’s (FDA) Family Smoking Prevention and Tobacco Control Act (FSPTCA) requires tobacco manufacturers and importers to test and report on chemical constituents included on their list of harmful and potentially harmful constituents (HPHCs) in tobacco products and tobacco smoke; however, this HPHC list excludes microorganisms. Nevertheless, over the past decade, an increasing number of studies have explored the bacterial microbiome of tobacco products (e.g., cigarettes, little cigars, cigarillos, hookah and smokeless tobacco) and mainstream smoke. These studies have yielded robust data on bacterial diversity and bacterial community composition within individual tobacco product types. However, to date, there are no comparative characterizations of the bacterial microbiome across diverse tobacco products. In particular, there have been no studies that have characterized the metabolically-active (live) bacterial communities across these products; bacterial communities that might be transferred to the user’s oral cavity and cause subsequent adverse health effects. Furthermore, from an oral health perspective, while smoking/using tobacco products causes significant oral dysbiosis (bacterial community disturbances), there is a lack of data on the potential transfer of bacteria from tobacco products to user’s oral cavities or transient temporal changes in the oral microbiome that might result from smoking these tobacco products. Moreover, there are limited data comparing oral microbiome differences between cigarette smokers and smokeless tobacco users. To address these knowledge gaps, my dissertation research involved a comparative analysis of the bacterial microbiome of commercially-available tobacco products and anevaluation of the impacts of tobacco use on the oral microbiome of users. My specific aims were: 1) To evaluate the compositional differences in the bacterial microbiome between conventional tobacco products; 2) To evaluate transient changes in the oral microbiome of cigarette smokers after a single use of a little cigar; and 3) To conduct a comparative characterization of the oral microbiome between cigarette users, smokeless tobacco users, and non-users over time. Overall, I found that each type of conventional tobacco product harbored a significantly different bacterial community, with mentholation and/or flavoring being a significant driver of bacterial community changes. However, across all products the majority of the metabolically-active bacterial community was identified as Pseudomonas, along with members of the phylum Firmicutes, as well as a few pathogenic species previously associated with animal/human respiratory diseases. In analyzing the oral microbiome of cigarette smokers, I found that a singleuse of a little cigar product did not cause transient changes in the oral microbiome. In analyzing longer temporal effects of smoking on the oral microbiome, I found that, even though total bacterial diversity and composition did not change over time, multiple bacterial taxa were significantly different, with regard to their relative abundance, after four months. In addition, I found that dysbiosis of the oral microbiome was dependent on the type of tobacco product used (cigarettes or smokeless tobacco), and that tobacco smokers/users’ oral microbiomes harbored a more diverse set of bacterial species when compared to that of non-users. In summary, this work provides a comparative analysis of the total and metabolically-active bacterial microbiome of tobacco products, as well as rich findings regarding the relationship between tobacco use and oral microbiome dysbiosis. These data address major research priorities of the FDA relating to furthering our understanding of the adverse health risksassociated with tobacco smoking. Specifically, my data will add to the current body of knowledge regarding the potential role of tobacco bacterial communities in the development of smoking-related diseases. My data also can be leveraged by tobacco regulatory bodies to make future evidence-based policy changes that help reduce risks associated with microorganisms in tobacco products and protect public health.
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    (2022) Mansfield, Tavis; Turner, Paul; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    In Ethiopia, the potential to be infected with malaria may increase this decade due to the expected increases in available breeding habitats created by the filling of the Grand Ethiopian Renaissance Dam (GERD) and its reservoir as well as internal displacement and forced migration of tens of thousands of people due to the flooding of local communities by the filling of the GERD’s reservoir and ongoing civil conflict in the Tigray Region of northern Ethiopia. A One Health framework was used in this research along with refugee migration and resettlement information and, risk evaluation tools to assess the potential health effects of the construction and filling of the GERD and its reservoir in Western Ethiopia on the burden of malaria and the human population living in the same area. This thesis shows Anopheles mosquitoes that are the primary vector of malaria are present in Western Ethiopia and present an entomological surveillance tool that can be implemented in the region. The author also considers the human population movement and illustrate the current vulnerabilities of the various groups involved.
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    (2022) Ezeugoh, Rosemary Ifeoma; Payne-Sturges, Devon; Puett, Robin; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    BackgroundExisting research has investigated the relationships between sociodemographic characteristics and air toxic exposure in the United States. However, a few studies have examined the neurological risk from exposure to air toxics. The purpose of the study was to determine the correlation between sociodemographic variables and neurological risk due to exposure to air toxics. Also, spatial meth-ods were used to understand the distribution of neurological risk and sociodemographic character-istics. Methods Air toxic neurological risk data were obtained from the United States Environmental Protection Agency's National-scale Air Toxics Assessment and sociodemographic data from the 2010-2014 American Community Survey US Census Bureau. The NATA dataset contains 24 neurotoxic air pollutants. The hazard quotient (HQ) for each air pollutant was quantified by calculating the ratio of the inhalation exposure concentration (EC) to the reference concentration (RfC). In addition, the EPA additively models the neurological risks of different pollutants (HQ) to estimate an aggregate neurological risk score (hazard index (HI)) for each census tract. We conducted statistical analysis using R and spatial analysis using ArcGIS 10. Results The mean cumulative neurological risk (HI) from all sources was 0.05, and all HI<1 for all tracts in Minnesota. The range of values for HI is 1 to >1, with >1 being the greatest harm. Percent pov-erty, percent without high school education and percent non-Hispanic white were weakly negative-ly correlated with cumulative neurological risk. In comparison, median household income, percent unemployed, percent non-Hispanic black, percent Hispanic and percent people of color were weak-ly positively correlated with cumulative neurological risk. The choropleth map of cumulative neuro-logical risk showed that individuals in Minneapolis-St. Paul may be disproportionately exposed to air toxics. Conclusions These findings suggest that there may be an unequal distribution of neurotoxic air pollutants, espe-cially in Minneapolis-St. Paul. Study results may inform and target public health efforts at specific locations to eliminate sociodemographic inequalities in exposure to neurotoxic air pollutants.
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    Unmasking risk variability in a changing climate: acute effects from exposure to outdoor heat and air pollution among patients with end-stage renal disease
    (2021) Remigio, Richard V; Sapkota, Amir; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    End-stage renal disease (ESRD) is a chronic condition that disproportionately affects communities of color and diabetics. Hallmark burdens include the lack of essential renal functions and routine life-saving dialysis treatments to filter and remove toxic wastes from the body. Given their compromised survival advantage, the ESRD population is vulnerable to adverse complications associated with acute environmental exposures. However, little is known about the effect of extreme heat events (EHE), air pollution, and ambient temperature on this targeted population. This dissertation focused on ESRD patients receiving hemodialysis treatments at Fresenius Medical Care facilities within the Northeastern United States region (n=60,717). Using longitudinal study design methods, we investigated the association between acute environmental exposures and the risk of all-cause mortality (ACM) and all-cause hospital admissions (ACHA).We applied case-crossover methods to estimate acute EHE effects on mortality and hospital admissions stratified by latitude, race/ethnicity, and comorbidities. Overall, risks varied, but same-day ACM and ACHA risks were most pronounced. ESRD patients with cardiovascular disease (rate ratio [RR], 2.14; 95% CI:1.91-2.40) and cerebrovascular disease (RR, 1.47; 95% CI:1.26-1.71) had notably increased risks of same-day EHE-related mortality. We furthered our investigation by studying PM2.5 and O3 effects using a similar study design but considered the role of EHE as a modifier and incorporated distributed lag nonlinear modeling to account for cumulative lag structures. Pooled same-day EHE-adjusted models estimated an 8% ACM rate increase when O3 concentrations exceeded air quality standards during warmer months. Our data suggest that EHE can act as a modifier between O3 and ACM. Though, no effect modification by EHE was observed for acute air pollutant exposures and ACHA. Lastly, this dissertation explored the mediating role of selected thermoregulatory responses to increased temperature on ACM or ACHA outcomes using traditional mediation analyses. Systolic blood pressure before dialysis treatment (preSBP) and interdialytic weight gain change (IDWG) were identified as significant pathways. However, we observed inconsistent mediation in the IDWG pathway for ACM (-6.26%) and ACHA (-2.67%). Concomitant physiological changes in preSBP and IDWG may have little intermediary effect in combined pathway models. Overall, this research provided additional lines of evidence for enhancing patient response protocols and early warning systems to improve healthcare delivery in an era of a changing climate specific to subpopulations living with ESRD.
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    (2019) Malayil, Leena; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Bacteria are ubiquitous in irrigation water resources and can include pathogens that may compromise food safety and public health. However, only a small fraction of total bacterial community members in water can be identified through standard culture-based laboratory methods. 16S rRNA and shotgun sequencing techniques have improved the identification of non-culturable bacteria in water resources. Nevertheless, because sequencing approaches are nucleic-acid based, they are unable to differentiate between the proportion of bacterial communities identified that are live and metabolically-active versus those that are represented by free, relic DNA, not present in viable cells. To bridge this knowledge gap, my dissertation research coupled DNA-labeling (using 5-bromo-2’- deoxyuridine (BrdU) and propidium monazide (PMA)) with next-generation sequencing approaches to identify and comprehensively characterize metabolically-active bacteria in multiple nontraditional irrigation water sources in the Mid-Atlantic region. My aims were as follows: 1) To characterize the metabolically-active fraction of bacterial communities, as well as antibiotic resistance genes and virulence gene profiles in nontraditional irrigation water sources; 2) To evaluate culture-dependent and -independent methods in the detection of metabolically-active pathogenic and non-pathogenic Vibrio species in four nontraditional irrigational water sources; and 3) To track metabolically-active bacterial communities from rooftop-harvested rainwater to irrigated produce in Maryland. Overall, we identified diverse metabolically-active bacterial communities in all nontraditional water sources. Notably, we observed the presence of viable bacteria of importance to both human and/or animal health (Actinobacterium spp., Flavobacterium spp., Aeromonas spp. Pseudomonas spp. and Vibrio spp.). Interestingly, diverse antimicrobial resistance and virulence genes were predominantly found in non-BrdU-treated samples, indicating that these genes can persist in relic DNA and could be transferred to other environmental bacteria through transformation events. We also source-tracked viable bacteria, including Sphingomonas spp., Enterobacter spp., Enterococcus spp, and Citrobacter spp. from rooftop-harvested irrigation water to produce. In summary, this work provides the first description of total, viable, and metabolically-active bacterial communities in different nontraditional irrigation water sources. These data can be used to improve risk characterization of these water sources, and ultimately inform the selection of appropriate cost-effective remediation methods to treat these waters prior to irrigation activities in order to prevent foodborne outbreaks.
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    (2019) Craddock, Hillary Anne; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Greywater is increasingly reused for agricultural irrigation in the Middle East. However, there is a dearth of data regarding antibiotics, herbicides, and antibiotic-resistant bacteria in household greywater reuse systems. Additionally, there are minimal data assessing consumer perceptions of water reuse practices. To address these gaps, my dissertation aims were to: 1) evaluate the presence of antibiotics and herbicides in greywater and treated effluent; 2) assess the prevalence of antibiotic-resistant Enterobacteriaceae in greywater and treated effluent; and 3) explore consumer perceptions of water reuse practices in Israel and the West Bank. For Aims 1 and 2, household greywater (n=23), treated effluent (n=23) and pond water (n=12) were collected from four farms in the West Bank from October 2017 to June 2018. The presence of antibiotics and herbicides was quantified using high performance liquid chromatography-tandem mass spectrometry, E. coli were enumerated via membrane filtration, and isolates were tested for antimicrobial susceptibility using microbroth dilution. For Aim 3, surveys (n=236) were administered in Eilat, Israel and Bethlehem, West Bank. Statistical analysis included ANOVA, chi-squared, and Fisher’s exact tests. Multiple antibiotics and herbicides were detected in greywater influent. Removal during treatment was variable across compounds. The majority of influent (76.5%) and effluent (70.6%) samples had detectable levels of E. coli. Resistance was most commonly observed against ampicillin, trimethoprim-sulfamethoxazole, tetracycline, and cefazolin. Regarding consumer perceptions, >50% of Israeli respondents were willing to serve raw and cooked produce irrigated with reused water. Palestinian respondents were more willing to engage in high-contact uses than Israeli respondents. The successful completion of this research has advanced knowledge regarding 1) the persistence of chemical and microbiological contaminants in treated household greywater that is used for food crop irrigation; and 2) consumer acceptance of water reuse practices. Farmers in the West Bank and around the world are combating decreasing quality and quantity of water and will increasingly rely on consumers willing to purchase produce irrigated with treated wastewater. Future work must ensure that farmers have access to safe and abundant irrigation water, and that consumers can be confident that they are purchasing safe food.
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    Exposure to Ambient Air Pollution and Correlates of Cardiovascular Disease among Youth with Type 1 Diabetes
    (2019) Montresor-Lopez, Jessica Anne; Puett, Robin C; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Air pollution from traffic-related sources is associated with cardiovascular disease (CVD), potentially through changes in systemic inflammatory responses, vascular function and oxidative stress leading to atherosclerosis, thrombosis or endothelial dysfunction. Individuals with type 1 diabetes (T1D) have a greater risk of CVD-related morbidity and mortality than the general population, and they may be more susceptible to the effects of air pollution on CVD. Although these increased risks begin during childhood, very few studies have assessed the impact of air pollution on children and youth with T1D. This dissertation directly addresses gaps in the epidemiologic evidence by: 1) evaluating the relationship of short-term exposures to traffic-related air pollutants with pulse wave velocity (PWV), a measure of arterial stiffness, 2) assessing the effects of changes in air pollution exposures on changes in inflammatory biomarkers, including C-reactive protein, fibrinogen and interleukin-6 (IL-6), and 3) examining the relationship of long-term exposures to traffic-related air pollution with allostatic load (AL), a measure of cumulative biological risk, among a cohort of youth with T1D. Data were obtained from the SEARCH for Diabetes in Youth (SEARCH) study. SEARCH was initiated in 2000 and includes a diverse population of US youth diagnosed with diabetes prior to age 20 years. Anthropometric and laboratory measures were taken at SEARCH study visits, and standardized questionnaires were used to collect information on important covariates. Air pollution exposures were estimated using spatio-temporal models and assigned to residential addresses for each participant. In the first study, we identified a significant association between increased exposure to PM2.5 on the day of the examination with higher PWV using generalized linear models adjusted for lifestyle and demographic characteristics. In the second analysis, we found consistent positive effects of increases in PM2.5 over the week prior to the examination with IL-6 using longitudinal mixed models. In the third study, no significant associations were observed for monthly and annual PM2.5 exposures or proximity to major roadways with AL in fully adjusted linear mixed models. However, effects differed by race/ethnicity and gender. Overall, this research indicates that youth with T1D may be at higher risk for air pollution-related cardiovascular impacts.
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    The Impact of Private Drinking Water Wells and Animal Feeding Operations on the Incidence of Acute Gastroenteritis in Maryland: A Mixed Methods Approach
    (2019) Murray, Rianna Teresa Frederika; Wilson, Sacoby M; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    More than 44.5 million people in the United States (approximately 14% of the population) rely on private domestic wells as their primary source of drinking water. The water quality of private wells is not regulated at the state or federal level, leaving homeowners with wells responsible for the safety of their water. Meanwhile, each year, an estimated 48 million people in the U.S. are sickened, 128,000 are hospitalized, and 3,000 die of gastrointestinal (GI) illnesses caused by microorganisms that are typically transmitted through contaminated food. Given that the potential of private wells as a non-foodborne transmission pathway for these microorganisms is not well understood, my dissertation evaluated these relationships, as well as characterized the quality of private well water in Maryland. My objectives were to: 1.) Investigate the water quality of private wells in Maryland and the effect of animal feeding operations on this water quality using fecal indicator bacteria; 2.) Investigate associations between the prevalence of private wells and the incidence of campylobacteriosis in Maryland at the zip code level using data from the FoodNet active surveillance System; and 3.) Investigate associations between the prevalence of private wells and the incidence of salmonellosis in Maryland at the zip code level using FoodNet data. My findings demonstrated that 43.2% of private wells tested in Maryland did not meet at least one federal health-based drinking water standard. Additionally, my data showed that the prevalence of private wells in Maryland is a risk factor for the incidence of campylobacteriosis and salmonellosis in the coastal counties of the state. The presence of broiler chicken operations in a zip code is also a risk factor for campylobacteriosis and salmonellosis in coastal counties. These findings provide evidence for the strengthening of private well water regulations and for improving education and outreach to private well owners on proper maintenance and testing for their wells.
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    Antimicrobial Resistance of Enterococci in Surface and Recycled Water in the Mid-Atlantic
    (2018) Patterson, Rebecca; Micallef, Shirley A; Payne-Sturges, Devon C; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Increasing demands for agricultural water require identification of alternative water sources. Enterococcus species can exhibit antimicrobial resistance and transfer resistance traits to other bacterial taxa, including human pathogens. This study evaluated the distribution and antimicrobial resistance of Enterococcus faecalis and E. faecium in surface and recycled waters. In all, 365 isolates from 129 water samples collected over one year were identified by species, and 95 were selected for antimicrobial susceptibility testing. Season, water type, temperature and salinity were statistically significantly associated with species probability, and season with antimicrobial resistance of E. faecalis. 1.3% of E. faecalis and 5.0% E. faecium were pan-susceptible but 100% were susceptible to ampicillin, vancomycin, daptomycin and linezolid. Multidrug resistance was detected in 16% of E. faecalis and 70% of E. faecium isolates. Enterococcus was ubiquitous in water and exhibited resistance to multiple antimicrobials, but resistance to antimicrobials of last resort for enterococcal infections was non-existent.
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    (2018) Ezeugoh, Rosemary Ifeoma; Wilson, Sacoby M; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Ambient air pollution from stationary sources, industrial traffic, and commuter traffic can negatively impact air quality and human health. Ernest Maier, a concrete block plant located in Bladensburg, Maryland wants to expand to include a concrete batching plant on the same property. This expansion could further degrade air quality and impact the health of vulnerable residents. Air quality monitoring were conducted in the community at five personal sites using the Airbeam and Atmotube, which are wearable, real-time sensors that can measure PM2.5 and VOCs respectively. Sampling and traffic counts were conducted in thirty minutes’ periods to capture morning on-peak, afternoon off-peak and evening on-peak periods. Pearson’s correlation revealed that a weak correlation among the PM2.5 and VOC concentrations observed between the different sites and some of the values were found to be statistically significant. ANOVA analysis showed that the PM2.5 levels were significantly different at the different sites (p-value 0.001).
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    (2018) Beins, Kaley Elizabeth; Milton, Donald K.; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    A series of rare autoimmune disorders that affect the blood vessels, vasculitis is chronic and potentially deadly. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) comprise three diagnostic forms of this autoimmune disorder: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA or Churg-Strauss syndrome). The limited resources available to vasculitis researchers have been mostly targeted toward treatment and relapse prediction with a small amount of research examining genetic and environmental etiologic factors. Therefore, additional research is needed to understand the role of gene-environment interactions in AAV etiology. This thesis reviews the current body of AAV literature with a focus on candidate genes, occupational and environmental exposures, and the hygiene hypothesis. It also designs an original survey and study methodology to further investigate these etiologic factors. A better understanding of AAV etiology will lead to prevention and improved treatment of these costly diseases.
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    (2017) Naney, Kristen Burwell; Wilson, Sacoby M; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Communities with environmental justice (EJ) issues usually have disparities in exposure to chemical and non-chemical stressors and health status compared to other communities without underlying EJ issues. Improving cumulative risk assessment (CRA) screening tools and models can provide the necessary information needed to reduce health disparities and create more resilient communities. To address these gaps in EJ science, this dissertation has three specific aims: 1) Identify perceptions of environmental and resilience factors that may influence health among African-Americans in North Charleston, South Carolina (SC) (Study 1), 2) Develop a Cumulative Stressors and Resiliency Index (CSRI) used to rank risk in SC (Study 2), and 3) Examine associations between CSRI scores and risk of asthma hospitalizations/emergency department (ED) visits in SC (Study 3). Community stakeholders (N=18) participated in key-informant interviews and completed a 26-item paper survey in study one. Interviews were transcribed and coded, while mode, frequencies, and percentages were calculated for each indicator based on its ability to influence health. Statistical tests performed in study two included a Principal Component Analysis (PCA), one-way analysis of variance (ANOVA), and linear regression performed in SAS Enterprise Guide 7.1. Choropleth maps were also developed in ArcMap 10.5. We concluded by calculating descriptive statistics by Environmental Affairs (EA) region, Spearman’s rank-order correlation, one-way ANOVA, and negative binomial regression analyses in study three. Many of the indicators (61%) were rated as extremely high priority items and included environmental hazards, sociodemographic attributes, and factors that may influence resiliency. CSRI scores ranged from 7.4 – 64.0 with a mean score of 29.1. Statistically significant differences in CSRI scores were evident by EA region (p <0.0001) and a one-unit increase in the percentage of non-white populations per census tract projected to increase CSRI scores by roughly 6.1%. The CSRI was not able to predict risk of asthma hospitalizations/ED visits as hypothesized. Overall, we demonstrated that identifying and addressing chemical and non-chemical stressors and resiliency gaps in areas impacted by environmental injustice may lead to overall improvements in community resilience. We anticipate this work will be used as a blueprint to build more resilient and equitable communities in SC.
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    Assessment of Zero-Valent Iron Capabilities to Reduce Food-borne Pathogens via Filtration and Residual Activities in Irrigation Water
    (2017) Bradshaw, Rhodel; Sapkota, Ph.D., Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Inadequate disinfection of contaminated freshwater that is used to irrigate food crops that are eaten raw can result in foodborne illnesses. Therefore, in this study we assessed the efficacy of a low-cost, water treatment technology, zero-valent iron (ZVI), in reducing microbiological contamination of synthetic irrigation water. Specifically, we compared the capabilities of a ZVI-sand filter versus a sand filter in reducing levels of Salmonella Newport MDD314 and E. coli TVS 353 through filtration or residual disinfection. Our data showed that ZVI-sand filtration was more effective than sand filtration alone in reducing levels of both of these microorganisms. Our results also showed that, after filtration, there seemed to be no residual disinfection capabilities associated with either the ZVI-sand system or the sand system alone. Our findings suggest that ZVI-sand filtration can effectively reduce microbial contaminants in irrigation water; however, there seem to be no residual disinfection capabilities after filtration.
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    A pilot comparison of first morning versus 24-hour urinary deoxynivalenol in UK adults
    (2017) Boonchaisri, Natalie; Turner, Paul; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Using unpublished data from an original study by Turner et al. (2010a), the relationship between first morning void (FMV) and 24-hour urine collections was examined in UK adults to determine if FMV collections provide a reasonable estimate of DON intake compared to 24-hour collections. The intraclass correlation coefficient (ICC) was computed to evaluate variability in DON concentrations and generalized estimating equation (GEE) models were used to assess the relationship between collection types. Greater between-person variability was observed in 24-hour collections, unadjusted and adjusted for creatinine (ICC=0.78 and 0.56, respectively). GEE models suggest urinary DON concentrations in FMV collections were strongly correlated with 24-hour collections (r=0.78, p<0.0001), meaning FMV collections may provide just as reasonable an estimate of DON intake compared to 24-hour collections when adjusting for age, sex, and BMI. These results strengthen the methodology behind exposure biomarkers and urinary assays when estimating DON intake.
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    Antibiotic Concentrations and the Composition of Bacterial Communities in Municipal Wastewater and Reclaimed Water
    (2016) Kulkarni, Prachi; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Before reclaimed water is used more widely within the current United States (U.S.) wastewater treatment infrastructure, it is important to examine the potential public health impacts of this emerging, alternative freshwater resource. My dissertation evaluated antibiotic concentrations and the composition of bacterial communities in conventionally treated municipal wastewater and resulting reclaimed water. I also evaluated the efficacy of a point-of-use filtration system in reducing antimicrobials present in reclaimed water. My objectives were to: 1) Assess the fate of antibiotics and; 2) Characterize the total bacterial community structure of differentially treated wastewater, and reclaimed water that has undergone on-site treatment and storage; and 3) Evaluate zero-valent iron (ZVI)-biosand filtration as a potential point-of use treatment technology for the reduction of antimicrobials from conventionally treated reclaimed water. I extracted nine antibiotics and total genomic deoxyribonucleic acid (DNA) from differentially treated wastewater and reclaimed water samples from two Mid-Atlantic and two Midwest WWTPs, and one associated Mid-Atlantic spray irrigation site. I quantified the presence of antibiotics using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and characterized total bacterial community structure using 16S rRNA gene sequencing. I also used HPLC-MS/MS to quantify the reduction of thirteen antimicrobials from conventionally treated reclaimed water after ZVI-biosand filtration. Statistical analyses included the Kruskal Wallis test, paired Wilcoxon signed-rank test, and differential abundance using normalization achieved by cumulative sum scaling. Activated sludge treatment used at all four WWTPs resulted in the reduction of some antibiotics and the increase of genera containing potentially pathogenic bacteria (Mycobacterium and Legionella). Treatment plant chlorination and spray irrigation site ultraviolet radiation (UV) treatment and open-air storage reduced the concentration of azithromycin and increased the relative abundance of Mycobacterium. ZVI-biosand filtration achieved significant reductions in azithromycin, ciprofloxacin, erythromycin, linezolid, oxolinic acid, pipemidic acid, penicillin and vancomycin. This research provided additional scientific evidence that activated sludge treatment and chlorination alone may not be sufficient for the removal of antimicrobials and potentially pathogenic bacteria from municipal wastewater and resulting reclaimed water. However, ZVI-biosand filtration may be an efficient reuse site technology for the reduction of antimicrobials from conventionally treated reclaimed water.
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    (2016) Raspanti, Greg Anthony; Sapkota, Amir; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The burden of chronic diseases such as cancer is increasing in low and middle income countries around the globe. Nepal, one of the world’s poorest countries, is no exception to this trend, with lung cancer as the leading causes of cancer deaths. Despite this, limited data is available on the environmental and behavioral risk factors that contribute to the lung cancer etiology in Nepal. The objectives of this dissertation are to: 1) investigate the ethnic differences in consumption of local tobacco products and their role in lung cancer risk in Nepal; 2) evaluate urinary metabolite of 1,3-butadiene as a biomarker of exposure to combustion related household air pollution (CRHAP); 3) investigate the association between CRHAP exposure and lung cancer risk using urinary metabolite of 1,3-butadiene as a biomarker of exposure; 4) investigate the association between CRHAP exposure and lung cancer risk using questionnaire based measure of exposure. Lung cancer cases (n=606) and frequency matched controls (N=606) were recruited from B.P. Koirala Memorial Cancer Hospital. We obtained biological samples and information on lifestyles including cooking habits and type of fuels used. We used liquid chromatograph tandem mass spectrometer (LC-MS/MS) to quantify urinary metabolites of 1,3-butadiene in urine samples. We employed a combination of logistic and linear regression models to detect any exposure-disease associations while controlling for known confounding variables. Overall, we found that ethnic groups in Nepal use different tobacco products that have different differing cancer potency -we observed the highest odds ratios for the traditional tobacco products. The biomarker analysis showed strong evidence that monohydroxybutyl mercapturic acid is associated with biomass fuel use among participants. However, we did not find significant association between urinary MHMBA and lung cancer risk. When we used questionnaire based measure of exposure to household air pollution, we observed significant, dose-response associations between CRHAP exposure and lung cancer risk, particularly among never-smokers. Our results show that important role of local tobacco products in lung cancer risk in Nepal. Furthermore, we demonstrate that CRHAP exposure is a risk factor for lung cancer risk, independent of tobacco smoking.