Global, Environmental, and Occupational Health Theses and Dissertations

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Autism Spectrum Disorder and Hazardous Air Pollutants in the U.S. and Maryland
(2010) Trousdale, Kristie; Dabney, Betty J; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The prevalence of Autism Spectrum Disorder (ASD) diagnoses in the United States has increased dramatically over the past 20 years, fueling investigations into possible environmental triggers for the disorder. Exposures to pesticides, persistent pollutants, prescription medications, and heavy metals through various routes have been examined, but very few studies have examined the potential role of chronic inhalation of hazardous air pollutants (HAPs) in the etiology of ASD. This thesis was designed to examine possible relationships between HAPs and ASD prevalence on a statewide level for the U.S., with sub-analyses on a finer, countywide level within the state of Maryland. Findings suggest consistent, positive associations between ASD prevalence and HAPs at the statewide level for the U.S. The findings do not persist at the county level in the Maryland sub-analyses. These results reinforce the concept of ASD as a spectrum of phenotypes best explained through multifactorial etiological models.
EVALUATION OF ANTIBIOTIC-RESISTANT BACTERIA IN TERTIARY TREATED WASTEWATER, RECLAIMED WASTEWATER USED FOR SPRAY IRRIGATION, AND RESULTING OCCUPATIONAL EXPOSURES
(2010) Goldstein, Rachel Elizabeth Rosenberg; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Occupational exposures to vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) in reclaimed wastewater used for spray irrigation were evaluated. In 2009, wastewater was collected from a tertiary-treatment facility, and reclaimed wastewater, nasal and dermal swab samples from an irrigation site. Samples were evaluated for MRSA and VRE using standard methods, PCR, and susceptibility testing. MRSA and VRE were isolated from all wastewater samples except effluent. While wastewater MRSA isolates were multidrug resistant (98%), no MRSA was isolated in irrigation water or swabs. VRE was isolated in one irrigation water sample. Fewer irrigation workers were colonized with S. aureus (31%) compared to controls (46%), but they harbored more multidrug resistant S. aureus. This is the first study to 1) evaluate antibiotic-resistant bacteria (ARB) in U.S. reclaimed wastewater and resulting occupational exposures, and 2) detect MRSA in U.S. wastewater. The findings suggested that tertiary wastewater treatment effectively reduced MRSA and VRE.
Influence of weekdays, weekends, bandhas and weather conditions on particulate matter (PM10) concentrations in the Kathmandu Valley in Nepal
(2011) Fransen, Michelle Julia; Sapkota, Amir; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Particulate matter (PM) exposure has been associated with a variety of adverse health effects. Quantifying the relative source contribution of PM is important as it provides policymakers critical information needed to formulate successful pollution reduction programs. The aim of this study was to evaluate the effects of bandhas (general strikes) and meteorological parameters on PM10 concentrations in the Kathmandu Valley. Within station seasonal differences in PM10 concentrations were compared using t-tests. Linear mixed effects regression models were used to examine the effects of weekends or bandh days on PM10 concentrations. Results showed significant (p<0.001) seasonal variability across all stations. In the urban high traffic (UHT) and urban residential (UR) areas, there were statistically significant (p<0.05) lower PM10 concentrations on weekends. In the UHT, PM10 concentrations were significantly lower on bandh days (p<0.05). These results suggest that a reduction in vehicular emissions may alleviate the PM10 pollution problem in the valley.
Maternal mercury exposure, season of conception and adverse birth outcomes in an urban immigrant community in New York City
(2012) Bashore, Cynthia Diana Jennings; Sapkota, Amir; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Adverse birth outcomes such as preterm birth (PTB: < 37 weeks gestation) and low birthweight (LBW: <2500g) result in severe infant morbidity and mortality. In the United States, there are racial and ethnic differences in the prevalence of preterm birth and low birth weight. The focus of this study is to examine the association between frequency of maternal fish consumption during pregnancy, prenatal mercury exposure, and season of conception with preterm birth and low birth weight in a population of African-American, Caribbean and West Indian women in an urban immigrant community in New York City. The proportion of preterm births and low birth rates in this cohort of women was higher than reported in other studies of African-American and Caribbean births in New York City. There was no association between maternal urinary mercury or infant cord blood concentrations and either LBW or preterm birth. Infants conceived in winter (December, January, February) were at increased odds of low birthweight.
Environmental Impacts on Fecal Indicator Bacteria in 5 National Park Recreational Water Areas
(2012) Raspanti, Greg A.; Sapkota, Amir; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The National Park Service oversees 397 park units throughout the 50 states and US territories. Due to the high visitation, protecting the health of visitors is a top priority. Fecal contamination in recreational water can occur as a result of land use practices and weather related factors. The aim of this study is to investigate weather related factors and land use factors that contribute to fecal contamination in five National Park units. Overall, rainfall proved to be highly predictive of subsequent elevations in fecal bacteria. Specifically, same day rainfall and day prior to the sampling day rainfall showed the strongest association with elevated fecal bacteria levels. Seasonal variation of fecal bacteria was generally higher in the summer months. The land use variables were not highly predictive of fecal bacteria levels. The results of this study can be used by park managers to better predict variations in fecal contamination.
Residual DNA in Commercial Taq DNA polymerase as a Source of Interference with Immuno-PCR assay
(2012) Guag, Jake; Milton, Donald K; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Polymerase Chain Reaction (PCR) was developed for a broad range of purposes. As part of developing a very sensitive Immuno-quantitative PCR (iqPCR) assay, we attempted to reproduce two of the published papers, almost always experienced false-positive amplification. Based on personal communication from one of the authors, we suspected that impure reagents were responsible for the false-positive amplification. However, PCR can amplify a small number of DNA into enormous numbers of copies and the possibility of environmental contamination cannot be excluded. In this paper we show that our primers appeared to amplify residual DNA in the Taq DNA polymerase, and induced false-positive results. This finding is not in the published methods papers for iqPCR.
An Assessment of Exposure to Pollution by Recreational Users of The Anacostia Watershed: Project Recreate
(2013) Murray, Rianna Teresa; Wilson, Sacoby; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The Anacostia River, a tributary of the Chesapeake Bay, is highly contaminated with raw sewage, heavy metals, oil and grease, trash, pathogens, excessive sediments and organic chemicals. Many people use this river on a regular basis for recreational purposes, including kayaking, canoeing, rowing and sport fishing. The contaminants in the river potentially pose threats to human health for recreational users. While there has been some study of the exposure to subsistence fishers in this region there is currently little information available on the risks faced by recreational users. This work gathered pilot data on recreational users with the purpose of assessing any associated exposure risks to contaminants. The high levels of contamination in the Anacostia River and the popularity of recreation makes this an important public health issue. This study is the first to combine an evaluation of risk and risk perception for the recreational population of the Anacostia River.
Assessing the Presence of Antibiotic-Resistant Enterococcus in Reclaimed Water Used for Spray Irrigation
(2013) Carey, Stephanie Ann; Sapkota, Amy R; Turner, Paul; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Reclaiming wastewater is increasing in the US to combat dwindling freshwater supplies. This water potentially contains pathogenic bacteria; therefore, we evaluated the occurrence, concentration, and antimicrobial susceptibilities of Enterococcus spp.--an important opportunistic pathogen that remains a leading cause of nosocomial infections--in reclaimed water used for spray irrigation (SI). A total of 48 wastewater effluent and SI samples were collected in 2009 and 2010 from the Mid-Atlantic and Midwest regions of the US. Enterococci were isolated using membrane filtration, confirmed using biochemical tests and PCR, and tested for antimicrobial susceptibility using the Sensititre® dilution system. We detected total enterococci and vancomycin-resistant enterococci (VRE) in 68% (27/40) and 8% (3/40), respectively, of all SI samples. VRE and vancomycin-intermediate enterococci (VIE) represented 2% (1/41) and 10% (4/41), respectively, of the total enterococci recovered from all SI sites. Our findings show that SI workers may be exposed to enterococci during spray irrigation activities.
Antibiotic-resistant bacteria in wastewater and potential human exposure through wastewater reuse
(2013) Goldstein, Rachel Elizabeth Rosenberg; Sapkota, Amy R.; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
As community-acquired antibiotic-resistant bacterial infections occur with increasing frequency, it is important to identify possible environmental reservoirs for these organisms. My dissertation evaluated the presence of antibiotic-resistant bacteria in U.S. wastewater intended for reuse and the related public health implications. My objectives were to: 1) Evaluate wastewater from four U.S. wastewater treatment plants (WWTPs) for the presence of methicillin-resistant Staphylococcus aureus (MRSA); 2) Evaluate the occurrence of vancomycin-resistant enterococci (VRE) at four U.S. WWTPs from which treated wastewater is reused; and 3) Determine and compare MRSA, methicillin-susceptible S. aureus (MSSA), VRE, and vancomcyin-susceptible enterococci (VSE) colonization among American reclaimed water spray irrigators and controls. Between 2009 and 2010, 44 wastewater samples were collected from four WWTPs, two in the Mid-Atlantic and two in the Midwest regions of the U.S. I analyzed samples for MRSA and VRE using standard membrane filtration. For the third objective, I collected 94 nasal and dermal swabs from 19 spray irrigators and 24 controls and analyzed them for MRSA, MSSA, VRE, and VSE. I confirmed all isolates and performed antimicrobial susceptibility testing by microbroth dilution. Statistical analyses included two-sample proportion tests and logistic regression. MRSA and VRE were detected at all WWTPs. The percentage of MRSA-positive samples and concentration of VRE decreased as treatment progressed. Neither MRSA nor VRE were identified in tertiary-treated samples, but I identified both in an un-chlorinated effluent sample. No MRSA or VRE were detected in nasal or dermal samples from spray irrigators or controls. MSSA and VSE were detected in 26% and 11% of spray irrigators and 29% and 0% of controls, respectively. The odds of MSSA, MDR MSSA, and either MSSA or VSE colonization were not significantly different between the spray irrigators and controls. My dissertation includes the first reports of MRSA at U.S. WWTPs and VRE at WWTPs whose effluent is intended for reuse. This is also the first U.S. evaluation of occupational exposure to antibiotic-resistant bacteria in reclaimed water. My findings provide additional scientific evidence that antibiotic-resistant bacteria can survive secondary-treated wastewater and may cause increased risks for infection among individuals exposed to reclaimed water.
Short-term effects of ambient ozone on stroke risk in South Carolina
(2013) 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.)
Recent reports have suggested that exposure to ozone is associated with stroke events; however, findings have been inconsistent. Utilizing a case-crossover study design, we explored the association between acute ozone exposure (maximum 8-hour daily average) and risk of stroke hospitalization among South Carolina residents and effect modification by race and gender. For total stroke (ischemic and hemorrhagic combined), a 10 ppb increase in ozone exposure on the day of hospitalization was associated with an increased risk of stroke hospitalization (OR: 1.08; 95% CI, 1.06, 1.11). Effects were similar for other lag days; however, the association was strongest for lag days 0-6 (OR: 1.20; 95% CIs 1.16, 1.24). We observed subtle differences in total stroke risk by gender, with females having a slightly lower risk than males, although CIs overlapped considerably. For hemorrhagic stroke, there was evidence of effect modification by race for all time periods of ozone exposure considered.
Alcohol exposure in preterm infants in neonatal isolettes
(2013) Braun, Rebecca Marie; Sapkota, Amir; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Preterm infants admitted to the NICU may spend up to 12 weeks in isolettes (incubators with controlled air temperature and humidity). Infants receive frequent contact with health-care professionals who use alcohol-based hygiene products. Ethanol is a known developmental neurotoxicant, and inhalation may have long-term effects on infant neurodevelopment. This study assessed alcohol concentration in isolette air after inserting hands cleaned with hand sanitizer, and effects of longer hand rubbing before insertion into the isolette. Each exposure consisted of two squirts (1.5 ± 0.1mL) of hand sanitizer, and hands rubbed for 10 or 20 seconds before insertion into isolettes. Air samples were collected by photoionization detector and breathalyzer. Average ethanol peaks were 387.04ppm (10s) and 104.36ppm (20s). Ethanol levels peaked within 1min, dissipated within 5min, and returned to background within 15 - 20min. Alcohol exposure from ethanol based hand sanitizer may be decreased significantly with longer duration of hand rubbing.
IMPACT OF RURALITY, BROILER OPERATIONS, AND COMMUNITY SOCIOECONOMIC FACTORS ON THE RISK OF CAMPYLOBACTERIOSIS IN MARYLAND
(2013) Zappe Pasturel, Barbara; Sapkota, Amy; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The combined impact of community-level environmental and socioeconomic factors on the risk of campylobacteriosis were evaluated. Campylobacter case data (2002-2010, n=3,694) were obtained from the Maryland Foodborne Diseases Active Surveillance Network. Community-level socioeconomic and environmental data were obtained from the 2000 U.S. Census and the 2007 U.S. Census of Agriculture. Data were linked by zip code. Incidence rate ratios were derived by Poisson regressions. A subset of zip code-level characteristics was mapped. In zip codes that were 100% rural, incidence rates of campylobacteriosis were 6 times (IRR=6.18; 95%CI=3.19-11.97) that of urban zip codes. In zip codes with broiler chicken operations, incidence rates were 1.45 times that of zip codes without broilers (IRR=1.45, 95%CI=1.34-1.58). Higher rates were also observed for zip codes that were predominantly white and had high median incomes. Findings suggest that the risk of campylobacteriosis could be significantly influenced by the community and environment where one lives.
Monitoring and Assessment of Residential Exposure to Noise Associated with Natural Gas Compressor Stations in West Virginia
(2014) Boyle, Meleah; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Noise is a growing concern for residents living near natural gas compressor stations. This study monitored and evaluated residential noise exposure associated with living near natural gas compressor stations in West Virginia. Short-term outdoor measurements (20 min) and medium-term (24-hour) indoor and outdoor measurements were collected at homes located near compressor stations. The average sound equivalent was calculated using logarithmic averages and stratified by distance from compressor station, time of day, and location. Average short-term noise levels were 61.43 dBA (45.3 to 76.1 dBA); average 24-hour noise levels were 60.20 dBA (35.3 to 94.8 dBA). Average noise levels at control homes were 51.40 dBA, with 45.02 dBA indoors and 54.03 dBA outdoors. Average noise levels at homes near compressor stations were 8.7 dBA higher, with a 16.25 dBA difference indoors and a 4.3 dBA difference outdoors. Results indicate that living near a natural gas compressor station may increase environmental noise exposure.
Impact of Cryptosporidium spp. interaction with co-occurring microorganisms on moderate-to-severe diarrhea in the developing world
(2015) Reid, Molly Carroll; Sapkota, Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Diarrheal illness is responsible for over a quarter of all deaths in children under 5 years of age in sub-Saharan Africa and South Asia. Recent findings have identified the parasite Cryptosporidium as a contributor to enteric disease. We examined 9,348 cases and 13,128 controls from the Global Enteric Multicenter Study to assess whether Cryptosporidium interacted with co-occurring pathogens based on adjusted odds of moderate-to-severe diarrhea (MSD). Cryptosporidium was found to interact negatively with Shigella spp., with multiplicative interaction score of 0.16 (95% CI: 0.07 to 0.37, p-value=0.000), and an additive interaction score of -9.81 (95% CI: -13.61 to -6.01, p-value=0.000). Cryptosporidium also interacted negatively with Aeromonas spp., Adenovirus, Norovirus, and Astrovirus with marginal significance. Odds of MSD for Cryptosporidium co-infection with Shigella spp., Aeromonas spp., Adenovirus, Norovirus, or Astrovirus are lower than odds of MSD with either organism alone. This may reduce the efficacy of intervention strategies targeted at Cryptosporidium.
LUNG CANCER IN NEPAL: THE ROLE OF TRADITIONAL TOBACCO PRODUCTS AND COMBUSTION RELATED HOUSEHOLD AIR POLLUTION
(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.
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.
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.
THE DEVELOPMENT OF A COMMUNITY INFORMED CUMULATIVE STRESSORS AND RESILIENCY INDEX (CSRI) TO EXAMINE ENVIRONMENTAL HEALTH DISPARITIES AND DISEASE RISK IN SOUTH CAROLINA
(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.
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.
NEW METHODOLOGY TO IDENTIFY POTENTIAL ENVIRONMENTAL TRIGGERS FOR ANCA-ASSOCIATED VASCULITIDES
(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.