Global, Environmental, and Occupational Health

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Prior to May 2024, previously known as the Maryland Institute for Applied Environmental Health.

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The Community Environmental Health Assessment Workbook: A Guide to Evaluating your Community's Health
(Environmental Law Institute, 2000-12) Payne-Sturges, Devon; Locke, Paul; Keiner, Suellen
This Workbook will help community leaders, local organizers, and citizens groups assess environmental health problems in their neighborhoods and assist them in tackling these problems. It outlines an approach to identifying problems, gathering information, and establishing the community’s priorities for improving the environmental health of its residents. The Workbook is divided into four parts. It is written mainly for the citizen organizer, community leader, or other person who will serve as the project manager and take the lead in organizing the assessment. Part One is a brief introduction and discussion of this Workbook. Part Two discusses the reasons why your community should undertake an environmental health assessment, and outlines the assessment process. Part Three explains the community environmental health assessment process step-by-step, and shows citizens in detail how to conduct an assessment. Part Four suggests possible next steps after a community assessment is completed.
Guide to Considering Children’s Health When Developing EPA Actions: Implementing Executive Order 13045 and EPA’s Policy on Evaluating Health Risks to Children
(U.S. Environmental Protection Agency, 2006-10) Payne-Sturges, Devon; Miles-McLean, Stuart; Kataoka, Mark; Patel, M; Owens, Nicole
This document is a step-by-step guide to assist Agency staff in integrating children’s health considerations into EPA’s Action Development Process (ADP). It describes the provisions of Executive Order 13045 “Protection of Children from Environmental Health Risks and Safety Risks” and EPA’s “Policy on Evaluating Health Risks to Children.” This guide also is designed to assist EPA staff in determining whether rules are subject to the Executive Order, whether the Agency Policy applies to an action and what should be done to address the Executive Order and/or EPA’s policy in the development of a rule or Agency action.
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.
Self-medication with antibiotics for the treatment of menstrual symptoms in southwest Nigeria: a cross-sectional study
(2010-10-15) Sapkota, Amy R; Coker, Morenike E; Rosenberg Goldstein, Rachel E; Atkinson, Nancy L; Sweet, Shauna J; Sopeju, Priscilla O; Ojo, Modupe T; Otivhia, Elizabeth; Ayepola, Olayemi O; Olajuyigbe, Olufunmiso O; Shireman, Laura; Pottinger, Paul S; Ojo, Kayode K
Background: Self-medication with antibiotics is an important factor contributing to the development of bacterial antibiotic resistance. The purpose of this study was to evaluate the prevalence of self-medication with antibiotics for the treatment of menstrual symptoms among university women in Southwest Nigeria. Methods: A cross-sectional survey was administered to female undergraduate and graduate students (n = 706) at four universities in Southwest Nigeria in 2008. The universities were selected by convenience and the study samples within each university were randomly selected cluster samples. The survey was self-administered and included questions pertaining to menstrual symptoms, analgesic and antibiotic use patterns, and demographics. Data were analyzed using descriptive statistics and logistic regression. Results: The response rate was 95.4%. Eighty-six percent (95% CI: 83-88%) of participants experienced menstrual symptoms, and 39% (95% CI: 36-43%) reported using analgesics to treat them. Overall, 24% (95% CI: 21-27%) of participants reported self-medicated use of antibiotics to treat the following menstrual symptoms: cramps, bloating, heavy bleeding, headaches, pimples/acne, moodiness, tender breasts, backache, joint and muscle pain. Factors associated with this usage were: lower levels of education (Odds Ratio (OR): 2.8, 95% CI: 1.1-7.1, p-value: 0.03); nonscience major (OR: 1.58, 95% CI: 1.03-2.50, p-value: 0.04); usage of analgesics (OR: 3.17, 95% CI: 2.07-4.86, p-value: <0.001); and mild to extreme heavy bleeding (OR: 1.64, 95% CI: 1.01-2.67, p-value: 0.05) and pimples/acne (OR: 1.57, 95% CI: 0.98-2.54, p-value: 0.06). Ampicillin, tetracycline, ciprofloxacin and metronidazole were used to treat the most symptoms. Doctors or nurses (6%, 95% CI: 4-7%), friends (6%, 95% CI: 4-7%) and family members (7%, 95% CI: 5-8%) were most likely to recommend the use of antibiotics for menstrual symptoms, while these drugs were most often obtained from local chemists or pharmacists (10.2%, 95% CI: 8-12%). Conclusions: This is the first formal study to report that approximately 1 out of 4 university women surveyed in Southwest Nigeria self-medicate with antibiotics to treat menstrual symptoms. This practice could provide monthly, low-dose exposures to antibiotics among users. Further studies are necessary to evaluate the impacts of selfmedication on student health.
Quantitative assessment of airborne exposures generated during common cleaning tasks: a pilot study
(Springer Nature, 2010-11-30) Bello, Anila; Quinn, Margaret M; Perry, Melissa J; Milton, Donald K
A growing body of epidemiologic evidence suggests an association between exposure to cleaning products with asthma and other respiratory disorders. Thus far, these studies have conducted only limited quantitative exposure assessments. Exposures from cleaning products are difficult to measure because they are complex mixtures of chemicals with a range of physicochemical properties, thus requiring multiple measurement techniques. We conducted a pilot exposure assessment study to identify methods for assessing short term, task-based airborne exposures and to quantitatively evaluate airborne exposures associated with cleaning tasks simulated under controlled work environment conditions. Sink, mirror, and toilet bowl cleaning tasks were simulated in a large ventilated bathroom and a small unventilated bathroom using a general purpose, a glass, and a bathroom cleaner. All tasks were performed for 10 minutes. Airborne total volatile organic compounds (TVOC) generated during the tasks were measured using a direct reading instrument (DRI) with a photo ionization detector. Volatile organic ingredients of the cleaning mixtures were assessed utilizing an integrated sampling and analytic method, EPA TO-17. Ammonia air concentrations were also measured with an electrochemical sensor embedded in the DRI. Average TVOC concentrations calculated for 10 minute tasks ranged 0.02 - 6.49 ppm and the highest peak concentrations observed ranged 0.14-11 ppm. TVOC time concentration profiles indicated that exposures above background level remained present for about 20 minutes after cessation of the tasks. Among several targeted VOC compounds from cleaning mixtures, only 2-BE was detectable with the EPA method. The ten minute average 2- BE concentrations ranged 0.30 -21 ppm between tasks. The DRI underestimated 2-BE exposures compared to the results from the integrated method. The highest concentration of ammonia of 2.8 ppm occurred during mirror cleaning. Our results indicate that airborne exposures from short-term cleaning tasks can remain in the air even after tasks' cessation, suggesting potential exposures to anyone entering the room shortly after cleaning. Additionally, 2-BE concentrations from cleaning could approach occupational exposure limits and warrant further investigation. Measurement methods applied in this study can be useful for workplace assessment of airborne exposures during cleaning, if the limitations identified here are addressed.
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.
Pesticides in house dust from urban and farmworker households in California: an observational measurement study.
(2011-03) Quiros-Alcala, Lesliam; Bradman, Asa; Nishioka, Marcia; Harnly, Martha; Hubbard, Alan; McKone, Thomas E.; Ferber, Jeannette; Eskenazi, Brenda
BACKGROUND: Studies report that residential use of pesticides in low-income homes is common because of poor housing conditions and pest infestations; however, exposure data on contemporary-use pesticides in low-income households is limited. We conducted a study in low-income homes from urban and agricultural communities to: characterize and compare house dust levels of agricultural and residential-use pesticides; evaluate the correlation of pesticide concentrations in samples collected several days apart; examine whether concentrations of pesticides phased-out for residential uses, but still used in agriculture (i.e., chlorpyrifos and diazinon) have declined in homes in the agricultural community; and estimate resident children's pesticide exposures via inadvertent dust ingestion. METHODS: In 2006, we collected up to two dust samples 5-8 days apart from each of 13 urban homes in Oakland, California and 15 farmworker homes in Salinas, California, an agricultural community (54 samples total). We measured 22 insecticides including organophosphates (chlorpyrifos, diazinon, diazinon-oxon, malathion, methidathion, methyl parathion, phorate, and tetrachlorvinphos) and pyrethroids (allethrin-two isomers, bifenthrin, cypermethrin-four isomers, deltamethrin, esfenvalerate, imiprothrin, permethrin-two isomers, prallethrin, and sumithrin), one phthalate herbicide (chlorthal-dimethyl), one dicarboximide fungicide (iprodione), and one pesticide synergist (piperonyl butoxide). RESULTS: More than half of the households reported applying pesticides indoors. Analytes frequently detected in both locations included chlorpyrifos, diazinon, permethrin, allethrin, cypermethrin, and piperonyl butoxide; no differences in concentrations or loadings were observed between locations for these analytes. Chlorthal-dimethyl was detected solely in farmworker homes, suggesting contamination due to regional agricultural use. Concentrations in samples collected 5-8 days apart in the same home were strongly correlated for the majority of the frequently detected analytes (Spearman ρ = 0.70-1.00, p < 0.01). Additionally, diazinon and chlorpyrifos concentrations in Salinas farmworker homes were 40-80% lower than concentrations reported in samples from Salinas farmworker homes studied between 2000-2002, suggesting a temporal reduction after their residential phase-out. Finally, estimated non-dietary pesticide intake for resident children did not exceed current U.S. Environmental Protection Agency's (U.S. EPA) recommended chronic reference doses (RfDs). CONCLUSION:Low-income children are potentially exposed to a mixture of pesticides as a result of poorer housing quality. Historical or current pesticide use indoors is likely to contribute to ongoing exposures. Agricultural pesticide use may also contribute to additional exposures to some pesticides in rural areas. Although children's non-dietary intake did not exceed U.S. EPA RfDs for select pesticides, this does not ensure that children are free of any health risks as RfDs have their own limitations, and the children may be exposed indoors via other pathways. The frequent pesticide use reported and high detection of several home-use pesticides in house dust suggests that families would benefit from integrated pest management strategies to control pests and minimize current and future exposures.
Plan EJ 2014: Science Tool Development Implementation Plan
(U.S. Environmental Protection Agency, 2011-09) Payne-Sturges, Devon
This Science Tools Development Implementation Plan discusses overarching goals, strategies, and activities, including a science and research agenda to ensure that U.S. EPA brings the best science to decision making around environmental justice issues. The science and research activities described in this plan build upon discussions and recommendations from “Strengthening Environmental Justice and Decision-Making: A Symposium on the Science of Disproportionate Environmental Health Impacts” (March 17-19, 2010) and the workshop on “Analytical Methods for Assessing the Environmental Justice Implications of Environmental Regulations” (June 9-10, 2010). The March 2010 Symposium was the principal event for the Agency to identify science needs for environmental justice and stimulate ideas for innovative research to meet those needs.
Temporal changes in the prevalence of childhood asthma and allergies in urban and rural areas of Cyprus: results from two cross sectional studies
(Springer Nature, 2011-11-11) Kolokotroni, Ourania; Middleton, Nicos; Nicolaou, Nicolas; Pipis, Spyros; Priftis, Kostas N; Milton, Donald K; Yiallouros, Panayiotis K
The prevalence of childhood asthma and allergies in Cyprus was significantly higher in urban compared to rural areas back in the year 2000, against a background of an overall low prevalence (e.g. current wheeze 6.9%) by comparison to northern European countries. In this study we aimed to assess temporal changes in the prevalence of asthma and allergies in Cyprus after an 8-year interval and to examine whether any differential changes have occurred in urban and rural parts of the island. During the academic years 1999-2000 and 2007-2008, the parents of 7-8 year old children residing in the same set of urban and rural areas completed the ISAAC core questionnaire. In addition to providing prevalence estimates of allergic diseases in 2000 and 2008, changes between the two periods were expressed as odds ratios estimated in multiple logistic regression models adjusting for survey participants' characteristics. The prevalence of current wheeze was higher in 2008 (8.7%, 95% confidence interval 7.5%-9.9%, n = 2216) than the previously recorded figure in 2000 (6.9%, 95% CI 6.2%-7.6%, OR = 1.25, 95% CI: 1.02-1.53, n = 4944). Significant increases were also seen in the prevalence of lifetime asthma (11.3% vs. 17.4%, OR = 1.59, CI: 1.36-1.86), eczema (6.8% vs. 13.5%, OR = 1.91, CI: 1.59-2.29) and allergic rhinoconjuctivitis (2.6% vs. 5.2%, OR = 1.82, CI: 1.39-2.41). The prevalence of current wheeze nearly doubled between 2000 and 2008 in rural areas (5.4% vs. 9.7%, OR 1.81, CI: 1.24-2.64) while no significant change was observed in urban areas (7.5% vs. 8.4%, OR 1.08, CI: 0.84-1.37); p value for effect modification = 0.04. Rises in asthma and rhinitis prevalence, but not eczema were also more pronounced in rural compared to urban areas. The prevalence of allergic diseases in Cyprus is still on the rise; recent increases appear more pronounced among children living in rural areas possibly indicating recent environmental and lifestyle changes in these communities.
Effects of endotoxin exposure on childhood asthma risk are modified by a genetic polymorphism in ACAA1
(Springer Nature, 2011-12-08) Sordillo, Joanne E; Sharma, Sunita; Poon, Audrey; Lasky-Su, Jessica; Belanger, Kathleen; Milton, Donald K; Bracken, Michael B; Triche, Elizabeth W; Leaderer, Brian P; Gold, Diane R; Litonjua, Augusto A
Polymorphisms in the endotoxin-mediated TLR4 pathway genes have been associated with asthma and atopy. We aimed to examine how genetic polymorphisms in innate immunity pathways interact with endotoxin to influence asthma risk in children. In a previous analysis of 372 children from the Boston Home Allergens and the Connecticut Childhood Asthma studies, 7 SNPs in 6 genes (CARD15, TGFB1, LY96, ACAA1, DEFB1 and IFNG) involved in innate immune pathways were associated with asthma, and 5 SNPs in 3 genes (CD80, STAT4, IRAK2) were associated with eczema. We tested these SNPs for interaction with early life endotoxin exposure (n = 291), in models for asthma and eczema by age 6. We found a significant interaction between endotoxin and a SNP (rs156265) in ACAA1 (p = 0.0013 for interaction). Increased endotoxin exposure (by quartile) showed protective effects for asthma in individuals with at least one copy of the minor allele (OR = 0.39 per quartile increase in endotoxin, 95% CI 0.15 to 1.01). Endotoxin exposure did not reduce the risk of asthma in children homozygous for the major allele. Our findings suggest that protective effects of endotoxin exposure on asthma may vary depending upon the presence or absence of a polymorphism in ACAA1.
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.
Organophosphorous pesticide breakdown products in house dust and children’s urine.
(2012) Quiros-Alcala, Lesliam; Bradman, Asa; Smith, Kimberly; Weerasekera, Gayanga; Odetokun, Martins; Barr, Dana B.; Nishioka, M; Castorina, R; Hubbard, AE; Nicas, M; Hammond, SK; McKone, TE; Eskenazi, B
Human exposure to preformed dialkylphosphates (DAPs) in food or the environment may affect the reliability of DAP urinary metabolites as biomarkers of organophosphate (OP) pesticide exposure. We conducted a study to investigate the presence of DAPs in indoor residential environments and their association with children’s urinary DAP levels. We collected dust samples from homes in farmworker and urban communities (40 homes total, n=79 samples) and up to two urine samples from resident children ages 3-6 years. We measured six DAPs in all samples and eight DAP-devolving OP pesticides in a subset of dust samples (n=54). DAPs were detected in dust with diethylphosphate (DEP) being the most frequently detected (>=60%); detection frequencies for other DAPs were <=50%. DEP dust concentrations did not significantly differ between communities, nor were concentrations significantly correlated with concentrations of chlorpyrifos and diazinon, the most frequently detected diethyl-OP pesticides (Spearman r=0.41 to 0.38, P>0.05). Detection of DEP, chlorpyrifos, or diazinon, was not associated with DEP and/or DEPþdiethylthiophosphate detection in urine (Kappa coefficients=-0.33 to 0.16). Finally, estimated nondietary ingestion intake from DEP in dust was found to be <=5% of the dose calculated from DEP levels in urine, suggesting that ingestion of dust is not a significant source of DAPs in urine if they are excreted unchanged.
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.