Dissertations / Theses on the topic 'Environmental health|Public health'

This dissertation addressed questions pertaining to mercury (Hg) fate and transport in aquatic ecosystems by applying stable Hg isotopes as a tracer. Mercury poses a public health burden worldwide. In parts of the developing world, Hg-use during artisanal and small-scale gold mining (ASGM) is pointed at as the source of elevated Hg in the environment. However, Hg from other sources including soil erosion associated with land cover and land-use change (LCLUC) may also contribute to local Hg pollution.

Stable Hg isotope profiles of sediment cores, surface sediments, and soils from two aquatic ecosystems in Amapá, Brazil, one downstream artisanal gold mining (AGM) and one isolated from AGM were assessed. Although previous studies attributed elevated environmental Hg levels in this area to AGM, stable Hg isotopic evidence suggests elevated Hg downstream of AGM sites is dominantly from erosion of soils due to LCLUC.

In contrast, the impact of Hg-use during small-scale gold mining (SGM) in the Southern Andean Region of Portovelo-Zaruma, Ecuador on Hg in the trans-boundary Puyango-Tumbes River was also investigated. By comparing preliminary isotopic Hg signatures from river sediment along the Puyango-Tumbes to soil and sediment from upstream locations along the Puyango tributaries, we suggest Hg-use during SGM in this region is likely responsible for elevated Hg downstream and into Peru. Technical and policy challenges in measuring and responding to gold mining-related cumulative impacts were also reviewed in the context of Portovelo-Ecuador.

Together, the findings not only answer questions of critical importance to preventing Hg pollution in two of the world's most vulnerable ecosystems but also provide information that can be used to better target interventions to reduce environmental Hg levels and subsequent human exposures. Furthermore, the validation and application of the stable Hg isotope method to trace Hg pollution from ASGM in different aquatic ecosystems represents a critical step to the application of stable Hg isotopes to trace pollution in other complex natural environments and to address public health-related questions.

Cardiovascular disease and diabetes are a growing problem around the world and both considered leading causes of death in the United States. Cardiovascular disease is often not diagnosed until it advances to causing serious problems such as heart attacks. Diabetes can greatly increase the risk of cardiovascular disease so diagnoses is important. Metabolic syndrome is a relatively easy way to predict who is at risk of these diseases or to make an early diagnoses. The syndrome is diagnosed in patients that meet 3 or more criteria relating to obesity, blood pressure, triglycerides, cholesterol, and glucose in an individual. Calcium scores, a result of a specific body scan, are a good indicator of cardiovascular disease but are not commonly performed. Metabolic syndrome can be diagnosed using information from a routine physical with blood work. This paper observed the prevalence rate of metabolic syndrome in a cohort of police officers who responded to the September 11th attack at the World Trade Center in New York City. In our study population, the prevalence of metabolic syndrome was 26%. We also found a correlation between calcium scores and the number of metabolic syndrome criteria met; patients meeting all 5 criteria had significantly higher calcium scores with a p-value of .02 and 95% confidence interval of 1.084-2.583.

Stakeholder engagement in a health impact assessment (HIA) is a way to involve communities in the decision-making process of a proposed project or policy. Research conducted on the proposed Wishbone Hill Coal Mine (WHM) in Alaska sought to identify if participants felt the stakeholder engagement process used in a recent HIA was able to respond to cultural differences and inequitable distribution of health impacts. Using a qualitative methodology, 12 interviews were conducted with individuals who participated in the WHM HIA. Results indicate that existing issues of trust between the general public, Alaska Native peoples, and the government impact how the findings of an HIA are received by stakeholders. Recommendations were developed from the research findings and are intended to support continued public trust in the use of HIA in the State of Alaska. Recommendations include ensuring HIA practitioner competencies when working with communities, and implementing transparent stakeholder engagement processes.

Long-term consequences of environmental lead exposure in Kosovo: Effects of pre and postnatal lead exposure in early adulthood Pashko R. Camaj Between May 1985 and December 1986, a cohort of 1,502 pregnant women was recruited at two government clinics in Kosovo (formerly a province of Yugoslavia) for a study of the relationship between environmental lead (Pb) exposure and birth outcomes. Subsequently, a representative group of 541 of their children were selected for long-term follow up. The children were followed longitudinally at six-month intervals for 12 years to examine the effects of environmental Pb exposure on a variety of health outcomes including cognitive and motor function, anemia, endocrine function and growth. This work produced numerous landmark publications (Popovac et al, 1982; Graziano et al., 1990, 1991, 2004; Murphy et al., 1990; Factor-Litvak et al, 1993, 1996, 1998, 1999; Wasserman et al,. 1992, 1994, 1997, 1998, 2000) that contributed to the modification of environmental policies to reduce Pb exposure worldwide. The long-term study ultimately linked environmental Pb exposure from the Trepca mining and smelting operations in Mitrovica to adverse effects on intelligence, motor function, blood pressure, renal, endocrine and hematological functioning. Follow up rates over time were excellent in that 70% of the total cohort was evaluated at 6 years of age, and 65% were evaluated at 12 years of age, at which point the study was - until now - concluded. For the present study, we located 101 members of the original study cohort and requested their participation in a follow-up study in which participants were evaluated to assess their current blood lead (BPb) levels and health outcomes as follows: a) blood pressure; b) biomarkers of endothelial cell function that are associated with cardiovascular disease; c) and measurements of erythropoietin, a glycoprotein hormone produced in the kidney that regulates the production of red blood cells in the bone marrow. The participants, whose environmental exposure history is very well documented from 12 weeks of gestation through 12 years of age, were between 25-26 years of age during the follow-up study. We found a statistically significant association between BPb and systolic blood pressure (sBP), and a marginally significant association between BPb and diastolic blood pressure (dBP), which is consistent with a multitude of studies and meta-analyses referenced in this dissertation. These results provide further evidence that recent circulating dose, as estimated by BPb, or as estimated by lifetime cumulative exposure, is associated with slight increase in sBP. Furthermore, we detected a suggestive relationship between BPb and levels of circulating serum intercellular adhesion molecules (sICAM-1) and serum intravascular adhesion molecules (sVCAM-1), possibly a mechanism by which Pb may lead to increased BP. These findings support the hypothesis that the exposure to Pb either prenatally or in early adulthood, may lead to increased BP and increased circulating levels of sICAM-1 and sVCAM-1 later in life. Lastly, the results regarding the serum erythropoietin (EPO) production presented here resemble the findings reported in this cohort at 4.5 and 6.5 years of age and in contrast with the findings in this cohort when the study participants were 9.5 and 12 years of age (Graziano et al., 2004). In addition, they also contrast the findings reported in the anemic mothers of this study cohort (Graziano et al., 1991) where serum-EPO levels were lower in those with higher BPb levels.

The use of pharmaceutical products has steadily increased in the United States from 2 billion prescriptions in 1999 to 3.9 billion in 2009. Half of patients do not comply with the recommended prescription regimen and dispose of unused drugs in the environment. The U.S. Environmental Protection Agency and many researchers have highlighted the human-health risks associated with improperly disposing of pharmaceutical products. This quantitative cross-sectional study examined the potential correlations between people’s actual disposal practices and their knowledge of the impact of disposal practices on the environment and human health, and availability of disposal options. The conceptual framework selected for this study comprised 2 models: the health belief model and the theory of planned behavior. Respondents to an online survey were 485 residents of the northeast United States, polled from the general population. Descriptive statistics and logistic regression were used to model responses from the dependent variable actual disposal practice (ADP) across the independent variables, and analysis of variance explored whether ADP differed across demographic variables. Statistically significant associations emerged among individuals’ knowledge of environment and human-health impact, recommended disposal practices, disposal options, and that person’s likelihood to practice recommended disposal. Demographic variables did not impact disposal behavior. To promote positive social change, it is recommended that policymakers plan and implement the expansion of convenient drug disposal options, as well as information campaigns on proper disposal practices. In parallel, health care professionals should stress to their patients the importance of complying with prescribed regimens, thus minimizing the amount of unused or expired medications.

Vibrio bacteria are emerging pathogens responsible for 80,000 illnesses and 100 deaths in the United States each year. Infections are directly linked to the marine environment and are acquired by consuming contaminated seafood or exposing wounds during aquatic activities. Florida has the highest national incidence of vibriosis, with 20% of its cases reported from the Indian River Lagoon region, a popular recreation destination. This study utilized a combination of cultivation and molecular techniques to investigate the local distribution of V. vulnificus, V. parahaemolyticus and V. cholerae in this local waterway.

The targeted species were found in an array of samples which may facilitate their transmission to humans. Overall, these bacteria were abundant in estuarine sediments (Vp: 2,439 CFU/g, Vv: 303 CFU/g, Vc: 176 CFU/g), on the sharp edges of oyster shells (Vp: 82 CFU/cm, Vv: 102 CFU/cm, Vc: 41 CFU/cm), and in the water column (Vp: 3.78 CFU/ml, Vv: 5.51 CFU/ml, Vc: 2.46 CFU/ml). Vibrio also pose a hazard to recreational anglers as they were recovered from fish (Vp: 61%, Vv: 55%, Vc: 30%), live bait shrimp (Vp: 80%, Vv: 37%, Vc: 0%) and hooks (Vp: 32%, Vv: 18%, Vc: 0%). Additionally, a molecular analysis of the V. vulnificus virulence revealed that the local population was dominated by disease-causing (vcgC) strains, which may explain why wound-related infections are common in this region.

Vibrio occurrence varied both spatially and temporally due to their relationship with salinity and temperature. These bacteria exhibited a strong negative correlation with salinity, being particularly abundant near freshwater discharge locations. Due to Florida’s year-round warm climate, these species were found to be permanent members of the local microbial community. Seasonal peaks in abundance occurred between August and October, a period which corresponds with the warmest water temperatures as well as frequent rainfall. Predictive models were constructed based on these parameters to provide a better understanding of how, when and where Vibrio spp. may be encountered by humans. This information is important for both water management and healthcare initiatives, with an overall goal of improving local recreational safety.