Thesis--University of Pittsburgh. / Vita. Includes bibliographical references.

<p> Non-alcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease. The spectrum of NAFLD ranges from simple steatosis, to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and potentially hepatocellular carcinoma. Dietary factors and chemical exposure have been associated with the disease progression. In addition, the presence of NAFLD changes the metabolism of drugs and chemicals, which may in turn increase the susceptibility of the liver to xenobiotic induced toxicity. To examine the potential interplay of chemicals on diet-induced NAFLD, three studies were conducted in this dissertation project. In the first study, a mouse model was established that recapitulated the spectrum of liver damages seen in human NAFLD. Using a high fat diet (HFD), steatosis, NASH, progressive fibrosis, and liver tumor formation were produced in mice. Modulations of nuclear receptors involved in metabolism of endogenous and xenobiotic compounds were characterized at various stages of NAFLD. Using this mouse model, a second study examined if perfluorooctanoate (PFOA), a ubiquitous environmental contaminant, modulated the progression of NASH. The results showed PFOA induced hepatic DNA synthesis and liver inflammation were exacerbated in the mice fed with HFD. In contrast, PFOA decreased the severity of hepatic steatosis and fibrosis induced by HFD. To further investigate the mechanisms underlying these observed effects, a third study was performed that analyzed the hepatic transcriptome in liver samples taken from studies 1 and 2. The results of the third study demonstrated that cytokine and chemokine-related genes played important role in the development of both inflammation and fibrosis in NAFLD. Comparing PFOA to vehicle controls in HFD fed mice, PFOA disrupted the lipid homeostasis to favor clearance in the fatty liver, as most of the genes were enriched in the fatty acid oxidation pathways. In summary, this project established and a mouse model of HFD induced NAFLD and characterized the interplay of diet and chemicals in the disease progression. The results from this dissertation also indicated that patients with NAFLD may respond differently compared with healthy individuals. The potential susceptibility of this population to chemically induced hepatotoxicity needs to be carefully considered when assessing risk.</p><p>

abstract: In recent years, overall consumption of meat products has been decreasing, and at the same time vegetarianism is on the rise. A variety of factors are likely driving changes in consumers' attitudes towards, and consumption of, meat products. Although concern regarding animal welfare may contribute to these trends, growing consumer interest in the roles that production and processing of meat play in terms of environmental degradation could also impact individuals' decisions about the inclusion of meat in their diets. Because these factors could be related to moral attitudes as well, the purpose of this study was to explore the relations among meat consumption, general environmental attitudes, and moral `foundations' of decision-making, including concern about minimizing `harm' and maximizing `care,' as well as issues of `purity' and `sanctity.' A survey was conducted among current college students using the New Ecological Paradigm scale and the Moral Foundations Questionnaire to assess environmental and moral attitudes. A food frequency questionnaire was used to assess meat consumption. Multiple linear regression analyses explored the relations of environmental and moral attitudes with meat consumption, controlling for potential confounding variables. The results showed no significant correlations among meat consumption, environmental attitudes or moral foundations of harm/care and purity/sanctity. / Dissertation/Thesis / M.S. Nutrition 2013

Seabird-derived nutrients enhance plant abundance in coastal ecosystems, increasing rates of primary productivity, and indirectly increasing consumer populations. However, at Cape Vera, concentrations of contaminants in the sediment of ponds below nesting colonies of northern fulmars (Fulmarus glacialis) are 10 to 60 times higher than in reference ponds (Blais et al. 2005). This pattern suggests that the colony concentrates hexachlorobenzene (HCB), total mercury (THg), and dichlorodiphenyltrichloroethane (DDT) through guano to pond sediments (Blais et al. 2005). It remains unclear whether the effects of these contaminants are localized to the ponds or whether they enter the food chain. This study was designed to determine whether organochlorines and mercury were transferred from a seabird colony to coastal food webs. Contaminant concentrations were measured in primary producers and animals. Nitrogen stable isotopes were used to detect seabird influence. Concentrations of SigmaPCB and SigmaDDT in organisms were high relative to other Arctic areas; however, THg concentrations were similar. Snow buntings (Plectrophenax nivalis ) had SigmaPCB (mean: 168 ng/g ww) and SigmaDDT (mean: 106 ng/g ww) concentrations that surpassed environmental guidelines for protecting wildlife. Biovector transport may be a source of contaminants to certain organisms at Cape Vera.

Sediments, located near Cornwall have been historically contaminated with Hg and other metals by local industries. Cornwall was designated an area of concern by the International Joint Commission (IJC) in 1985. The concentrations of mercury in these sediments exceeded the sediment quality guideline (SQG), of 170 ng g-1 set by Environment Canada for the protection of aquatic biota. To identify the role of these contaminated sediments on mercury dynamics in the river, I measured concentrations of total mercury (THg) and methyl mercury (MeHg) in both the porewater and solid phase of sediment cores and in the overlying water to determine whether sediments are a net source or sink for Hg. A comparison of porewater profiles in June, July and August of 2007 revealed little seasonal variation in MeHg concentrations. I also compared THg and MeHg vertical profiles in sediments with complimentary redox-dependent variables, including sulfate, sulfide, and Fe2+ distributions which showed that zones of active sulfate reduction and Fe reduction have little effect on the distribution of dissolved MeHg in the sediments. THg in sediment cores was related to the sediment accumulation rates by 210Pb radiochronology which showed the history of industrial Hg emissions to the river. MeHg contributed 4% to 100% of the THg in the porewater samples, whereas in the solid phase it contributed less than 1% of the THg. There was little to no diffusion of THg and MeHg from sediments to the overlying water. I have concluded that sediments are a major sink for THg and MeHg to the St. Lawrence River near Cornwall.

<p> Industrialized and developed urban centers surround the aquatic ecosystem of San Francisco Bay, and are historic and current sources of anthropogenic contaminants to which resident wildlife is exposed and impacted. An indigenous fish species, the shiner perch (Cymatogaster aggregata), was demonstrated to exhibit significant reductions in plasma tetraiodothyronine (T4) concentrations when sampled from highly industrial Oakland Inner Harbor (OAK) as compared with less impacted locations like Redwood City (RED). This study combined histomorphological evaluation of thyroid follicular tissues and characterization of plasma thyroid hormones, T4 and triiodothyronine (T3). Fish from OAK, but not RED, exhibited reduced plasma T4, T3, and total thyroid hormones, changes that were significantly correlated with thyroid glandular changes including reduced follicular colloid sizes. The findings indicate environmental disruption of thyroid hormone biosynthesis and possible thyroid gland compensatory responses (to low thyroid hormone levels) given the reduced colloid volumes.</p><p>

M.Dip.Tech.(Environmental Health) / At the onset of this project the aim was to utilise fly ash, supplemented with lime, to stabilise sewage sludge, in so doing create an artificial soil. This would be an environmentally friendly method of disposing of both the fly ash 'and the sewage sludge which are both considered wastes. The sewage sludge was pasteurised by the temperature produced by the exothermic reaction between the moisture ofthe sewage sludge and the high pH ofthe fly ash and the lime. Initially very high concentrations of lime were utilised to achieve the pasteurisation of the sewage sludge. These levels proved to be adequate to completely sterilise the sludge, rather than pasteurise it, as temperatures in excess of 1000e were obtained and maintained for a prolonged period. The product, SLASH, should ideally maintain some of the non-pathogenic microorganisms to facilitate natural degradation processes in the soil. .It was thus decided to minimise the lime addition and maximise the ash usage without losing the necessary soil-like texture of the SLASH product and still insuring pasteurisation. Various 10kg tests were conducted on differing ratios of sewage sludge, ash and lime. The mixtures were contained in insulated 220 litre drums in order to ensure a minimum of interference from environmental factors. The tests were conducted with the drums sealed and unsealed, as well as with coarse and finely milled lime-stone. These laboratory scale tests led to the establishment of a preferred 6:3:1 ratio ofsewage sludge to ash to lime. After an international visit to a plant manufacturing a similar product, it was suggested that the ratio be amended to 6.3:3.4:0.6 of sewage sludge to ash to lime. Tests showed that although the temperatures obtained when using this ratio were insufficient for pasteurisation, pasteurisation did occur. This was attributed to the maintenance of the pH of the product above 12 for more than 24 hours. This severely stressed the microorgansims and they died. No pathogenic bacteria were detected in the analyses from these tests, but the total aerobic bacterial count indicated the presence of some microorganisms which would become part of the soils natural flora.

<p> The adverse effects of air pollution on human life is of serious concern for today&rsquo;s society. Two population groups that are especially vulnerable to air pollution are pregnant women and their growing fetuses, and the focus of this thesis is to study the effects of air pollution on these populations. In order to address the methodological limitations in prior research, we quantify the impact of air pollution on various adverse pregnancy outcomes, utilizing machine learning and novel causal inference methods. Specifically, we utilize two semi-parametric, double robust, asymptotically efficient substitution estimators to estimate the causal attributable risk of various pregnancy outcomes of interest. Model fitting via machine learning algorithms helps to avoid reliance on misspecified parametric models and thereby improve both the robustness and precision of our estimates, ensuring meaningful statistical inference. Under assumptions, the causal attributable risk that we estimate translates to the absolute change in adverse pregnancy outcome risk that would be observed under a hypothetical intervention to change pollution levels, relative to currently observed levels. The estimated causal attributable risk provides a quantitative estimate of a quantity with more immediate public health and policy relevance.</p><p>

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The goal of this study was to determine the instantaneous vs. integrated effects of waste on the water quality of the Chorobamba River. I sampled 9 stations upstream and downstream of the Town of Oxapampa, Peru during the dry season (June-August) of 2004. I measured in-situ parameters such as pH, DO, temperature, etc. as well as vegetation, riverbank erosion, nutrients (N03, NH4, P04), coliform bacteria and macroinvertebrate communities to determine the current conditions of the river, as well as the integrated effects of pollution. Although water quality conditions remained stable, high fecal coliform concentrations and macroinvertebrate communities indicate deterioration in river health over a longer period of time. If riparian areas along the Chorobamba continue to decrease and if inputs of sewage into the rivers continue to increase, as a function of population, then, conditions will continue to deteriorate in the coming years.