BACKGROUND: Military personnel are occupationally exposed to chemical mixtures at domestic locations and in theater. At military bases, a chemical hazard of concern is JP-8 jet fuel, the largest chemical exposure in the United States Air Force (USAF). We examined blood concentrations of JP-8 constituents as biomarkers of exposure and determined if workday exposure is associated with diminished balance control. Veterans of the 1990-1991 Gulf War (GW) were exposed to mixtures of chemicals in theater and about a third of GW veterans developed GW illness (GWI) on return from deployment. We identified health symptom profiles in the GWI literature and examined longitudinal exposure-symptom relationships in a subset of GW veterans. METHODS: In USAF personnel, personal air, urine, and blood samples were analyzed for components of JP-8. Separate multivariate linear regression analyses were conducted to examine relationships between personal air and post-shift blood volatile organic compounds (VOCs) and between JP-8 exposure and postural sway. Meta-analytic techniques were conducted to determine pooled prevalence and combined odds ratios of symptoms comparing GW and GW-era control veterans. Repeated logistic regression models stratified by sex examined the association of GW exposures and symptoms. RESULTS: Blood VOC concentrations were higher among participants with work-shift JP-8 exposure and breathing zone total hydrocarbons significantly predicted VOC blood levels. Postural sway outcomes were associated with personal variables and task difficulty but not JP-8 exposure. GW veterans had higher odds of reporting all analyzed symptoms compared to GW-era controls, with 20% excess prevalence for fatigue, memory problems, and joint pain. Men had more significant associations between GW exposures and symptoms compared to women. Specific exposures were significantly associated with higher symptom reporting over time. CONCLUSION: In USAF personnel, blood VOC concentrations reflected work-shift exposure to jet fuel, supporting their use as biomarkers of JP-8 exposure. Work-shift exposure to JP-8 did not diminish balance control. Health symptoms evaluated through meta-analysis with the largest summary odds ratios were consistent with the symptom clusters reported in case definitions of GWI. The associations between GW exposure and longitudinal symptom reporting differed between men and women. / 2019-11-08T00:00:00Z

Beginning in the inter-war years and ending in the early 1970s, this thesis explains how and why the 'environment' came to play a significant role in mainstream British politics. During this period, a range of rural and urban problems became conceptualised as 'environmental', and governments came to understand their responsibilities not simply in terms of providing basic standards of public health, but also in terms of improving the broader 'quality of life' of all citizens. Chapter two explores rural preservation in the inter-war period, and the passage of town and country planning and National Parks legislation in the 1940s. Chapter three examines air pollution, focusing on the London smog of 1952 and the passage of the 1956 Clean Air Act. Chapter four explores Britain's early nuclear power programme, and shifting attitudes towards modernisation, risk and the countryside in the 1950s and 1960s. Chapter five examines the growth of political interest in 'environmental' problems during the 1960s, and the eventual formation of the Department of the Environment in 1970. Finally, chapter six focuses upon the challenge of traffic in towns, exploring proposals for the construction of a motorway network in London in the late 1960s and early 1970s. The thesis concludes that the 'environment' was established as a field of public policy by the early 1970s. Whereas many existing accounts have emphasised the importance of radical critiques of human interaction with the environment, it is the contention of this thesis that environmental politics in Britain developed in the political mainstream, taking shape amid efforts to address new challenges of governance. The rejection of modernity, in the form of industrialisation, urban life, consumer culture and economic growth, was never more than a minority position within British politics, and successful arguments for environmental protection had to be framed in line with dominant social and economic priorities.

This dissertation research represents one of the first attempts to investigate the structural and functional microbial ecology of methanol, ethanol and glycerol fostered denitrification. The overarching goal of this research was to elucidate the link between the structure and function of denitrifying microbial populations grown on different carbon sources. Specific objectives were to: 1) diagnose bacteria specifically assimilating methanol and ethanol and determine denitrification kinetics induced by the two carbon sources; 2) investigate factors leading to nitrous oxide (N2O) and nitric oxide (NO) emissions from methanol and ethanol feeding denitrification reactors; 3) characterize glycerol assimilating populations that perform suspended- and biofilm-growth denitrification; 4) examine the potential of using alcohol dehydrogenase gene as a biomarker for methanol and glycerol induced denitrification activity; 5) evaluate the impact of different carbon sources (methanol and ethanol) on the transcript and proteome of a model facultative methylotroph, Methyloversatilis universalis FAM5. First, the technique of DNA stable isotope probing and quantitative polymerase chain reaction were adapted to diagnose and track methylotrophic denitrifying bacteria in activated sludge. Methanol assimilating populations in the methanol fed denitrifying sequencing batch reactor (SBR) were Methyloversatilis spp. and Hyphomicrobium spp. related species. Upon switching to ethanol, only Methyloversatilis spp. was sustained pointing to their metabolic versatility at least with respect to carbon assimilation. This study represents one of the first investigations of the existence and utilization of facultative methylotrophy in activated sludge. Second, the potential of N2O and NO emitted from methanol and ethanol fed denitrifying SBRs was studied during different transient shocks, including organic carbon limitation, nitrite inhibition and oxygen inhibition. Organic carbon limitation and exposure to nitrite did not result in statistically significant emissions over the control. However, statistically higher N2O emissions were observed during exposure to oxygen on the ethanol fed biomass and coincided with sustained denitrification activity in the presence of oxygen. Therefore, the results suggest that the dosage of ethanol to anoxic zones needs to be strictly controlled to minimize N2O emissions in the downstream aerobic zones. Third, the structure-function analysis of denitrification was extended to glycerol (the main component of biodiesel waste and a potential replacement for methanol) in both suspended and biofilm phases of a hybrid integrated fixed-film bioreactor. During long-term operation on glycerol, the biofilm community had a higher phylogenetic diversity (dominated by Comamonas spp., Bradyrhizobium spp., and Tessaracoccus spp.), and lower denitrification kinetics than the suspended community (dominated by Comamonas spp. and Diaphorobacter spp.). Distinct identities of glycerol assimilating populations due to the different substrate availability in the suspended and biofilm phases were shown for the first time. Fourth, carbon source-specific biomarkers of denitrification activity based on gene expression were developed. Based on short-term batch denitrification activity assays as well as long-term bioreactor operation, the applicability of alcohol dehydrogenase gene expression as quantitative descriptors of denitrification activity on methanol and glycerol in mixed cultures was demonstrated. Finally, Methyloversatilis universalis was selected as model organism to study the effects of varying electron donors (from methanol to ethanol) on its gene and protein expression profiles. Genes encoding essential enzymes that involve carbon oxidation, C1 assimilation and central metabolism were found to be differentially expressed during growth on methanol and ethanol. Several physiological and metabolic responses by M. universalis pointed to a well-defined strategy to overcome carbon limitation for surviving in engineered or natural denitrifying environments. In sum, the structural and functional ecology and the metabolism of heterotrophic denitrification on methanol, ethanol and glycerol as applicable to engineered denitrifying bioreactors was investigated in detail. From an engineering perspective, the knowledge gained can help to guide the selection and application of potential organic carbon sources for denitrification in biological nitrogen removal systems. It is expected that such judicious selection can also eventually result in better design, operation and control of engineered nitrogen removal processes and thus help attain ever more stringent nitrogen standards.

Choosing among technologies is difficult and requires a means of making comparisons across different technologies. This dissertation proposes a new methodology to make comparisons across different technologies and across different times based on a user supplied set of evaluation criteria. A simple model is developed to evaluate different technologies and to identify optimal technologies and technology pathways based on a user supplied set of evaluation criteria which allow ranking of different plants, and technology pathways, which represent different time sequences of introducing new power plant designs. This model is applied to a simple set of choices for power plant designs that invovle eight basic operation modules and a total of 96 possible power plant designs, of which 18 are physically feasible. The model also considers five unique pathways of transition over time from one type of power plant to another type. These pathways are ranked based on penalties assigned on the module level, plant level and pathway level. This dissertation studies two cases, where CO2 regulation does and does not take effect. The results show that a shorter path is favorable, and multiple changes at the same time is undesirable. The relative ranking of different pathways are different in the two cases. To find the optimal path among the entire space of solutions, we develop two combinatorial optimization algorithms. The objective function is defined as the minimum of penalties which are imposed for all deviations from an ideal or perfect system. The numerical problem of finding an optimum is solved by means of a branch-and-bound method, and a heuristic based on the label-correcting algorithm for solving the shortest-path problem. The proposed algorithms are applied to the practical examples of finding the optimal sequence of various power plant designs. The computational results show that the performance of the path-dependent shortest path algorithms depends on the structure of the problem. For average problems, the branch-and-bound algorithm is more efficient compared with the brute force search approach. In the worst case, the branch-and-bound algoirthm degenerates into the brute-force search approach. Both branch-and-bound and the brute-force search approach are exact methods. For average problems, the heuristic is more efficient than the branch-and-bound algorithm. The heuristic is not an exact method and there is no guarantee that it always finds the optimum. However, it can find a good result in a reasonable time. We use these algorithms to study technology pathways which consist of power plant designs with CO2 post-combustion capture technologies. We consider a small problem that consists of 6 designs and 14 levels of decisions, a medium problem consisting of 84 designs and 15 levels of decisions, and a big problem consisting of 492 designs and 15 decisions. We use the branch and bound algorithm for the small problem, and the heuristic for the medium and big problems. The results of small, medium and big problems show that, the best technology pathway, or the best sequence of technologies, does not agree with the sequence of best technologies of various times. By choosing a suboptimal design upfront, one can obtain a better technology pathway than the pathway with a sequence of best designs. We develop a flexible software tool that enables process modeling and optimization of complicated energy systems. The software tool models a plant in terms of basic operation modules and streams that connect the modules with material and energy flows. The software represents the beginning of new modling capability that is useful for studying individual energy systems. It introduces a new concept in comparison to traditional software tools by optimizing over entire technology pathway consisting of a time sequence of plant designs and technology choices.

A major challenge in integrating high penetrations (>20%) of solar- and wind-energy rests in the grid's ability to cope with the intrinsic variability of these renewable resources. Although such high levels of penetration may be a decade or two away in most operating regions, we must find measures to manage the variability of these sources, especially when conventional market-based approaches are exhausted or ineffective. Furthermore, besides assuring reliability, effective integration of high levels of solar- and wind-power can reduce the `hidden' environmental costs and emissions associated with larger than necessary backup capacity. With large-scale PV plants (>250 MW) becoming significant generators on the grid in the near future, system operators became concerned about the plants' inherent variability, and questions were raised regarding the predictability and reliability of the output from such PV plants. In the first part of this research, the variability in the power output of six PV plants in the United States and Canada, with a total installed capacity of 195 MW (AC), is characterized. A new metric called the Daily Aggregate Ramp (DAR) is introduced to quantify, categorize, and compare daily variability across multiple sites. With this metric, and by harmonizing for climatic differences across the plants, we quantified the effect of geographic dispersion in reducing the cloud-induced power fluctuations. In addition, the reduction in variability was assessed by simulating a step by step increase of the plant size at the same location, using individual inverter data. Our data analysis showed maximum ramp rates 0.7, 0.58, 0.53, and 0.43 times the plant's capacity for 5, 21, 48, and 80 MW (AC) plants, respectively. After the variability in plant outputs was understood and quantified, we investigated algorithms for operating Energy Storage Units (ESU) to perform ramp rate control at the plant level. This task is designed to support proposed plans of grid balancing authorities to deal with ramps of variable energy resources (i.e., solar and wind). ESUs can be used to mitigate penalty fees caused by sharp ramps and perhaps allow for additional revenue streams by participating in grid balancing markets (e.g. frequency regulation). Consequently, we focused on building and optimizing ESU dispatch models for controlling ramp rates of individual PV plants within predetermined levels. The model comprised dispatch strategies tailored to specific fast response ESU technologies (e.g., flywheels, capacitors, batteries). The optimization involved trial and error testing of different combinations of ESU technologies, power and energy capacities, dispatch strategies and violation reduction requirements. For four PV plants (5, 21, 30.24 and 80 MW) in various North American locations, we found a required ESU power capacity of 2.2, 9, 12 and 22 MW respectively, to mitigate 99% of the violations of a 10%/minute ramp rate limit. These ESU capacities may add capital costs of about $0.35-0.63 per Watt PV for the 80 MW plant and $0.56-0.94 per Watt PV for the 5 MW plant. Lowering the mitigation requirement to 90% reduces the necessary ESU power capacity (and per Watt PV costs) to 1.1 MW ($0.27), 4.4 MW ($0.27), 6.4 MW ($0.27) and 10.8 MW ($0.18), respectively. Curtailment of power at the inverter during upward ramps reduces the number of violations even further and effectively decreases the necessary ESU capacity to approximately: 0.8, 3.1, 4.5, and 7.6 MW (for the 90% violation mitigation). It is noted that the reported ESU capacity additions and associated costs are based on the assumption of no forecasting or only a one-minute ahead forecasting of cloud-induced solar variability. If forward time forecasting is available, the optimization we developed should result in lower ESU capacity requirements as gradual ramp rate controls could be implemented in advance. Another way to reduce the costs associated with ramp-rate controls is to use the ESU for other revenue-generating activities, such as frequency regulation for which markets exist in different operating regions (e.g. the Real-Time Market of the New York Independent System Operator (NYISO)). Since ramp rate violations in the various facilities we studied, occurred in less than 2% of the time during the year, such additional uses of ESUs are possible.

<p> Mutations are the ultimate source of genetic variation. Understanding the rate and environmental influence on mutation rate is therefore critical for understanding the origin of human disease and all evolutionary change. Environments, including chemical environments, are rapidly changing around the globe. Over the past seven decades, more than 140,000 novel chemicals have introduced into the market. However, less than 2% of these chemicals have been thoroughly characterized with toxicological assays. </p><p> Because the majority of germline mutations have a neutral or negative impact on fitness, pollutant-induced mutagenesis can be devastating for ecosystems and can increase the rate of human disease. However, the influence of chemicals on the rate of germline mutation has been largely ignored. We therefore utilized Daphnia pulex to, (1) characterize the rate and spectrum of genome-wide mutation, (2) measure the influence of chronic, cadmium exposure on the germline mutation rate, and (3) investigate if adaptation protects the germline from mutagenesis. </p><p> The single nucleotide mutation (SNM) rate in <i>D. pulex</i> is similar to other model organisms. However, the rate of large-scale de novo copy number variants is 10 to 100-fold higher than other organismal models and is identical to the estimated rate in humans. Exposure to cadmium was mutagenic in the germline, altering the genome-wide rates and spectra of multiple SNM classes and changing the SNM rates in multiple genome regions. Since drastic, pollutant-induced changes to germline mutation have not previously been described, we developed a quantitative model for predicting population response to mutagenic pollutants. Finally, with a cadmium-adapted genotype we show adaptation protects the germline from cadmium-induced mutagenesis. The knowledge gained through this research stands to have profound implications for society and the long-term health of populations, which are living longer in the presence of a growing diversity of potentially mutagenic chemicals.</p><p>

abstract: Iodide (I-) in surface and groundwaters is a potential precursor for the formation of iodinated disinfection by-products (I-DBPs) during drinking water treatment. The aim of this thesis is to provide a perspective on the sources and occurrence of I- in United States (US) source waters based on ~9200 surface water (SW) and groundwater (GW) sampling locations. The median I- concentrations observed was 16 μg/l and 14 μg/l, respectively in SW and GW. However, these samples were rarely collected at water treatment plant (WTP) intakes, where such iodide occurrence data is needed to understand impacts on DBPs. Most samples were collected in association with geochemical studies. We conclude that I- occurrence appears to be influenced by geological features, including halite rock/river basin formations, saline aquifers and organic rich shale/oil formations. Halide ratios (Cl-/I-, Br-/I- and Cl-/Br-) were analyzed to determine the I- origin in source waters. SW and GW had median Cl-/I- ratios of ~3600 μg/μg and median Br-/I- ratios of ~15 μg/μg. For states with I- concentration >50 μg/l (e.g., Montana and North Dakota), a single source (i.e., organic rich formations) can be identified. However, for states like California and Texas that have wide-ranging I- concentration of below detection limit to >250 μg/l, I- occurrence can be attributed to a mixture of marine and organic signatures. The lack of information of organic iodine, inorganic I- and IO3- in source waters limits our ability to predict I-DBPs formed during drinking water treatment, and new occurrence studies are needed to fill these data gaps. This is first of its kind study to understand the I- occurrence through historical data, however we also identify the shortcomings of existing databases used to carry out this study. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2018

Fast moving hurricanes and stationary nor’easters have resulted in significant flood damage in Chesapeake tidewater communities. The Chesapeake Bay region is one of A m erica’s most vulnerable regions with respect to sea-level rise, which will only increase storm surge impacts over upcoming decades. While the general trends are well documented, there is limited information relevant to specific communities’ relative flood risk and response. The dearth o f data is especially troublesome given the lengthy period o f time generally needed for communities to plan and implement adaptive action. This study contributes to the regional understanding of flood and sea-level rise vulnerability by applying physical, social, and combined vulnerability indices to tidally influenced localities along the Chesapeake Bay. Unlike other combinations of physical and socioeconomic data, the physical vulnerability index for this study is calculated at a scale that can directly link into social vulnerability index information at local and regional levels. The research also considers the distribution of coastal natural capital (in the form o f marshes and forests) alongside these indices at comparable scales. By calculating the indices for conditions o f the early 2000s, this study also tested their predictive value against Hurricane Isabel, a landmark 2003 storm that flooded areas across the region. Systematic verification “hindcasts” o f past events are relatively rare for vulnerability index evaluation. By attempting to establish connections between real flooding data, socioeconomic activity, and vulnerability indices, this study questions whether theoretical vulnerability indices work as true proxies for real world conditions. The results question the true utility o f these indices by showing limited relationships between vulnerability and changes in community socio-economic activity. The research also emphasizes the need for more data collection and consideration in order to better comprehensively understand coastal flood impacts and their management implications.

As created wetlands are becoming more common due to compensatory mitigation under section 404 of the Clean Water Act, it has become important to understand how the vegetation community and the soil nutrient availability develop over time. For a created wetland to replace the function of the destroyed natural wetland, the biogeochemical cycling and vegetation community must replicate the natural system. In this study, I sampled the vegetation community as well as the soil and porewater nutrient availability in four created wetlands in southeastern Virginia, constructed and managed by the Virginia Department of Transportation. All the sites used in this study had areas of dense Typha spp. stands, which had been identified as problem areas by the site managers,based on inferences from previous research indicating Typha are invasive in other types of wetlands. In many of these sites, the Typha populations were removed by cutting and herbicide spraying, due to the assumption that the dense Typha stands hinder the biodiversity and therefore reduce the functionality of the created wetlands. As part of this study, I sampled the composition of the vegetation community both within Typha stands and in areas dominated by other species. I was able to show that the dense Typha stands do not lower the species richness or the Shannon diversity index of the vegetation community. I also measured the nutrient availability associated with Typha stands and areas dominated by other vegetation and found no consistent significant differences in soil nutrient availability. However, I did observe a change in nutrient concentration across all vegetation communities and in all study sites from 2006 to 2007. The soil a range of 20 and 55 in 2007. These results may indicate that as created wetlands mature the amount of soil total phosphorus (TP) decreases and the amount of total nitrogen (TN) increases, resulting in a steady state of P limitation relative to N as the site matures. Since these conclusions are based on only two years of data, longer-term research is needed in created wetlands to verify trends in soil TP and TN dynamics as these sites mature.

A time-series of erodibility measurements and physical and biological sediment properties was used to evaluate spatial and temporal variability in cohesive bed erodibility and controls on erodibility in the York River estuary, VA. Two sites near Clay Bank displayed dramatic seasonal variations in bed erodibility while a third near Gloucester Point displayed a more consistent level of low erodibility. Total bed solids fraction and cohesive sediment grain size were not correlated with bed erodibility. The surficial sediments were characteristically composed of 2% to 50% sand supported in a mud matrix. The total solids fraction of the bed was shown to be a function of sand fraction, complicating its use as a measure of bed consolidation. The solids fraction of the mud matrix was calculated to evaluate changes in consolidation independent of sand content. An evaluation of data from multiple studies available in the literature demonstrated that when a large range of data was considered, the solids fraction of the mud matrix provided a better correlation to erodibility than did the total solids fraction. However, the range in solids fraction of the mud matrix in York River sediments was quite small and no significant relationship was found locally between this parameter and bed erodibility. Common proxies for bioadhesion including colloidal carbohydrate concentration, extracellular polymeric substance concentration, and organic content were measured to evaluate the influence of biostabilization on bed erodibility. In contrast to the results of many published works studying erodibility on mudflats, these bioadhesion proxies did not exhibit systematic variation in either space or time and were not correlated to bed erodibility. The seasonal timing of erodibility maxima and presence of laminations during periods of highest erodibility indicated that bioturbation was not responsible for increases in erodibility during the winter and spring at Clay Bank. Although not quantified in this study, anecdotal evidence from sediment cores and seabed camera images suggest that biological reworking and repackaging may alter bed cohesivity and structure potentially influencing the relationship between erodibility and bed solids fraction. Periods of rapid deposition, as indicated by the presence of thick sequences of laminated sediments, suggest that periodic sediment flux convergence processes are responsible for the observed seasonal cycle in bed erodibility at Clay Bank. High bed erodibility was associated with rapid deposition in the likely presence of the mid-estuary turbidity maximum while low erodibility was associated with sediment bypassing and decreased deposition in the absence of a local turbidity maximum. Finally, a consistent, low erodibility condition was observed at the Gloucester Point site for the majority of the study period and at Clay Bank in the summer and fall. A comparison of these data to other published data from the Chesapeake Bay indicated that the low erodibility background state may be characteristic of an “equilibrium” bed condition often present in many regions of the Chesapeake Bay. In the absence of recent, rapid deposition, the data set presented from the York River reasonably characterizes both the range and the profile information of the bed critical erosion stress for mid-depth, muddy regions in other similar estuaries.