Native oysters have been promoted as a means to improve water quality in Chesapeake Bay. This project added important insights into the potential of oyster aquaculture to process and remove nutrients from Bay waters. Results clarified that nutrient removal of nitrogen (N), phosphorous (P), and carbon (C) through harvest of cultivated oyster biomass can be quantified and modeled with high levels of statistical confidence. A simple, yet accurate, method is now available for estimating the amount of nutrients removed via harvesting aquacultured oysters. Based on model estimates, 106 harvest sized oysters (76 mm TL) remove 132 kg TN, 19 kg TP, and 3,823 kg TC. Previous work suggested that potentially substantial quantities of N may be removed through enhancement of the coupled nitrification-denitrification pathway in sediments as a result of oyster biodeposition. Using 15N and N2/Ar methods to measure N2 production in sediments, encompassing direct denitrification (DNF), coupled nitrification- denitrification, and anaerobic ammonium oxidation (anammox) pathways, at two oyster aquaculture sites and two reference sites (no aquaculture), we found that oyster biodeposition did not accelerate sediment N removal. We estimate sediment N removal rates via N2 production at an oyster cultivation site producing 5 x 105 oysters (1750 m2) to range from 0.49-12.60 kg N yr-1, compared to 2.27-16.72 kg N yr-1 at a reference site of the same area; making the contribution of oyster cultivation to N removal via sediment N2 production inconsequential as a policy initiative for Chesapeake Bay eutrophication mitigation. Molecular approaches and direct abundance measures have improved our understanding of the sediment microbial community response to oyster biodeposition. Overall, sediments impacted by oyster biodeposition had a significantly different denitrifying community composition than sediments a few meters away or at the non-aquaculture reference sites. Bacterial abundance in sediments was determined by site rather than by oyster biodeposition. No apparent effects of oyster biodeposition were evident in nitrifying bacterial abundance patterns at either site, indicating that oyster biodeposition does not enhance coupled nitrification-denitrification by increasing the abundance of nitrifiers in sediments.

Coagulation is a ubiquitous process in the treatment of raw surface water for eventual potable use. Despite its capabilities, the sheer scale of its use is manifested in the volumes of chemicals it demands and waste sludge it produces. Recovering and reusing the chemical activity of the coagulant sludge in water treatment is a logical solution but this practice has been restricted by the presence of contaminants within the sludge. This thesis has investigated methods that can separate the coagulant metals from these primarily natural organic contaminants, with an aim of producing a sufficiently pure coagulant for effective treatment performance when reused. A process of ultrafiltration of the impure regenerated coagulant followed by a powdered activated carbon polishing stage compared favourably to a number of other separation processes and was found to remove the most dissolved organic compounds. When the purified coagulant was used to treat raw water, it provided better turbidity removal than commercial coagulant and matched its removal of trihalomethane precursors, making the process suitable for consideration at full-scale. Analysis of the whole life cost suggested that such performance could be reproduced at full-scale within a 25 year payback period. The reuse of even purified recovered coagulants in drinking water treatment still carries risks which may deter its implementation. Therefore the efficacy of recovered coagulants in the role of phosphorus removal from wastewater was also investigated. This showed that both acidified and unacidified waterworks sludges, with sufficient contact time, could remove similar levels of phosphorus as fresh coagulants, at approximately half the whole life cost.

Text of this thesis deals with the creation and termination of the position of a member of the governing body of a limited company. The first part of this text sets out the conditions under which this member is legally able to perform in his position, these are full legal capacity, no record of criminal conviction and there are no obstacles to undertaking a trade in the meaning of the Act No. 455/1991 Coll. The text also mentions the provisions § 38l of the Commercial Code, for it still applies on some cases on behalf of the provision § 779, paragraph 3 of the Act on Business Corporations. This text of this thesis continues to deal with the consequences of incapacity to perform in this position and states that in this case, the creation of such position is seen, as it never happened. In the case of capacity to perform in a position being lost after the position was created, the position terminates. Newly, a legal entity can become a member of an elective organ. However, to perform in this position, they have to choose a natural person as their representative. If there is no representative, the legal entity is represented by a member of board of directors or a company director. There were warnings of a possibility of multiplication, as there may be legal entities in such statutory bodies. Further,...

In recent years, endocrine disruption of corticosteroid signaling pathways in wildlife and humans by environmental chemicals have attracted increasing attention. The integrated potential of chemicals in the aquatic environment that disrupt corticosteroid actions have been evaluated using in vitro glucocorticoid receptor (GR) mediated bioassays. Exogenous natural and synthetic corticosteroids (CSs), which are widely used in human and animal therapeutic applications, were demonstrated to be the most important GR agonists, that can potentially cause adverse effects, especially on aquatic organisms. To date, only a few studies have investigated the occurrence and behavior of GR agonists in the aquatic environment and their removal in conventional wastewater treatment plants. Furthermore, there are hardly any data reported on the removal of GR agonists by advanced water and wastewater treatment, especially those synthetic CSs with high potency. To further understand the fate of GR agonists in water and wastewater treatment processes, a sensitive and robust LC-MS/MS method was successfully developed for analyzing a wide range of GR agonists in various environmental waters. The occurrence of GR agonists in surface water and groundwater was monitored along the Lower Santa Cruz River (SCR). Several GR agonists were detected, and a trend of degradation was observed downstream the two WWTP outfalls for both surface water and groundwater. The fate of GR agonists in a local wastewater treatment plant (WWTP) was investigated, and up to 14 GR agonists were detected at different stages. Highly potent synthetic CSs, including clobetasol propionate (CBP), fluticasone propionate (FTP), fluocinolone acetonide (FCA), and triamcinolone acetonide (TCA), were poorly removed in WWTP. Negative removal of some CSs was observed in primary treatment, which may due to the deconjugation of CS conjugates. Removal of GR agonists in secondary effluent during various advanced water treatment processes, including UV, ozonation, MF, RO and chlorination, were studied. UV and RO appeared to be the most efficient treatment process for the attenuation of GR agonists, followed by ozone, while chlorination had little effects on GR agonists in water. Bench-scale experiments were then carried out to investigate the removal of GR agonists by ultraviolet based advanced oxidation processes (UV/AOPs), and powder activated carbon (PAC). UV/chlorine and UV/H2O2 were demonstrated to be effective in removal GR agonists in wastewater, and UV photolysis would be the predominant mechanism in UV/AOP processes. Four types of PACs were tested for removing GR agonists in wastewater effluent, and Cabot HDB carbon was suggested, while Calgon PWA carbon was not recommended due to its low removal efficiency.

Doctor of Philosophy / Agronomy / DeAnn R. Presley / Crop residue removal for livestock feeding and biofuel production at large scales must be evaluated to assess impacts on soil productivity and properties. Among all the potential negative impacts, wind erosion is a major concern in the central Great Plains. We conducted an on-farm study from 2011 to 2013 by removing crop residue at five levels (0, 25, 50, 75, and 100%) to determine the effects of crop residue removal on soil wind erosion parameters such as dry aggregate size distribution including soil wind erodible fraction (EF <0.84 mm aggregates), geometric mean diameter (GMD) and geometric standard deviation (GSD), dry aggregate stability, and soil surface roughness. The sub-model of Wind Erosion Prediction System (WEPS) developed by the USDA-ARS, Single-event Wind Erosion Evaluation Program (SWEEP) is a stand-alone companion software package that can be applied to simulate soil loss and dust emission from a single windstorm event. We applied measured data (i.e. EF, GMD, GSD, and roughness) to SWEEP for predicting wind velocity that can initiate wind erosion and soil loss under each crop residue removal condition with wind velocity at 13 m sˉ¹. The threshold wind velocity to initiate wind erosion generally decreased with increase in crop residue removal levels, particularly for residue removal >75%. The total amount of soil loss in 3 hours ranged from about 0.2 to 2.5 kg mˉ² and depends on soil condition and crop residue cover. On the other hand, high-yielding crops can produce abundant crop residue, which then raises the question that if a farmer wants to reduce residue, what could they do without removing it? The application of fertilizer on crop residue to stimulate microbial activity and subsequent decomposition of the residue is often debated. We conducted wheat straw decomposition field experiments under different fertilizer rates and combinations at three locations in western Kansas following wheat harvest in 2011 and 2012. A double shear box apparatus instrumented with a load cell measured the shear stress required to cut wheat straw and photomicrography was used to measure the cross-sectional area of wheat straw after shearing. Total C and N were also analyzed. The fertilizer rate and timing of application during summer 2012 and Fall 2013 at the Hays site had impacts on wheat straw shear stress at break point. Across site years, earlier (fall) fertilizer application generally resulted in lower remaining aboveground biomass as compared to a spring application. Multivariate and linear regressions suggested that N and C:N ratio partially explain the results observed with respect to treatment effects on winter wheat residue decomposition.

M.Sc. (Geology) / Most rural communities in developing countries rely on borehole water as their only source of water. Since borehole water comes from underground, it is often considered pure and clean, but this is frequently not the case. Groundwater contains certain amounts of trace elements that may become deleterious to human health. The objectives of this investigation were to assess the concentration levels of Potential Harmful Trace Elements (PHTEs) and their spatial distribution patterns in borehole water in the Greater Giyani area of Limpopo, South Africa, and the potential human health risks associated with this. The method of research comprised two phases: (I) In the first phase, I assessed the occurrence and distribution patterns of PHTEs in the boreholes of the Giyani area. A total of 29 water samples were collected from boreholes (including 15 community boreholes and 14 primary school boreholes) in the Greater Giyani area during the dry season (July/August 2012), and for comparison another 27 samples (including 15 community boreholes and 12 schools boreholes) from the same localities during the wet season (March 2013). The samples were analysed for the trace elements arsenic (As), cadmium (Cd), chromium (Cr), selenium (Se) and lead (Pb) using the Inductively Coupled Plasma Mass-Spectrometry (ICPMS) technique. In order to assess the groundwater quality, PHTEs concentrations were compared with the South African National Standard of Drinking water (SANS 241-1:2011). (II) In the second phase, I evaluated the geographic variation between PHTEs and associated human health effects. This involved acquisition of data on a total of 100 cancer cases recorded during the period 2011-2014 at Nkhensani Hospital. ArcGIS Spatial analyst tool was used to create thematic maps illustrating spatial distribution of clinical data and arsenic concentrations in boreholes.

<p>Selenium (Se) is a micronutrient necessary for the function of a variety of important enzymes; Se also exhibits a narrow range in concentrations between essentiality and toxicity. Oviparous vertebrates such as birds and fish are especially sensitive to Se toxicity, which causes reproductive impairment and defects in embryo development. Selenium occurs naturally in the Earth's crust, but it can be mobilized by a variety of anthropogenic activities, including agricultural practices, coal burning, and mining. </p><p>Mountaintop removal/valley fill (MTR/VF) coal mining is a form of surface mining found throughout central Appalachia in the United States that involves blasting off the tops of mountains to access underlying coal seams. Spoil rock from the mountain is placed into adjacent valleys, forming valley fills, which bury stream headwaters and negatively impact surface water quality. This research focused on the biological impacts of Se leached from MTR/VF coal mining operations located around the Mud River, West Virginia. </p><p>In order to assess the status of Se in a lotic (flowing) system such as the Mud River, surface water, insects, and fish samples including creek chub (Semotilus atromaculatus) and green sunfish (Lepomis cyanellus) were collected from a mining impacted site as well as from a reference site not impacted by mining. Analysis of samples from the mined site showed increased conductivity and Se in the surface waters compared to the reference site in addition to increased concentrations of Se in insects and fish. Histological analysis of mined site fish gills showed a lack of normal parasites, suggesting parasite populations may be disrupted due to poor water quality. X-ray absorption near edge spectroscopy techniques were used to determine the speciation of Se in insect and creek chub samples. Insects contained approximately 40-50% inorganic Se (selenate and selenite) and 50-60% organic Se (Se-methionine and Se-cystine) while fish tissues contained lower proportions of inorganic Se than insects, instead having higher proportions of organic Se in the forms of methyl-Se-cysteine, Se-cystine, and Se-methionine. </p><p>Otoliths, calcified inner ear structures, were also collected from Mud River creek chubs and green sunfish and analyzed for Se content using laser ablation inductively couple mass spectrometry (LA-ICP-MS). Significant differences were found between the two species of fish, based on the concentrations of otolith Se. Green sunfish otoliths from all sites contained background or low concentrations of otolith Se (< 1 µg/g) that were not significantly different between mined and unmined sites. In contrast creek chub otoliths from the historically mined site contained much higher (&#8805; 5 µg/g, up to approximately 68 µg/g) concentrations of Se than for the same species in the unmined site or for the green sunfish. Otolith Se concentrations were related to muscle Se concentrations for creek chubs (R2 = 0.54, p = 0.0002 for the last 20% of the otolith Se versus muscle Se) while no relationship was observed for green sunfish. </p><p>Additional experiments using biofilms grown in the Mud River showed increased Se in mined site biofilms compared to the reference site. When we fed fathead minnows (Pimephales promelas) on these biofilms in the laboratory they accumulated higher concentrations of Se in liver and ovary tissues compared to fathead minnows fed on reference site biofilms. No differences in Se accumulation were found in muscle from either treatment group. Biofilms were also centrifuged and separated into filamentous green algae and the remaining diatom fraction. The majority of Se was found in the diatom fraction with only about 1/3rd of total biofilm Se concentration present in the filamentous green algae fraction </p><p>Finally, zebrafish (Danio rerio) embryos were exposed to aqueous Se in the form of selenate, selenite, and L-selenomethionine in an attempt to determine if oxidative stress plays a role in selenium embryo toxicity. Selenate and selenite exposure did not induce embryo deformities (lordosis and craniofacial malformation). L-selenomethionine, however, induced significantly higher deformity rates at 100 µg/L compared to controls. Antioxidant rescue of L-selenomethionime induced deformities was attempted in embryos using N-acetylcysteine (NAC). Pretreatment with NAC significantly reduced deformities in the zebrafish embryos secondarily treated with L-selenomethionine, suggesting that oxidative stress may play a role in Se toxicity. Selenite exposure also induced a 6.6-fold increase in glutathione-S-transferase pi class 2 gene expression, which is involved in xenobiotic transformation. No changes in gene expression were observed for selenate or L-selenomethionine-exposed embryos.</p><p>The findings in this dissertation contribute to the understanding of how Se bioaccumulates in a lotic system and is transferred through a simulated foodweb in addition to further exploring oxidative stress as a potential mechanism for Se-induced embryo toxicity. Future studies should continue to pursue the role of oxidative stress and other mechanisms in Se toxicity and the biotransformation of Se in aquatic ecosystems.</p> / Dissertation

With the passage of the Federal Aid Highway Act of 1956, the interstate system included an elevated segment of Interstate 10 constructed over Claiborne Avenue in New Orleans, Louisiana. The I-10 Claiborne Expressway provided access to downtown by destroying a tree-lined boulevard and contributing to the decline of an African American neighborhood. In 2005, after hurricane Katrina, several community-based plans proposed that the elevated I-10 Claiborne Expressway be removed. This thesis compares the removal proposals to the decision making processes of five case cities that have removed expressways. Necessary conditions were applied to all expressway removal cases. Currently, the I-10 Claiborne Expressway decision making process lacks defined structural integrity and safety concerns, a reduction in the value of freeways by power brokers, documented support of the business community and “selling” of idea by a public agency. These conditions were necessary to the decision to remove expressways in all case cities.

Ph.D. (Chemistry) / This study addressed the incorporation of nanotechnology-based materials, either through incorporating nanomaterials or by introducing nanostructures onto the membrane matrix, to form nano-enabled polymeric membranes with high specific flux and better anti-fouling profile. The aim of the study was to integrate nanotechnology and membrane science in order to improve the performance of water filtration membranes by alleviating some of the specific shortcomings of water treatment membranes......

L’Orge est une petite rivière de plaine fortement segmentée, du bassin parisien. En 2010, elle comptait en moyenne un clapet tous les kilomètres sur sa partie aval. Pour rétablir la continuité écologique du cours d’eau, le Syndicat de l’Orge efface progressivement ces ouvrages. L'objet de cette thèse est le suivi biogéochimique, hydro-sédimentaire et écologique d'un bief de l’Orge de 6 km où 3 clapets consécutifs ont été effacés.Les hauteurs d’eau dans la rivière ayant baissé, des bancs de vase ont été mis à l'air. Ces banquettes de sédiments subissent des séquences d’inondation/exondation au rythme des crues. Les transformations de l’azote et du soufre y sont particulièrement actives et dynamiques. Cependant, les faibles flux d’eau échangés (modélisation) limitent l’impact des banquettes sur la rivière. Des processus intenses de précipitation/solubilisation des sulfates, liés aux variations des niveaux d’eau, ont une importance non négligeable sur la dégradation de la matière organique et la production d’ammonium dans la banquette.La capacité de transport de sédiments de la rivière a fortement évolué suite aux effacements, ce qui se traduit par l’apparition d'une granulométrie plus grossière en fond de lit. Ont été évalué la nouvelle vitesse de transit des particules charriées et le temps nécessaire pour atteindre un nouvel équilibre du lit et des espèces biologiques qui y vivent. Les indicateurs biologiques montrent que les effacements améliorent l’habitabilité de la rivière.Ces suivis montrent l’impact positif des effacements de barrage sur une rivière de plaine, même si un suivi dans la durée reste nécessaire pour confirmer les évolutions mises en évidence. / Orge is a lowland river from Seine’s watershed, France. In 2010, Orge River was highly segmented with on average one dam (< 2m) every kilometer in downstream part. To restore the ecological continuity of the river, the “Syndicat de l’Orge” gradually removes these little dams. The purpose of this thesis is the monitoring of hydro-morphology, biogeochemistry and ecological of a section of 6 km of Orge where 3 consecutive dams have been removed in spring 2010.After the water level decrease, some previously drowned sediment deposits appear along the river bank. These sediment banks are frequently inundated by high flows. Nitrogen and sulfate processes are very intense onto these banks. However, a model shows that water fluxes limited biochemical impact of sediment banks on the river. Intense precipitation/solubilization sulfate processes, link with water level variations, have a significant importance on organic matter degradation and ammonium production in sediment banks.The sediment transport capacity of the river has changed significantly after dam removal. It results in an increase of the maximum transportable diameter of the river, leading to the appearance of a coarser bed in-situ. It was possible to evaluate the new transit speed of particles carried along and highlight the time required to reach a new equilibrium of the bed and the biological species that live there. Biological indicators show that removals enhanced the livability of the river.All these studies show the positives impacts of dam removal on a lowland river, even if a monitoring in time is still needed to confirm the first developments highlighted here.