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Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2013. / In title on title page, "[delta]" appears as lower case Greek letters. Cataloged from PDF version of thesis. / Includes bibliographical references. / The stable isotopes, [delta]¹⁵N and [delta]¹⁸O, of nitrite and nitrate can be powerful tools used to interpret nitrogen cycling in the ocean. They are particularly useful in regions of the ocean where there are multiple sources and sinks of nitrogenous nutrients, which concentration profiles alone cannot distinguish. Examples of such regions are "oxygen deficient zones" (ODZ). They are of particular interest because they are also important hot spots of fixed N loss and production of N₂O, a potent greenhouse gas. In order to interpret these isotope profiles, the isotope systematics of each process involved must be known so that we can distinguish the isotopic signature of each process. One of the important processes to consider here is nitrification, the process by which ammonium is oxidized nitrite and then to nitrate. This thesis describes numerous experiments using both cultures of nitrifying organisms as well as natural seawater samples to determine the oxygen isotope systematics of nitrification. These experimental incubations show that the accumulation of nitrite has a large effect on the resulting [delta]¹⁸ONO3. In experiments where nitrite does not accumulate, [delta]¹⁸ONO3 produced from nitrification is between -1 to l%o. These values will be applicable for the majority of the ocean, but the nitrite isotopic exchange will be important in the regions of the ocean where nitrite accumulates, such as the base of the euphotic zone and oxygen deficient zones. [delta]¹⁸ONO2 was developed as a unique tracer in this thesis because it undergoes abiotic equilibration with water [delta]¹⁸O at a predictable rate based on pH, temperature and salinity. This rate, its dependencies, and how the [delta]¹⁸ONO2 values can be used as not only biological source indicators but also indicators of age are described. This method was applied to samples from the primary nitrite maximum in the Arabian Sea, revealing that the dominant source and sinks of nitrite are ammonia oxidation and nitrite oxidation with an average age of 37 days. Finally, using the isotope systematics of nitrification as well as the properties of nitrite oxygen isotope exchange described in this thesis, the final chapter interprets multiisotope nitrate and nitrite profiles in the Costa Rica Upwelling Dome using a simple ID model. The nitrite isotopes showed that there were multiple sources of nitrite in the primary nitrite maximum including (1) decoupling of ammonia oxidation and nitrite oxidation, (2) nitrate reduction during assimilation and leakage of nitrite by phytoplankton. In the oxygen deficient zone and secondary nitrite maximum, there were equal contributions of nitrite removal from nitrite oxidation and nitrite reduction. This recycling of nitrite to nitrate through oxidation indicates that the percentage of reduced nitrate fully consumed to N2 gas is actually smaller than previous estimates. Overall, this thesis describes new nitrogen and oxygen isotopic tracers and uses them to elucidate the complicated nitrogen biogeochemistry in oxygen deficient zones. / by Carolyn Buchwald. / Ph.D.

Factors influencing natural attenuation of dinitrotoluenes (DNT) in surface soils and the application of monitored natural attenuation (MNA) as a remediation strategy were examined using contaminated soils from Badger Army Ammunition Plant (BAAP). Based on the previous research involving contaminated media obtained from locations at BAAP, and the fact that groundwater at the site is not contaminated, it seemed likely that aerobic biodegradation of DNT is active without intervention, and that natural attenuation may be an effective strategy for managing the contamination that exists at BAAP. Microcosms showed that microbes indigenous to soils are capable of 2,4-DNT mineralization and that DNT will adsorb reversibly and become bioavailable. In column studies 2,4-DNT biodegradation was observed and the nitrite evolved during DNT degradation was presumably removed due to oxidation by nitrite oxidizers. The use of simulated rainwater as influent with no nutrient amendments suggests that nutrients do not limit the biodegradation of low concentrations of DNT in the soil tested. In the chemostat study carried out to study effect lowering of temperature (22㬠15㬠10㬠7.5㠡nd 4㩠on biodegradation of DNT at hydraulic retention time of 2.5 days, no sustained change in the DNT substrate removal was observed with change in temperature, but it had a large effect on the nitrite oxidizers. This suggests that the seasonal fluctuations in temperature will have minimal effect on the DNT removal via biodegradation at temperatures above 0㮠Nitrite oxidizers were active at 22㬠their activity decreased at 15㠡nd ceased at temperatures 10㠡nd lower. Nitrite is generally taken as a line of evidence for biodegradation of DNT. The results from the soil column study and chemostat showed that nitrite measurement should not be always taken as a conclusive indicator of DNT degradation. It should be taken into consideration that absence of nitrite does not necessarily mean absence of DNT biodegradation (probably at high temperatures).

La spécialisation des techniques agricoles que nous connaissons ces dernières décennies, particulièrement dans les régions rurales, est à l’origine de l’abus de fertilisants. Ces derniers sont actuellement reconnus comme étant les causes principales de la contamination de l’eau souterraine par les nitrates. Suite à leur ingestion via l’eau potable, les nitrates sont transformés en nitrites par la flore buccale. Une fois dans l’estomac les nitrites réagissent avec certaines amines provenant de l’alimentation pour générer des nitrosamines cancérogènes. L’objectif de notre étude était d’estimer quantitativement l’excès de risque de cancer (ER) pour les populations de sept régions rurales du Québec qui consomme l’eau potable provenant de réseaux municipaux alimentés en eau souterraine. Le territoire à l’étude était caractérisé par une agriculture intensive d’élevage. Les médianes (et 95e centiles) régionales des concentrations de nitrates mesurées dans les réseaux de ces régions étaient de : 0,18 (2,74); 0,48 (10,35); 0,15 (1,28); 0,32 (11); 0,05 (0,76); 0,10 (4,69); 0,09 (2,13) mg N-NO3-/l. Nous avons envisagé un scénario de transformation complète des nitrites et de certaines amines (diméthylamine, diéthylamine, n-butylamine, méthyléthylamine) en nitrosamines spécifiques : N-diméthylnitrosamine (NDMA), N-diéthylnitrosamine (NDEA), N-n-dibutylnitrosamine (NDBA) et N-méthyléthylnitrosamine (NMEA). Pour estimer la concentration de nitrites formés dans l’estomac, nous avons considéré une consommation définie d’eau potable, le volume de l’estomac et un taux de transformation des nitrates en nitrites. Supposant les quantités de nitrites et de chaque amine constantes pendant 1h, nous avons considéré la constante de nitrosation spécifique à chaque amine pour évaluer la dose d’exposition journalière à chaque nitrosamine équivalente formée. Par la suite, la combinaison de cette dose à un estimateur de potentiel cancérogène qhumain spécifique à chaque nitrosamine, nous a permis d’évaluer l’ER associé à chacune d’elles. Globalement l’analyse a démontré que les ER les plus élevés, estimés pour le NDBA, étaient de l’ordre de 10-6, ne contribuant pas de façon significative à une augmentation du risque de cancer pour ces populations. / Specialization of agricultural practices in rural regions over the past few decades has led to overuse of fertilizers which are main causes of groundwater contamination by nitrates. After their ingestion through drinking water, nitrates are transformed into nitrites by the oral flora. Once in the stomach, nitrites react with some amines from food supply to form nitrosamines with some being probably carcinogenic to humans. The aim of this study was to quantitatively estimate the possible excess cancer risk (ER) for populations of seven rural regions in Quebec that consume water from public drinking water systems using groundwater. The studied regions practice extensive breeding agriculture. The regional medians (and 95th percentile) of nitrate levels in water from those seven regions were: 0.18 (2.74); 0.48 (10.35); 0.15 (1.28); 0.32 (11); 0.05 (0.76); 0.10 (4.69) and 0.09 (2.13) mg N-NO3-/l, respectively. Indeed, we first considered a scenario of complete transformation of nitrites and some amines (dimethylamine, diethylamine, n-butylamine and methylethylamine) into specific nitrosamines: N-dimethylnitrosamine (NDMA), N-diethylnitrosamine (NDEA), N-nitrosodi-n-butylamine (NDBA) and N-nitrosomethylethylamine (NMEA). Gastric nitrite concentrations were estimated on the basis of defined drinking water intake, stomach volume, and the transformation rate of nitrates into nitrites. Considering that levels of nitrites and each amine were kept constant for 1 hour, and taking in account the nitrosatability rate constant specific to each amine, we then estimated the daily doses of the corresponding endogenously formed nitrosamines. Furthermore combination of dose with the human cancer potency factor qhuman specific to each nitrosamine, allowed the estimation of excess cancer risk. The highest ER estimated for NDBA was in the order of 10-6, thus not contributing to a significant increase in the risk of cancer for that population.

The aim of the diploma thesis is generation of active particles in plasma activated water (PAW) using a low-temperature plasma discharge. In this work I focus on the determination of hydrogen peroxide, nitrites and nitrates as active particles. The practical part is focused on a specific case of use of a plasma discharge in selected electrolytes dissolved in an aqueous solution. Here, three phosphates, differing in the number of acidic hydrogens, were selected for each experiment, and sodium chloride and tap water were compared for comparison. Phosphates were selected for their stable pH during plasma discharge in solution to monitor the effect of pH. The experiments were focused on investigating the stability of active particles in PAW, under which conditions is the highest production rate of these particles and what effect the pH value has on the result. It was found that hydrogen peroxide is generated the most in an alkaline environment but shows better stability in neutral. The concentration of generated nitrites is not high, but it shows stability, regardless of the polarity of the main electrode used for PAW generation. Nitrites were generated the most in alkaline environment and nitrates in acidic environment. One of the conclusions is that nitrates are not a very stable particle in PAW. Thanks to the activation and oxidation properties of plasma activated water, this method can be used in medicine or agriculture

Chronic pancreatitis (CP) is a heterogeneous disease defined as chronic inflammatory changes of the pancreatic tissue caused by variety of aetiologies. Oxidative stress accompanying the inflammatory processes has been suggested as an important factor contributing to CP development. The aim of this study was to determine levels of lipid peroxidation products malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), together with nitrites, the total antioxidant capacity, cytokines, biochemical and haematological parameters in the plasma of patients with CP and control subjects. Levels of MDA and 4-HNE were analyzed using high-performance liquid chromatography. The total antioxidant capacity of plasma against peroxyl radicals was evaluated using chemiluminescence determination. Nitrites were determined using Griess reaction. Cytokines - TNF-alfa; TNF RI; PDGF-AB; TGF-beta, together with myeloperoxidase and hyaluronan were determined using ELISA Kits. Biochemical and haematological parameters were measured by standard methods.

La evidencia sobre el efecto de las nitrosaminas (NA) sobre el cáncer gástrico (CG) es insuficiente. El objetivo fue evaluar el efecto de las NA (exógenas y endógenas ) y sus alimentos fuente sobre el riesgo de CG. El estudio incluyó 521.457 individuos del estudio EPIC (European prospective Investigation into Cancer and Nutrition) y 314 casos incidentes de C. Estimamos la exposición exógena aplicando una tabla de composición que desarrollamos para tal fin. Para estimar las NA endógenas creamos un índice de formación endógena (ENOC) basado en datos previamente publicados. Observamos un efecto de carnes rojas, procesadas y ENOC restringida a la región distal y en individuos positivos el Helicobacter Pylori. No se observó ningún efecto de las NA exógenas sobre el CG. Se observo una interacción entre ENOC y vitamina C. En resumen, el riesgo de CG se ve afectado por la interrelación entre ENOC, Hp y vitamina C. / Evidence relating nitrosamines (NA) and gastric cancer (GC) risk is not conclusive. The risk of GC associated with meat and NA intake and endogenous formation of NA (ENOC) was investigated in the European Prospective Investigation into Cancer and Nutrition with a population of 521.457 subjects and 314 incident cases of GC. To estimate NA intake we developed a food composition database. An index of ENOC was created using information from previous published studies. The risk of CG increases with intake of red and processed meat and ENOC restricted to non-cardia site and mainly in Helicobacter pylori (Hp) infected subjects. There were no association between NA intake and GC. We observed an interaction between ENOC and vitamin C. In summary, Hp infection, vitamin C and ENOC play an important role on GC risk.

This thesis is focused on the selected methods of calculating basic runoff on a small catchment basin known as the P6, which belongs to the basin Kopaninsky flow and assess the impact on the basic runoff concentration of nitrate nitrogen in the total runoff. The thesis also analyzes the total, surface and subsurface runoff with its detailed division. There are also described in detail the chosen methods used for the separation of basic drainage. There is shown their mutual comparison too. We dealt with the nitrogen in groundwater. The methods for separation of basic runoff are described with regard to the content of nitrogen compounds, which are practically the most common type of pollution of groundwater used as drinking water sources.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The nitrogen balance of a watershed near the city of New Prague, Minnesota was evaluated as part of an overall study on lake and stream eutrophication. Although the n-balance of a humid Midwest watershed cannot be expected to be identical to that of an arid watershed, the processes are the same and differences should be mainly quantitive. Sources of input and causes of depletion are reviewed for 4 points in the nitrogen cycle: the atmospheric zone, the soil-atmosphere interface, the plant-root and soil-water zone and the surface water zone. In the New Prague watershed, commercial fertilizer and bulk precipitation were the major sources of input, contributing, respectively, 53% and 34.4% of the total input of 2.34 million lb/yr. Crop yield and soil or groundwater storage contributed 52.1% and 20.4% of non-enrichment depletions. The closeness of the values of crop yield and commercial fertilizer application was an unfortunate coincidence and is certainly not an indication that the entire fertilizer supply was taken up cry crops. In an arid environment, free from fertilized agriculture, bulk precipitation probably provides the major source of nitrogen compounds.