Les ions nitrate présents dans les effluents agricoles et agroalimentaires sont la cause majeure de la pollution de l'eau induisant eutrophisation et risques sanitaires dûs à la méthémoglobinémie. Le traitement de ces effluents avant de les rejeter est alors impératif. De nombreux procédés biologiques et physicochimiques ont été mis en oeuvre pour le traitement de ces effluents. Cependant, l'adsorption s'avère une alternative prometteuse grâce à sa simplicité et sa rapidité. Dans le présent travail, l'objectif principal est l'étude du procédé d'adsorption des ions nitrate par un organosilicate mésoporeux de type SBA-15. Les essais ont été réalisés avec des solutions synthétiques en batch et analysés par HPLC ionique. Les matériaux ont été caractérisés par les techniques de DRX et BET. L'équilibre de l'adsorption a été modélisé par les modèles de Langmuir, Freundlich et Temkin afin de déterminer les paramètres thermodynamiques. La capacité d'adsorption maximale obtenue est de 50 mg/g. L'étude des conditions opératoires a révélé que le rendement d'adsorption augmente avec la charge en adsorbant et diminue avec la concentration initiale en nitrate. Le pH optimum est situé entre 4 et 8. Par ailleurs, l'étude de l'effet des ions S0₄²⁻, CO₃²⁻, Mg²⁺ et Ca²⁺ a montré que le sulfate et le carbonate ont un effet négatif sur l'adsorption. Les isothermes d'adsorption ont montré que la capacité d'adsorption diminue en augmentant la température. Aussi, le modèle de Langmuir s'applique le mieux aux résultats expérimentaux pour toutes les températures investiguées. L'adsorbant testé sur des solutions en présence de matière organique (acides phytiques et humiques) simulant les conditions réelles des effluents d'origine agricole nous a permis de conclure que la matière organique n'a pas d'effet significatif sur l'adsorption du nitrate.

Les impacts environnementaux majeurs de l'agriculture sont associés à l'eutrophisation des eaux de surface causée par un enrichissement excessif en nutriments (azote et phosphore) et à la contamination des eaux souterraines par les ions nitrate. L'objectif principal de ce projet de doctorat est l'utilisation de matériaux mésoporeux fonctionnalisés à base de silice pour l'adsorption des ions phosphate et nitrate contenus dans des solutions acqueuses synthétiques simulant les effluents d'origine agricole. Trois matériaux mésoporeux (MCM-41, MCM-48 et SBA -15) fonctionnalisés avec des groupements ammonium par la technique de greffage et de co-condensation ont été synthétisés, caractérisés puis testés en mode discontinu. Les conditions opératoires ont été optimisées aussi en mode discontinu. L'équilibre et la cinétique d'adsorption ont été modélisés. Finalement, l'adsorption des ions nitrate et phosphate a été menée en mode d'écoulement continu pour simuler les conditions opératoires à l'échelle industrielle.

Dans la synthèse des matériaux catalytiques, deux aspects orientent en particulier les recherches actuelles: le contrôle de taille afin d’obtenir des nanoparticules finement divisées et le contrôle précis de la morphologie. Dans cette étude, nous avons utilisé les milieux non aqueux pour élaborer des matériaux catalytiques à base d’oxydes des métaux de transition (Ti, Zr, Mn). Trois méthodologies ont été employées pour la préparation des solides à base de TiO2. La synthèse dans les nitrates fondus dopés avec différents anions permet un boncontrôle des propriétés texturales des matériaux et de la nature des plans cristallins exposés. Les préparations utilisant le nitrate d’ammonium stabilisé avec des molécules organiques azotées conduit à des solides présentant des tailles et des formes de particules variables en fonction de la nature du stabilisateur. Le traitement à reflux dans des solvants organiques polaires conduit à l’obtention des supports TiO2 de grandes surfaces spécifiques. Pour la valorisation catalytique de ces matériaux, deux réactions appliquées au domaine de la photocatalyse ont été employées: la production d’H2 par déshydrogénation du méthanol etl’oxydation photocatalytique de l’acide formique. La réaction modèle de décomposition del’isopropanol a été utilisée comme test de caractérisation des propriétés acido-basiques de nossystèmes. La technique de nitrates fondus a été également appliqué avec succès pourl’obtention en une seule étape des catalyseurs supportés Mn-Zr et Mn-Ti. Ces catalyseursmontrent une excellente activité pour l’oxydation totale de composés organiques volatils(COV). / Two major challenges are particularly important for current research in the catalytic materials synthesis: preparation of finely divided particles and control of their shape. In this work we used non aqueous solvents to prepare catalytic materials containing transition metals oxides (Ti, Mn, Zr). Three techniques were applied to prepare TiO2-based solids. Reactions in molten alkali metal nitrates doped with different anions offered good control of textural properties and of the nature of exposed facets of nanocrystalline particles. Synthesis in molten ammonium nitrate stabilized with organic nitrogen-containing compounds provided TiO2 solids with variable size and shape as a function of stabilizer used. The reflux treatment in polar organic solvents leads to titania supports having high specific surface area. Two reactions from the field of photocatalysis were employed to valorize the obtained catalysts: H2 production by methanol dehydrogenation and photocatalytic oxidation of formic acid. Isopropanol decomposition has been used to determine the acid-base properties of the solids. Molten nitrate technique was then successfully applied in order to obtain in one-step highly dispersed Mn-Zr and Mn-Ti supported oxide catalysts. These systems showed excellent activity for the total oxidation of volatile organic compounds (VOC).

The aim of this thesis is to evaluate the impact of agricultural activity on hydrochemical parameters of surface waters in connection with the occurence of specially protected species within the surface waters of a monitored area. A model was chosen for the evaluation of the situation - Bedřichovský potok, which is located in Novohradské hory. The river consists of lower and upper sub-waters. Forest management is applied within upper sub-basin, while agricultural management on arable land, meadows and pastures is used in the lower sub-basin. The monitored parameters were indicators of eutrophication of surface waters: Nitrate nitrogen (N-NO3-), Phosphate phosphorus (P-PO43-), and conductivity of undissolved material (NL105). The results showed that the agriculture management (especially on arable land) burdens the soil with nutrients and consequently erosion enters the substances, bringing them to the surface and ground water as a result. There was an increase of substances in the water after rain.

A reação entre nitratos, cloretos e percloratos dos lantanídeos e de ítrio com a 2,6-lutidina-N-óxido (2,6-LNO) conduziu à formação de compostos de adição de composição geral: Ln(NO3)3.4(2,6-LNO), LnCl3.3 (2,6-LNO) e Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er e Y). Os produtos de reação são cristalinos, apresentam as mesmas colorações dos íons lantanídeos hidratados, porém bastante esmaecidas. Os compostos de adição contendo o íon cloreto não fundem até 300ºC. Os compostos de adição contendo os íons nitratos e percloratos são solúveis em acetona, acetonitrila, etanol, metanol, nitrobenzeno e nitrometano, ligeiramente solúveis em clorofórmio. Os compostos de adição contendo o íon cloreto são solúveis em etanol e metanol e praticamente insolúveis em acetona, acetonitrila, clorofórmio, nitrobenzeno e nitrometano. Todos os compostos de adição são praticamente insolúveis em benzeno; tetracloreto de carbono e éter etílico. Os compostos foram caracterizados por meio de análise elementar, espectros na região do infra-vermelho e do visível, medidas de condutância molar em nitrometano, acetonitrila e etanol, e diagramas de raios-x. Para alguns compostos de adição contendo o íon nitrato foram obtidos os espectros Raman. Os dados obtidos nos espectros na região do infravermelho indicam que a coordenação da 2,6-LNO ao ion lantanídeo ocorre pelo oxigênio do grupo N-O. Foram observadas cinco bandas que podem ser atribuídas ao íon nitrato, nos correspondentes compostos de adição, indicando que estes íons estão coordenados aos íons lantanídeos. As bandas atribuídas aos íons percloratos indicaram que os mesmos não estão coordenados. Os espectros eletrônicos dos compostos de adição contendo o íon perclorato, no estado sólido e em solução de nitrometano são muito semelhantes, sugerindo que a simetria em torno do íon central, é a mesma em ambos os casos. Os dados de condutância eletrolítica indicaram que os nitratos comportam-se como não-eletrólitos em nitrometano e acetonitrila e como eletrólito 1:1 em metanol. É interessante notar que os percloratos comportam-se como eletrólitos 1:3 em nitrometano e acetonitrila, mas em metanol, provavelmente devido a existência de pares iônicos, comportam-se como eletrólitos 1:2. Os dados para os cloretos em metanol estão de acordo com aqueles para eletrólitos 1:1. Todos os compostos preparados foram caracterizados por meio de diagramas de raios-X. De acordo com os dados três séries diferentes foram obtidas para os nitratos: (a) para o composto de La, (b) para os compostos de Pr, Nd and Gd, que são isomorfos, (c) para os compostos de Ho, Er and Y, que também são isomorfos. Para os percloratos duas séries de substâncias são observadas: a primeira série contém os compostos de Y, Pr, Gd, Ho e Er, e a segunda série os compostos de La e Nd. Para os cloretos duas séries diferentes foram também obtidas: (a) para os compostos de La, Pr e Nd, (b) para os compostos de Y, Gd, Ho e Er. / The reaction between hydrated lanthanide and ytrium nitrates, chlorides and perchlorates with 2,6-lutidine-N-oxide (2,6-LNO) provided adducts of general composition: Ln(NO3)3.4(2,6-LNO), LnCl3.3(2,6-LNO) and Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er and Y). The products are crystalline, present the same, but less intense colors of the hydrated lanthanide ions. The chloride adducts do not melt up to 300ºC. The nitrate and perchlorate adducts are solube in acetone, acetonitrile, ethanol, methanol, nitrobenzene and nitromethane, slightly soluble in chloroform. The chloride adducts are soluble in ethanol and methanol and practically insoluble in acetone, acetonitrile, chloroform, nitrobenzene and nitromethane. All the adducts are practically insoluble in benzene, carbon tetrachloride and ethyl eter. The compounds were characterized by elemental analyses, infrared and visible spectra, molar conductance measurements in nitromethane, acetonitrile and methanol, and X-ray powder patterns. For some of the nitrate adducts the Raman spectra were obtained. Infrared data indicate that the 2,6-LNO is coordinated to the lanthanide ions through of oxygen. Five bands attributed to the nitrate ions were observed for the corresponding adducts, indicating these ions are coordinated to the lanthanides ions. The bands due to perchlorate ions indicate that they are not coordinated to the lanthanides ions.The electronic spectra of the perchlorates adducts in the solid state and in nitromethane solution indicate the existence of the same symmetry around the central ions in both cases. The electrolytic conductance data indicate that the nitrates behave as non-electrolytes in nitromethane and acetonitrile and 1:1 electrolytes in methanol. It is interesting to note that the perchlorates behave as 1:3 electrolytes in nitromethane and acetonitrile, but in methanol, probably due to the existence of ions pairs, they behave as 1:2 electrolytes. The data for the chlorides in methanol are in accordance of 1:1 electrolytes. to that All the compounds prepared were characterized by X-ray powder patterns. According to the data three different patterns were obtained for the nitrates: (a) for the compounds of La; (b) for the compounds of Pr, Nd and Gd, that are isomorphous, (c) for the oompounds of Ho, Er and Y, that are also isomorphous. For the perchlorates two series of isomorphous substances were observed: the first series contains the compounds of Y, Pr, Gd, Ho and Er, and the second series the adducts of La and Nd. For the chlorides two different patterns were also obtained: (a) for the compounds of La, Pr and Nd, (b) for the compounds of Y, Gd, Ho and Er.

No description available.

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.

Devido ao seu elevado teor de nutrientes e potencial de neutralização da acidez do solo, a utilização de lodos de curtume em áreas agrícolas tem sido uma alternativa para disposição e reciclagem desses resíduos. Por outro lado, o aumento do pH e do teor de nitrogênio amoniacal no solo, quando da aplicação superficial do lodo de curtume, podem favorecer a perda de nitrogênio (N) por volatilização da amônia (NH3). Altos teores de nitrogênio inorgânico no solo podem gerar efeitos negativos, principalmente quando a amonificação e nitrificação não são sincronizadas com a absorção pelas plantas, possibilitando lixiviação e conseqüente contaminação das águas subsuperficiais. Um experimento de campo foi instalado em Rolândia (PR) com os objetivos de avaliar a perda de nitrogênio por volatilização da amônia, as alterações em alguns atributos microbiológicos do solo envolvidos no ciclo do nitrogênio e carbono, a lixiviação de nitrogênio mineral no solo, a produtividade da cultura de milho e o efeito residual, após a aplicação de doses crescentes de lodo de curtume no solo. O delineamento experimental foi de blocos completos casualizados, com quatro repetições. As doses de lodo foram calculadas em função do teor de N total contido no lodo de curtume. Os tratamentos foram: controle, 120, 480, 840 e 1200 kg ha-1 de N total adicionados via lodo de curtume, correspondendo, respectivamente, a 0, 3,4, 13,5, 23,6 e 33,7 Mg ha-1 de lodo de curtume (base seca). O lodo foi aplicado na superfície de um Nitossolo Vermelho distroférrico, muito argiloso, onde permaneceu por 89 dias, período em que foi determinada a perda de amônia por volatilização. Em seqüência, o lodo foi incorporado, com posterior semeadura da cultura de milho. Nesse momento foi instalado um tratamento adicional (Tratamento agronômico - 120 kg ha-1 N via uréia). Após a colheita do milho, a aveia preta foi semeada em sistema direto, sendo conduzida até o estádio de florescimento. Durante todo o período experimental foram realizadas coletas de solo nas camadas de 0-10, 10-20, 20-40, 40-60 cm e solução do solo nos tratamentos controle, 120 e 1200 kg ha-1 N total via lodo, a 1,2 m de profundidade. A volatilização da amônia foi mais intensa nos 30 primeiros dias após a aplicação, decaindo depois desse período. A fração volatilizada como NH3 correspondeu, em média, a 17,5% do N total contido no lodo de curtume. A densidade dos grupos funcionais de microrganismos, respiração do solo e atividade enzimática apresentaram aumentos transientes após aplicação de lodo de curtume. Dentre os atributos avaliados, as enzimas glutaminase, urease e asparaginase mostraram maior atividade em resposta à aplicação de lodo de curtume. A dose 120 kg ha-1 de N via lodo de curtume não apresentou risco de contaminação do lençol freático, enquanto que na maior dose (1200 kg ha-1 N total) o teor de nitrato na solução do solo coletada a 1,2 m foi até 12 vezes maior que no controle. A dose de 521 kg ha-1 de N total proporcionou ganhos de produtividade de grãos de 13% e 11% em relação ao controle e ao tratamento agronômico, respectivamente. Foi observado efeito residual sobre a massa de matéria seca da parte aérea da aveia preta 390 dias após a aplicação do lodo. Ou seja: Doses elevadas de lodo de curtume (equivalentes a altas doses de N), aplicadas ao solo, podem resultar em poluição do ar e das águas subsuperficiais. / Due to its high nutrient content and its neutralizing potential for soil acidity, the utilization of tannery sludge in agricultural areas can be an alternative for its disposal and recycling. On the other hand, the pH and ammonia nitrogen content increase in soil as a result of surface tannery sludge application and may induce the loss of nitrogen (N) by ammonia (NH3) volatilization. The high N content in soils can generate negative effects, mainly when the organic N ammonification and nitrification does not coincide with the plant N uptake, allowing the nitrate to leach through the soil profile to the groundwater. A field experiment was installed in Rolândia (Paraná State, Brazil). The aims of this experiment were to evaluate the N loss through ammonia volatilization, changes in soil microbial attributes that are linked to the carbon and N cycles, mineral N leaching through the soil profile, corn yield and the residual effect as affected by tannery sludge application on the soil surface. A randomized complete block design was used with four replicates. The tannery sludge treatments were: control, 120, 480, 840 and 1200 kg ha-1 total N applied as tannery sludge, equivalent to 0, 3.4, 13.5, 23.6 and 33.7 Mg ha-1 tannery sludge (dry weight). The tannery sludge was surface applied on a clayey Rhodic Kandiudult. The tannery sludge was left on the soil surface for 89 days, and during this period the N loss through NH3 volatilization was determined. Afterwards, tannery sludge was incorporated and the corn was sown. At this moment, an additional treatment (agricultural treatment - 120 kg ha-1 N as urea) was applied. After the corn harvest, black oat was sown and carried on until flowering. Soil samples were taken at the following depths: 0-10, 10-20, 20-40 and 40-60 cm for all treatments. Soil solution was extracted at 1.2 m soil depth only in the control, 120 and 1200 kg ha-1 total N treatments. NH3 volatilization was more intense during the beginning of the experiment (30 days). The volatilized fraction as NH3 corresponded in average to 17.5% of the total N of the tannery sludge. The functional microorganism density, soil respiration and enzyme activity showed transient increases after tannery sludge application. The glutaminase, urease and asparaginase enzymes showed a more pronounced increase in activity in response to tannery sludge application. The lowest dose of 120 kg ha-1 total N did not show a contamination risk to the groundwater, while in the highest dose (1200 kg ha-1 total N), the amount of nitrate detected at 1.2 m was 12 times higher than in the control. The dose of 521 kg ha-1 total N corresponded to the maximum corn yield and caused increases of 13% and 11%, when compared to the control and to the agricultural treatment, respectively. Even after 390 days, a residual effect of tannery sludge application was observed as an increase in shoot dry matter of black oat. In short: it was demonstrated that high doses of tannery sludge (equivalent to high doses of total N), applied to soil, result in prohibitively high values of air and ground water pollution.

A reação entre nitratos, cloretos e percloratos dos lantanídeos e de ítrio com a 2,6-lutidina-N-óxido (2,6-LNO) conduziu à formação de compostos de adição de composição geral: Ln(NO3)3.4(2,6-LNO), LnCl3.3 (2,6-LNO) e Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er e Y). Os produtos de reação são cristalinos, apresentam as mesmas colorações dos íons lantanídeos hidratados, porém bastante esmaecidas. Os compostos de adição contendo o íon cloreto não fundem até 300ºC. Os compostos de adição contendo os íons nitratos e percloratos são solúveis em acetona, acetonitrila, etanol, metanol, nitrobenzeno e nitrometano, ligeiramente solúveis em clorofórmio. Os compostos de adição contendo o íon cloreto são solúveis em etanol e metanol e praticamente insolúveis em acetona, acetonitrila, clorofórmio, nitrobenzeno e nitrometano. Todos os compostos de adição são praticamente insolúveis em benzeno; tetracloreto de carbono e éter etílico. Os compostos foram caracterizados por meio de análise elementar, espectros na região do infra-vermelho e do visível, medidas de condutância molar em nitrometano, acetonitrila e etanol, e diagramas de raios-x. Para alguns compostos de adição contendo o íon nitrato foram obtidos os espectros Raman. Os dados obtidos nos espectros na região do infravermelho indicam que a coordenação da 2,6-LNO ao ion lantanídeo ocorre pelo oxigênio do grupo N-O. Foram observadas cinco bandas que podem ser atribuídas ao íon nitrato, nos correspondentes compostos de adição, indicando que estes íons estão coordenados aos íons lantanídeos. As bandas atribuídas aos íons percloratos indicaram que os mesmos não estão coordenados. Os espectros eletrônicos dos compostos de adição contendo o íon perclorato, no estado sólido e em solução de nitrometano são muito semelhantes, sugerindo que a simetria em torno do íon central, é a mesma em ambos os casos. Os dados de condutância eletrolítica indicaram que os nitratos comportam-se como não-eletrólitos em nitrometano e acetonitrila e como eletrólito 1:1 em metanol. É interessante notar que os percloratos comportam-se como eletrólitos 1:3 em nitrometano e acetonitrila, mas em metanol, provavelmente devido a existência de pares iônicos, comportam-se como eletrólitos 1:2. Os dados para os cloretos em metanol estão de acordo com aqueles para eletrólitos 1:1. Todos os compostos preparados foram caracterizados por meio de diagramas de raios-X. De acordo com os dados três séries diferentes foram obtidas para os nitratos: (a) para o composto de La, (b) para os compostos de Pr, Nd and Gd, que são isomorfos, (c) para os compostos de Ho, Er and Y, que também são isomorfos. Para os percloratos duas séries de substâncias são observadas: a primeira série contém os compostos de Y, Pr, Gd, Ho e Er, e a segunda série os compostos de La e Nd. Para os cloretos duas séries diferentes foram também obtidas: (a) para os compostos de La, Pr e Nd, (b) para os compostos de Y, Gd, Ho e Er. / The reaction between hydrated lanthanide and ytrium nitrates, chlorides and perchlorates with 2,6-lutidine-N-oxide (2,6-LNO) provided adducts of general composition: Ln(NO3)3.4(2,6-LNO), LnCl3.3(2,6-LNO) and Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er and Y). The products are crystalline, present the same, but less intense colors of the hydrated lanthanide ions. The chloride adducts do not melt up to 300ºC. The nitrate and perchlorate adducts are solube in acetone, acetonitrile, ethanol, methanol, nitrobenzene and nitromethane, slightly soluble in chloroform. The chloride adducts are soluble in ethanol and methanol and practically insoluble in acetone, acetonitrile, chloroform, nitrobenzene and nitromethane. All the adducts are practically insoluble in benzene, carbon tetrachloride and ethyl eter. The compounds were characterized by elemental analyses, infrared and visible spectra, molar conductance measurements in nitromethane, acetonitrile and methanol, and X-ray powder patterns. For some of the nitrate adducts the Raman spectra were obtained. Infrared data indicate that the 2,6-LNO is coordinated to the lanthanide ions through of oxygen. Five bands attributed to the nitrate ions were observed for the corresponding adducts, indicating these ions are coordinated to the lanthanides ions. The bands due to perchlorate ions indicate that they are not coordinated to the lanthanides ions.The electronic spectra of the perchlorates adducts in the solid state and in nitromethane solution indicate the existence of the same symmetry around the central ions in both cases. The electrolytic conductance data indicate that the nitrates behave as non-electrolytes in nitromethane and acetonitrile and 1:1 electrolytes in methanol. It is interesting to note that the perchlorates behave as 1:3 electrolytes in nitromethane and acetonitrile, but in methanol, probably due to the existence of ions pairs, they behave as 1:2 electrolytes. The data for the chlorides in methanol are in accordance of 1:1 electrolytes. to that All the compounds prepared were characterized by X-ray powder patterns. According to the data three different patterns were obtained for the nitrates: (a) for the compounds of La; (b) for the compounds of Pr, Nd and Gd, that are isomorphous, (c) for the oompounds of Ho, Er and Y, that are also isomorphous. For the perchlorates two series of isomorphous substances were observed: the first series contains the compounds of Y, Pr, Gd, Ho and Er, and the second series the adducts of La and Nd. For the chlorides two different patterns were also obtained: (a) for the compounds of La, Pr and Nd, (b) for the compounds of Y, Gd, Ho and Er.

Nitrate concentration in excess of national drinking-water standards (10 mg/l) are present in the shallow alluvial aquifer and Saddle Mountains Basalt (SMB) aquifer in the Lower Umatilla Basin, Oregon. To determine sources responsible for elevated nitrate concentrations in the SMB aquifer mass-balance and reaction-path models (NETPATH and PHREEQE) were used to understand observed geochemical trends. Nitrate-nitrogen isotopes were used to distinguish potential nitrate sources in the shallow alluvial aquifer. NETPATH-validated simple water/rock reactions in the SMB aquifers in Irrigon (dissolving glass, precipitating smectite, dissolving or precipitating calcite, and cation exchange) using constituents (calcium, magnesium, sodium and carbon). Diversity of composition for the shallow alluvial water and limited number of wells available made obtaining a mass balanced solution for the SMB aquifer near Boardman impossible. Irrigon basalt groundwaters were consistent with the PHREEQE models prediction of natural hydrochemical trends, where Boardman basalt groundwaters plotted consistently with impacted alluvial groundwater. Nitrogen-isotopic values of nitrate (o 15NNo3) were measured in the shallow alluvial groundwater from 17 wells in 4 land-use settings, 3 lysimeter samples and 1 surface water effluent sample. The landuse setting and corresponding average ranges for nitrate concentrations (as N) and 015NNo3 values for wells near: commercial fertilizer-irrigated fields range from 25-87 mg/l, +3.5 to +4.6 per mil; explosive washout lagoons ranged from 10-18 mg/l, +4.6 to +4.9 per mil; potato waste water application ranged from 6.4-17.8 mg/l, +4.4 to +35 per mil; past confined animal feeding operations (CAFO) ranged from 16-56 mg/l, +4.9 to 10.4 per mil; lysimeters 5.4-39.9 mg/l, +9.1 to +21.9 per mil; surface water effluent ranged from 60-61 mg/l, +3.5 to 6.5 per mil; and varying landuse ranged from 9.3-19.5 mg/l, +2.7 to +7.1 per mil. Commercial fertilizer 0 15NNo3 signatures are consistent for this source. Explosive 015NNa3 values are consistent with an atmospheric signature. CAFO o15NNo3 signatures probably result from mixing between currently applied commercial fertilizer and past CAFO's. High 015NNo3 Signatures (+22 to +35 per mil) imply denitrification. Potato waste water and varying land-use 015NNo3 signatures indicate probable mixing of nitratenitrogen sources in the groundwater.