Le fer est un métal abondant dans l'environnement. La présence d'espèces de fer dans l'environnement peut affecter un grand nombre de processus. Les contaminants peuvent être largement trouvés dans les systèmes environnementaux. Différentes espèces peuvent exister, y compris pour les polluants inorganiques et les polluants organiques. L'étude de la transformation et la mobilité de ces contaminants en présence d'espèces de fer aura sans doute des implications importantes sur l'environnement. Le mémoire de thèse est divisé en quatre chapitres. Dans le premier chapitre, nous présenterons une synthèse bibliographique sur la contamination actuelle de l'arsenic et plusieurs contaminants émergents, la présence d'espèces de fer (fer dissous et oxydes de fer) dans l'environnement, et les interactions entre les contaminants et les espèces de fer. Le deuxième chapitre est une étude de l’adsorption de l’As(III) sur l'hydroxyde ferrique colloïdal et sa transformation sous lumière visible dans un système de fer(III)/ sulfite. Dans ce travail, l'oxydation de l’As(III) en As(V) dans un système de fer(III)/sulfite en utilisant la lumière du soleil ou d'une lampe à diode électroluminescente (λ = 404 nm) a été étudiée. Plusieurs types d’agents de piégeage des radicaux hydroxyles, d'azote et agents de complexation ont été utilisés pour l'étude du mécanisme d’oxydation. En comparant le a) le fer(III) avec l'irradiation et b) le fer(III)/sulfite sans irradiation, nos résultats montrent une amélioration significative de l’oxydation de l’As(III) à pH 6 dans un système de fer(III)/sulfite-visible correspondant à une constante de vitesse initiale de 0,196 min-1. L’étude du mécanisme a révélé que les voies de l'oxydation d’As(III) à pH neutre est assez complexe. En effet, les radicaux libres (principalement les HO•, SO4-• et SO5-•) et mécanismes de transfert ligand-métal charge entre As (III) et ferrique colloïdal hydroxyde (CFH) des particules sont impliqués. Le troisième chapitre est une étude de l'adsorption coopérative d'acide nalidixique (NA) et de l'acide niflumique (NFA) sur goethite. Dans ce travail, la cinétique d’adsorption de NA et NFA a été réalisée en single et binaire. Les résultats montrent que le qe de NA est 8 fois de NFA dans un système à seul composant. Dans le système binaire, qe de NA était légèrement plus grand que pour le système single, alors que l’adsorption de NFA était environ 4 fois plus grande que pour le système single, ce qui suggère que l'adsorption est coopérative ou une co-liaison a eu lieu entre NA et NFA. La désorption a confirmé qu'aucune transformation de NA ou NFA a eu lieu en présence de la goethite. Des expériences en infra-rouge (ATR-FTIR) et la modélisation de complexation multi-site (MUSIC) ont été également effectuées. L'adsorption de NA et NFA dans les deux systèmes de composants simples et binaires peut être décrit par MUSIC. Ensuite, le quatrième chapitre est une étude de l'adsorption de NA et NFA sur du sable recouvert de goethite (GCS) sous conditions hydrodynamiques contrôlées. L'étude cinétique et les isothermes d’adsorption ont confirmé l'effet de co-liaison de NA et NFA sur la surface de GCS. Le comportement de NA et de NFA dans la colonne a montré de différence significative en raison de la différence de capacité et des mécanismes d'adsorption. Dans le système binaire, le comportement d'une substance peut être affectée par la présence de l'autre substance, tandis que l'effet sur la NFA est beaucoup plus prononcée que celle de NA. La modélisation de la complexation de surface a été utilisée pour prédire les courbes de percée, mais un désaccord a été observée entre la modélisation et les données expérimentales. Le point de percée et la quantité d'adsorption sont surestimés par le modèle, ce qui pourrait du à des limitations cinétique d’origine chimique. / Iron is an abundant metal in the environment. The occurrence of iron species in the environment can affect a wide range of processes. Contaminants can be widely found in the aqueous and solid phase environment. Their species are complex and diverse, including inorganic pollutants and organic pollutants. The studying on the mobility and redox transformation of these contaminants in the presence of iron spices and thereby the treatment methods have important environmental implications. This thesis includes 4 chapters. In the first chapter, we presented the bibliography on the current contamination situation of arsenic and several emerging contaminants, occurrence of iron species (dissolved iron and iron oxides) in the environment, and the interactions between contaminations and iron species. The second chapter is a study of the sorption of As(III) on colloidal ferric hydroxide and the transformation of As(III) under the visible light induced iron(III)/sulfite system. In this work, the oxidation of As(III) to As(V) in an iron(III)/sulfite system under visible light using sunlight or a light-emitting diode lamp (λ = 404 nm) were investigated. Several kinds of free radical quenchers, nitrogen and complexation competing agent were used for mechanism study. Comparing to a) iron(III) system with irradiation of light and b) iron(III)/sulfite system without irradiation light, our results show a significant enhancement of As(III) oxidation efficiency at pH 6 in iron(III)/sulfite-visible light (LED) system, corresponding to an initial rate constant of 0.196 min−1. Mechanism investigation revealed that the pathways of As(III) oxidation at circumneutral pH is complicated that involved free radicals (mainly HO•, SO4−• and SO5−•) and ligand-to-metal charge transfer between As(III) and colloidal ferric hydroxide (CFH) particles. The third chapter is a study of cooperative adsorption of nalidixic acid (NA) and niflumic acid (NFA) on nano-size goethite. In this work, the adsorption of NA and NFA in single and binary component systems was conducted by kinetic adsorption experiments and batch experiments for macroscopic study. Results show that qe of NA is 8 times of NFA in the single component system. In the binary component system, qe of NA was slightly larger than for the single system, whereas NFA adsorption was about 4 times larger than for the single system, suggesting that cooperative adsorption or co-binding occurred between NA and NFA. Desorption experiment confirmed no transformation of NA and NFA occurred in the presence of goethite. Attenuated Total Reflectance-Fourier Transform InfraRed (ATR-FTIR) spectroscopy and multi-site complexation (MUSIC) modeling was used for the microscopy study. The adsorption of NA and NFA in both single and binary component systems can be described by MUSIC modeling well. Afterwards, the fourth chapter is a study of the cooperative adsorption of NA and NFA onto goethite coated sand (GCS) under batch and flow through conditions. Batch experiments, including kinetic study, pH edges and isotherms, confirmed the co-binding effect of NA and NFA on GCS surface. The breakthrough behavior of NA and NFA in the column study showed significant difference in single component system due to the difference in adsorption ability and mechanisms. In binary component system, the breakthrough behavior of one substance can be affected by the presence of the other substance, while the effect on NFA is much pronounced than NA. Surface complexation modeling was used to predict the breakthrough behavior, however a disagreement was observed between modeling and experimental data in breakthrough point and adsorption amount, which might due to the chemical sorption kinetic limitation.

En Lorraine, le drainage fréquent des sols argileux favorise les transferts des intrants agricoles (pesticides et engrais) vers les eaux de surface. Dans ce cas, les bandes enherbées réglementaires (BCAE de la PAC) installées en bordure de cours d’eau sont court-circuitées et ne jouent plus leur rôle épurateur vis-à-vis des eaux de surface. Ainsi, des zones tampons humides artificielles (ZTHA) sont préconisées pour prendre le relais des bandes enherbées. Généralement, ces ZTHA sont installées à l’échelle du bassin versant ou du groupe de parcelles et sont donc de taille conséquente, les rendant concurrentielles de la surface agricole utile (SAU). L’objectif de ce projet de recherche est donc d’évaluer l’efficacité de deux ZTHA de taille réduite, installées dans la bande enherbée entre la parcelle drainée et le ruisseau. Pour cela, une approche multi-échelles intégrant des expériences de laboratoire en batch, des suivis dynamiques en bacs pilotes et un monitoring à la parcelle a été mise en place. Afin d’évaluer l’efficacité des ZTHA au cours des saisons de drainage 2012/13 et 2013/14, le suivi des teneurs en nitrate et de 79 pesticides a été réalisé dans les eaux en entrée et en sortie des ZTHA, ainsi que dans diverses matrices environnementales (sols, sédiment, paille, végétaux). Pour les deux dispositifs, la réduction du flux de nitrate s’est montrée stable, comprise entre 5,4 et 10,9 %, alors que la réduction du flux de pesticides s’est montrée très variable, comprise entre -618,5 et 100 %. Cette variabilité a été expliquée par quatre comportements distincts des molécules. Les fortes valeurs négatives d’efficacité ont été expliquées par une contamination des dispositifs à la suite d’épisodes de ruissellement connexes pour des molécules solubles telles que le 2,4-MCPA ou l’isoproturon. Pour ces deux molécules, l’étude de sorption a montré leur faible affinité avec les matrices environnementales, facilitant leur transport par les eaux de ruissellement et de drainage. D’autres molécules, telles que le boscalide ou l’OH-atrazine, ont présenté des abattements proches de 0. Pour le boscalide, ce comportement a été montré au laboratoire, en accord avec ses fortes capacités d’adsorption et de désorption observées lors des études de sorption et en bacs pilotes. Enfin, certaines molécules ont montré des abattements, allant de 9,9 à 100 %, en lien avec leur faible persistance (2,4-MCPA, clopyralid, mésosulfuron-méthyl,…) ou leur forte affinité pour les matrices environnementales (diflufenicanil, propiconazole, propyzamide,…). Ces ZTHA de taille réduite, installées dans les bandes enherbées, sont donc efficaces pour limiter la contamination des eaux de surface par les eaux de drainage agricole. Ainsi, la multiplication de ces dispositifs à l’échelle de la parcelle dans le paysage agricole permettrait de réduire la contamination des eaux de surface par les pesticides et les nitrates tout en préservant la SAU. Toutefois, l’efficacité de ces ZTHA restant limitée vis-à-vis de certains pesticides présentant un Koc faible et une DT50 élevée, leur installation ne doit pas remettre en cause la réduction en amont des apports phytosanitaires sur les parcelles / In Lorraine, the drainage of clay soils contributes to transfer of agricultural inputs (pesticides and fertilizers) towards surface waters. In this case, the regulatory grass strips (CAP regulation) installed along rivers are bypassed and no longer effective in purifying surface water. Thus, constructed wetlands (CWs) are recommended to take over grass cover bands. Generally, these CWs are installed at watershed scale or at that of several plots and they are therefore quite huge, making them competitive in the cultivated land. The objective of this project is to assess the effectiveness of two small CW, installed in the grass cover band between the drained plot and the river. For this, a multi-scale approach was set up integrating laboratory experiments in batch, pilot study taking into account the water dynamics and monitoring at field scale. The effectiveness of CW was assessed during the 2012/13 and 2013/14 drainage seasons. The nitrate and 79 pesticides concentrations were monitored at inlet and outlet of CWs and in various substrates (soils, sediment, straw and plants). For both devices, the removal efficiencies measured for nitrate were stable and ranged from 5.4 to 10.9 % of inlet amounts while the reduction of pesticide flows was very variable, ranging from -618.5 to 100 %. This variability was explained by four distinct behaviors. The high negative efficiency values were attributed to neighboured runoff events after heavy rains, for soluble molecules such as 2,4-MCPA or isoproturon. For both molecules, the sorption study showed low affinity for environmental substrates, facilitating their transport by runoff and drainage water. Other molecules such as boscalid or OH-atrazine showed effectiveness close to 0 %. For boscalid, this behavior has been observed in laboratory sorption and pilots studies, in agreement with its strong adsorption and desorption capacities. Finally, some molecules have shown reductions ranging from 9.9 to 100 %, in agreement with their low persistence (2,4-MCPA, clopyralid, mesosulfuron-methyl, ...) or their high affinity for environmental substrates (diflufenican, propiconazole or propyzamide). These small CWs, located in the grass cover bands, are effective in minimizing the contamination of surface waters by agricultural drainage water. Thus, multiplying the number of these devices at the plot scale in the agricultural landscape would reduce the contamination of surface waters by pesticides and nitrates while preserving the cultivated land. However, the effectiveness of these CWs are limited for pesticides with a low Koc and a long DT50; thus their installation in plot must not call into question the reduction in the use of pesticides

Les biochars sont au cœur de la lutte contre les changements globaux. Ils constituent aussi un enjeu pour la gestion durable des sols contaminés. Ces travaux ont été conduits afin de mieux comprendre les effets du biochar sur la mobilité des métaux dans les sols et leur transfert vers les plantes. Une série d’expériences de complexité croissante ont été conduites, impliquant un biochar obtenu par pyrolyse de bois à 450 °C, et deux sols, l’un acide et l’autre alcalin, contaminés par Cd, Pb et Zn suite à l'activité d'une fonderie. Une gamme d’espèces végétales aux réponses contrastées vis-à-vis des métaux a été testée. Des essais de sorption en batch et de lixiviation en colonnes couplés à une caractérisation microscopique et spectroscopique du biochar ont été réalisés, ainsi que des expériences de croissance végétale en vases de végétation, en rhizotrons et en lysimètres. Les résultats démontrent que les phases minérales carbonatées du biochar jouent un rôle prépondérant dans l'immobilisation des métaux. Elles interviennent dans la sorption directe des métaux à la surface du biochar par co-précipitation. Leur dissolution contribue également à l'augmentation du pH du sol, conduisant à une rétention accrue des métaux à la surface des particules du sol. Le biochar modifie le transfert des métaux vers la plante en diminuant la disponibilité des métaux, mais également en diminuant la mobilité de cations majeurs et en modifiant la surface racinaire développée par la plante. Une diminution du transfert du métal vers les parties aériennes de la plante a généralement été observée avec Lolium perenne ou Zea mays, alors qu'une augmentation du prélèvement de Cd et Zn par l'hyperaccumulateur Noccaea caerulescens a été mise en évidence. En conclusion, le biochar contrôle la mobilité des métaux dans les systèmes sol-plante grâce à une série de mécanismes différents. Au plan pratique, le biochar favorise les stratégies de phytostabilisation et de phytoextraction des métaux dans les sols contaminés / Biochars play a central part in the mitigation of global changes. They also represent a challenge for the sustainable management of contaminated soils. This work was conducted in order to better understand the effects of biochar on the mobility of metals in soils and their uptake by plants. A range of experiments was set up following a gradual increase of complexity, with a wood-derived biochar obtained by pyrolysis at 450 °C and two soils, acidic or alkaline, contaminated by Cd, Pb and Zn from smelter activity. Various plant species with contrasting response to metals were tested. Batch sorption and column leaching experiments coupled to microscopic and spectroscopic characterization of biochars were conducted, together with plant growth experiment in pots, rhizoboxes and lysimeters. Results demonstrate that biochar's carbonated mineral phases play a dominant role in the immobilization of metals. They lead to metals direct sorption on the surface of biochar by co-precipitation. Their dissolution also contributes to the increase of soil pH, leading to an increased retention of metals on soil particles. Biochar alters the transfer of metals to the plants by decreasing the availability of metals, but also by decreasing the mobility of major cations and by modifying root surface. A decrease of metal transfer to the shoots was generally observed with Lolium perenne or Zea mays, while an increase of the uptake of Cd and Zn by the hyperaccumulator Noccaea caerulescens was evidenced. In conclusion, biochar controls the mobility of metals in soil-plant systems through a range of different mechanisms. From a practical point of view, biochar promotes both strategies of phytostabilization and phytoextraction of metals in contaminated soils

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第21936号 / 地環博第182号 / 新制||地環||36(附属図書館) / 京都大学大学院地球環境学舎地球環境学専攻 / (主査)教授 勝見 武, 教授 高岡 昌輝, 准教授 高井 敦史 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

For the safety assessment of high-level nuclear waste repositories, it is mandatory to know the transportation paths of contaminants, e.g. actinyl ions, in the geological barrier. The most attention needs to be focused on the transport in aquifers, because water contamination, depending on retention and migration processes of radionuclides in the geosphere, is of primary environmental concern. The migration behavior of actinides in ground water is mainly controlled by aquatic speciations and sorption processes at water-mineral interfaces. Hence, the investigation of complexspecies in aqueous solutions and at mineral surfaces becomes essential for the safety assessment in the near and far field of nuclear repositories. For deep ground repositories, clay and clay minerals are considered as possible host rocks, because they show a low permeability and are expected to have a high retention capacity towards actinyl ions. But the complexity of naturally occurring minerals in particular their surface often hampers the unequivocal interpretation of results obtained from sorption experiments. The use of model phases only showing one particular functional group at the surfaces with a well defined surface topology is an appropriate approach for the understanding of the basic sorption processes. Aluminum oxide and hydroxides are of special interest because they represent main components in clays and clay minerals. In particular, gibbsite is widely used as a model system because it represents not only the most common crystalline aluminum hydroxide but also a ubiquitous weathering product of alumosilicates. Furthermore, the elemental structural unit of gibbsite, that is the Al(OH)6 octahedron, occurs ubiquitously as part of the structure of common clay minerals like kaolinite. In the present study, the sorption processes of U(VI) and Np(V) on gibbsite were studied under consideration of the aqueous speciation.

No description available.

Geosorption processes play an important role as retardation mechanism in subsurface transport of organic water constituents. Geosorption behaviour of Ionisable Hydrophobic Organic compounds (IHOCs) especially influence of dissolved natural organic materials on their sorption coefficients is poorly investigated. In this study influence of pH and NOM on the sorption of three different phenols (2-methyl-4,6-dinitrophenol, 2,4,6-trichlorophenol and pentachlorophenol) on a natural sandy aquifer material collected from a bank filtration site was studied in flow through column experiments. In first step the sorption coefficients of investigated phenols from NOM-free solutions with different pH values were determined. Single as well as multi (mixed) solutes experiments confirmed that there was no competition effect among the phenols investigated. An increasing sorption/retardation was observed with decreasing pH. A linear model was used to resolve the apparent sorption coefficient into an ionised species and neutral species component. This model allows a prediction of apparent sorption coefficients for any pH value. Analysis of data also revealed that the anion of 2-M-4,6-DNP show no significant sorption and a simple model based on the neutral form sorption coefficient was useful in predicting the apparent sorption coefficient over the entire pH range investigated. For 2,4,6-TCP and PCP, the anion sorption is much lower than that of the neutral species but cannot be neglected completely. For PCP, the anion sorption is even as high as the sorption of neutral 2,4,6-TCP. Thus for such hydrophobic phenols prediction of sorption based only on the partitioning of non-dissociated species may lead to an error, especially at high pH values (> pKa), where ionised form is present predominantly. On the other hand prediction of sorption based on the partitioning of non-dissociated species is useful at pH < pKa or in cases where the anion sorption can be neglected. The advantage of this prediction is that it allows predicting the pH-dependent sorption only on the basis of LFER correlations. It was shown that the organic carbon normalized sorption coefficients of the neutral forms of the phenols can be predicted better by solubility based regression correlations than by n-octanol-water partition coefficient based correlations. In second step the apparent sorption coefficients of investigated phenols from NOM-containing solutions (mixed solution of phenols dissolved in natural river water) with different pH values were determined; the sorption coefficients obtained from this step were compared with the results of the first step examinations. Analysis of data revealed that binding of 2-M-4,6-DNP by dissolved humic substances (DHS) reduces the sorption coefficient significantly. In contrast to it, the sorption of the more hydrophobic chlorinated phenols was not affected by DHS. A strong reduction of sorption onto aquifer material caused by complex formation with DHS was also observed for a second nitrophenol (2,4-DNP) and seems to be typically for nitrophenols. A combined sorption and complex formation model was proposed which could be used successfully to describe the effect of pH and NOM concentration on sorption reduction and to estimate binding constants. The binding constant found for 2-M-4,6-DNP is much higher than those reported by Ohlenbusch and Frimmel, 2001, for chlorophenols associated with Aldrich humic acid. This can be interpreted as a result of specific interactions between the nitrophenol and DHS. This phenomenon may cause an increase of the amount of nitrophenols, which can be transported with the groundwater flow and has to be considered in transport modelling, especially in cases where pH is lower than pKa. The models developed here are a useful tool to describe the influence of pH and NOM on geosorption processes and to estimate the Kd values which have to be used in transport models.

The objective of the work described in this thesis was to understand sorption reactions of uranium occurring at the water-clay mineral interfaces in the presence and absence of arsenic and other inorganic ligands. Uranium(VI) removal by clay minerals is influenced by a large number of factors including: type of clay mineral, pH, ionic strength, partial pressure of CO2, load of the sorbent, total amount of U present, and the presence of arsenate and other inorganic ligands such as sulfate, carbonate, and phosphate. Both sulfate and carbonate reduced uranium sorption onto IBECO bentonite due to the competition between SO42- or CO32- ions and the uranyl ion for sorption sites, or the formation of uranyl-sulfate or uranyl-carbonate complexes. Phosphate is a successful ligand to promote U(VI) removal from the aqueous solution through formation of ternary surface complexes with a surface site of bentonite. In terms of the type of clay mineral used, KGa-1b and KGa-2 kaolinites showed much greater uranium sorption than the other clay minerals (STx-1b, SWy-2, and IBECO montmorillonites) due to more aluminol sites available, which have higher affinity toward uranium than silanol sites. Sorption of uranium on montmorillonites showed a distinct dependency on sodium concentrations because of the effective competition between uranyl and sodium ions, whereas less significant differences in sorption were found for kaolinite. A multisite layer surface complexation model was able to account for U uptake on different clay minerals under a wide range of experimental conditions. The model involved eight surface reactions binding to aluminol and silanol edge sites of montmorillonite and to aluminol and titanol surface sites of kaolinite, respectively. The sorption constants were determined from the experimental data by using the parameter estimation code PEST together with PHREEQC. The PEST- PHREEQC approach indicated an extremely powerful tool compared to FITEQL. In column experiments, U(VI) was also significantly retarded due to adsorptive interaction with the porous media, requiring hundreds of pore volumes to achieve breakthrough. Concerning the U(VI) desorption, columns packed with STx-1b and SWy-2 exhibited irreversible sorption, whereas columns packed with KGa-1b and KGa-2 demonstrated slow, but complete desorption. Furthermore, most phenomena observed in batch experiments were recognized in the column experiments, too. The affinity of uranium to clay minerals was higher than that of arsenate. In systems containing uranium and arsenate, the period required to achieve the breakthrough in all columns was significantly longer when the solution was adjusted to pH 6, due to the formation of the uranyl-arsenate complex. In contrast, when pH was adjusted to 3, competitive sorption for U(VI) and As(V) accelerated the breakthrough for both elements. Finally, experiments without sorbing material conducted for higher concentrations of uranium and arsenic showed no loss of total arsenic and uranium in non-filtered samples. In contrast, significant loss was observed after filtration probably indicating the precipitation of a U/As 1:1 phase.

<p>In Sweden more than 400 000 private households have not yet sufficient wastewater purification. These effluent is considered as an increasing problem and many onsite purification methods have been studied. In this investigation, the method of reactive bed filters have been tested by column and batch experiments. Five different kinds of filter materials with reactive surfaces have been studied concerning their capacity to absorb ammonium and phosphorus from wastewater. The materials that were examined are Filtra N, wollastonite Filtra P, blast furnace slag and Polonite®. The first two materials were examined for their capacity to remove ammonium, and the others for their phosphorus removal capacity.</p><p>Ten columns were used, two for each material. A synthetic solution with the ammonium and phosphate concentration similar to that of domestic wastewater (NH4-N 30 mg/l; PO4-P 5 mg/l) were pumped to the columns under two flow regimes. Five columns were continuously saturated with solution and the other five columns were saturated under three one hour periods a day The solution was pumped three times a day to the columns at a volume equal to the pore volume of each material. The objective of the batch experiment was to find out how variations in pH-value and concentration of the nutrients influenced the sorption capacity of the materials. The result was then used for modelling in the computer program Visual Minteq to determine the probability of precipitation of known compounds.</p><p>Results from the column experiment showed that sorption of phosphorus in both saturated columns and intermittently saturated columns were 96 % or more for blast furnace slag, Filtra P and Polonite®. Filtra N showed the best ammonium sorption with 92 %. Sorption of ammonium was much better in periodically saturated columns for the material wollastonite. The wollastonite used in this experiment showed a higher phosphorus sorption capacity than expected. A possible explanation could be that the easy weathering of Ca-silicate compounds favoured the sorption of phosphorus. Results from Visual Minteq modelling showed that the probability of calcite formation in Filtra P and Polonite® are very likely. The two materials had high pH-values and the calcite was most likely formed at values of pH > 10. Hydroxyapatite is the most common precipitation when phosphorus sorption occurs and is suggested to be formed in wollastonite.</p> / <p>Mer än hälften av Sveriges enskilda avlopp bedöms inte uppfylla kraven i miljöbalken på längre gående rening än slamavskiljning. Dessa står för en betydande del av fosfor- och kväveutsläppen till hav, sjöar och vattendrag. Åtskilliga systemlösningar utreds, men i denna rapport har filter med fosfor- och kvävesorberande förmågor testats eller s.k. reaktiva filter. Mineraliska filter som ingått i studien är Filtra N, wollastonit, Filtra P, hyttsand och Polonite®. De två första filtren studerades speciellt på deras förmåga att avskilja ammonium och de tre övriga främst på deras fosforavskiljnings förmåga.</p><p>Kolonnförsök utfördes med tio kolonner där fem belastades med mättat flöde och de övriga med intermittent mättat flöde. Kolonnuppsättningen var två kolonner per filtermaterial med vardera olika flödesförhållanden. Belastningen på kolonnerna sattes till betydligt högre än traditionell infiltration/markbädd. Ett artificiellt avloppsvatten användes och tillreddes med en koncentration av kväve (NH4-N) på 30 mg/l och fosforkoncentration (PO4-P) på 5 mg/l. De valda koncentrationerna efterliknar ett vanligt hushållsspillvatten. Skakförsök utfördes för att undersöka sorptionsförmågan hos de olika mineraliska filtren där vikten låg på hur koncentrationen av näringsämnena och pH påverkar sorptionen. Resultaten från skakförsöken utvärderades med jämviktsmodellen Visual Minteq. Sannolikheten att kända utfällningar bildas studerades.</p><p>Resultaten från kolonnförsöken visade att hyttsand, Filtra P och Polonite® gav bäst fosforavskiljning med över 96 % för båda flödesregimerna. Filtra N var den bästa ammoniumavskiljaren med över 92 %. Wollastonit hade en bättre avskiljning med intermittent mättat flöde med 65 % jämfört med 11 % för mättat flöde. En intressant iakttagelse var att wollastonit hade en bättre fosforavskiljning än ammoniumavskiljning med ca 60 % för båda flödena. Det kan bero på att filtret innehåller lättvittrade Ca-silikatföreningar som ökar fosfatavskiljningen. Skakförsöken resulterade i att för Filtra P, hyttsand och Polonite® sorberades all tillsatt fosfat. Filtra N visade samma resultat som i kolonnförsöken med över 92 % sorption. Endast fosfat sorberades vid försök med tillsättning av både fosfat och ammonium till hyttsand och wollastonit. Vid modellering i Visual Minteq finns det en viss sannolikhet att kalcit bildats i Filtra P och Polonite® p g a deras höga pH, kalcit fälls ut vid pH > 10. Hydroxyapatit som är den vanligaste utfällningen av kalciumfosfat vid avskiljning av fosfor bildades mycket troligt i wollastonit.</p>

The effects of predicted future climate change was investigated with special emphasis on the association of organic contaminants with dissolved organic carbon (DOC) in the Baltic Sea. An automated method was developed for the measurements of DOC - water distribution constants at realistic DOC concentrations in brackish water. The method proved to be valid for 30 organic contaminants with different structural elements in the 5 – 100 mg car bon/L DOC concentration range. There were limitations of this method. Firstly, its applicability is limited towards contaminants with lower affinity to DOC. Secondly, at higher (&gt;100 mg carbon/L) DOC concentrations the sorption of contaminants was underest imated. Afterwards, water samples were collected from 15 points within the Baltic Sea in a north - south gradient t o examine the spatial differences in DOC characteristics and sorption properties . The DOC samples were analyzed using proton nuclear magnetic resonance and ultraviolet spectroscopy. Results from both techniques indicated that the aromatic nature of the DOC pool increased towards the northern Baltic Sea. This was expected as the freshwater inflow has high significance in controlling the hydrograp hic conditions in the Bothnian Bay. Sorption of organic contaminants was subsequently measured in the same samples. The results showed decreased sorption from north to south for hydrophobic contaminants such as chlorinated benzenes but for contaminants lik e tributyl - phosphate no spatial tendencies were observed. The data generated was used to determine molecular descriptors of DOC using linear free energy relationships. The results indicated a higher significance of hy drogen bond donor/acceptor functional g roups of the DOC in the south. Changes in contaminant distribution were simulated in model pelagic ecosystems at possible endpoints predicted by future climate change scenarios. Separate and combined effects of temperature a nd DOC were studied in mesocosms. The results indicated interesting tendencies. Increased temperature resulted in increased losses in the amounts of organic contaminants. Increased DOC levels promoted sedimentation and sorption of contaminants to particulate matter and biota. Hi gher amounts of contaminants were retained. The combined effects of the two factors led to and overall decrease in dissolved amounts. Higher losses or increased sedimentation and sorption to particles were also observed depending on contaminant properties. / EcoChange