Elevated manganese (Mn) concentrations have been measured in groundwater within the Roanoke River watershed, Virginia. Concentrations of Mn often exceed the secondary drinking water standard. A historic belt of Mn ores, the James River-Roanoke River Manganese District (JRRRMD), occurs in the eastern part of the watershed. The project objectives were to 1) evaluate the formation of the JRRRMD ore deposits and 2) analyze existing groundwater chemistry data to evaluate sources and processes that control groundwater Mn. Analysis of ore minerals, morphologies, and chemistry provides support that the ore deposits are supergene in origin, consistent with previous work. Spatial correlations between Mn ore locations and stream terrace deposits support a model of ore formation in which Mn-oxides were precipitated near discharge zones as anoxic groundwater mixed with oxic groundwater. Terrace deposits present at elevations higher than modern streams suggests that topography has been inverted, allowing ores to be found at higher elevations than what is typically associated with ores formed in discharge zones. Analysis of groundwater chemistry data shows positive correlations between Mn, calcium and bicarbonate concentrations in groundwater, suggesting that carbonate-bearing lithologies are probable sources of Mn to groundwater. Regionally, groundwater flows toward the Roanoke River where the flowpath terminus is marked by elevated Mn. The inverse correlation of Mn with dissolved oxygen suggests that reducing conditions that develop along flowpaths allow for Mn to persist in groundwater. Overall, results suggest that the same processes that allowed for formation of the JRRRM ore deposits continue to occur today. / Master of Science

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.

Les intégrons sont des plateformes génétiques bactériennes de capture et d'expression de gènes. Les intégrons cliniques sont les principaux responsables de la forte augmentation récente des bactéries multirésistantes aux antibiotiques. Cependant, dans l’environnement, ils ne représentent qu’une part minime de l’importante diversité des intégrons. Ainsi, les objectifs de cette thèse étaient (i) d’évaluer l’étendue de la diversité des intégrons dans l’environnement, (ii) de comprendre les phénomènes responsables de la structuration du pool d’intégrons dans le compartiment sédimentaire d’un milieu estuarien anthropisé et (iii) de rechercher l’existence potentielle d’intégrons indicateurs du niveau de contamination chimique.Le suivi des intégrons de classes 1, 2 et 3 et des populations d’E. coli dans des sédiments du bassin versant de la Risle impactés par des sources de contamination fécale bien caractérisées ont montré qu’en étiage, les souches d’E. coli d’origine humaine se disséminaient sur de courtes distances. Les intégrons de classe 1 se disséminent sur des distances un peu plus importantes et se maintiennent dans les 12 premiers centimètres du compartiment sédimentaire au moins.Une méthode a été développée permettant, pour la première fois, l’analyse de la diversité des intégrons via séquençage haut-débit. L’application de cette méthode sur une carotte sédimentaire de 4,8 m de profondeur prélevée dans l’estuaire fluvial de la Seine a permis de mettre en évidence plusieurs milliers de classes d’intégrons dont de nombreuses intégrases encore jamais répertoriées. La diversité des intégrons chute fortement avec la profondeur. Les intégrons de classe 1, majoritaires dans les sédiments de surface, ont une abondance qui chute fortement avec la profondeur cependant ils répondent plutôt positivement à la contamination chimique renforçant l’idée de leur utilisation comme proxy de pollutions anthropiques récentes. Trois classes d’intégrons dominent dans la vase consolidée représentant 38% des séquences obtenues dans la carotte sédimentaire mais répondant plutôt négativement à la contamination chimique. Enfin, la structure du pool d’intégrons est fortement corrélée à celle de la communauté bactérienne mais semble en partie indépendante de la communauté bactérienne dans deux des fractions sédimentaires profondes avec la dominance d’une nouvelle classe d’intégrons qui semble sélectionnée par les HAP. / Integrons are bacterial genetic platforms allowing acquisition and expression of genes. Clinical integrons play a major role in the strong increase of antibiotic multi-resistant bacteria recently observed. However, in the environment, they represent only a tiny fraction of the large integron diversity. Therefore, the aims of this thesis were (i) estimating the extent of the integron diversity in the environment, (ii) understanding phenomena responsible for integron pool structure in anthropized estuarine sediments and (iii) looking for integrons potentially proxy of chemical pollution level. The research of class 1, 2 and 3 integrons and the analysis of E. coli populations in sediments from the Risle drainage basin impacted by well-characterized fecal contamination sources show that E. coli strains with human origins were spread on short distances during low water level periods. However, class 1 integrons are spread on slightly longer distances and remain present in the 12 first centimeters of sediments at least. A methodology was developed allowing, for the first time, the analysis of integron diversity by high-throughput sequencing. In this way, the analysis of a 4.8 meter core sediment from the fluvial Seine estuary highlighted several thousands integron classes including many new integrases absent from data bases. Integron diversity decreases along with depth. Class 1 integrons are the majority integrons in surface sediments but their abundance strongly decreases in deep sediments. Class 1 integron abundance rather responds positively to chemical pollutions accentuating the idea that class 1 integrons could be used as proxy of recent anthropogenic pollutions. In the sediment core, three integron classes outshine the whole dataset: they represent 38% of all the sequences from the sediment core. However, abundances of these three majority integron classes rather respond negatively to chemical pollution levels. Integron pool structure is highly correlated to bacterial community diversity but seems to be partially independent to bacterial community diversity within two deep fractions from the sediment core: in these two sediment fractions, a new integron class outshines the rest of integron classes and seems to be specific to these two sediment fractions. Furthermore, this new integron class seems to be selected by PAH.

<p>More than 50% of wastewater biosolids are applied to agricultural fields as fertilizer in the U.S. This technique has been used for decades as a widely accepted beneficial reclamation method for biosolids, which meet the established regulatory levels for nutrients, metals, and pathogens. A major drawback to land application is the potential environmental release of non-regulated organic contaminants, which accumulate in biosolids during the wastewater treatment process. Recent studies have been performed to identify and quantify the presence of emerging contaminants in biosolids, and others have investigated the effects of compounds already identified as `priority pollutants' and whose use is waning. However, there is limited research on the effect of emerging organic contaminants on soil microbial ecology and nutrient cycling. Because many of the compounds found in biosolids are specifically designed to elicit biological modifications (e.g., antimicrobials), there is a risk that these compounds will disrupt microbial soil functions, decrease soil productivity, and ultimately affect the long term viability of these ecosystems, resulting in unforeseen economic and social costs. Therefore, there is a clear need to characterize the effects of novel contaminants on soil health.</p><p>This dissertation was divided into three distinct parts examining the impacts of emerging organic contaminants on soil microbial ecology with increasing complexity to better reflect environmental conditions. To assess the ecological impacts, the functional endpoint of denitrification was selected because it provides a vital indication of soil health. Denitrifying bacteria play a critical role in this process, and thus, were used as indicator organisms for determining contaminant ecotoxicological potential. Furthermore, antimicrobial agents (a.k.a., bactericides or biocides) were selected as model contaminants because they are designed specifically to deactivate microorganisms, are heavily used in the U.S with over $1 billion in yearly sales, and have been measured in biosolids.</p><p>Overall, the objectives of this dissertation were to: 1) develop a rapid, high-throughput functional assay that measured denitrification inhibition for screening potential ecological impacts of biosolids-derived antimicrobial agents, 2) determine the potential effects of common and emerging biosolids-derived antimicrobial agents on denitrification by a model soil denitrifier, Paracoccus denitrificans PD1222, 3) examine the impacts of the most commonly used antimicrobial, triclosan (TCS), on wastewater treatment efficiency in bench scale sequencing batch reactors (SBRs) coupled with anaerobic digesters, 4) examine the impacts of biosolids aged and spiked with TCS on denitrification under simulated agricultural soil conditions, and 5) evaluate potential impacts of TCS in `traditional' biosolids on denitrification in agricultural soil under field conditions.</p><p>The first phase of research pertaining to Objectives 1 and 2 examined the baseline interactions between biosolids-derived antimicrobial agents and soil microbial ecology. However, to isolate the effect of an individual contaminant from the myriad of contaminants found in biosolids, there was a need for developing a rapid, high-throughput method to evaluate general ecotoxicity. In the first part of this dissertation, we developed a novel assay that measured denitrification inhibition in a model soil denitrifier, Paracoccus denitrificans Pd1222. Two common (TCS and triclocarban) and four emerging (2,4,5 trichlorophenol, 2-benzyl-4-chlorophenol, 2-chloro-4-phenylphenol, and bis(5-chloro-2-hydroxyphenyl)methane) antimicrobial agents found in biosolids were analyzed as model contaminants. Overall, the assay was reproducible and measured impacts on denitrification over three orders of magnitude exposure. The lowest observable adverse effect concentrations (LOAECs) were 1.04 &mu;M for TCS, 3.17 &mu;M for triclocarban, 0.372 &mu;M for bis-(5-chloro-2-hydroxyphenyl)methane, 4.89 &mu;M for 2-chloro-4-phenyl phenol, 45.7 &mu;M for 2-benzyl-4-chorophenol, and 50.6 &mu;M for 2,4,5-trichlorophenol. Compared with gene expression and cell viability based methods, the denitrification assay was more sensitive and resulted in lower LOAECs. Of the six compounds examined, four resulted in LOAECs that were below or within an order of magnitude of concentrations that were measured in the environment, indicating potential ecological impacts.</p><p>In the second part of the dissertation, the impacts of emerging contaminants were examined first under laboratory conditions mimicking wastewater treatment processes (Objective 3) and then agricultural fields (Objective 4). For this phase, TCS, which is the most widely used antimicrobial agent and identified in the first phase for potential ecological impacts, was used as the model contaminant. To mimic wastewater treatment processes, bench scale SBRs coupled with anaerobic digesters were set up and operated. The SBRS and digesters were seeded with activated and anaerobically digested sludge from the North Durham Water Reclamation Facility (NDWRF, Durham, NC). Reactors were fed synthetic wastewater with or without 0.73 &muM of TCS. Samples were taken periodically to monitor chemical oxygen demand (COD), ammonium (NH₄<super>+</super>), nitrate (NO₃<super>-</super>), nitrite (NO<sub>2</super>-</super>), total suspended solids (TSS), volatile suspended solids (VSS), dissolved oxygen (DO), and phosphate (PO₄<super>3-</super>) and pH. In addition, biomass samples were collected for DNA extraction and microbial community analysis using terminal restriction fragment length polymorphism (T-RFLP) of 16S SSU rDNA. Methane production was also monitored for the anaerobic digesters. In addition, the final digested biosolids that were generated from the SBRs fed with and without TCS were analyzed for TCS concentration, TSS, VSS, TKN, phosphorus (as P₂O₅), potassium (as K₂O), and pH. Overall, biological processes associated with nitrogen removal (nitrification and denitrification), were impacted by TCS entering the SBRs regardless of the starting microbial community. Both of the SBRs that were not receiving TCS reached steady-state at greater than 92% NH₄<super>+</super>, removal within the first week of operation, whereas the SBRs receiving TCS took 42 and 63 days to reach steady-state removal at that level. However, while NH₄<super>+</super> removal was temporarily inhibited, elevated levels of NO₃<super>-</super> and NO₂<super>-</super> in the effluent of the TCS fed SBRs, suggested longer-term impacts on nitrite oxidizing bacteria (NOB) and denitrifiers. After Day 58, the NO₃<super>-</super> effluent concentration for the SBRs receiving TCS was 3.9 ± 0.16 mg/L, which was 2.4 times greater than the NO₃<super>-</super> effluent of the SBRs not receiving TCS (1.7 ± 0.08 mg/L). Similarly, after Day 58, the NO₂<super>-</super> effluent of the SBRs receiving TCS reached a steady-state concentration of 8.7 ± 0.75 mg/L. The mean NO₂<super>-</super> concentration in the controls after Day 58 was 7.7 times lower at 1.1 ± 0.78 mg/L, but was still trending towards 0 when the reactors were stopped. No inhibition was observed for COD and PO₄<super>3-</super> removal. In addition, non-metric multidimensional scaling (NMS) ordination analysis showed that the microbial communities between SBRS fed with and without TCS were similar on Day 0, but increased in difference to Day 41, around when the major changes in nitrification were observed. After a slight increase in similarity between the control and TCS SBR microbial communities on Day 41, the communities increased in difference to Day 63.</p><p>To mimic agricultural field conditions, containers of soil were amended with the biosolids generated from the SBRs. The containers were maintained in a growth-chamber to simulate field lighting and watering conditions. Three biosolids treatments were examined: 1) biosolids generated from the SBRs not fed TCS, but that still had low backgrounds of TCS (a.k.a., Control Biosolids); 2) biosolids generated from the SBRs fed with TCS (a.k.a., Aged TCS Biosolids); and 3) biosolids that were generated by the SBRs not fed TCS, but spiked with TCS 24 h before application (a.k.a., Spiked TCS Biosolids). Alfalfa was planted in half of the containers receiving the Control and Aged TCS Biosolids to assess differences due to vegetation. To assess the overall ecotoxicity of biosolids aged and spiked with TCS, the function, abundance, and diversity of the soil denitrifying communities were examined. The impacts on total bacteria abundance and diversity were also examined for comparison. Specifically, the denitrifying enzyme activity (DEA) assay was used to measure functional impacts, quantitative polymerase chain reaction (qPCR) was used to measure impacts on abundance, and T-RFLP was used to measure impacts on diversity. Correlations between these methods were also examined for possible interactions between denitrifier function and community structure and to provide insight into targets of inhibition. Lastly, a denitrification inhibition score was developed to quantify global impacts of TCS on denitrification. The containers with plants that received biosolids aged with and spiked with TCS showed potential long-term inhibition based on measurement of soil denitrification at 26.9 ± 4.6 &mu;g/kg and 68.6 ± 26.9 &mu;g/kg of TCS, respectively. Denitrifier abundance and diversity, however, were more sensitive to TCS in biosolids and inhibition was observed throughout the experiment, with maximum inhibition on Days 7 and 28. Inhibition of denitrifier abundance and diversity was observed at TCS concentrations as low as 17.9 ± 1.93 &mu;g/L, which was about 10 to 3000 times lower than concentrations reported by other studies that showed impacts on other functional endpoints (i.e., respiration, phosphatase activity, NO₃<super>-</super> and NO₂<super>-</super> production, and Cy17 stress biomarker abundance), even after taking pH into account. Five significant correlations were developed, three of which related qPCR and the DEA assay, or abundance and activity. However, the analyses that were correlated did not yield the same results as far as significant inhibition in the presence of TCS. Thus, while the results suggested some relatedness between activity, abundance, and diversity, the results generally support the use of multiple methods to determine the ecotoxicity of biosolids-derived organic contaminants. As a result, a denitrification inhibition score was developed that took into account all three methods to determine the overall ecotoxicity of TCS in biosolids. Overall, the denitrification inhibition score showed that denitrification was inhibited by both biosolids that were aged and spiked with TCS over the extent of the 84 day experiment, but maximum inhibition occurred after a week to about a month. While the denitrification inhibition score indicated that the TCS in the biosolids aged with TCS was less bioavailable than in the spiked biosolids, the impacts of the aged and spiked biosolids could have also been due to differences in TCS concentrations.</p><p>Objective 5 consisted of a long-term soil sampling campaign on four agricultural fields receiving Class B municipal biosolids. Soil samples were taken before and after biosolids application and were analyzed to elucidate potential impacts of TCS in the biosolids on denitrification. Again, to assess the overall impacts of TCS on the soil denitrifying community, the DEA assay, qPCR, and T-RFLP were used to measure impacts on function, abundance, and diversity, respectively. Similar to Objective 4, the analysis included an examination of potential correlations between denitrifying community structure and function, and quantification of global impacts using the denitrification inhibition score. As expected, the results in this pilot-study reflected the complexity of the system that was analyzed and many more samples, which account for variables including, but not limited to soil characteristics, biosolids characteristics, biosolids application rates, and chemical composition and quantities, would be needed to show any statistically significant differences. Nevertheless, several key results were obtained. Again potential long-term inhibition of denitrification was observed using the DEA assay, however the effects of exhaustion of resources, such as NO₃<super>-</super>, or significant changes in the local environment were suspected, but could not be verified. Inhibition was also observed for denitrifier abundance, but little to no inhibition was observed when examining the relative number of denitrifying species. Thus, while the abundance of denitrifiers was reduced, and denitrification was eventually depressed, the number of species in the soil remained constant. When looking at the denitrification inhibition score, which took all three measurements into account, increased inhibition over time was observed with the exception of the measurements on Days 30 and 103, which indicated overall, but weak inhibition of denitrification by the application of biosolids. NMS ordinations showed no correlation between the shift in denitrifying microbial community and TCS. Because of the complexity of the soil and biosolids and because of the myriad of contaminants likely in the biosolids, the results may not be significant and a more in-depth study was recommended.</p><p>Overall, the results presented in this dissertation provide a systematic evaluation of the effects of biosolids-derived TCS on agricultural soil microbial ecology. First, it was demonstrated that statistically significant inhibition of denitrification could be used as a potential indicator of biosolids-derived emerging organic contaminant ecotoxicity. The denitrification assay that was developed was then used to analyze ecotoxicological potential of six emerging biosolids-derived antimicrobial agents, and found inhibition of denitrification at environmentally relevant concentrations. The most widely used antimicrobial agent, TCS, was further shown to inhibit wastewater treatment processes, as well as, denitrification in simulated agricultural conditions after being aged with and spiked into biosolids. In addition, evidence showing potential inhibition of denitrification by TCS in `traditional' biosolids under field conditions was also obtained. Based on these results, this dissertation asserts that biosolids-derived emerging organic contaminants pose a potential risk to agricultural soil microbial ecology and overall soil health. Future studies, however, are needed to examine the impacts of other contaminants that might be flagged with the assay developed in this dissertation under more complex conditions mimicking the environment. Furthermore, other research is needed to examine the role microbial communities play in the bioavailability of emerging contaminants, especially TCS, and a more extensive, in-depth study is needed to characterize the individual impacts of emerging contaminants on soil microbial communities under field conditions.</p> / Dissertation

Les lixiviats des sites d’enfouissement, formés des eaux de pluie et de fonte de neige percolées à travers les cellules d’enfouissement, constituent un défi pour les filières conventionnelles de traitement des eaux. Ceci est dû à la complexité de ce type d’eaux polluées, mais aussi à la panoplie de contaminants émergents qu’elles peuvent contenir. Par ailleurs, l’évolution des exigences réglementaires en matière de l’environnement requiert un traitement séparé et distinct de eaux de lixiviats par rapport aux stations de traitement des eaux usées urbaines. L’un des produits ubiquitaire au lixiviat est le bisphénol A (BPA) qui est considéré comme un perturbateur endocrinien dû à sa capacité de mimer certaines hormones endocriniennes. Il conduit, entre autre, à la féminisation de certaines espèces aquatiques suite à une réduction d’hormones masculines lors de la différenciation embryonnaire. La destruction de cellules testiculaires, la diminution de production de spermatozoïdes et des oeufs sont également reportés lors de tests au laboratoire. La majorité des études conduites à ce niveau sont par rapport à la présence de BPA dans les eaux usées urbaines. Le présent projet vise l’investigation de la présence et de l’élimination du BPA au niveau d’une station de traitement biologique de lixiviats d’un site d’enfouissement technique au Centre-du-Québec (Canada). Cette installation consiste principalement en un traitement biologique comprenant un réacteur biologique séquentiel précédé par un étang d’accumulation et de régulation. Les résultats de quantification des échantillons prélevés montrent une concentration élevé en BPA de l’ordre de 5 823 ± 575 μg /L à l’entrée de la station et de 256 ± 9 μg/L à la sortie. Le rendement global d’élimination de la station affiche une valeur de 98%. L’adsorption du BPA sur les biosolides semble être un mécanisme d’élimination qui doit être pris en considération. Les tests menés au laboratoire montrent que le BPA s’adsorbe sur les biosolides selon le modèle de Freundlich avec un coefficient de corrélation de 0,986 contrairement au modèle de Langmuir (0,766) ou encore de Dubinin-Radushkevich (0,811). La cinétique réactionnelle de l’adsorption suit une réaction de pseudo deuxième ordre avec une vitesse d’adsorption de 0,0043 g/μg.min et est contrôlée par la diffusion intraparticulaire et la couche limite. D’un point de vue thermodynamique, la réaction est spontanée et exothermique avec des liaisons faibles de type van der Waals et électrostatiques.

8 pp. / The land application (non-hazardous sewage sludge) biosolids has been in practice in Arizona since the 60s.

80 pp. / Arizona: Know Your Water. A consumer's guide to water source, quality, regulations and home water treatment. / This well owners guide presents detailed sections to assist the reader in becoming familiar with water quality concepts, drinking water guidelines and water testing. The reader can also become familiar with Arizona specific aquifers, conditions and activities that determine ground water quality. Well owners can also review and become familiar with well construction, components and maintenance needed for the safe and proper function of their wells. Finally, a section on water treatment technologies and selection, based on water quality conditions is presented. Well owners will be able to refer to this section for the selection of water treatments, should they choose to improve the water quality of their wells. Includes numerous illustrations.

Every year, new trace chemicals are detected in natural waters as well as treated wastewater effluents all over the world. Public health and environmental concerns have driven the development of new technologies to treat water and eliminate chemicals that may pose risk to humans and wildlife. This work presents a detailed statistical analysis on the removal of some of the most widely occurring chemicals of emerging concern in wastewater based on information available in the literature. Results show that existing water treatment processes only partially eliminate most of these contaminants. Advanced oxidation processes (AOPs) are some of the technologies that have shown the most promising results for the removal of recalcitrant organics in water. Hydrogen peroxide photolysis (UV/H₂O₂) and Fenton’s reaction are some examples of AOPs that use hydroxyl radicals to oxidize organics. The kinetics of UV/H₂O₂ and Fenton’s reaction were studied from the experimental and mathematical points of view. Comprehensive models with no adjustable parameters successfully accounted for radical initiation via photolysis of H₂O₂ or radical initiation via Fenton’s mechanism; reaction of organic targets such as p-cresol and nonylphenol with hydroxyl radicals; and recombination mechanisms, as well as changes in solution pH due to evolution of carbon dioxide because of target mineralization. The presence of radical scavengers was successfully handled by the models, suggesting that they can be generalized to the treatment of complex matrices. The UV/H₂O₂ model was also extended to solar catalyzed applications. Using an atmospheric solar irradiation model (SMART) and data from the Giovanni-NASA online database, ground-level solar spectral irradiance were obtained and used as model inputs. The kinetic model provided an excellent fit to experimental results obtained with p-cresol and fluorescein targets using no fitted parameters. The UV/H₂O₂ process was also studied in commercial flow-through UV reactors with monochromatic and polychromatic light sources. Organic targets of interest such as pcresol can be degraded effectively in these reactors at relatively low peroxide concentrations. Results with wastewater effluents suggest that these commercial reactors can be used for AOP tertiary treatment as a way to reduce dissolved organic matter and eliminate potential harmful chemicals present in the water.

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

Human pharmaceuticals have been shown to be entering the aquatic environment in quantities sufficient to produce adverse effects to aquatic organisms, particularly fish. The impacts of synthetic oestrogens have been well documented, but other groups of steroidal pharmaceuticals have not yet been studied. Hence, the present research was designed to study synthetic glucocorticoids (GCs), which are used in large amounts as immunosuppressive and anti-inflammatory drugs. This study involved different approaches, including in silico, in vitro, in vivo and genomics, to assess the effects of GCs on fish. Using reliable data on consumption of GCs in the UK and the LF2000-WQX hydrological model, mean concentrations of GCs in the river Thames were predicted to be in the range from 30 ng/L to 850 ng/L. Mammalian cell lines were transiently transfected with trout corticosteroid receptors (GR1, GR2 and MR) and the transactivation abilities of ten of the most prescribed GCs in the UK were measured in vitro. All tested GCs showed significantly higher activity with GR2 than with GR1. In order to assess the impact of low concentrations of GCs in vivo, two chronic exposure experiments were conducted with adult fathead minnows (Pimephales promelas). Both experiments showed potency-related and concentration-related impacts on various endpoints. There was a concentration-related increase in plasma glucose concentrations and a decrease in blood lymphocyte count. Induction of secondary sexual characters in females suggests a concentration-related masculinisation of fathead minnows. There was a decreasing trend in plasma vitellogenin concentrations in female fish with increasing exposure concentration of GCs. Expression profiles of selected genes (PEPCK, GR and Vtg) in liver also demonstrated concentration-related effects at all three tested concentrations. Hence, it was not possible to define a no effect concentration for the tested GCs. This study probably provides reliable estimates of the likely range of concentrations of GCs in a typical river, impacted by effluent from many sewage treatment plants. The in vitro results indicate that all tested GCs bind to fish GR in a similar manner to that reported for mammalian receptors. The in vivo results suggest that GCs could cause effects at very low (as low as 100 ng/L) concentrations that could be environmentally-relevant. The immunosuppresive effects could make fish susceptible to disease and the reproductive effects may have population-level impacts. It is very likely that the effects of different GCs will be additive, as has been shown for oestrogenic chemicals. Therefore, this study warrants further environmental risk assessment of GCs, especially in mixture scenarios.