Nas questões ambientais legais, muitas vezes a referência à toxicidade de uma substância é vaga. No entanto, essa informação é essencial para a determinação da extensão do dano. Para fazer a previsão desses valores para o benzeno e hidrocarbonetos policíclicos aromáticos (PAHs), componentes do petróleo, foi feito um estudo QSAR (Quantitative Structure Activity Relationship) por meio de cálculos de mecânica quântica e quimiometria. O objetivo foi construir modelos para prever os valores de coeficiente de partição n-octanol/água, Kow (n-octanol/water partition coefficient) além do estudo das toxicidades dos PAHs. Para este estudo, as geometrias de todas as moléculas foram otimizadas utilizando os métodos semiempíricos AM1, PM3, PM6 e PM7. Desses resultados ainda foram extraídos os descritores teóricos que foram utilizados para descrever os valores de log Kow. Entre todos aqueles calculados, os descritores: energia total, energia eletrônica, área, volume e massa molar foram escolhidos como os parâmetros para o estudo PLS (Partial Least Squares). Além disso, as toxicidades dos PAHs foram calculadas por meio do programa T.E.S.T (Toxicity Estimation Software Tool) disponibilizado gratuitamente pelo EPA (Environmental Protection Agency) e estimados por meio de modelo PLS e gráficos de correlação. Observou-se com esse estudo que todos os métodos apresentaram resultados bastante satisfatórios, uma vez que valores próximos de 1 foram obtidos tanto para o coeficiente de correlação interno, Q2, quanto para o externo, R2. / In the environmental legal issues, often the reference to toxicity of a substance is vague. However, this information is essential for determining the extent of damage. To forecast these values for benzene and polycyclic aromatic hydrocarbons (PAHs), petroleum components, one study QSAR (Quantitative Structure Activity Relationship) was done by calculation of quantum mechanics and chemometrics. The goal was to build models to predict the values of the partition coefficient n-octanol / water, Kow (n-octanol / water partition coefficient) beyond the study of the toxicity of PAHs. For this study, the geometries of all molecules were optimized using the semi-empirical methods AM1, PM3, PM6 and PM7. These theoretical results also descriptors that were used to describe the Log Kow values were extracted. Among those calculated descriptors: total energy, electronic energy, area, volume and molar mass were chosen as the parameters for the study PLS (Partial Least Squares). Furthermore, the toxicities of PAHs were calculated using the TEST (Toxicity Estimation Software Tool) program available free of charge by the EPA (Environmental Protection Agency) and estimated by PLS model and correlation charts. It was observed in this study that all the methods have shown promising results, since values near one were obtained for the standard and cross-validated correlation coefficients R2 and Q2.

Nas questões ambientais legais, muitas vezes a referência à toxicidade de uma substância é vaga. No entanto, essa informação é essencial para a determinação da extensão do dano. Para fazer a previsão desses valores para o benzeno e hidrocarbonetos policíclicos aromáticos (PAHs), componentes do petróleo, foi feito um estudo QSAR (Quantitative Structure Activity Relationship) por meio de cálculos de mecânica quântica e quimiometria. O objetivo foi construir modelos para prever os valores de coeficiente de partição n-octanol/água, Kow (n-octanol/water partition coefficient) além do estudo das toxicidades dos PAHs. Para este estudo, as geometrias de todas as moléculas foram otimizadas utilizando os métodos semiempíricos AM1, PM3, PM6 e PM7. Desses resultados ainda foram extraídos os descritores teóricos que foram utilizados para descrever os valores de log Kow. Entre todos aqueles calculados, os descritores: energia total, energia eletrônica, área, volume e massa molar foram escolhidos como os parâmetros para o estudo PLS (Partial Least Squares). Além disso, as toxicidades dos PAHs foram calculadas por meio do programa T.E.S.T (Toxicity Estimation Software Tool) disponibilizado gratuitamente pelo EPA (Environmental Protection Agency) e estimados por meio de modelo PLS e gráficos de correlação. Observou-se com esse estudo que todos os métodos apresentaram resultados bastante satisfatórios, uma vez que valores próximos de 1 foram obtidos tanto para o coeficiente de correlação interno, Q2, quanto para o externo, R2. / In the environmental legal issues, often the reference to toxicity of a substance is vague. However, this information is essential for determining the extent of damage. To forecast these values for benzene and polycyclic aromatic hydrocarbons (PAHs), petroleum components, one study QSAR (Quantitative Structure Activity Relationship) was done by calculation of quantum mechanics and chemometrics. The goal was to build models to predict the values of the partition coefficient n-octanol / water, Kow (n-octanol / water partition coefficient) beyond the study of the toxicity of PAHs. For this study, the geometries of all molecules were optimized using the semi-empirical methods AM1, PM3, PM6 and PM7. These theoretical results also descriptors that were used to describe the Log Kow values were extracted. Among those calculated descriptors: total energy, electronic energy, area, volume and molar mass were chosen as the parameters for the study PLS (Partial Least Squares). Furthermore, the toxicities of PAHs were calculated using the TEST (Toxicity Estimation Software Tool) program available free of charge by the EPA (Environmental Protection Agency) and estimated by PLS model and correlation charts. It was observed in this study that all the methods have shown promising results, since values near one were obtained for the standard and cross-validated correlation coefficients R2 and Q2.

Determining the root uptake of xenobiotic organic chemicals into plants is critical for assessing the human and ecological health risks associated with the consumption of plants growing in contaminated environments. Root uptake of xenobiotic organics occurs passively in conjunction with transpiration and the transport from root to shoot is ultimately controlled by passage through one or more lipid root membranes. The transpiration stream concentration factor (TSCF), the ratio between the concentration of a chemical in the xylem to that in the solution used by the roots, is used to describe the relative ability of an organic chemical to be passively transported from root to shoot. However, relatively few experimental TSCF values exist due to the cost and the lack of regulatory requirements for generating such data. Where literature data exist for chemicals having more than one TSCF, the variability is often large due to the lack of standardized methods and difficulty in accounting for metabolism and volatilization losses occurring during the uptake experiments. Because of the scarcity of experimental values, estimated TSCFs are often used. Widely cited estimation approaches relating TSCF and the logarithm octanol/water partition coefficient (log KOW) suggest that only compounds that are in the intermediate lipophilicity range (log KOW = 2) will be taken up and translocated by plants. However, recent data for highly water soluble compounds such as 1,4-dioxane, MTBE, and sulfolane suggest that these estimation techniques should be critically reviewed. To re-evaluate the relationship between TSCF and log Kow, TSCFs were measured for 25 organic chemicals ranging in log KOW from -0.8 to 5 using an improved pressure chamber technique. The technique provides an approach for efficiently generating consistent plant uptake data. By using this data, a new mass transfer model relating TSCF and log KOW was developed that indicates that neutral, polar organic compounds are most likely taken up by plant roots and translocated to shoot tissue. An extensive review of literature TSCF studies supports the updated model.

A new approach for predicting octanol-water partition coefficients (Log P) of linear perfluorinated compounds, making use of the limited experimental data available, previous observations and the consistent similarities observed between the experimental and calculated (with electronic structure methods and using EPI suite) slopes of the linear plots of Log P values with the number of carbon atoms (N = 2 to 11) is described here. Eight families of linear organic compounds were investigated: carboxylic acids, perfluorinated carboxylic acids, sulfonic acids and perfluorinated sulfonic acids, together with their corresponding conjugate bases. To the best of our knowledge, this work reports the first application of density functional theory methods to the calculation of Log P values of perfluorinated compounds. A second part of the thesis, describes the study of the thermodynamic stability of the PFOA family of 39 structural isomers with the M06-2X, LC-ωPBE, B97D and B3LYP functionals and with the PM6 method. The PM6 results closely resemble the M06-2X results for neutral PFOAs, but greatly disagree regarding anions. The four functionals applied behave similarly from a qualitative point of view, but quantitatively speaking, the LC-ωPBE and B97D results are between the M06-2X and B3LYP stability results. M06-2X ranks highly substituted isomers as more stable than did B3LYP, and ranks less-branched isomers quite low in relative stability compared to B3LYP. Various similarities with a former PFOSs study applying the M06-2X and B3LYP functionals have been identified. The degree of branching within structural isomers cannot always be precisely determined, and is not the only aspect that determines thermodynamic stability; the pattern of substitution seems to also play a significant role. / Graduate

Ce travail de thèse porte sur l’étude des mécanismes et des bilans de transfert des pesticides vers les cours d’eau sur deux bassins versants agricoles emboités, de tailles différentes en Gascogne (Sud Ouest de la France) : la Save à Larra (1110 km2).et le Montoussé (3,28 km2) à Auradé. Dans cette région, les pratiques d’une agriculture intensive conduisent à des risques importants pour les ressources en eau, notamment pendant les périodes de crue. C’est pour cela que nous avons porté une attention particulière dans cette étude à ces événements au cours desquels une grande quantité de contaminants sont transportés par les cours d’eau. Quatorze molécules de pesticides (herbicides et fongicides) largement utilisées sur ces bassins versants ont été étudiées grâce à un échantillonnage intensif, notamment en périodes de crue, durant deux années hydrologiques (2007/2008 et 2008/2009). La majorité des molécules étudiées présentent des concentrations qui dépassent les limites autorisées par l’Union Européenne pour l’eau potable (0.1 μg.L-1 pour chaque molécule et 0.5 μg.L-1 pour l’ensemble des molécules), notamment en périodes de crue. L’analyse des hystérésis mises en évidence sur les relations entre les concentrations (pesticides, MES, COD, POC) et les débits du cours d’eau permet de mieux comprendre les mécanismes de transfert des pesticides et de leurs paramètres de contrôle. Ces hystérésis montrent pour un même débit des concentrations différentes en montée et en descente de crue ; elles peuvent être dextres (sens des aiguilles d’une montre) ou senestres (sens inverse) suivant l’origine des molécules et l’écoulement responsable de leur transfert des sols vers les eaux. C’est pourquoi nous avons procédé dans cette étude à une séparation des différentes composantes (ruissellement superficiel, écoulement hypodermique, écoulement de nappe) de l’écoulement fluvial pour mieux comprendre la dynamique de transferts des pesticides et de leurs paramètres de contrôle. On peut ainsi mettre en évidence des relations positives entre MES, COD, COP ou certaines molécules de pesticides et les débits des écoulements de surface (ruissellement superficiel ou écoulement hypodermique suivant les caractéristiques physico-chimiques des molécules). Les calculs de flux des différents pesticides exportés par les cours d’eau montrent que 60 à 90% (suivant les molécules) des transports annuels se font durant les épisodes de crue. Les flux spécifiques (masse exportée par unité de surface) calculés sont plus importants sur le bassin versant de la Save que sur celui du Montoussé et les relations flux spécifiques-débits mettent en évidence des concentrations plus élévées sur la Save où l’utilisation des pesticides est globalement plus importante que sur le Montoussé où les pratiques sont raisonnées. L’analyse des pesticides dans l’eau filtrée et non filtrée nous a permis d’estimer la distribution de chaque molécule entre les phases particulaires et dissoutes (Kd). De plus, les valeurs de flux calculés pour chaque crue nous ont permis d’estimer un Kd moyen pour chaque molécule. Ces valeurs de Kd présentent une très bonne relation avec les valeurs de Kow (coefficient de partage octanol-eau) extraites de la littérature. De même, les pourcentages calculés de chaque pesticide exporté sous forme particulaire sont aussi très bien corrélés au Kow de chaque molécule. / The mechanisms of pesticides transport to stream flow were studied in two agricultural nested catchments of different size in Gascogne region (South West of France): the Save river basin at Larra (1110 km2) and the Montoussé experimental watershed at Auradé (3.28 km2). The intensive agricultural practices used in this region lead to an important risk for water resources by pesticides, especially during storm events. This is why we have paid special attention on storm events when a large quantity of contaminant was transported during hydrological periods. Fourteen molecules of pesticides (herbicides and fungicides) were investigated during the study period. Both of these groups are widely used for agricultural purposed in these catchments. The results achieved over the two years monitoring (2007-2009) enable us to emphasize the principal processes, implied in pesticide transfer on these agricultural catchments. The majority of compounds are detected during storm runoff events. And, the average concentrations of some pesticides are exceeded at the authorization limit of the European Union for pesticide concentrations in drinking water (0.1 µg.L-1 for individual pesticides and 0.5 µg.L-1 for total pesticides). To better understand the mechanisms of pesticide transport hysteresis, patterns on the concentration-discharge relationship (result of different concentration of pesticides in rising and falling limb of storm) were studied. However, clockwise or anticlockwise hysteresis patterns could be observed for some molecules of pesticide and their controlling factors such as dissolved organic carbon (DOC), particulate organic carbon (POC) and total suspended matters (TSM) according to their transfer dynamic in the catchment. We proceeded with hydrograph separation of the main stormflow components (surface runoff, subsurface flow and groundwater) so that the main pesticide routing could be traced for its soil-river transfers. We also came to the conclusion that there is a positive relationship between riverine TSM, DOC and pesticide, concentrations and the discharges of surface or subsurface runoffs according to pesticide properties. Pesticide flux calculation shows between 60 to 90% of the molecule transport takes place during storm periods. Specific flux calculation also demonstrated the higher flux value in Save catchment than in Aurade with higher pesticide concentration for a given specific discharge. The latter result may be due to the more consumption of pesticide in Save catchment. The analyses of pesticides both in filtered and unfiltered water enabled us to estimate the distribution of pesticides into particulate and dissolved phases. Moreover, the pesticide flux values allow calculating average partition coefficients kd between dissolved and particulate fractions which present good relationship with Kow values (octanol-water) extracted from literature. The percentage of each pesticide transported as particulate forms is also well correlated to Kow.

This project focus on investigating the dissolution of low water-soluble intermediate organic compounds called active pharmaceutical ingredients (API) and organic substances that are manufactured by a pharmaceutical company, Cambrex Karlskoga in Sweden. Several dissolution methods were used and evaluated using methods including total organic carbon (TOC), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and Microtox toxicity test. The selection of solvents were based on previous studies and specifications from the Swedish Institute of Standards, SIS.The performance of eight solvents for different organic substances were evaluated using the above mentioned methods. Solvents that are highly volatile and have low solubility in water were excluded. Therefore, dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and Pluronic F-68, that had highest water solubility, low acute toxicity and not degradable by microorganisms, were further used to dissolve four organic substances. Furthermore, DMSO and DMF were then also used to dissolve four censored chemicals with addition of physical treatment and solvent mixtures (DMF:DMSO with ratio 1:2).Results from each method were discussed and statistical tests were also performed in order to compare different dissolution methods. In addition, quality control and quality assurance were made in order to ensure the quality of measured values from analytical methods. Four organic substances were dissolve in DMSO, DMF and Pluronic F-68 with dissolution ≥79% using six ratios of DMSO and DMF and five ratios of Pluronic F-68 which were analyzed using TOC. Physical treatment increased dissolution of two APIs with 40%. Using BOD, para-aminobenzonic acid (PABA) and 5-nitroisophthalic acid (5-NIPA) had values higher than the guideline values, which indicate high biodegradability of these organic substances. PABA, 5-NIPA and bupivacaine base were acute toxic where PABA showed EC50 values of 27.9 mg/L using DMSO and 36.0 mg/L using DMF, and EC50 values of 5-NIPA were 102 mg/L using DMSO and 84.0 mg/L using DMF, and bupivacaine base had EC50 value of 174 mg/L using solvent mixture (DMF:DMSO with ratio 1:2). With increasing amount of Pluronic F-68, 5-NIPA had increased values of EC50, thereby Pluronic F-68 was not appropriate to use.In conclusion, DMSO and DMF were most appropriate solvents to use in order to dissolve APIs and organic substances with analyte: DMSO ratio of 1:0.5 and analyte: DMF ratio of 1:0.25. In addition, physical treatment could be used in order to increase dissolution of the APIs.