Este trabalho investigou a oxidação eletroquímica do herbicida glifosato e suas formulações comerciais em eletrodos do tipo anodo dimensionalmente estáveis (ADE) a base de RuO2 e IrO2. As eletrólises foram feitas em modo galvanostático em função de parâmetros como pH, eletrólito suporte e densidade de corrente. A influência da composição eletródica na degradação do HG se mostra significante na ausência de cloreto. Nestas condições o anodo Ti/Ir0.30Sn0.70O2 foi o melhor material para degradação do herbicida. A degradação do HG é favorecida em baixos valores de pH. O uso de cloreto como eletrólito suporte aumentou significativamente a eficiência do processo, e, no entanto, a composição eletródica já não apresentou tanta influência. Aplicando-se 30 mA cm-2 por 4 h, observa-se completa remoção do HG é obtida. Em meio de cloreto, aplicando-se 50 mA cm-2 elevados valores de mineralização do herbicida são obtidos (liberação de íons fosfato = 91 %) para todas as composições estudadas. Os parâmetros, que podem influenciar na formação de compostos organoclorados (AOX) foram também avaliados. São apresentados os efeitos da concentração de cloreto, composição eletródica, densidade de corrente e tempo de eletrólise. Os resultados mostram que existe uma estreita relação entre a composição eletródica e a formação de AOX. As formulações comerciais apresentam uma menor taxa de degradação comparada à amostra padrão e levam a formação de maiores quantidades de AOX. Em elevadas concentrações de cloreto, tem-se além do aumento na mineralização uma relação direta com a formação de AOX, sendo que apenas em baixas concentrações de cloreto, a quantidade de AOX fica abaixo do limite permitido no Brasil. A formação de AOX durante a eletrólise aumenta significativamente com a corrente aplicada e mesmo após longo tempo de eletrólise, ainda tem-se a formação espécies organohalogenadas / This paper has investigated the electrochemical oxidation of glyphosate herbicide (GH) and its formulations on RuO2 and IrO2 DSA® electrodes. Electrolysis was achieved under galvanostatic control as a function of pH, supporting electrolyte, and current density. The influence of the oxide composition on GH degradation seems to be significant in the absence of chloride; Ti/Ir0.30Sn0.70O2 is the best electrode material to oxidize GH. GH oxidation is favored at low pH values. The use of chloride medium increases the oxidizing power and the influence of the oxide composition is meaningless. At 30 mA cm-2 and 4 hours of electrolysis, complete GH removal from the electrolyzed solution has been obtained. In chloride medium, application of 50 mA cm-2 leads to virtually total mineralization (release of phosphate ions = 91%) for all the evaluated oxide materials. Parameters that could influence the formation of organochloride compounds during electrolysis are studied. The effects of chloride concentration, electrodic composition, current density, and electrolysis time are reported. The results shows a straight relationship between anode composition and AOX formation. Commercial herbicide formulations have lower degradation rates and lead to the formation of a larger quantities of organochloride compounds. In high chloride concentrations there is a significant increase in organic mineralization, and the relationship between chloride concentration and AOX formation is direct. Only in low chloride concentrations is AOX detected above the limit values allowed in Brazil. AOX formation during electrolysis increases significantly with the applied current. Even during long term electrolysis a large amount of organochloride compounds is formed.

Univ., Diss.--Münster, 2000.

Este trabalho investigou a oxidação eletroquímica do herbicida glifosato e suas formulações comerciais em eletrodos do tipo anodo dimensionalmente estáveis (ADE) a base de RuO2 e IrO2. As eletrólises foram feitas em modo galvanostático em função de parâmetros como pH, eletrólito suporte e densidade de corrente. A influência da composição eletródica na degradação do HG se mostra significante na ausência de cloreto. Nestas condições o anodo Ti/Ir0.30Sn0.70O2 foi o melhor material para degradação do herbicida. A degradação do HG é favorecida em baixos valores de pH. O uso de cloreto como eletrólito suporte aumentou significativamente a eficiência do processo, e, no entanto, a composição eletródica já não apresentou tanta influência. Aplicando-se 30 mA cm-2 por 4 h, observa-se completa remoção do HG é obtida. Em meio de cloreto, aplicando-se 50 mA cm-2 elevados valores de mineralização do herbicida são obtidos (liberação de íons fosfato = 91 %) para todas as composições estudadas. Os parâmetros, que podem influenciar na formação de compostos organoclorados (AOX) foram também avaliados. São apresentados os efeitos da concentração de cloreto, composição eletródica, densidade de corrente e tempo de eletrólise. Os resultados mostram que existe uma estreita relação entre a composição eletródica e a formação de AOX. As formulações comerciais apresentam uma menor taxa de degradação comparada à amostra padrão e levam a formação de maiores quantidades de AOX. Em elevadas concentrações de cloreto, tem-se além do aumento na mineralização uma relação direta com a formação de AOX, sendo que apenas em baixas concentrações de cloreto, a quantidade de AOX fica abaixo do limite permitido no Brasil. A formação de AOX durante a eletrólise aumenta significativamente com a corrente aplicada e mesmo após longo tempo de eletrólise, ainda tem-se a formação espécies organohalogenadas / This paper has investigated the electrochemical oxidation of glyphosate herbicide (GH) and its formulations on RuO2 and IrO2 DSA® electrodes. Electrolysis was achieved under galvanostatic control as a function of pH, supporting electrolyte, and current density. The influence of the oxide composition on GH degradation seems to be significant in the absence of chloride; Ti/Ir0.30Sn0.70O2 is the best electrode material to oxidize GH. GH oxidation is favored at low pH values. The use of chloride medium increases the oxidizing power and the influence of the oxide composition is meaningless. At 30 mA cm-2 and 4 hours of electrolysis, complete GH removal from the electrolyzed solution has been obtained. In chloride medium, application of 50 mA cm-2 leads to virtually total mineralization (release of phosphate ions = 91%) for all the evaluated oxide materials. Parameters that could influence the formation of organochloride compounds during electrolysis are studied. The effects of chloride concentration, electrodic composition, current density, and electrolysis time are reported. The results shows a straight relationship between anode composition and AOX formation. Commercial herbicide formulations have lower degradation rates and lead to the formation of a larger quantities of organochloride compounds. In high chloride concentrations there is a significant increase in organic mineralization, and the relationship between chloride concentration and AOX formation is direct. Only in low chloride concentrations is AOX detected above the limit values allowed in Brazil. AOX formation during electrolysis increases significantly with the applied current. Even during long term electrolysis a large amount of organochloride compounds is formed.

Au cours des dernières années, divers travaux visant à identifier et à quantifier les sous-produits organohalogénés (SPOX) issus du traitement des eaux brutes de rivières à la monochloramine ont été menés. Un effort particulier a été porté sur le suivi des sous-produits organohalogénés réglementés et/ou connus et au paramètre analytique AOX (composés organohalogénés adsorbables sur charbon actif). Ce paramètre permet d’estimer la quantité totale de sous-produits organohalogénés générés.Un état des lieux récent montre qu’en dépit du nombre important de ces composés sur des échantillons d’eau « réels », le pourcentage de ces sous-produits identifiés imputables au traitement à la monochloramine reste très faible.Le travail réalisé dans la thèse s’inscrit dans la continuité des travaux menés par EDF R&D sur la spéciation des SPOX constitutifs d’AOX, selon une démarche analytique interconnectée. Cette dernière a permis la réduction d’incertitudes liées à la manière d’établissement du bilan de matière par (1) la mise en place de protocoles efficaces d’extraction et d’enrichissement des SPOX sur phase solide, (2) le développement de méthodes d’analyse sensibles permettant de doser simultanément plusieurs SPOX ou familles de SPOX connus, (3) la fiabilisation de la méthode de mesure des AOX en améliorant son étape de préparation d’échantillon et le développement d’une méthode d’analyse permettant d’établir le taux d’incorporation des différents halogénures (Cl, Br, I) dans les AOX, et (4) la réalisation d’essais de « screening » non ciblé par GC-MS et LC-MS ainsi que l’analyse en haute résolution par le FT-ICR/MS, pour l’identification des SPOX de haut poids moléculaire.Cette démarche a été appliquée sur des échantillons d’eau réels et a permis un gain de sensibilité par rapport aux méthodes actuelles, ainsi que l’identification de nouveaux SPOX, non répertoriés dans les études antérieures d’EDF R&D. / Over the last years, various studies have been carried out to identify and quantify the organohalogen by-products (OXBPs) resulting from the treatment of river waters with monochloramine. A particular effort was made to monitor the regulated and/or known organohalogen by-products with the analytical parameter AOX (Adsorbable Organic Halides). This parameter estimate the quantity of organohalogen by-products generated.A recent inventory shows that despite the large number of these compounds on "real" water samples, the percentage of these identified by-products attributable to monochloramine treatment remains very low.The thesis project is a continuation of previous studies carried out by EDF R&D on the speciation of OXBPs constituents of AOX, according to an interconnected analytical approach. This latter allowed the reduction of uncertainties related to how the material balance was established : (1) setting up efficient extraction and enrichment protocols for OXBPs on solid phase, (2) the development of sensitive analytical methods for monitoring simultaneously several known OXBPs, (3) improving the reliability of the AOX measurement method by improving its sample preparation step and developing a method of analyzing Analysis in order to establish the rate of incorporation of the various halides (Cl, Br, I) in AOX, and (4) non-targeted screening tests by GC-MS and LC-MS, as well as analysis in high resolution by FT-ICR/MS for the identification of OXBPs with high molecular weight.This approach was applied to real water samples and increased sensitivity to current methods, as well as the identification of new OXBPs not listed in previous EDF R&D studies.

Le champignon filamenteux Podospora anserina constitue un système modèle pour l’étude de plusieurs processus biologiques, notamment le vieillissement. Une relation de causalité entre le fonctionnement de la chaine respiratoire et la longévité a été établie pour la première fois chez P. anserina et cette relation de causalité semble conservée. Le lien entre fonctionnement de la chaîne respiratoire et longévité pourrait se faire en partie par l’induction d’une régulation rétrograde en réponse à un dysfonctionnement mitochondrial. Les études des régulations rétrogrades mitochondriales et chloroplastiques montrent qu’en réponse à un dysfonctionnement de ces organites, il y a une reprogrammation de l’expression génique qui participe à la plasticité adaptative des espèces en réponse à l’environnement. Un gène cible d’une régulation rétrograde mitochondriale a été identifié chez P. anserina: le gène aox. L’oxydase alternative appartient à une voie respiratoire alternative en conditions de dysfonctionnement de la voie des cytochromes. Deux facteurs de transcription acteurs de cette régulation rétrograde mitochondriale ont été identifiés par une approche génétique. Ces protéines, RSE2 et RSE3, appartiennent à la famille des protéines Zn2Cys6 et sont les régulateurs majeurs du gène aox. Outre le gène aox, ces deux facteurs de transcription corégulent les deux enzymes de la néoglucogenèse FBP (Fructose-1,6-biphosphatase) et PCK (Phosphoénolpyruvate carboxykinase). Des allèles gain de fonction des gènes rse2 et rse3 ont été isolés et le crible pratiquement saturé. L’analyse de ces mutations ainsi que des approches de mutagenèse dirigée, ont permis de proposer l’existence de régions régulatrices dans les séquences protéiques RSE2 et RSE3. Une approche transcriptomique a permis d’identifier de nouvelles cibles de RSE2 et RSE3 activées lors d’un dysfonctionnement mitochondrial : le gène fhb (codant une flavohémoglobine) et le gène Pa_6_4030 (codant une α/β hydrolase). Une approche métabolomique a permis une meilleure compréhension de la reprogrammation métabolique en réponse à un dysfonctionnement de la chaîne respiratoire et du rôle de RSE2/RSE3 dans cette reprogrammation.RSE2 et RSE3 sont donc des acteurs d’une régulation rétrograde mitochondriale responsables de l’activation de voies respiratoires alternatives mais aussi d’une reprogrammation du métabolisme de P. anserina qui permettrait de maintenir une homéostasie cellulaire en condition de dysfonctionnement mitochondrial. / The filamentous fungus Podospora anserina is a model system for the study of many biological processes, including aging. A causal relationship between the respiratory chain efficiency and longevity has been established for the first time in P. anserina. This causal relationship seems to be conserved between species. The link between the respiratory chain efficiency and longevity could be in part explained by the induction of retrograde regulation in response to mitochondrial dysfunction. Studies of mitochondrial and chloroplast retrograde regulation show that in response to a dysfunction of these organelles, there is a reprogramming of gene expression involved in the adaptive plasticity of organisms in response to the environment.A target gene of mitochondrial retrograde regulation was identified in P. anserina: the aox gene. The alternative oxidase belongs to the respiratory alternative pathway induced when the mitochondrial electron transport chain is impaired. Two transcription factors involved in mitochondrial retrograde regulation were identified by a genetic approach. These proteins, RSE2 and RSE3 belong to the family of Zn2Cys6 proteins and are major regulators of aox. Besides the aox gene, these two transcription factors are responsible for the coregulation of two gluconeogenic enzymes: FBP (fructose-1,6-bisphosphatase) and PCK (phosphoenolpyruvate carboxykinase). By a genetic approach, several gain-of-function mutations were isolated in RSE2 and RSE3 and our screen was likely to be saturated. Analysis of these mutations, together with other mutagenesis approaches allowed us to propose the existence of regulatory regions in RSE2 and RSE3 sequences.Microarray transcriptional profiling was conducted on rse2 and rse3 gain of function mutants. This identified new targets of RSE2 and RSE3 activated during mitochondrial dysfunction: FHB (a gene encoding a flavohemoglobin) and Pa_6_4030 (a gene encoding an α / β hydrolase). A metabolomic approach was also used and it gave new insight to the metabolic reprogramming in response to a malfunction of the respiratory chain and the role of RSE2/RSE3 in this reprogramming.Thus we showed that RSE2 and RSE3 play a role in mitochondrial retrograde regulation that is responsible for the activation of the respiratory alternative pathway, and also for the activation of metabolic reprogramming of P. anserina that would maintain cellular homeostasis under conditions of mitochondrial dysfunction.

<p><p>Chlorine is an element commonly found in the environment of our planet, in the atmosphere, the earth crust and the oceans. Chlorine occurs in two forms, inorganic chloride (Cl_in) and organically bound chlorine (Cl_org), also called organochlorine. For a long time, the organic halogens (among them the organic chlorine) had been considered as produced only by human activities. However, the research of the recent decades suggests a considerably amount of naturally produced organic chlorine in soil and water. Through the research, a hypothesis have emerged, suggesting that there occur a formation of organic chlorine in the top soil layer where chloride is consuming, while the organic chlorine is degrading on deeper soil levels, causing a release of chloride. The study in this thesis attempts to explore the transportation of organic chlorine through soil. 49 soil water samples were collected at three transects, S04, S12 and S22, nearby a stream in northern Sweden and analysed for Cl_org, using an AOX-analyser. The results suggest a decrease in concentrations of Cl_org by soil depth for transects S04 and S12. The study also indicates that concentrations of Cl_org are decreasing with increasing distance from the stream, where the highest mean concentration was found in the organic matter-rich riparian transect S04. Further conclusions are that the spring flood and changes in groundwater level may influence the concentrations of Cl_org.</p></p> / <p><p>Ämnet klor är vanligt förekommande på vår planet och finns både i atmosfären, jordskorpan och världens oceaner. Klor uppträder i två olika former: oorganisk klorid (Cl_in) och organiskt bundet klor (Cl_org). De organiska halogenerna (bland vilka organiskt klor ingår) har under lång tid ansetts härstamma från enbart antropogena källor. De senaste decenniernas forskning har dock tytt på en naturlig produktion av organiskt klor i mark och vatten. Genom denna forskning har en hypotes tagit form som föreslår en bildning av organiskt klor i de övre marklagren, där klorid binds, medan det i djupare marklager sker en nedbrytning av det organiska kloret vilket medför ett frigörande av klorid. Denna studie syftar till att studera transporten av organiskt klor genom mark. 49 stycken markvattenprover insamlades vid tre provpunkter (S04, S12 och S22) på ett avrinningsområde i norra Sverige och analyserades med hjälp av ett AOX-instrument. Resultaten tyder på en minskning av Cl_org med ökande markdjup för provpunkterna S04 och S12. Studien visar även en minskning i koncentration av organiskt klor med ökande avstånd till vattendraget, där den högsta medelkoncentrationen återfanns i provpunkten S04 som ligger nära bäcken och är rik på organiskt material. Vidare slutsater är att vattenflödena under vårflod samt variasionen i grundvattennivå har en påverkan på koncentrationerna av Cl_org.</p></p>

Chlorine is one of most common element on earth and it is essential in every living organism, but can also cause problems in the environment. Chlorine can exist both as inorganic (Clin) and organically bound (Clorg). Earlier was the common opinion that Clorg only occurs from anthropogenic sources, but the last years, research has shown that chlorine is a part of the biogeochemical cycle and Clorg also can have natural sources. Many chlorinated substances are poisonous, so the fact that they have a natural source created attention. Fertilizations with nitrogen in forest areas have shown unexpected consequences, such as an increase leakage of nitrogen to ground and surface water. Clear-cutting is a disturbance on the ecosystem and the environment is sensitive for disturbances. Because of the fact that both chlorine and fertilization can be environmental problems and that clear-cutting is a big disturbance in the nature, this study will investigate if there are changes of organic chlorine (Clorg) in soil water after clear-cutting and if fertilization with nitrogen has any influence on the concentration of Clorg. This study was made in a forest area in Värmland, Sweden (Hagfors). Chemical analyses were made in the laboratory though measuring AOX (absorbable organic halogens). The result of this study showed that clear-cutting probably has some effect on the Clorg concentration and that nitrogen doesn’t have any influence.

<p>Chlorine is one of most common element on earth and it is essential in every living organism, but can also cause problems in the environment. Chlorine can exist both as inorganic (Clin) and organically bound (Clorg). Earlier was the common opinion that Clorg only occurs from anthropogenic sources, but the last years, research has shown that chlorine is a part of the biogeochemical cycle and Clorg also can have natural sources. Many chlorinated substances are poisonous, so the fact that they have a natural source created attention. Fertilizations with nitrogen in forest areas have shown unexpected consequences, such as an increase leakage of nitrogen to ground and surface water. Clear-cutting is a disturbance on the ecosystem and the environment is sensitive for disturbances. Because of the fact that both chlorine and fertilization can be environmental problems and that clear-cutting is a big disturbance in the nature, this study will investigate if there are changes of organic chlorine (Clorg) in soil water after clear-cutting and if fertilization with nitrogen has any influence on the concentration of Clorg. This study was made in a forest area in Värmland, Sweden (Hagfors). Chemical analyses were made in the laboratory though measuring AOX (absorbable organic halogens). The result of this study showed that clear-cutting probably has some effect on the Clorg concentration and that nitrogen doesn’t have any influence.</p>

Chlorine is an element commonly found in the environment of our planet, in the atmosphere, the earth crust and the oceans. Chlorine occurs in two forms, inorganic chloride (Clin) and organically bound chlorine (Clorg), also called organochlorine. For a long time, the organic halogens (among them the organic chlorine) had been considered as produced only by human activities. However, the research of the recent decades suggests a considerably amount of naturally produced organic chlorine in soil and water. Through the research, a hypothesis have emerged, suggesting that there occur a formation of organic chlorine in the top soil layer where chloride is consuming, while the organic chlorine is degrading on deeper soil levels, causing a release of chloride. The study in this thesis attempts to explore the transportation of organic chlorine through soil. 49 soil water samples were collected at three transects, S04, S12 and S22, nearby a stream in northern Sweden and analysed for Clorg, using an AOX-analyser. The results suggest a decrease in concentrations of Clorg by soil depth for transects S04 and S12. The study also indicates that concentrations of Clorg are decreasing with increasing distance from the stream, where the highest mean concentration was found in the organic matter-rich riparian transect S04. Further conclusions are that the spring flood and changes in groundwater level may influence the concentrations of Clorg. / Ämnet klor är vanligt förekommande på vår planet och finns både i atmosfären, jordskorpan och världens oceaner. Klor uppträder i två olika former: oorganisk klorid (Clin) och organiskt bundet klor (Clorg). De organiska halogenerna (bland vilka organiskt klor ingår) har under lång tid ansetts härstamma från enbart antropogena källor. De senaste decenniernas forskning har dock tytt på en naturlig produktion av organiskt klor i mark och vatten. Genom denna forskning har en hypotes tagit form som föreslår en bildning av organiskt klor i de övre marklagren, där klorid binds, medan det i djupare marklager sker en nedbrytning av det organiska kloret vilket medför ett frigörande av klorid. Denna studie syftar till att studera transporten av organiskt klor genom mark. 49 stycken markvattenprover insamlades vid tre provpunkter (S04, S12 och S22) på ett avrinningsområde i norra Sverige och analyserades med hjälp av ett AOX-instrument. Resultaten tyder på en minskning av Clorg med ökande markdjup för provpunkterna S04 och S12. Studien visar även en minskning i koncentration av organiskt klor med ökande avstånd till vattendraget, där den högsta medelkoncentrationen återfanns i provpunkten S04 som ligger nära bäcken och är rik på organiskt material. Vidare slutsater är att vattenflödena under vårflod samt variasionen i grundvattennivå har en påverkan på koncentrationerna av Clorg.

Syftet med denna studie är att undersöka inverkan av förbehandlingar på ljushetsstabiliteten av Northern Bleached Softwood Kraft (NBSK) som har blekts enligt (OO) (OP) D/Dn (PO) bleksekvensen. Effekten av förbehandling med xylanas (X), mild sur (A), DTPA (Q) samt ett kombinerad DTPA- &amp; xylanassteg (Q+X) har studerats.  Resultaten indikerar att Q+X förbehandlingen var mest effektiv i minskningen av skadliga metalljoner i massan. Den Q+X förbehandlade massan hade dessutom lägst kappa och högst ljushetsvärde bland förbehandlingarna. Kemisk sammansättningsanalys av de förbehandlade massorna visar vidare att den Q+X förbehandlingen ledde till den högsta minskningen av såväl xylan som lignin. Det milda A förbehandlingen var inte effektivt för att avlägsna alla viktiga skadliga metalljoner och visade ingen effekt på reduktionen av xylan eller lignin. Den X behandlade massan visade ingen förmåga att ta bort metaller och är därför ofördelaktigt.  Q och Q+X förbehandlade massaströmmar har blekts vidare för att studera effekterna av dessa förbehandlingar på den slutliga massakvaliteten samt för att jämföra ett konventionellt klordioxidsteg (D) och en nästan neutral pH klordioxidsteg (Dn). Resultaten bekräftar att Dn-steget ledder till en reducerad grad av AOX.  Ljusheten direkt efter klordioxidsteget är vidare högre för de Dn-behandlade massorna, men processen är begränsad med avseende på ljushetsstabilitet, vilket är en viktig nackdel.  Q+X (OP) D (PO) blekningssekvensen visade den högsta ljushetsstabilitet, medan den Q+X (OP) Dn (PO) blekningssekvensen visade ingen förbättring jämfört med Q (OP) Dn (OP) blekningssekvensen. Slutsatsen är att den enzymatisk medförda kvalitetsförbättringen inte räcker för att kompensera för bristerna i ett Dn-steg. / This is a study on Northern Bleached Softwood Kraft (NBSK) and the (OO) (OP) D/Dn (PO) bleaching sequence. The effects of a xylanase (X), mild acidic (A), DTPA (Q), and a combined DTPA &amp; xylanase (Q+X) pre-treatments have been studied. The results indicate that the Q+X pre-treatment most effectively reduced the presence of harmful metal ions in the pulp. The Q+X pre-treated pulp furthermore yielded the lowest kappa number and highest brightness values among the pre-treatments tested. Chemical analysis of this pulp also shows the highest reduction in xylans and lignin. The mild A stage was ineffective in removing all harmful metal ions and showed no effect on the reduction of xylans or lignin. The X stage cannot meanwhile remove metals and is thus disadvantageous. Subsequently, the Q+X pre-treated pulp as well as a Q-treated pulp stream were further bleached to study the effects of these pre-treatments on the final pulp quality as well as to compare these streams of pulp bleached using a conventional chlorine dioxide stage (D) and a near neutral pH chlorine dioxide (Dn) stage. The results confirmed that the Dn stage causes a reduced degree of AOX in the effluent. Furthermore, the brightness directly after the chlorine dioxide stage is higher for the Dn-treated pulps but the process is limited in brightness stability which is a significant drawback. The Q+X (OP) D (PO) bleaching sequence showed the highest brightness stability while the Q+X (OP) Dn (PO) bleaching sequence displayed no improvement over the Q (OP) Dn (OP) bleaching sequence. The conclusion can be made that the enzymatic boost in bleaching is not enough to compensate for the shortcomings of a Dn stage.