<p>The Central African Monetary and Economic Community, known by its French acronym CEMAC (Communaut&eacute / Economique et Mon&eacute / taire de l&rsquo / Afrique Centrale), is one of the oldest regional economic blocs in the African, Caribbean and Pacific (ACP) group of states. Its membership comprises of Cameroon, the Central African Republic, Chad, the Republic of Congo, Equatorial Guinea, and Gabon. It has a population of over 32 million inhabitants in a three million (3 million) square kilometre expanse of land. The changes in the world economy, and especially between the ACP countries, on the one hand, and the European Economic Community-EEC (hereinafter referred to as European Union (EU)), on the other hand, did not leave the CEMAC region unaffected. CEMAC region, like any other regional economic blocs in Africa was faced with the need to readjust in the face of a New International Economic Order (NIEO). The region which had benefited from preferential access to the EU market including financial assistance through the European Development Fund (EDF) had to comply with the rules laid down in the World Trade Organisation (WTO). This eventually led to a shift in the EU trade policy, in order to ensure that its trade preferences to developing countries were compatible to the rules and obligations of the WTO.</p>

Malaria, caused by the parasite Plasmodium, continues to exact high global morbidity and mortality rate next only to tuberculosis. It causes 300-500 million clinical infections out of which more than a million people succumb to death annually. Worst affected are the children below 5 years of age in sub-Saharan Africa. Plasmodium is a protozoan parasite classified under the phylum Apicomplexa that also includes parasites such as Toxoplasma, Lankestrella, Eimeria and Cryptosporidium. Of the four species of Plasmodium affecting man viz., P. falciparum, P. vivax, P. ovale and P. malariae, Plasmodium falciparum is the deadliest as it causes cerebral malaria. The situation has worsened recently with the emergence of drug resistance in the parasite. Therefore, deciphering new pathways in the parasite for developing lead antimalarial compounds is the need of the hour. The discovery of the type II fatty acid biosynthesis pathway in Plasmodium falciparum has opened up new avenues for the design of new antimalarials as this pathway is different from the one in human hosts. Although many biochemical pathways such as the purine, pyrimidine and carbohydrate metabolic pathways, and the phospholipid, folate and heme biosynthetic pathways operate in the malaria parasite and are being investigated for their amenability as antimalarial therapeutic targets, no antimalarial of commercial use based on the direct intervention of these biochemical pathways has emerged so far. This is due to the fact that the structure and function of the targets of these drugs overlaps with that of the human host. A description of the parasite, its metabolic pathways, efforts to use these pathways for antimalarial drug discovery, inhibitors targeting these pathways, introduction to fatty acid biosynthesis pathway, discovery of type II fatty acid biosynthesis pathway in Plasmodium falciparum and prospects of developing lead compounds towards antimalarial drug discovery is given in Chapter 1 of the thesis. In the exploration of newly discovered type II fatty acid biosynthesis pathway of P. falciparum as a drug target for antimalarial drug discovery, one of the enzymes; β-hydroxyacyl- acyl carrier protein dehydratase (PfFabZ) was cloned and being characterized in the lab. The atomic structure of PfFabZ was not known till that point of time. Chapter 2 describes the homology modeled structure of PfFabZ and docking of the discovered inhibitors with this structure to provide a rationale for their inhibitory activity. Despite low sequence identity of ~ 21% with the closest available atomic structure then, E. coli FabA, a good model of PfFabZ could be built. A comparison of the modeled structure with recently determined crystal structure of PfFabZ is provided and design of new potential inhibitors is described. This study provides insights to further improve the inhibition of this enzyme. Enoyl acyl carrier protein reductase (ENR) is the most important enzyme in the type II fatty acid biosynthesis pathway. It has been proved as an important target for antibacterial as well as antimalarial drug discovery. The most effective drug against tuberculosis – Isoniazid targets this enzyme in M. tuberculosis. The well known antibacterial compound – Triclosan, a diphenyl ether, also targets this enzyme in P. falciparum. I designed a number of novel diphenyl ether compounds. Some of these compounds could be synthesized in the laboratory. Chapter 3 describes the design, docking studies and inhibitory activity of these novel diphenyl ether compounds against PfENR and E. coli ENR. Some of these compounds inhibit PfENR in nanomolar concentrations and EcENR in low micromolar concentrations, and many of them inhibit the growth of parasites in culture also. The structure activity relationship of these compounds is discussed that provides important insights into the activity of this class of compounds which is a step towards developing this class of compounds into an antimalarial and antibacterial candidate drugs. Components of the green tea extract and polyphenols are well known for their medicinal properties since ages. Recently they have been shown to inhibit components of the bacterial fatty acid biosynthesis pathway. Some selected tea catechins and polyphenols were tested in the laboratory for their inhibitory activity against PfENR. I conducted docking studies to find their probable binding sites in PfENR. On kinetic analysis of their inhibition, these compounds were found to be competitive with respect to the cofactor NADH. This has an implication that they could potentiate inhibition of PfENR by Triclosan in a fashion similar to that of NADH. As a model case, one of the tea catechins; EGCG ((-) Epigalocatechin gallate) was tested for this property. Indeed, in the presence of EGCG, the inhibition of PfENR improved from nanomolar to picomolar concentration of Triclosan.conducted molecular modeling studies and propose a model for the formation of a ternary complex consisting of EGCG, Triclosan and PfENR. Docking studies of these inhibitors and a model for the ternary complex is described in Chapter 4. Docking simulations show that these compounds indeed occupy NADH binding site. This study provides insights for further improvements in the usage of diphenyl ethers in conjugation or combination with tea catechins as possible antimalarial therapeutics. In search for new lead compounds against deadly diseases, in silico virtual screening and high throughput screening strategies are being adopted worldwide. While virtual screening needs a large amount of computation time and hardware, high throughput screening proves to be quite expensive. I adopted an intermediate approach, a combination of both these strategies and discovered compounds with a 2-thioxothiazolidin-4-one core moiety, commonly known as rhodanines as a novel class of inhibitors of PfENR with antimalarial properties. Chapter 5 describes the discovery of this class of compounds as inhibitors of PfENR. A small but diverse set of 382 compounds from a library of ~2,00,000 compounds was chosen for high throughput screening. The best compound gave an IC50 of 6.0 µM with many more in the higher micromolar range. The compound library was searched again for the compounds similar in structure with this best compound, virtual screening was conducted and 32 new compounds with better binding energies compared to the first lead and reasonable binding modes were tested. As a result, a new compound with an IC50 of 240 nM was discovered. Many more compounds gave IC50 values in 3-15 µM range. The best inhibitor was tested in red blood cell cultures of Plasmodium, it was found to inhibit the growth of the malaria parasite at an IC50 value of 0.75 µM. This study provides a new scaffold and lead compounds for further exploration towards antimalarial drug discovery. The summary of the results and conclusions of studies described in various chapters is given in Chapter 6. This chapter concludes the work described in the thesis. Cloning, over-expression and purification of PanD from M. tuberculosis, FabA and FabZ from E. coli are described in the Appendix.

Dans les domaines de l'analyse, du contrôle et de la mesure physique, le laser constitue un outil métrologique particulièrement puissant et polyvalent, capable d'apporter des réponses concrètes à des problématiques variées, y compris d'ordre sociétal. Parmi ces dernières, la contamination des sites et des sols par les métaux lourds est un enjeu de santé publique important qui requiert de disposer de moyens de mesure adaptés aux réglementations existantes et suffisamment souples d'utilisation. Technique rapide et ne nécessitant pas de préparation de l'échantillon, la spectroscopie sur plasma induit par laser (LIBS) présente des avantages très intéressants pour réaliser des mesures sur site de la teneur en métaux lourds à l'échelle de la dizaine de ppm; la conception d'un appareil portable à moyen terme est envisageable.<br />Dans cette thèse nous montrons d'abord que le régime femtoseconde ne présente pas d'avantages par rapport au régime nanoseconde standard pour notre problématique. Ensuite nous mettons en œuvre un traitement avancé des spectres LIBS par des méthodes chimiométriques dont les performances améliorent sensiblement les résultats des analyses qualitatives et quantitatives d'échantillons de sols.

Les nouvelles technologies développées ces dernières années dans le domaine de la génétique ont permis de générer des bases de données de très grande dimension, en particulier de Single Nucleotide Polymorphisms (SNPs), ces bases étant souvent caractérisées par un nombre de variables largement supérieur au nombre d'individus. L'objectif de ce travail a été de développer des méthodes statistiques adaptées à ces jeux de données de grande dimension et permettant de sélectionner les variables les plus pertinentes au regard du problème biologique considéré. Dans la première partie de ce travail, un état de l'art présente différentes méthodes de sélection de variables non supervisées et supervisées pour 2 blocs de variables et plus. Dans la deuxième partie, deux nouvelles méthodes de sélection de variables non supervisées de type "sparse" sont proposées : la Group Sparse Principal Component Analysis (GSPCA) et l'Analyse des Correspondances Multiples sparse (ACM sparse). Vues comme des problèmes de régression avec une pénalisation group LASSO elles conduisent à la sélection de blocs de variables quantitatives et qualitatives, respectivement. La troisième partie est consacrée aux interactions entre SNPs et dans ce cadre, une méthode spécifique de détection d'interactions, la régression logique, est présentée. Enfin, la quatrième partie présente une application de ces méthodes sur un jeu de données réelles de SNPs afin d'étudier l'influence possible du polymorphisme génétique sur l'expression du vieillissement cutané au niveau du visage chez des femmes adultes. Les méthodes développées ont donné des résultats prometteurs répondant aux attentes des biologistes, et qui offrent de nouvelles perspectives de recherches intéressantes

<p>The Central African Monetary and Economic Community, known by its French acronym CEMAC (Communaut&eacute / Economique et Mon&eacute / taire de l&rsquo / Afrique Centrale), is one of the oldest regional economic blocs in the African, Caribbean and Pacific (ACP) group of states. Its membership comprises of Cameroon, the Central African Republic, Chad, the Republic of Congo, Equatorial Guinea, and Gabon. It has a population of over 32 million inhabitants in a three million (3 million) square kilometre expanse of land. The changes in the world economy, and especially between the ACP countries, on the one hand, and the European Economic Community-EEC (hereinafter referred to as European Union (EU)), on the other hand, did not leave the CEMAC region unaffected. CEMAC region, like any other regional economic blocs in Africa was faced with the need to readjust in the face of a New International Economic Order (NIEO). The region which had benefited from preferential access to the EU market including financial assistance through the European Development Fund (EDF) had to comply with the rules laid down in the World Trade Organisation (WTO). This eventually led to a shift in the EU trade policy, in order to ensure that its trade preferences to developing countries were compatible to the rules and obligations of the WTO.</p>

En se basant sur une étude détaillée depuis l'été 2003 à l'hiver 2005 sur différentes matrices (roches, sédiments, matière en suspension, phase colloïdale et phase dissoute), on a établi un bilan géochimique (éléments majeurs et traces) sur le bassin versant du Bouregreg au Maroc. L'étude géochimique des eaux et des produits solides ou colloïdaux transportés dans l'ensemble du bassin peut être particulièrement performante pour d'une part comprendre les processus de transport et d'échanges des différentes composantes naturelles et anthropiques (en solution ou adsorbées sur les particules en suspension) et d'autre part évaluer la contribution anthropique au sein du bassin. L'objet de ce travail a été de développer une méthodologie permettant d'établir un bilan géochimique de ce bassin et de mieux comprendre le fonctionnement d'un système naturel, en intégrant les phénomènes de transfert solide-liquide La méthodologie adoptée regroupe ainsi : (i) un échantillonnage semestriel, depuis l'été 2003 jusqu'à l'hiver 2005, des différentes matrices sur l'ensemble du bassin versant du Bouregreg. (ii) un protocole analytique multi-élémentaire couplant l'analyse par activation neutronique instrumentale (INAA), la spectrométrie de masse couplée à un plasma d'argon (ICP-MS) et la spectrométrie d'émission atomique couplée à un plasma d'argon (ICP-AES). (iii) des techniques de traitement des données recueillies (comparaison des moyennes obtenues pour chaque échantillon et des variabilités pour chaque site, diagrammes de normalisation par rapport aux croûtes continentales moyenne et supérieure, comparaison des rapports d'éléments, choix des éléments inertes comme références (exemple Ta ou Yb), et finalement une analyse en composantes principales (ACP)). De l'analyse des roches et des sédiments on en déduit : (i) L'importance de l'héritage géochimique de l'environnement géologique du bassin versant du Bouregreg (comparaison entre sédiments et roches, permanence des distributions le long du fleuve,.....). Cela découle du comportement très compatible et de l'inertie de certains éléments au cours de l'altération (éléments de transitions 3d (Co, Ni, Cr, ...), éléments de transition interne f (lanthanides, Zr, Hf, Nb, Ta,....), (ii) L'homogénéité géochimique du bassin qui traduit à son tour un héritage lors de l'accrétion crustale (magmatisme-métamorphisme-sédimentation), (iii) La typologie de ce domaine continental ; plutôt de type croûte continentale supérieure. L'étude de la chimie des eaux dans les phases dissoute et particulaire a également permis de confirmer la différence de comportement entre les éléments dits solubles, dont les concentrations dans la masse d'eau sont liées à la lithologie du bassin versant, et les autres éléments quasiment insolubles tels que les terres rares. Les concentrations de ces derniers dans la phase dissoute sont davantage liées à la chimie interne du fleuve et à l'existence d'une phase colloïdale. Ceci est notamment mis en évidence lors des très basses-eaux où les concentrations en matières organiques peuvent être importantes. L'influence des activités humaines de type pollution métallique semble par ailleurs très limitée : les facteurs d'enrichissement n'ont pas montré de valeur importante excepté pour Cs, Li, Sb, Pb et As. Ce résultat confirme donc la faiblesse actuelle de la pollution chimique de la rivière Bouregreg.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Monitoring of process control systems is extremely important for industries to ensure the quality of the product and the safety of the process. Predictive controllers, also known by MPC (Model Predictive Control), usually has a well performance initially. However, after a period, many factors contribute to the deterioration of its performance. This highlights the importance of monitoring the MPC control systems. In this work, tools based on multivariate statistical methods are discussed and applied to the problem of monitoring and Performance Assessment of predictive controllers. The methods presented here are: PCA (Principal Component Analysis) and ICA (Independent Component Analysis). Both are techniques that use data collected directly from the process. The first is widely used in Performance Assessment of predictive controllers. The second is a more recent technique that has arisen, mainly in order to be used in fault detection systems. The analyzes are made when applied in simulated processes characteristic of the petrochemical industry operating under MPC control. / O monitoramento de sistemas de controle de processos é extremamente importante no que diz respeito às indústrias, para garantir a qualidade do que é produzido e a segurança do processo. Os controladores preditivos, também conhecidos pela sigla em inglês MPC (Model Predictive Control), costumam ter um bom desempenho inicialmente. Entretanto, após um certo período, muitos fatores contribuem para a deterioração de seu desempenho. Isto evidencia a importância do monitoramento dos sistemas de controle MPC. Neste trabalho aborda-se ferramentas, baseada em métodos estatísticos multivariados, aplicados ao problema de monitoramento e avaliação de desempenho de controladores preditivos. Os métodos aqui apresentados são: o PCA (Análise por componentes principais) e o ICA (Análise por componentes independentes). Ambas são técnicas que utilizam dados coletados diretamente do processo. O primeiro é largamente utilizado na avaliação de desempenho de controladores preditivos. Já o segundo, é uma técnica mais recente que surgiu, principalmente, com o intuito de ser utilizado em sistemas de detecção de falhas. As análises são feitas quando aplicadas em processos simulados característicos da indústria petroquímica operando sob controle MPC.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Monitoring of process control systems is extremely important for industries to ensure the quality of the product and the safety of the process. Predictive controllers, also known by MPC (Model Predictive Control), usually has a well performance initially. However, after a period, many factors contribute to the deterioration of its performance. This highlights the importance of monitoring the MPC control systems. In this work, tools based on multivariate statistical methods are discussed and applied to the problem of monitoring and Performance Assessment of predictive controllers. The methods presented here are: PCA (Principal Component Analysis) and ICA (Independent Component Analysis). Both are techniques that use data collected directly from the process. The first is widely used in Performance Assessment of predictive controllers. The second is a more recent technique that has arisen, mainly in order to be used in fault detection systems. The analyzes are made when applied in simulated processes characteristic of the petrochemical industry operating under MPC control. / O monitoramento de sistemas de controle de processos é extremamente importante no que diz respeito às indústrias, para garantir a qualidade do que é produzido e a segurança do processo. Os controladores preditivos, também conhecidos pela sigla em inglês MPC (Model Predictive Control), costumam ter um bom desempenho inicialmente. Entretanto, após um certo período, muitos fatores contribuem para a deterioração de seu desempenho. Isto evidencia a importância do monitoramento dos sistemas de controle MPC. Neste trabalho aborda-se ferramentas, baseada em métodos estatísticos multivariados, aplicados ao problema de monitoramento e avaliação de desempenho de controladores preditivos. Os métodos aqui apresentados são: o PCA (Análise por componentes principais) e o ICA (Análise por componentes independentes). Ambas são técnicas que utilizam dados coletados diretamente do processo. O primeiro é largamente utilizado na avaliação de desempenho de controladores preditivos. Já o segundo, é uma técnica mais recente que surgiu, principalmente, com o intuito de ser utilizado em sistemas de detecção de falhas. As análises são feitas quando aplicadas em processos simulados característicos da indústria petroquímica operando sob controle MPC.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Among the products of the hive, honey is considered the principal, standing out as natural food and for having multiple pharmacological applications. Honey can be produced by honey bees (Apis mellifera, L.) from the nectar, fruit, plant secretions and excretions of aphids or other sweetened solutions.Their nutritive power, pharmacologic and commercial value depends on its botanical origin, which can be obtained through classical methods as sensory evaluation, physicochemical analyses or melissopalynology. Although, these methods require much experience of the analyst and are costly.In view of the current difficulties in conducting these analyses, methods based on the study of volatile constituents have emerged as an alternative in the search for the source of compound markers of floral honeys. For the identification of these compounds, techniques such as solid in solid phase (SPME) and dynamic headspace (HSD) followed by analysis on gas chromatography coupled to mass spectrometer (GC-MS) are suggested. In this work, different honeyproducing regions in the State of Sergipe were studied, as well as samples of honey originated from other states of Brazil, purchased in local supermarkets. Analyses of volatile components were obtained by dynamic headspace using Porapak Q® and Peat in natura as adsorbent materials. For both, parameters such as amount of sample, salt addition, time and temperature of extractionhave been optimized. Optimization, made possible the identification of 112 different compounds belonging to classes of aliphatic alcohols, aliphatic aldehydes, benzene derivatives, monoterpene hydrocarbons, oxygenated hydrocarbons, norisoprenoids, sesquiterpenes, oxygenated sesquiterpenes, carboxylic acids and others. Among these, a group of senior compounds were studied by principal components analysis and hierarchical cluster analysis. With these analyses was likely to identify the components with biggest weights in the samples and cluster them into five groups with a similarity of 48% based on Euclidean distance. Among the weighty compounds are furfuraldehyde, benzaldehyde, cis-linalool oxide (furanoid), trans-linalool oxide (furanoid), linalool, hotrienol, 4-ketoisoforone, aldehyde lilac (isomer I), cis-linalool oxide (pyranoid) and -terpineol. / Dentre os produtos apícolas o mel é considerado o principal por se destacar como alimento natural e ter várias aplicações farmacológicas, podendo ser produzido por abelhas Apis mellifera a partir do néctar, secreções das plantas e frutos, excreções de afídeos e outras soluções adocicadas. Seu poder nutritivo, farmacológico e valor comercial dependem de sua origem botânica, a qual pode ser obtida através de métodos clássicos como a avaliação sensorial, a melissopalinologia ou análises físico-químicas, porém estes métodos exigem muita experiência do analista e são dispendiosas. Em virtude das dificuldades atuais em realizar essas análises os métodos baseados no estudo dos constituintes voláteis têm surgido como uma alternativa na procura de compostos marcadores da origem floral de méis. Para a identificação destes compostos, técnicas como a microextração em fase sólida (SPME) e headspace dinâmico (HSD) seguido de análise em cromatógrafo em fase gasosa/espectrômetro de massas (CG/EM) são sugeridas. Neste trabalho foram estudados méis de diferentes regiões produtoras do estado de Sergipe, bem como amostras de méis adquiridos em supermercado de Aracaju oriundas de outros estados do Brasil através da análise dos componentes voláteis obtidos por headspace dinâmico utilizando Porapak Q® e Turfa in natura como materiais adsorventes. Para tanto foram otimizados parâmetros como quantidade de amostra, adição de sal, tempo e temperatura de extração. Nas condições otimizadas foi possível identificar 112 diferentes compostos pertencentes às classes dos álcoois alifáticos, benzenóides, aldeídos alifáticos, hidrocarbonetos lineares, monoterpenos, monoterpenos oxigenados, sesquiterpenos, sesquiterpenos oxigenados, norisoprenóides, ácidos carboxílicos e outros. Dentre estes, um grupo de compostos majoritários foram estudados por análise de componentes principais e análise de agrupamento hierárquico. Com estas análises foi possível identificar os componentes de maiores pesos das amostras e agrupá-las em cinco grupos com uma similaridade de 48%, tendo como base a distância Euclidiana. Dentre os compostos de maiores pesos estão o furfural, benzaldeído, cis-óxido de linalol (furanóide), trans-óxido de linalol (furanóide), linalol, hotrienol, 4-ceto-isoforona, lilac aldeído (isômero I), cis-óxido de linalol (piranóide) e o -terpineol.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study addresses the distribution of trace metals in sediment cores from the dam Marcela in order to evaluate the occurrence of impacts associated with human and industrial activity. The dam is located in the city Itabaiana in the state of Sergipe, it was built in the period 1953 - 1957 barring Fuzil stream. It has an area of 1.4 km2 with storage capacity of 2,700,000 m3. Two sediment cores were collected in November of 2008 with approximately 45cm in two distinct points. The samples were sectioned in 5 cm each and they were analyzed by to determine the following chemical elements: Co, Cr, Cu, Ni, Pb, Zn, Mn, Al, Fe, Corg and Ntotal. The average value of Corg/Ntotal in the range 4,97- 7,64 and 6,39-7,69, for cores I and II respectively, indicative autochthonous and allochthonous origin of the organic matter. The multivariate statistical analysis (Principal component analysis) applied to the set of results showed that the two cores in relation to concentrations of metals are different, with evidence of enrichment for Cr, Cu, Mn and Zn in the surface layers. The contamination factor calculed showed contamination moderate level for metals Cr, Cu, Mn and Zn. The risk assessment code (RAC), which consider the percentage of metal extracted in the label fraction (F1) of BCR procedure, showed that chromium does not present risk to the environment, copper, nickel and lead were low to medium risk, and zinc had of very high to High risk to the aquatic environment. Small variations in environmental conditions, such as pH or salinity, could therefore increase availability of the elements to the aquatic system. The metals concentrations were always at the lower limit the TEC and PEC, defined by consensual sediment quality guidelines (SQGs), in this case, it is not possible to predict what adverse effects the metal can cause in this environment. / Neste trabalho foi determinada a distribuição de metais traço em testemunhos de sedimento do Açude Marcela com o objetivo de avaliar a ocorrência de impactos associados à atividade humana e industrial, desenvolvidas naquela região. O Açude Marcela localiza-se na cidade de Itabaiana Sergipe, foi construído no período 1953 à 1957 pelo barramento do riacho Fuzil e tem uma área de 1,4km2 , com capacidade de armazenamento de 2.700.000 m3. Foram coletados em novembro de 2008 dois testemunhos de sedimentos com aproximadamente 45cm de profundidade em dois pontos distintos do açude. Os testemunhos foram secionados a cada 5cm para determinação dos seguintes elementos químicos: Co, Cr, Cu, Ni, Pb, Zn, Mn, Al, Fe, Corg e Ntotal. A relação Corg/Ntotal variou de 4,97-7,64 e 6,39-7,69 para os testemunhos I e II, respectivamente, indicando origem autóctone e alóctone para a matéria orgânica presente no sedimento. A análise estatística multivariada (análise de componentes principais-ACP), aplicada ao conjunto dos resultados, mostrou que os dois testemunhos, em relação às concentrações dos metais, são estatisticamente diferentes, com evidências de enriquecimento por Cr, Cu, Mn e Zn, nas camadas mais superficiais. O fator de contaminação calculado mostrou um nível de contaminação moderado para os metais Cr, Cu, Mn e Zn. O Fator de Risco (RAC), que compreende a percentagem do metal extraída na fração lábil (F1) do procedimento (BCR) empregado, indicou que o cromo não apresentou risco ao ambiente. Cobre, níquel e chumbo apresentaram risco baixo a médio, e zinco apresentou risco alto a altíssimo para o ambiente aquático. Sendo assim, pequenas variações nas condições ambientais podem remobilizar esses elementos do sedimento para a coluna d água. As concentrações dos metais nos testemunhos estiveram entre TEC e o PEC, definidos pelos valores guias de qualidade de sedimento consensual (VGQS), indicando que, nas condições atuais, o sedimento pode exercer efeito adverso aos organismos do açude em questão.