Caractérisation Physico-Chimique Des Eaux De Surface Dans Un Environnement Minier Du Centre-Ouest De La Côte d’Ivoire : Cas Du Département De Divo

Les ressources en eaux de surface du département de Divo sont soumises à de fortes pressions anthropiques suscitées par le développement. Pour ce faire, cette étude a été initiée pour déterminer les caractéristiques physico-chimiques des eaux du département et celles situées à proximité des sites miniers. A cet effet, treize paramètres physicochimiques ont été étudiés. Ce sont les ions majeurs (Ca 2+ , Mg 2+ , Na+ , K + , Cl - , SO4 2- , HCO3 - ), pH, Eh, température, turbidité, conductivité électrique (EC) et NO3 - . Les ions analysés et les paramètres de terrain ont été comparés aux normes des eaux brutes. Les résultats ont été traités d’une part à l’aide de la méthode hydrochimique (diagramme de piper) pour déterminer la typologie des eaux et d’autre part à l’aide de l’analyse statistique multivariée (l’Analyses en Composantes Principales Normée (ACPN)), pour mettre en évidence l’origine de la minéralisation des eaux. Les résultats montrent que la plupart des eaux sont voisines de la neutralité. Les concentrations en nitrates sont parfois élevées, elles ont pour valeur maximale 164,8 mg/l. Les eaux sont moyennement minéralisées avec une conductivité moyenne de 608,4 S/cm. Les eaux à proximité des sites d’exploitation industriels sont les plus minéralisées. Ces eaux sont fortement caractérisées par un hydrofaciès de type chloruré calcique et magnésien. Les phénomènes à l’origine de la minéralisation des eaux de Divo sont essentiellement liés à l’agriculture et aux rejets urbains. Cette étude nous a permis de caractériser les paramètres physico-chimiques des eaux de surface du département. Une étude plus détaillée doit être réalisée afin de caractériser avec précision l’origine de la minéralisation des eaux. The surface water resources of Divo’s department are subjected to strong anthropic pressures caused by the development. With this intention, this study was initiated to determine the physicochemical characteristics of water of the department and those located near the sites mines. To this end, thirteen physicochemical parameters were studied. These are the major ions (Ca 2+ , Mg2+ , Na + , K + , Cl - , SO4 2- , HCO3 - ), pH, Eh, temperature, turbidity, electrical conductivity (EC) and NO3 - . The analyzed ions and the field parameters were compared with the standards raw water. The results were treated on the one hand using the hydrochemic method (diagram of piper) to determine the typology of water and on the other hand using the multivariate statistical analysis (Normed Principal component Analysis (NPCA) to underline the origin of the mineralization of water. The results show that most of the waters are close to neutrality. The nitrate concentrations are sometimes high, they have as a maximum value 164.8 mg/l. water is moderately mineralized with an average conductivity of 608.4 µS/cm. water near the mining sites is the most mineralized. This water is strongly characterized by a hydrofacies of the calcic and magnesian chlorinated type. The phenomena behind the mineralization of water of Divo are mainly linked to agriculture and urban rejections. This study enabled us to characterize the physicochemical parameters of surface water of the department. A more detailed study must be carried out in order to characterize precisely the origin of the mineralization of water

Analyse comparative entre la distribution des fréquences de conductivité électrique et les faciès géochimiques des eaux des aquifères de socle (Côte d’Ivoire)

La conductivité électrique est un indicateur de la minéralisation totale des eaux et son étude permet de faire un suivi hydrochimique des systèmes hydrologiques. L'objectif de ce travail est d’analyser l’apport de l’étude de la distribution des fréquences de conductivité électrique à la caractérisation géochimique des eaux des aquifères fissurés de socle cristallin et cristallophyllien. Les zones tests utilisées dans le cadre de ce travail appartiennent au socle ivoirien. La méthodologie adoptée est basée d’une part sur l’étude des courbes de fréquence de conductivité électrique. D’autre part, les faciès chimiques des eaux souterraines ont été déterminés à partir du diagramme de Piper. L’analyse de la distribution des fréquences de conductivité électrique a fait ressortir diverses familles d’eau. La projection des échantillons d’eau sur le diagramme de Piper a permis de mettre en évidence plusieurs faciès des eaux souterraines. La comparaison des différents résultats met en évidence une concordance au niveau de quatre échantillons (Bondoukou, Tiassalé, ex-N’zi- Comoé et Tiébissou-Didievi) et une non concordance au niveau de deux échantillons (Guiglo-Duekoué et Agboville). On peut conclure que l’analyse des fréquences de conductivité électrique permet en général de confirmer les différents faciès hydrogéochimiques.© 2016 International Formulae Group. All rights reserved.Mots clés: Hydrogéochimie, conductivité électrique, diagramme de Piper, socle cristallin et cristallophyllien, Côte d’IvoireEnglish Title: Comparative analysis of electrical conductivity frequencies distribution and geochemical facies of hard rock aquifers waters (Ivory Coast)English AbstractElectrical conductivity is a measure of the total mineralization of the water and its study allows for a hydrochemical monitoring of water systems. The objective of this work was to analyze the contribution of the  study of electrical conductivity frequencies distribution to the geochemical characterization of the hard rock aquifers waters. The test zones used in the context of this work belong to the Ivorian hard rock aquifers. The methodology is based firstly on the study of the frequency curves of the electrical conductivity. On the other hand, chemical facies of groundwater have been determined from the Piper diagram. The analysis of the distribution of the electrical conductivity of frequencies has highlighted various water families. The projection of water samples on the Piper diagram helped highlight several facies of groundwater. Comparing the results of different methodological approaches reveals a match in four samples (Bondoukou, Tiassalé, N'zi-Comoé and Tiébissou-Didievi) and a mismatch in two samples (Guiglo-Duékoué and Agboville). Given concordances results in most cases, we can say that the analysis of the electrical conductivity of frequencies generally allows confirming the different hydrogeochemical facies in the hard rock aquifers.© 2016 International Formulae Group. All rights reserved.Keywords: Hydrogeochemistry, electrical conductivity, Piper diagram, hard rock aquifers, Ivory Coas

Cartographie Et Identification Des Activites Sources De Nuisances Et De Pollutions Dans Le Bassin Versant Du Barrage Du Kan De Bouake (Côte d’Ivoire)

This study focuses on mapping and identification of pollution factors in the Kan dam basin in Bouaké (Côte d'Ivoire); All through the use of GIS and field investigations. The consequences of socio-economic development on the Kan dam are important. Indeed, the watershed of the dam appears to be the outlet for all the waters (used and rain) of the town of Bouaké. The mapping of land use in the dam basin allows the identification of nuisance and pollution sources. Mainly five (05) types of nuisance and pollution activities were identified: urbanization (habitat zones); Agriculture (agricultural areas); Fishing (fishing zone); Poultry farming (poultry farming); Cattle breeding (pasture area)

Influence Des Activites Anthropiques Sur La Degradation De La Qualite Des Sediments De La Lagune Ouladine (Sud-Est De La Côte d’Ivoire)

La contamination des sédiments lagunaires par les éléments traces métalliques constitue un danger pour l’eau, les espèces vivantes et pour la santé de l’homme. L’objectif de cette étude est d’évaluer le niveau de contamination des sédiments de la lagune Ouladine en éléments traces. Les éléments traces (Pb, Zn, Cu, Cd et Cr) ont été dosés dans les sédiments lagunaires à l’aide d’un spectromètre d’absorption atomique de type VARIAN AA 20. L’intensité de la contamination des sédiments a été estimée à partir du calcul de plusieurs indices, notamment le Facteur de Contamination (FC), le Degré de Contamination modifié (DCm) et l’Indice de Pollution Sédimentaire (IPS). La toxicité des sédiments a été mise en évidence en comparant les concentrations des éléments traces dosés aux valeurs guides américaines SQGs (Sediment Quality Guidelines). Les résultats mettent en évidence l’ordre d’abondance des teneurs en ETM (Eléments Traces Métalliques) des sédiments suivants : Cr (83,92 mg.kg-1)>Pb (62,03 mg.kg-1)>Zn (60,06 mg.kg-1)> Cu (13,76 mg.kg-1)> Cd (1,45 mg.kg-1). Le Facteur de Contamination (FC) et le Degré de Contamination modifiée (DCm) révèlent une contamination faible à considérable. Les valeurs de l’IPS montrent que les sédiments de la lagune Ouladine sont faiblement pollués sauf à la station S7 où les sédiments sont sains. Hormis le Zinc, les autres ETM dosés s’avèrent néfastes pour les organismes vivants de la lagune Ouladine à toutes les stations qui ont fait l’objet d’échantillonnage. Contamination of lagoon sediments by trace metal elements constitutes a danger to water, living species and human health. The objective of this study is to evaluate the level of trace element contamination in the sediments of the Ouladine lagoon. Trace elements (Pb, Zn, Cu, Cd and Cr) were assayed in lagoon sediments using a VARIAN AA 20. The intensity of sediment contamination was estimated from the calculation ofseveral indices, including the Contamination Factor (CF), the Modified Degree of Contamination (MDC) and the Sediment Pollution Index (SPI). Sediment toxicity was demonstrated by comparing the concentrations of the measured trace elements with the American Sediment Quality Guidelines (SQGs). The results show the order of abundance of the following sediment VEC levels: Cr (83.92 mg.kg1 )>Pb (62.03 mg.kg-1 )>Zn (60.06 mg.kg-1 )> Cu (13.76 mg.kg-1 )> Cd (1.45 mg.kg-1 ). The Contamination Factor (CF) and the Modified Degree of Contamination (MDC) indicate low to considerable contamination. The SPI values show that the sediments of the Ouladine lagoon are slightly polluted except at station S7 where the sediments are healthy. Except for Zinc, the other measured TE (Trace elements) were found to be detrimental to the living organisms of the Ouladine lagoon at all the stations that were sampled

Hydrochemical Characterization and Assessment of Groundwater Quality in the Mining Environment of Afema Township (South-East of Côte d’Ivoire)

Afema Township, located in the department of Aboisso, was mined from 1992 to 1998. At the end of the exploitation, the sites did not undergo any real rehabilitation work. In order to determine the impact of these mining activities on the physicochemical characteristics and quality of groundwater, this study was undertaken. The results of the water analyses collected in the mining area were processed using Piper's triangular diagram and Principal Component Analysis (PCA). The methodological approach consisted, first of all, in determining the hydro-facies of the waters studied, then in dividing them into different groups on the basis of their hydro-chemical similarity and in identifying the factors likely to explain both the origin of the parameters studied and their correlation. Finally, the overall quality of these waters was estimated from the calculation of the quality index. The results showed that the waters studied were divided into two main families: chloride-calcium-magnesium waters and bicarbonate-calcium-magnesium waters. They were on the whole weakly mineralized, with an average electrical conductivity of 195.76 μS.cm-1. This mineralization was controlled by two essential phenomena, the residence time of water in the aquifers and surface infiltration and leaching from unsaturated ground. The physico-chemical quality of the groundwater studied complied with the standards of potability recommended by the WHO. However, the results also showed high levels of cadmium (0.052 mg.L-1) and lead (0.058 mg.L-1); this explained the overall poor quality of these waters according to the water quality index. Thus, the studied waters presented a real risk for human consumption. The consumption of these waters by local communities exposes them to health risks

Hydrochemical Characterization and Assessment of Groundwater Quality in the Mining Environment of Afema Township (South-East of Côte d’Ivoire)

Afema Township, located in the department of Aboisso, was mined from 1992 to 1998. At the end of the exploitation, the sites did not undergo any real rehabilitation work. In order to determine the impact of these mining activities on the physicochemical characteristics and quality of groundwater, this study was undertaken. The results of the water analyses collected in the mining area were processed using Piper's triangular diagram and Principal Component Analysis (PCA). The methodological approach consisted, first of all, in determining the hydro-facies of the waters studied, then in dividing them into different groups on the basis of their hydro-chemical similarity and in identifying the factors likely to explain both the origin of the parameters studied and their correlation. Finally, the overall quality of these waters was estimated from the calculation of the quality index. The results showed that the waters studied were divided into two main families: chloride-calcium-magnesium waters and bicarbonate-calcium-magnesium waters. They were on the whole weakly mineralized, with an average electrical conductivity of 195.76 μS.cm-1. This mineralization was controlled by two essential phenomena, the residence time of water in the aquifers and surface infiltration and leaching from unsaturated ground. The physico-chemical quality of the groundwater studied complied with the standards of potability recommended by the WHO. However, the results also showed high levels of cadmium (0.052 mg.L-1) and lead (0.058 mg.L-1); this explained the overall poor quality of these waters according to the water quality index. Thus, the studied waters presented a real risk for human consumption. The consumption of these waters by local communities exposes them to health risks

Variation Saisonnière De La Qualité Physico-Chimique Des Eaux Souterraines Des Aquifères d’Altérites Du Département d’Agboville (Sud-Est De La Côte d’Ivoire)

The main objective of this study was to evaluate the seasonal quality to explain the phenomena at the origin of the mineralization of groundwater in the department of Agboville. Hydrochemical analysis was performed in 24 wells located throughout the study area. Hydrochemical different methods and techniques of multivariate statistical analysis were used to study these waters. The physicochemical analyzes show that the water is acidic with an average pH of 6.09 in the rainy season and 6.29 in the dry season. Overall, these waters are soft and slightly mineralized with an average electrical conductivity of 172.92 μS / cm in the rainy season and 196.71 μS / cm in the dry season. These waters are mineralized in the dry season than rainy. The hydrochemical classification of water from the Piper diagram showed one hydrofacies is calcium chloride-facies. Quality chemical parameters are mostly below the WHO (2011) guideline values, except for some points (29.17%) where levels of nitrites and ammonium sometimes exceed the guide values. The various processes responsible for the acquisition of the chemistry of groundwater are studied: the residence time of water in contact with the host rock, the redox infiltration of substances linked to human activities and litter decomposition. In the mineralization mechanisms, hydrolysis of silicates is the dominant process

Lead-based paint detection using perovskite fluorescence and X-ray fluorescence

Ingestion of flakes of Pb-based paint by infants remains a health hazard with life-long consequences throughout the world. Pb-based paint was banned for residential use in the US and Western Europe decades ago but is still sold in many countries. This study evaluates the performance of a new kit for detecting exposed Pb-based paint. The kit relies on the formation of Pb-halide perovskite that fluoresces bright green under a UV flashlight after spraying a non-toxic reagent. Tests with the Lumetallix kit were conducted in parallel with X-fluorescence and inductively-coupled plasma atomic emission analysis upon acid digestion using paint currently sold in Ivory Coast and samples of older US paint. Comparison of the three different methods indicates a detection limit for the Lumetallix kit of approximately 500 ppm Pb in paint, with a sensitivity of 95% and a selectivity of 94% relative to that threshold (n=76). This detection limit is an order of magnitude below the US definition of Pb-based paint of 0.5% Pb by weight. Because the kit is easy to use, exposed paint posing a risk could therefore reliably be screened at scale by the general public. Any follow-up for confirmation and mitigation based on XRF measurements will need to consider that Pb-based paint covered with paint without Pb will not respond to the kit but will be detected through the upper layer by XRF