Removal of Heavy Metals from Aqueous Solution by the Algerian Bentonite

The adsorption onto bentonite of three heavy metals often found in industrial effluents （chromium, iron ana zinc） was studied. The kinetic equilibrium data show that the bentonite fixes more chromium（VI） than iron（II） and zinc（II）. The adsorption capacities of heavy metals in equilibrium with the bentonite are influenced by the stirring speed and environment temperature. The thermodynamic parameters obtained indicate that the adsorption of heavy metals onto bentonite is a spontaneous and exothermic process.

Sediment Speciation from Dekin Groundwater at District of Dangbo (South Benin)

The objective of this research is to determine the physicochemical elements contained in the groundwater and in the deposits originating from these waters of the Arrondissement of Dêkin, Commune of Dangbo in the South of Benin. Physical parameters were measured from the multi-parameter and the chemical parameters by reagent assays. The precipitate from the groundwater was studied by speciation. The different assays were carried out using the Hach Lange DR2800 Spectrophotometer. The data processing was done with different software including ArcGis 10.1, Diagram.Ink of Roland SIMLER and PHREEQC 2.17.4137. Strong mineralization of the deposit from the drilling water was indicated in these three elements: Copper (220.1 mg/kg), iron (2528 mg/kg) and zinc (239.5 mg/kg) whose contents are higher than the French guideline values for heavy metal content in sediments in mg/kg. The calculation of the Saturation Indices of the drilling water shows saturation with respect to Goethite and Hematite. All these results have led us to conclude that the high content of Metallic Trace Element (MTE) in the deposit and especially of the iron in the drilling water originates from the dissolution-precipitation of the aquifer rock.

Characterization of Four University Hospitals Wastewater in Cotonou, Benin

Introduction: Because of the specificity of their care activities, hospital wastewater contains various contaminants such as germs, disinfectants, metals, pharmaceuticals and chemical reagents, potentially infectious or toxic, which can be harmful to living organisms, or create ecological damage. This study aimed to analyze the quality of wastewaters produced by university hospitals of Cotonou in Benin. Methods: We conduct an analytical cross-sectional study including 30 wastewater samples from selected hospitals. An analysis of variance was performed at the significance level of 0.05. Results: Microbiological analysis showed the presence of germs such as total coliform types, faecal coliforms, fecal streptococcus, staphylococcus, yeasts and Clostridium perfringens in hospital wastewater samples. There was a significant difference (p < 0.05) in the microbial loads of various germs, except staphylococcus, between hospitals. With regard to the physicochemical parameters, only the conductivity complied with the standards for the discharge of wastewater into the environment. A significant difference was noted between hospitals, for the electrical conductivity of wastewater (p < 0.05). The average levels of metals detected in the wastewaters were in line with Benin’s standards. There was no difference between the average concentrations of metals except for copper (p < 0.05). Conclusion: The wastewater produced by the university hospitals of Cotonou is of poor quality and therefore requires adequate prior treatment before discharge into the environment.

Assessment of the Risk of Toxicity of Fish in the River So by Contamination in Heavy Metals(Southern Benin,West Africa)

The purpose of this study is to assess the state of contamination of fish in the S? River by trace metal elements including Zinc, Lead, Cadmium, Copper and Arsenic. Water samples and four species of both sexes (Clarias anguillaris, Kribia kribensis, Tilapia guineensis and Eleotris vittata) were collected and analyzed. The pH, temperature and values of the chemical species present in the water of the S? River characterize an ecosystem favorable to the growth of aquatic species. The Metallic Traces Elements (MTE) concentrations vary from one fish species to another and depend on the sex and age of the animal. Zinc and copper are more concentrated in males than females with the exception of copper in Tilapia. The Pb concentration is higher in young Kribia and Clarias as well as Zn and Cd in young Tilapia. The concentrations in Cd and Pb are well above the European standards and those in the Republic of Benin, worrying results that express a health toxicity risk related to the consumption of fish of the river S?.