Effect of pre-chlorination on the efficiency of iron and manganese removal from surface water by coagulation-flocculation using aluminium sulphate: case of the Okpara dam in the Republic of Benin

Okpara dam water contained significant amounts of iron and manganese that could be problematic for consumers. In this study, we perfected a deferrization and demanganization technique by coagulationflocculationpreceded by chlorination. The maximum iron and manganese concentrations varied from 30 to 50 mg/L and 1.5 to 4.5 mg/L respectively before treatment. Purification yields depended on the conditions of operation. Under the least favourable conditions (coagulation at free pH), the removal yields varied from 10 to 73% for iron and from 2 to 24% for manganese. Under the best conditions (pre-chlorination and coagulation at pH 6.5), we obtained between 50 and 95% elimination for iron and 20 and 45% for manganese. The treatment was therefore little adapted for the removal of manganese

Characterization of the Ngouache Landslide by Geotechnical Survey (Bafoussam, Cameroon)

The heavy rainfall during the night of October 28-29, 2019, caused a landslide in the Ngouache 4 neighborhood in Bafoussam in the West Cameroon region. This landslide caused 43 deaths, several missing persons and the destruction of several houses and plantations. The present investigation attempts to find the causesof this landslide. First, the landslide area was identified and heavy dynamic penetrometer surveys were conducted. Next, intact and reworked samples were taken and, finally, slopes were measured on the slide area to determine the soil parameters. The results of the heavy dynamic penetrometer showed the presence of altered clay layers which, when saturated, exert hydrostatic pressure and unbalance the soil. The granulometric analysis noted a soil with more than 50% of grains of ϕ>80µm with liquidity limits between (50-65.3%), a consistency index between (1.01-1.24), a low cohesion between (0.22-0.30 bars) for a high internal friction angle (20.72°-23.86°), slopes between 48° and 56° and a degree of saturation Sr between (80.5° and 139.9°). These characteristics associated with the large water columns of the night of October 28 to 29, 2019 demonstrated that the water had exerted a hydrostatic pressure having made the clay material reach the limit of plasticity to the creep and raised the level of the water table. Thistherefore promoted the saturation of the substrate yet the increase in the water content reduces the cohesion of the materials and that triggered the saturation at the origin of this deadly slide. The results of the present research may help the public authorities in the decision making regarding the characterization and the securing of risk zones

Characterization of the Ngouache Landslide by Geotechnical Survey (Bafoussam, Cameroon)

The heavy rainfall during the night of October 28-29, 2019, caused a landslide in the Ngouache 4 neighborhood in Bafoussam in the West Cameroon region. This landslide caused 43 deaths, several missing persons and the destruction of several houses and plantations. The present investigation attempts to find the causesof this landslide. First, the landslide area was identified and heavy dynamic penetrometer surveys were conducted. Next, intact and reworked samples were taken and, finally, slopes were measured on the slide area to determine the soil parameters. The results of the heavy dynamic penetrometer showed the presence of altered clay layers which, when saturated, exert hydrostatic pressure and unbalance the soil. The granulometric analysis noted a soil with more than 50% of grains of ϕ>80µm with liquidity limits between (50-65.3%), a consistency index between (1.01-1.24), a low cohesion between (0.22-0.30 bars) for a high internal friction angle (20.72°-23.86°), slopes between 48° and 56° and a degree of saturation Sr between (80.5° and 139.9°). These characteristics associated with the large water columns of the night of October 28 to 29, 2019 demonstrated that the water had exerted a hydrostatic pressure having made the clay material reach the limit of plasticity to the creep and raised the level of the water table. Thistherefore promoted the saturation of the substrate yet the increase in the water content reduces the cohesion of the materials and that triggered the saturation at the origin of this deadly slide. The results of the present research may help the public authorities in the decision making regarding the characterization and the securing of risk zones

World Health Organization Discontinues Its Drinking-Water Guideline for Manganese

Background: The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-Water Quality in July 2011. In this edition, the 400-µg/L drinking-water guideline for manganese (Mn) was discontinued with the assertion that because “this health-based value is well above concentrations of manganese normally found in drinking water, it is not considered necessary to derive a formal guideline value.

New pneumococcal conjugate vaccine introductions in four sub-Saharan African countries: a cross-country analysis of health systems\u2019 impacts

Background: Pneumonia is a main cause of under-five mortality in low-income settings. The pneumococcal conjugate vaccine (PCV) has been introduced in many countries as a tool in the disease\u2019s prevention. Although PCV\u2019s effectiveness has been established, less is known about the effects of introducing additional injectable vaccines into routine immunisation programmes, particularly in the context of resource-constrained settings. Objectives: To explore the effects of PCV introduction on the immunisation programmes and health systems in four low-income countries. Methods: This study was carried out in Cameroon, Ethiopia, Kenya and Mali. Three to four regions and nine to 10 districts were selected within each country. Semi-structured interviews were carried out at national, regional and district levels (n=173). Researcher-administered questionnaires were completed with facility staff (n=124). Routine data on monthly vaccination activities were collected at district and facility levels. Results: PCV was generally well integrated into existing routine immunisation. Little or no impact was found in most areas of the health systems. Some minor effects were found on immunisation programmes, particularly in areas with either planning activities or investments e.g. staff skills were strengthened and there were limited improvements in surveillance. Although health sector workers perceived increases in the coverage of other vaccines following the introduction of PCV, routine service data did not confirm this claim. No substantial impacts were seen in health system management, service delivery or performance. Conclusions: The introduction of PCV had marginal impacts on the Expanded Programme for Immunisation and little to none on broader health systems

Elimination de la couleur et de la turbidité d’une eau de surface par coagulation-floculation au sulfate d’aluminium : cas de la retenue d’eau de l’Okpara en République du Bénin

Cette étude nous a permis de déterminer les meilleures conditions d’élimination de la turbidité et de la couleur de l’eau de la retenue de l’Okpara. Le traitement appliqué est la coagulation-floculation au moyen d’unjar test. Les essais ont été réalisés à pH de l’eau brute ou à pH 6,5. Les principaux résultats obtenus sont présentés comme suit: à pH de l’eau brute et pour des doses de coagulant comprises entre 10 et 60 mgl-1, lacouleur est mieux éliminée que la turbidité. Les rendements d’élimination sont de l’ordre de 15 à 80% pour la couleur et de 5 à 18% pour la turbidité; à pH 6,5 les rendements d’élimination des deux paramètres pour lesmêmes doses de coagulant sont très importants (82 à 88% pour la turbidité et 50 à 84% pour la couleur). Deux mécanismes sont envisageables. A pH libre, le mécanisme de neutralisation des charges est dominant et à pH6,5, le mécanisme d’adsorption l’emporte

New vaccine adoption: qualitative study of national decision-making processes in seven low- and middle-income countries.

As more new and improved vaccines become available, decisions on which to adopt into routine programmes become more frequent and complex. This qualitative study aimed to explore processes of national decision-making around new vaccine adoption and to understand the factors affecting these decisions. Ninety-five key informant interviews were conducted in seven low- and middle-income countries: Bangladesh, Cameroon, Ethiopia, Guatemala, Kenya, Mali and South Africa. Framework analysis was used to explore issues both within and between countries. The underlying driver for adoption decisions in GAVI-eligible countries was the desire to seize GAVI windows of opportunity for funding. By contrast, in South Africa and Guatemala, non-GAVI-eligible countries, the decision-making process was more rooted in internal and political dynamics. Decisions to adopt new vaccines are, by nature, political. The main drivers influencing decisions were the availability of funding, political prioritization of vaccination or the vaccine-preventable disease and the burden of disease. Other factors, such as financial sustainability and feasibility of introduction, were not as influential. Although GAVI procedures have established more formality in decision-making, they did not always result in consideration of all relevant factors. As familiarity with GAVI procedures increased, questioning by decision-makers about whether a country should apply for funding appeared to have diminished. This is one of the first studies to empirically investigate national processes of new vaccine adoption decision-making using rigorous methods. Our findings show that previous decision-making frameworks (developed to guide or study national decision-making) bore little resemblance to real-life decisions, which were dominated by domestic politics. Understanding the realities of vaccine policy decision-making is critical for developing strategies to encourage improved evidence-informed decision-making about new vaccine adoptions. The potential for international initiatives to encourage evidence-informed decision-making should be realised, not assumed