Pollution De L'eau De Consommation Humaine Et Risques Sanitaires A Court Terme : Cas Du Bassin Versant De La Menoua (Ouest-Cameroun)

The health risk associated with the consumption of water polluted by humans in the World, particularly in Africa, is a real public health problem. This is why WHO, from its inception in 1948, has always been concerned with defining limit values. The aim of this work was to study the physicochemical and microbiological quality of water in the Menoua watershed through a spatiotemporal dynamics to assess its degree of anthropogenic pollution and to estimate the level of risk of infection and diseases inherent in its consumption. Physicochemical analysis (pH, temperature, turbidity and dissolved oxygen) and microbiological (E-coli, salmonella and shigellas) was carried out on 132 samples taken from 33 sites distributed in two seasons, two in dry seasons and two in rainy season. The results show that these waters have an acidic pH, a low dissolved oxygen content, strong microorganism levels all correlated with high turbidity. These very high levels of microorganism, illustrate well the effect of the action of the man on the pollution of the water. This pollution could have several origins, the most important of which are related to spilled household discharges, without any prior treatment in rivers, manure from livestock and used in agriculture. The level of microbiological risk is very high for consumers and typhoid is the most recurrent waterborne disease in the region. This diagnosis would help decision-makers to better pronounce on the management of this resource in order to reduce the health risks inherent in its consumption

Assessment of Physical-Chemical Drinking Water Quality in the Logone Valley (Chad-Cameroon)

Unsafe drinking water is one of the main concerns in developing countries. In order to deal with this problem, a cooperation project was set up by the ACRA Foundation in the Logone valley (Chad-Cameroon). Water supplies were sampled throughout the villages of this area mostly from boreholes, open wells, rivers and lakes as well as some piped waters. The samples were analysed for their physical-chemical and microbiological quality in order to identify the contamination problems and suggest appropriate solutions. Results of the assessment confirmed that in the studied area there are several parameters of health and aesthetic concern. Elevated lead levels were detected both in aquifers and in surface waters, confirming that further investigations of the occurrence of lead contamination in the Logone valley are warranted. In addition, many groundwater sources are negatively impacted by parameters of aesthetic concern, such as turbidity, iron and manganese. Even though they do not affect human health, elevated levels of these parameters cause consumers to abandon improved water supplies, often in favour of surface water sources that are microbiologically contaminated. The use of alternative sources, improvement of water supply structures and water treatment are possible solutions to improve the quality of drinking water in the Logone valley

Identification of an Appropriate Formulation for Domestic Water Ceramic Filters from Soukamna Clay (Cameroon)

This paper deals with the formulation of ceramic filters having the porosity adapted to domestic potable water treatment. The filters were made from clays and rice husk obtained from the Far North region of Cameroon (Logone Valley). Nine formulations were investigated to choose those that might have the porosity standing between 35 and 50% (the ideal porosity adapted for water treatment) [1]. The nine formulations investigated were as follow: clay:rice husk mixture weight ratio 0.7:0.3; 0.8:0.2 and 0.9:0.1 with the particle size of 100:100 microns. The sintering temperatures of 900°C, 950°C and 1000°C were applied for each of the mixtures. The results showed that only filters with weight ratio 0.7:0.3 sintered at 900°C, 950°C and 1000°C had porosity between 35 and 50% with values of 39.41±0.96; 40.15±1.59; 40.14±1.31 respectively. Mechanical strength, permeability and iron leaching behavior were investigated for these three formulations. The formulation 0.7:0.3 with sintering temperature of 1000°C had the higher permeability and was the more stable for iron leaching so it is the more adapted for water treatment in terms of flow rate and iron leaching behavior, pore size distribution showed that these filters were macroporous and designed for microfiltration with average pore diameter of 0.46µm

Pratiques Paysannes De Production Durable Des Graines De Voandzou [Vigna Subterranea (L.) Verdc.] Pour La Sécurité Alimentaire Dans Le Cameroun Septentrional

Bambara groundnut is a leguminous plant with high nutritive value of Sub Saharan Africa. In spite of its high potential in alimentation, the Bambara groundnut is less popularized. This crop grows on acid, dry and less fertile soils and may therefore be a resilient crop in the context of climatic variability. The present work aims to identify of all the morphotypes of this culture and the usual tools of conservation of its seeds during the storage process. Investigations carried out during 3 agricultural campaigns showed that women more than 40 years old represents more than 98% of producers of Bambara groundnuts in northern Cameroon. The production concerns 54 morphotypes use as food or as medicinal plants. During storage of grains of this legumes, the major pest is the bruchid Callosobruchus maculatus Fab. (Coleoptera : Chrysomelidae). Under traditional production way, the limitation of the postharvest losses due to this pest is done either by the use of 21 local plants as botanical insecticide or by the use of 25 industrial chemical pesticides

Formulation d'insecticides en poudre par adsorption des huiles essentielles de Xylopia aethiopica et de Ocimum gratissimum sur des argiles camerounaises modifiées

En Afrique sud- saharienne, plusieurs méthodes de protection des stocks alimentaires sont utilisées ; parmi elles, les insecticides synthétiques qui représentent un risque réel pour la santé humaine. Pour apporter une alternative à ces insecticides chimiques potentiellement dangereux, le présent travail a pour objectif de développer des bio-insecticides en formulant des poudres par adsorption d huiles essentielles sur des argiles. Deux argiles naturelles du Cameroun ont été utilisées comme adsorbants des composés terpéniques des huiles essentielles de Xylopia aethiopica et Ocimum gratissimum pour la préparation d insecticides. Dans le but d améliorer leur capacité d adsorption, ces argiles ont été traitées par la soude et l acide sulfurique. Elles ont également été modifiées par des solutions de polycations d aluminium ou de fer de rapport molaire varié ainsi que par des cations d alkylammoniums. Une bentonite commerciale a été utilisée comme référence dans le suivi des modifications. Ces différentes matrices ont été caractérisées avant et après modifications par diffraction des rayons X, adsorption-désorption d azote, spectroscopie infra rouge à transformée de Fourier, analyses thermogravimétriques et différentielles, et photométrie de flamme. Il ressort de la caractérisation que l échantillon de Wak est majoritairement constitué de kaolinite, et celui de Maroua de montmorillonite. Le traitement par l acide sulfurique et par les polycations métalliques entraînent une augmentation de la surface spécifique des argiles, tandis que la soude et les cations d alkylammoniums la réduisent fortement. La surface spécifique de la montmorillonite passe de 82 m .g-1 à 4,5 m .g-1 après traitement au céthyl triméthyl ammonium (CTMA). Les diffractogrammes montrent une augmentation de la distance interfoliaire des argiles étudiées après modification aux cations alkylammoniums. La distance interfoliaire augmente de 5,5 Å et de 10,6 Å respectivement pour la montmorillonite et la bentonite traitée par le CTMA. Les argiles de type smectite après modifications aux polycations métalliques, présentent en revanche un étalement du pic caractéristique de l espace interfoliaire. Les cations alkylammoniums entraînent donc une intercalation effective des molécules de CTMA et phényl triméthyl ammonium (PTMA) entre les feuillets de montmorillonite et de bentonite tandis que les polycations métalliques entraînent une exfoliation du matériau argileux. Les argiles-alkylammoniums présentent les plus grandes capacités d adsorption des composés terpéniques malgré les plus faibles surfaces spécifiques. Ainsi, face aux composés terpéniques, la capacité d adsorption des argiles ne dépend pas uniquement de la surface spécifique mais également de l espacement interfoliaire de l adsorbant ainsi que de l affinité des molécules d adsorbât vis-à-vis de l adsorbant. Des tests insecticides ont montré que les formulations à base de la Mont-CTMA présentent une toxicité plus stable que celle préparée à partir de l argile brute (Mont-Na). La formulation Mont-Na-HE perd la totalité de son activité insecticide au bout de 30 jours de conservation dans les boîtes ouvertes. La formulation Mont-CTMA-HE par contre n en perd qu environ 60% dans les mêmes conditions. La rémanence de la formulation varie avec l adsorbant utilisé ; car l effet insecticide de l huile essentielle d O. gratissimum persiste pendant 107 jours lorsqu elle est fixée sur la Mont-CTMA, tandis que fixée sur l argile brute, elle perd son activité au bout de 45 jours. Ces résultats nous permettent d affirmer que les argiles modifiées augmentent la durée de l effet insecticide des huiles essentielles et peuvent être utilisées pour une application industrielle dans la production des bio-insecticides.In sub-Saharan Africa, several methods to protect food stocks are used ; amongst them are synthetic insecticides. These synthetic insecticides pose high real risk to human health. This study aims at providing an alternative to the dangerous synthetic chemical insecticides, by developing bioinsecticides formulating powders through adsorption of essential oils on Cameroonian clays. Two natural clays collected in Cameroon were used as adsorbents of terpene compounds of Xylopia aethiopica and Ocimum gratissimum essential oils, for the preparation of insecticides. The clay fractions were obtained from soil aggregates by sedimentation. In order to improve their adsorption capacity, these clays were treated with sodium hydroxide and sulfuric acid. They were also modified with solutions of aluminum, iron polycations with molar ratio varied and alkylammoniums cations. A commercial bentonite was used as reference for these modifications. These different adsorbents materials were characterized before and after modifications by X-ray diffraction, nitrogen adsorption-desorption, infrared Fourier transform spectroscopy, thermal analysis, and flame photometry. According to the characterizations of the clay materials, Wak sample contained more kaolinite clay, while Maroua sample contained more montmorillonite clay. The sulfuric acid and metallic polycations caused an increase in the specific surface of clays, while sodium hydroxyl and alkylammoniums cations greatly reduced the SBET. For example, the Mont-Na+ SBET decreased from 82 m . g-1 to 4.5 m .g-1 after treatment with cetyl trimethyl ammonium (CTMA). Diffractogrammes showed spacing of smectites interlayer (montmorillonite and bentonite) after treatments with alkylammoniums cations at 5.5 Å and 10.6 Å respectively, for the interlayer space of Mont- CTMA and Bentonite- CTMA clays. After treatments with metallics polycations, smectite clays show a broadening of characteristic peak. Alkylammoniums cations led to an effective insertion of CTMA molecules and phenyl trimethyl ammonium (PTMA) between the interfoliar space of montmorillonite and bentonite while the metal polycations led to an exfoliation of the same clays. The interreticular spacings of kaolinite remain unchanged after any treatments. The kinetic model of pseudo second order is applicable to the adsorption of terpenic compounds by clays. Finding also showed that spread is not the only limiting factor in the process of adsorption of terpene compounds. Alkylammoniums-clays have the largest adsorption capacities of terpene compounds despite the lower specific surface they present. All this allows us to maintain that in the presence of terpenic compounds, the adsorption capacity of clays depends not only on the SBET but more on the interlayer spacing of the adsorbent and on the affinity of the adsorbate molecules toward the adsorbent. Concerning bioassays, it appears that the formulations made with Mont- CTMA presented a more stable toxicity than Mont-Na. Mont-Na-EO formulation loses all its insecticidal activity after 30 days of storage in the open boxes ; while Mont-CTMA- EO formulation only loses about 60% under the same conditions. Moreover, the Mont-Na-EO loses 50% of its insecticidal power (LD50) after 6 days ; while Mont-CTMA- EO loses the same quantity after 16 days when stored in open boxes. The remnance effect of the formulations based on essential oil varied with the adsorbent used. Because the insecticidal effect of O. gratissimum essential oil persisted during 107 days when it is adsorbed on Mont-CTMA, when adsorbed on Mont-Na, it loses all its activity for about 45 days. These results allow us to assert that modified clays increase the duration of the insecticidal effect of essential oils and can be used for industrial application in the production of bio-insecticides based on essential oils.MONTPELLIER-Ecole Nat.Chimie (341722204) / SudocSudocFranceF

The use of plants in the traditional management of diabetes in Nigeria: Pharmacological and toxicological considerations

Ethnopharmacological relevance: The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system. Materials and methods: Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. ‘Diabetes’ and ‘Nigeria’ were used as keywords for the primary searches; and then ‘Plant name – accepted or synonyms’, ‘Constituents’, ‘Drug interaction’ and/or ‘Toxicity’ for the secondary searches. Results: The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs. Conclusion: This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb–drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided

Caracterisation analytique des structures sulfurees dans les fractions petrolieres lourdes

SIGLECNRS T 59162 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Chronic Toxicity Of Essential Oils Of 3 Local Aromatic Plants Towards Sitophilus Zeamais Motsch (Coleoptera : Curculionidae)

peer reviewe

Source and Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Water from Mboppi River in Douala–Cameroon

Having a source attributed to anthropogenic activities such as incomplete combustion or pyrolysis of organic materials, polycyclic aromatic hydrocarbons are toxic organic pollutants that the ubiquity is no more to be proved. The purpose of this work is to identify and quantify the hydrocarbons pollution of the Mboppi River. Eight (8) samples of water were collected in the river during the dry and the rainy season (4samples for each season). Hydrocarbon fraction was extracted by magnetic agitation of the mixture water/hexane followed by clean-up, fractionation and subsequently, analysis using gas chromatography coupled to a Flame Ionization Detector (GC-FID). Total concentrations of polycyclic aromatic hydrocarbons in the samples were ranged between 196.3-1040.19 µg/L in the river. Polycyclic aromatic hydrocarbons with more than four rings showed the highest concentrations in the river independently from the seasonal variation while the polycyclic aromatic hydrocarbons with 2 or 3 rings were usually present in low concentrations or sometimes undetectable. From the data, it was also possible to conclude that there is predominance of petroleum sources, and essentially closed to the more industrialized areas. Mboppi River can then be considered as being among the most polycyclic aromatic hydrocarbons polluted environment in comparison with some rivers and estuaries