Caractéristiques physico-chimiques de l’eau des puits dans la commune de Pobè (Bénin, Afrique de l’ouest)

Objectif : L’objectif de cette étude est d’évaluer la qualité de l’eau des puits à partir de ses caractéristiques physico-chimiques dans la commune de Pobè. Méthodologie et résultats : L’étude entreprise entre juin 2012 et mars 2013 a permis de mesurer au niveau de quinze puits les paramètres physiques tels que le pH, la conductivité électrique (CE) et la température (T) de l’eau ainsi que les paramètres chimiques suivants : bicarbonates (HCO3-), chlorures (Cl-), calcium (Ca2+), magnésium (Mg2+), titre hydrotimétrique ou dureté totale (TH), ammonium (NH4+), nitrates (NO3-), nitrites (NO2-), sulfates (SO42-), phosphates (PO43-) et fluorures (F-). Les valeurs moyennes annuelles sont comparées aux normes relatives à la qualité de l’eau de boisson. L’analyse statistique multivariée dont l’Analyse en Composantes Principales (ACP) et la Classification Hiérarchique Ascendante (CHA) a été également appliquée à l’ensemble des paramètres mesurés. L’eau des puits est légèrement acide avec un pH moyen de 5,83 ± 0,6. Elle est faiblement minéralisée et légèrement dure avec une conductivité moyenne de 236,62 ± 135,54 FS/cm et une dureté totale moyenne de 107,8 ± 40,63 mg/L. La pollution azotée est un indicateur majeur de la qualité de l’eau des puits étudiés. Cette pollution se traduit par des taux élevés en nitrates et en ammonium dans plus de 50 % des puits. Une forte corrélation est signalée entre la conductivité électrique et les paramètres suivants : pH, NO3-, NO2-, SO42-, TH, Cl-, HCO3- et Ca2+. La typologie est principalement gouvernée par cette conductivité qui permet de classifier les puits selon leur qualité physico-chimique. Conclusion et applications : L’eau des puits est soumise à une pollution organique dans la commune de Pobè. Cette pollution d’origine anthropique serait liée à l’infiltration des eaux usées et des engrais chimiques. Les fortes teneurs en nitrates et en ammonium montrent que cette eau est chimiquement non appropriée à la consommation humaine et nécessite dans la majorité des puits un traitement préalable.Mots clés : Physico-chimie, eau de puits, pollution, analyses multivariées, Pobè.Physicochemical characteristics of well water in Pobè municipality, Benin, West Africa Objective : The aim of this study is to evaluate the quality of well water for its physical and chemical characteristics in the municipality of Pobè. Methodology and Results: The study conducted from June 2012 to March 2013 measured in fifteen wells the level of physical parameters such as pH, electrical conductivity and water temperature as well as the following chemical parameters: bicarbonate (HCO3-), chloride (Cl-), calcium (Ca2+), magnesium (Mg2+), total hardness (TH), ammonium (NH4+), nitrate (NO3-), nitrite (NO2-), sulphate (SO42-), phosphate (PO43-) and fluoride (F-). The annual mean values are compared to standards for drinking water quality. Statistical multivariate analysis including Principal Component Analysis and hierarchical clustering was also applied to all measured parameters. Well water is slightly acidic with an average pH of 5.83 ± 0.6. It is weakly mineralized and slightly hard with an average of 236.62 ± 135.54 FS/cm electrical conductivity and a total hardness of 107.8 ± 40.63 mg/L. Nitrogen pollution is a major indicator of well water quality. This pollution finds expression in high rates of nitrate and ammonium in more than 50 % of the wells. It was observed that electrical conductivity show good positive correlation with pH, NO3-, NO2-, SO42-, TH, Cl-, HCO3- and Ca2+.The typology is mainly governed by the conductivity for classifying the wells according to their physical and chemical quality. Conclusion and applications: Well water is subjected to organic pollution in the municipality of Pobè. This anthropogenic pollution is linked to the infiltration of sewage and chemical fertilizers. The high levels of ammonium and nitrate indicate that the water is chemically unsuitable for human consumption and requires that water in most wells be pretreated.Keywords : Physicochemical, well water, pollution, multivariate analysis, Pobè

Partial replacement of fish meal with Azolla meal in diets for Nile tilapia (Oreochromis niloticus L.) affects growth and whole body fatty acid composition

The replacement of fishmeal (FM) with Azolla meal (AM) in diets on growth and fatty acid in Nile tilapia, Oreochromis niloticus (initial mean weight: 16.4 g) was studied. Fish were fed with six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ.g-1) diets containing 0%, 10%, 20%, 30%, 40% and 50% AM respectively, as partial FM substitute. Diet A0 acted as a control. The final weight (51.0-88.3 g), the weight gain (210.8-438.3%) and the SGR (1.3-1.9%day-1) decreased when AM level higher than 10% in diets (P < 0.05). The FCR (1.44 to 2.35) significantly increased when AM level exceeded 20% (P < 0.05). The protein efficiency ratio and the apparent net protein utilization decreased consequently. The fatty acids in the whole fish were significantly influenced by the diets. The replacement of FM by AM produced fish with lower (n-3) highly unsaturated fatty acids mainly docosahexaenoic acid, and higher arachidonic acid (P < 0.05). The n-3/n-6 fatty acid ratio ranged from 0.08 to 0.17, and was lower in fish fed A40 and A50 (P < 0.05). The findings suggest that high AM in diets affects Nile tilapia growth and the fern could be incorporated in diets up to 30% without any adverse effect on fish fatty acid composition. However, alternative additional source of lipid must be used to improve the quality of fish fed AM-diets.Keywords: Azolla, Fish meal replacement, Growth, Fatty acids, Oreochromis niloticus, bioconversio

Assessing the feasibility of interrupting the transmission of soil-transmitted helminths through mass drug administration: The DeWorm3 cluster randomized trial protocol

DeWorm3 collectionThe file attached is the Published/publisher’s pdf version of the article.© 2018 Ásbjörnsdóttir et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Schistosomiasis and Soil Transmitted Helminths Distribution in Benin: A Baseline Prevalence Survey in 30 Districts

<div><p>In 2013, Benin developed strategies to control neglected tropical diseases and one of the first step was the disease mapping of the entire country in order to identify endemic districts of schistosomiasis and soil transmitted helminths (STH). This study was carried out in 30 of the 77 districts of Benin. Of these 30 districts 22 were previously treated for Lymphatic Filariasis (LF) using the Ivermectin and Albendazole combination. In each district, five schools were selected and 50 children aged 8 to 14 years were sampled in each school, making a total of 250 children sampled in the district. The schools were selected mainly according to their proximity to lakes or any bodies of water that were likely to have been used by the children. Samples of faeces and urine were collected from each pupil. Urinary schistosomiasis was identified using the urine filtration technique while STH and intestinal schistosomiasis were identified through the Kato Katz method. Overall a total of 7500 pupils were surveyed across 150 schools with a gender ratio of 1:1. Hookworm was identified in all 30 districts with a prevalence ranging from 1.2% (95%CI: 0.0–2.5) to 60% (95%CI: 53.9–66.1). <i>Ascaris lumbricoides</i> was detected in 19 districts with a prevalence rate between 1% (95%CI: 0.0–2.2) and 39% (95%CI: 32.9–45.0). In addition to these common STH, <i>Trichuris trichiura</i>, <i>Enterobius vermicularis</i> and <i>Strongyloides stercoralis</i> were found at low prevalence. Only 16 districts were endemic to <i>Schistosoma mansoni</i>, while 29 districts were endemic to <i>S</i>. <i>haematobium</i>. The <i>S</i>. <i>haematobium</i> prevalence ranged from 0.8% (95% CI: 0.0–1.9) to 56% (95% CI: 50.2–62.5) while the prevalence of <i>S</i>. <i>mansoni</i> varied from 0.4% (95%CI: 0.0–1.2) to 46% (95% CI: 39.8–52.2). The 22 districts, where LF was successfully eliminated, still require mass drug administration (MDA) of albendazole indicating that school-based MDA would be needed even after LF elimination in districts co-endemic to LF and STH in Benin.</p></div

Comparison of the average prevalence of <i>S</i>. <i>haematobium</i> in each department.

<p>Comparison of the average prevalence of <i>S</i>. <i>haematobium</i> in each department.</p

Comparison of the average prevalence of Hookworm in each department.

<p>On the chart, the department sharing similar letter are not significantly different. Those sharing different letters indicate a significant difference [p<0.0001]</p

Intensity of urinary and intestinal schistosomiasis infection in districts surveyed.

<p>N: Number of positive samples out the total (250) examined in each commune. For <i>S</i>. <i>haematobium</i> intensity Light: 1–50 eggs/10ml of urine; High: ≥ 50 eggs/10ml of urine For <i>S</i>. <i>mansoni</i> intensity Light: 1-99EPG; Moderate: 100–399 EPG; High: ≥ 400EPG.</p