Approvisionnement en eau et risques sanitaires dans le bassin versant amont de l’Abiergué à Yaoundé (Cameroun)

La santé des populations dépend de la qualité de l’eau et des aliments qu’elles consomment. En milieu urbain, notamment dans les quartiers précaires des pays en développement où l’accès à la ressource en eau demeure difficile, les eaux consommées ne sont pas toujours de bonne qualité à cause de leur contamination par diverses sources de pollution. Cette situation expose les populations aux maladies hydriques. L’objectif de cet article est de montrer l’impact des différents modes d’approvisionnement en eau sur la santé des populations du bassin versant amont de l’abiergué. La méthodologie adoptée était basée sur la revue de littérature, l’observation participante, les entretiens semi-structurés, les enquêtes par questionnaires puis les analyses physicochimiques et bactériologiques. La recherche documentaire a consisté à collecter un certain nombre de données qualitatives sur le sujet en consultant divers documents sur internet et certains ouvrages (mémoires, thèses, etc.) sur cette thématique. Par ailleurs, les autres méthodes utilisées, nous ont permis de collecter des données quantitatives et qualitatives sur les modes d’approvisionnement en eau, l’usage desressources en eau, la gestion des eaux usées et des déchets, etc. En parallèle, des analyses physico-chimiques et bactériologiques ont été effectuées dans trois types d’ouvrages d’approvisionnement en eau. Les résultats obtenus indiquent que les populations des quartiers étudiés s’approvisionnent essentiellement au niveau des puits (n=136), sources (n=7) et bornes fontaines (n=8) se trouvant à proximité des latrines, des ordures ménagères et des eaux usées susceptibles de les polluer. Les paramètres physico-chimiques (pH, nitrate, température et conductivité) des eaux prélevées dans la zone d’étude ne respectent pas totalement les normes camerounaises, françaises et de l’OMS relatives à la potabilité de l’eau. De plus, les résultats des analyses bactériologiques montrent une concentration élevée des coliformes fécaux dans les eaux collectées (237 UFC/100 ml pour les eaux du puits sommaire de Melen 7A ; 57 UFC/100 ml pour les eaux du puits amélioré de Melen 9 ; 38 UFC/100 ml pour les eaux de la source aménagée de Melen 6). De même, les résultats obtenus révèlent une forte concentration des streptocoques fécaux dans les eaux de la zone d’étude (11 UFC/100 ml pour les eaux de source aménagée de Melen 6 ; 6 UFC/100 ml pour les eaux du puits sommaire de Melen 7A et 9 UFC/100 ml pour les eaux du puits amélioré de Melen 9). Au regard de ces résultats, il ressort que les eaux de la zone d’étude sont impropres à la consommation et susceptibles de nuire à la santé humaine. The health of the population depends on water quality and food they consume. Dwellers living in slums of urban areas in developing countries have difficult access to water resources. Water is contaminated by diverse sources of pollution which reduces its quality. This situation exposes the population to waterborne diseases. The objective of this article is to show case the impacts of different water provision modes on the health of the population in the upstream of Abiergué drainage basin. The literature review, participatory observation, semi structured interviews, questionnaire survey, physicochemical and bacterial analysis constituted the methodological base of this study. The documentary research permitted this study to obtain qualitative data from diverse documents consulted (memoires, theses, etc). Other methods utilized permitted this study to collect quantitative and qualitative data on different modes of water provision, water usages, management of waste and used water. Moreover, physico-chemical analysis were carried out on three different water provision sources. The results obtained showed that the population ofstudy districts, are essentially supplied by wells(n=136), springs (n=7), bore holes (n=8) that are closer to toilets, household waste and used water susceptible of polluting them. Physico-chemical parameters(pH, nitrate, temperature and conductivity) of water samples taken from the study area show that they do not respect Cameroonian, French, and WHO norms on potable water. Bacterial analysis attest that there is high concentration of fecal coliforms collected (237 UFC/100 ml for rudimentary wells of Melen 7A; 57 UFC/100 ml for ameliorated wells of Melen 9; 38 UFC/100 ml for good springs of Melen 6).In the same vain, the results obtained shows a high concentration of fecal streptococcus in waters of the study area (11UFC/100 ml for good springs of Melen 6; 6 UFC/100 for rudimentary wells of Melen 7A and 9 UFC/100 ml for ameliorated wells of Melen 9). Conclusively, these results show that water sources found in the study area are not good for consumption and susceptible to cause health problems

Outil d'aide au choix de procédés d'épuration des eaux usées en milieu isolé

International audienceDans les refuges et les restaurants d'altitude en Haute-Savoie (France), l'épuration des eaux usées est rendue difficile par les contraintes extrêmes de climat, d'accessibilité et d'irrégularité d'usage. Une enquête sur les habitats présents au sein des réserves a montré que les ! sont mal équipés. Généralement situés en amont de captage d'eaux potables et dans une montagne sensible à l'eutrophisation, les risques lors de rejet d'eaux non traités sont indéniables. La directive cadre sur l'eau de 2000, traduite en 2006 par la loi sur les eaux et les milieux aquatiques impose aux propriétaires d'habitats non raccordés au réseau public d'assainissement de mettre avant le 31 décembre 2012 un système d'assainissement effectuant la collecte, le prétraitement, l'épuration et l'infiltration des eaux usées domestiques. Pour répondre à ces objectifs, une méthodologie d'aide aux choix de système d'assainissement pour les habitats de montagne a été rédigée. Elle permet selon le confort de l'habitat, le niveau de contraintes du site, la surface disponible, le contexte hydrogéologique, de choisir les filières de traitement adaptées. La méthode a été validée sur deux sites test présents dans le massif du Mont Blanc. Le refuge de Tré la Tête, à 1970 m et d'une capacité de 40 personnes qui est représentatif de la majorité des refuges de Haute-Savoie en terme de contraintes climatiques (80 % des refuges de Haute-Savoie sont en dessous 2 200m) et de type d'habitat (75 % des refuges de Haute-Savoie ont une capacité d'accueil inférieure à 50). Le refuge des Conscrits, à 2 600 m, équipé depuis 1999 d'un système complet d'assainissement, a également été choisi compte tenu de ces problèmes d'optimisation de procédés. Ce guide de choix permet soit de choisir un procédé, soit de vérifier la cohérence de l'existant. Il permet de sélectionner un ensemble de filières s'adaptant aux spécificités d'un refuge. Ce guide est destiné aux habitations montagnardes à vocation touristique (refuges, restaurants d'altitude) mais peut également être utilisé par des groupements de chalet d'alpage

Impact of the urban development of the Mingoa River watershed on the Municipal Lake of Yaoundé, Cameroon

10 p.International audienceCurrently, Africa is the less urbanized region in the world. But that trend will change by 2020. Their urban development and globalization have promoted developed countries lifestyle, despite poverty. That means the use of chemicals. Sanitation issues have led to the discharge of untreated wastewater, and as a result, to the emission of persistent pollutants, harmful for human health and for the aquatic environment. Chemicals leading role in economy and in the improvement of life quality has to be weight against their potential negative impacts. The risk represented by these impacts makes chemicals management, an issue of sustainable development. According to a UNEP report, that topic is little documented in Africa. Our work aims at reconstructing an historical link between the urban development of the Mingoa River watershed and the Municipal Lake organic pollution. Thus, we are going to examine the sedimentary compartment using pollutants as tracers. Given that we have not started yet the laboratory work, this article is an introduction to the study

Water supply, sanitation and health risks in Douala, Cameroon

With a view to contribute to the hygiene condition and improvement in the urban zones of Cameroon, a survey was carried out in March 2007 among 1400  households with respect to the water supply, sanitation and health risks in seven quarters of spontaneous habitat of Douala town. It results from this study that the majority of participants were married (76%). The populations are supplied with of  water especially by CAMWATER network (49% of households) and wells (50% of  households). The majority of participants evacuate solid waste in public refuse vats (56% of households). Household’s wastewater is especially discharged around the houses (21% of households) and in rivers (20% of households). The companies  present in the quarters discharge their wastewater in the drains. 52% of households deposit their excrements in latrines. We noticed in these quarters a prevalence of residences made out of hard materials (43% of households). Cholera (88.5% of households), Diarrhoea (70% of households), Dysenteries (74% of households), Typhoid fever (72% of households), Malaria (32% of households) and skin diseases (76% of households) were the most frequent diseases. These results highlight problems for which, it would firstly be necessary to attack in the research of the  improvement strategies for hygiene conditions in the populations of an urban  environment.Key words: Environment, sanitation, water, diseases, Douala

Water supply, sanitation and health risks in Yaounde, Cameroon

Population growth and rapid urbanization in Cameroon have led to major demographic changes in the urban centres, potentially resulting in serious environmental problems in the most populated cities such as Yaounde. In order to better understand the impacts on the hygiene conditions in certain quarters of this political capital, we carried out in March 2007, an investigation on the difficulties of water supply, sanitation and health problems. The investigation involved 1397 households distributed among 7 quarters with informal settlements. 17% of households only had a private connection to national company of drinking water distribution (CAMWATER) because of the lack of infrastructure and the high cost of the connection. The households which are unable to afford the cost of getting connected to CAMWATER network, exploit water from CAMWATER public paying fountain (56% of households), wells (17% of households), springs (4% of households), bore-holes (0.07% of household) and rivers (0.001% of household) to satisfy their needs. The majority of these water points (wells, springs and rivers) could be polluted, because of the informal nature of settlements which leads to proximity of habitats to latrines and to points of discharge of waste (solid and liquids). The health problems issuing probably from these potential polluted water points which at times occur as stagnant ponds around the dwellings is shown by the population of the zone of study in particular cases of malaria (100% of households), diarrhoea (24% of household), dysentery (24% of household), typhoid (0.07% of household), skin disease (0.07% of households). These results highlight the problems to which the authorities in charge of the environment and health must first bring a solution in a context to fight against poverty in Cameroon.Key words: Environment, cleansing, drinking water, peri-urban zone, Yaounde

Charge parasitaire des eaux usées brutes de la ville de Kénitra (Maroc)

Parasitic load of rough wastewater in the Kenitra city, (Morocco)Like the majority of Moroccan cities, Kenitra is confronted with problems concerning the wastewater management and protection of the quality of water resources (Sebou estuary, Maamora wetland and lake Fouarat). Indeed, a great part of wastewater is released into the estuary of Sebou, in the neighborhood of the Saknia popular districts.In this present work charged to evaluate the parasitic load of roughwastewater of three collectors of the city in relation to the demographicand socio-economic profile of the populations connected to thesecollectors, our results highlighted a diversity of parasites in the form ofeggs of helminths with following average concentrations: Ascaris sp.(13,68 eggs/L), Trichuris sp. (3,84 eggs/L), Enterobius vermicularis (0,60 eggs/L), Ankylostome sp. (2,51 eggs/L), Nematodirus sp. (0,88 eggs/L), Hymenolepis nana (1,96 eggs/L), Moniezia expansa (2,46 eggs/L) and Taenia sp. (1,81 eggs/L). The distribution of parasitic eggs of helminths varied according to the size of the urban centres and the socio-economic level of the urban  populations connected to each collector. This study also highlighted the qualitative and quantitative seasonal variations of eggs of helminths in wastewater of the different collectors of the Kenitra city

Groundwater flow modelling in the upper Anga’a river watershed, Yaounde, Cameroon

The Anga’a River watershed is located within the Yaounde IV district, South-east of Yaounde City, Cameroon. The groundwater flow and particle tracking modelling was carried out to determine in detail the groundwater flow and particle migration in the shallow unconfined aquifer of the Upper Anga’a river watershed. The watershed was modelled with a grid of 106 columns x 68 rows with two layers viz., unconfined and semi-confined aquifers extending up to 50 m depth. The Anga’a river traverses in the central part of the watershed and generally flows North-South. Lateral inflows and outflows were simulated with constant head. The Anga’a river heads and the Lake levels were simulated using a river package. Natural recharge due to rainfall formed the main input to the aquifer system and the output was made of abstraction from pumping wells, base flow to Anga’a River, lake, springs and Evapotranspiration. A steady state groundwater flow simulation was carried out using Visual MODFLOW software and calibrated for the February, 2008 groundwater levels at 18 observation wells. The model computation has converged after 170 iterations with a convergence criterion of 0.01 m. The computed groundwater level contours have been following the trend of observed ones. The computed groundwater balance indicated that the Anga’a river base flows come from the groundwater regime. Groundwater Flow model results indicated that the topography controls groundwater flow in the watershed and that base flow to river is an important factor moderating groundwater movement in the Anga’a river watershed