Caractérisation physico-chimique et évaluation du risque d’eutrophisation du lac Nokoué (Bénin)

Mama, Daouda; Aïna, Martin Pépin; Alassane, A.; Boukari, OT; Chouti, Waris Kéwouyèmi; Deluchat, Véronique; Bowen, J.; Afouda, Abel; Baudu, Michel

doi:10.4314/ijbcs.v5i5.29

Cited by 26 publications

(30 citation statements)

References 5 publications

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“…This is due to evapotranspiration in the dry season, resulting in a high concentration of nitrates compared to the rainy season. These nitrate contents are similar to those obtained by Mama et al (2011) in Lake Nokoué (Benin). The NH 4+ contents (0 to 0.36 mg / L) were low, they are far lower than those recorded in the Municipal Lake of Yaoundé, a lake qualified as eutrophe (Zébazé Togouet, 2008 and2011).…”

Section: -1-1-physico-chemistry Of the Waters Of Lake Lérésupporting

confidence: 88%

Spatio-temporal dynamics of zooplankton communities (Rotifers, Cladocerans, Copepods) and water quality of Lake Léré (TCHAD)

Tahir¹,

Otchoum²,

Ibrahim³

et al. 2020

IJEAB

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Lake Léré is situated in the Mayo-Kebbi locality southwest of Chad, it is the site for RAMSAR since 2001 hosting manatee (Trichechus senegalensis). This lake has been under study with the aimed of determining the structure of zooplankton community from February 2016 to April 2017. For this study, three sampling stations were chosen and divided into 2 to 3 layers from water surface towards the bottom. A total of 49 zooplanktonic species were identifiedin LakeLéré. This was dominated by Rotifers community with more than 75% (38 species).Rotifers and Copepodsdominated withabundance proportions of 78.10 and 60.04% respectively in the dry season. This was relatively higher compared to the rainy season (21.89 and 39.95%). In the Cladocère communities, a higherabundance was observed in the rainy season of 85.39% and 14.6% in the dry season. Therewere no significant differences between the physicochemical parameters, the sampling stations and between the different sampling levels.Thehigh values of Sorensen similarity index, shows the homogeneity of the waters of the lake and justifies the absence of significant differences in the specific richness between stations. The specific richness of zooplankton community in Lake Léré and its physico-chemical variables lead to a conclusion of the mesotrophic state of the lake's waters.

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Section: -1-1-physico-chemistry Of the Waters Of Lake Lérésupporting

confidence: 88%

Spatio-temporal dynamics of zooplankton communities (Rotifers, Cladocerans, Copepods) and water quality of Lake Léré (TCHAD)

Tahir¹,

Otchoum²,

Ibrahim³

et al. 2020

IJEAB

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“…On the other hand, these values are very low compared to those obtained by Tapsoba et al (2016) with an average value of nitrates (5.3 mg / l) during the various months of their study, also low compared to those found by Mama et al (2011) andSomé et al (2008), which found values of 7 mg / l.…”

Section: Discussioncontrasting

confidence: 47%

Assessment of the pollution in Aghien lagoon and its tributaries (Côte d’Ivoire, West Africa)

Effebi¹,

Adou²,

Koffi³

et al. 2017

Int. J. Bio. Chem. Sci

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The influence of the pollutants in surface water quality when used for drinking water is of great concern in many developing countries. This study seeks to characterize the types of pollution in Aghien lagoon and its tributaries. For the sampling, water was taken at a depth of 50 cm from the earth surface. Samples were analyzed by the spectrometric method of molecular absorption with sulfosalicylic acid for the nitrate, spectrophotometric method of molecular absorption for the nitrites, colorimetric determination with indophenol blue for the ammonium, colorimetric method for the orthophosphates and the phosphorus, filtration method on glass fiber (0.45 μm) for the Suspended Solids (SS), manometric method based on the respirometer principle for the Biochemical Oxygen Demand (BOD 5 ), Dichromate method for the Chemical Oxygen Demand (COD), inductively coupled plasma optical emission spectrometry (ICP-OES) technique for the heavy metals (iron, Manganese), on April and June 2015. The analysis of these physico-chemical parameters revealed that, all the year round, these waters contain real conductivity values comprised between 51 and 161.1 µS/cm, redox potential between 100.3 and 174.4 mV; nitrate between 0.23 and 6.72 mg/L. On the other hand, and over the same period, the waters of the Mé river and the channel had COD values comprised between 33 and 58.7 mg/L. Concerning the Djibi rivers SS were between 36.66 and 50 mg/L, dissolved oxygen between 1.46 and 1.59 mg/L; ammonium between 2.44 and 2.69 mg/L regardless the seasons. The results show that during the two seasons, the Aghien lagoon is the less polluted by the physico-chemical parameters, whereas for the same period, Mé and channel waters are the most charged with organic matters deriving from plants. As for the Djibi river, it remained the most polluted, as certified by the high values in SS and nutrient regardless of the seasons.

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“…En effet, la prolifération des plantes aquatiques est à l'origine de la formation d'un écran en surface des eaux qui empêche l'oxygénation du milieu. De plus la décomposition de ces plantes, induit une augmentation de la quantité de matière organique dans le milieu dont la dégradation favorise l'asphyxie des espèces halieutiques (Mama et al, 2011). La production de sulfure et de nitrite (substances toxiques) inhibent le développement d'autres producteurs primaires et des poissons à grande sensibilité.…”

Section: Discussion Et Conclusionunclassified

Qualité et usages de l'eau de la retenue d'eau de Kogbétohoue, dans la commune d'Aplahoue (Sud-Ouest, Bénin)

et al. 2021

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Abstract. Le comblement et l'eutrophisation des retenues d'eau constituent des contraintes majeures pour les usages qu'en font les populations riveraines. L'étude bathymétrique a révélé une diminution moyenne de 0,116 m/an de la profondeur sur sept (07) ans. Ce niveau élevé de comblement s'explique par l'érosion des terres due à la dégradation du couvert végétal et le surpâturage. Les mesures directes de la qualité physique : le pH, la température et l'oxygène dissous avec le multi paramètre PC HORIBA WATER QUALITY CHECKER U-10; les paramètres chimiques par la méthode chromatographique ICS 1000 et de dosage de la chlorophylle a avec le spectrophotomètre DR 5000 par la Norme AFNOR T90-117 ont permis d'évaluer le risque d'eutrophisation par la grille de diagnostic d'Ifremer (2000). Les eaux sont dans un état eutrophe. Le comblement et l'eutrophisation de la retenue constituent des menaces potentielles à court terme pour la pisciculture, l'irrigation et la consommation tandis que la disponibilité quantitative de la ressource est menacée à moyen terme. Des relevés bathymétriques périodiques et des actions d'aménagement du bassin versant de la retenue sont nécessaires à la gestion intégrée de la retenue d'eau.

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Caractérisation physico-chimique et évaluation du risque d’eutrophisation du lac Nokoué (Bénin)

Cited by 26 publications

References 5 publications

Spatio-temporal dynamics of zooplankton communities (Rotifers, Cladocerans, Copepods) and water quality of Lake Léré (TCHAD)

Spatio-temporal dynamics of zooplankton communities (Rotifers, Cladocerans, Copepods) and water quality of Lake Léré (TCHAD)

Assessment of the pollution in Aghien lagoon and its tributaries (Côte d’Ivoire, West Africa)

Qualité et usages de l'eau de la retenue d'eau de Kogbétohoue, dans la commune d'Aplahoue (Sud-Ouest, Bénin)

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