Composition and dynamic of benthic macroinvertebrates community in semi-arid area rivers of Burkina Faso (West Africa)

The benthic macroinvertebrates communities dynamic were investigated in rivers from Burkina Faso in the purpose to analyze the taxonomic composition, the structure of benthic macroinvertebrates community and the composite environmental variables that correspond to the major distribution patterns of this community. The results showed that a total of 132 taxa was recorded and the large majority of these (103 taxa) belonged to 57 families from 8 orders of insects that represent 95% of relative abundance. We also observed some distinct differences relative to the spatial and temporal variation in the taxonomic composition. The canonical correspondance analysis (CCA) revealed a strong correlationship between Chironomidae, Syrphidae, Culicidae, Psychodidae, as well as the Pulmonates molluscs and organic nutriments feeding dynamics. These findings showed the sensitivity of benthic macroinvertebrates at different level: sensitivity which could be attributable to man-induced activities.© 2016 International Formulae Group. All rights reserved.Keywords: Benthic macroinvertebrates, enviromental variables, dynamic, Burkina Fas

Water Quality and Aquatic Ecosystem Assessment Using Water Quality Indices in West Africa: Challenge and Perspectives

“Water quality is health” as it is said, “water is life.” The water quality and aquatic ecosystem health assessment is essential for early detection of water habitat degradation and overall aquatic ecosystem disturbances. All water management programs/agencies need simple and cheaper tools for water quality assessment. However, in West Africa there is an urgent need of water quality assessment tools, as far they are very limited. This chapter presents water quality indices as simple and cost-effective tool to monitor water quality. We explore the categories of water quality indices (WQIs), their use/application, and their scope in West African countries. We found that some multimetric indices (MMIs) are developed in West Africa, but they are not well known/used by local water managers and decision makers. There are not yet biotic indices (BIs) and physicochemical water quality indices (PCQWIs) typical to Western African countries areas, but most of them are applied/adapted to meet the needs of West African water quality and ecosystem health assessment. In this chapter, we present the results of some studies led in some West African countries regarding water quality indices (MMIs, BIs, PCWQIs), and address challenges and perspectives for long-term management of water and biological resources in developing countries

QUALITÉ ET POLLUTION DES EAUX D’UN HYDROSYSTÈME LITTORAL TROPICAL : CAS DU SYSTÈME LAGUNAIRE DE LOMÉ, TOGO

This study was conducted to evaluate the physicochemical quality and heavy metals (HM) in the water of Lomé lagoon system. The conductivity, pH, nitrogen, phosphorus, organic matter and HM were determined by AFNOR methods. The results showed that the waters of Lomé lagoon system have generally pH close to neutral (pH between 7.34 and 8.5). However, the balance of the water in the equilibrum canal has an acid pH (pH 6.53). The levels of nitrogen and phosphorus are relatively high 1.27 mg/L phosphorus against 0.15 mg/L in natural waters. Dissolved organic matter is higher at the site C4 over the entire lagoon system. The East Lake E3 and E1 sites recorded a high rate of mineralization with 2536 mg/L of dissolved salts. The contents of the major ions such as Ca2+, Na+, K+, Mg2+,Cl-, NO3-, SO42- and HCO3- helped to highlight the nature of brackish water of Lomé lagoon system. The material suspended (77 mg/L) and turbidity (35 NTU) are also very high in the waters of the equilibrium canal. C4 websites, C2, E3, O11, O5 and B3 have recorded the highest levels of HM. This indicates a potential bioavailability of HM in the waters of Lomé lagoon system. The degree of contamination and the interrelationships between the physical and chemical parameters of water and metallic micropollutants were confirmed by Principal Component Analysis (PCA)