No abstract

The study investigates the seasonal and spatial variations in water quality parameters at four different locations along Potou lagoon for seventeen consecutive months. In order to explore spatial variation among different stations and seasonal changes, no parametric test of ANOVA was used to compare the mean values of the tested parameters for all the different sampling sites and seasons. Seasonal observations on water quality parameters and chlorophyll-a in Potou coastal lagoon revealed that the coastal water was significantly influenced by freshwater during the long and short rainy seasons. The seasonal significant variation (p < 0.05) was generally recorded between the long dry season and the short rainy season. Temperature, salinity, pH, dissolved oxygen, transparency and chlorophyll-a increased during the long dry season, whereas, the concentration of nutrients (nitrite, nitrate, ammonium and soluble reactive phosphorus) increased in the rainy periods. Contrary to the seasonal variation, a spatial homogeneity (horizontal) was registered for all variables, a condition related to the low human occupation in the lagoon watershed. Comparing this study with others conducted in Potou lagoon in 2008, no critical differences that evidence alteration in the water quality were found.

No abstract

Ultraviolet absorption at 254 nm (UV 254 ) and peaks (A, C and T) fluorescence intensities were evaluated to assess dissolved organic carbon (DOC) removal during coagulation-flocculation. The consistency of fluorescence data was checked to ensure that no inner filter effect, quenching or enhanced intensities affected the data. The decreases in UV 254 and peak intensities were calculated in percentage terms between raw and clarified water and compared with measured DOC removal. The results indicate that peak A, peak C, peak T and UV 254 exhibit strong linear relationships (R 2 : 0.91, 0.89, 0.92 and 0.99, respectively) with DOC removal, implying that these parameters are useful indicators of DOC removal.

The aim of this paper is to highlight the impact of anthropization on the runoff Djibi and Bete rivers, tributaries of the Ivorian Aghien watershed. The classification method with the maximum likelihood used to the diachronic study of satellite imagery Landsat Thematic Mapper (1987), Enhance Thematic Mapper Plus (2000) and Operational Land Imager (2015) and Geographic Information System remote sensing has been applied. It has permitted to note the total disappearance of the forest at risk of subsistence crops, fallows, habitats and bare soils. The forest area that was 4 ha in 1987 for the Bete Watershed has been destroyed entirely. This change in the land cover between 1987 and 2015 had considerable consequencies on the