Chemical and biological assessment for Egyptian surface freshwater environment with reference to human activities

The Egyptian freshwater was assessed in the River Nile, branches, main canals and certain drainages in eight Governorates, over eight successive seasons starting from spring 2008. Chemical assessment was made through ten parameters and the biological one was made through macro-invertebrates information. Results showed that means of Cd, Pb, Cu, Hg, Mn, Fe, Ni, Na, K and Ca varied in watercourses seasonally within somewhat narrow ranges, which may exceed the level of concern but with some elevations in branches, Rayahs and canals during certain seasons. Sites showed chemical levels over the permissible one or those gain total points

Impact of water quality and soils on the molluscicidal activity of the plants A gave attenuata and A gave fihifera

The effect of water quality, salinity, an organic compound [Na[2]EDTA] and soil types [alluvial and sandy] on the molluscicidal activity of the two plants A gave attenuata and A gave filjfera against Biomphalaria alexandrina snails under laboratory conditions were studied. The LC[50] of the two tested plant molluscicides against B. alexandrina in all tested water samples [Nile, irrigation and drainage water] were lower than the tap water [as a control]. Thus, the molluscicidal activity of the two plants slightly increased when tested at the studied water samples. LC[50] values of the plant A. altenuata against B. alexandrina for the Nile water and drainage water were 50 and 54.5 ppm, respectively compared to 68 ppm for tap water. The corresponding values of A. fiIfera were 50, 54.5 and 60 ppm respectively. The molluscicidal activity of the two tested plants was not affected by the salinity levels used. Slight effect of the organic compound Na[2]EDTA on the molluscicidal activity of the two plants was recorded. However, the tested soils [alluvial and sandy] had a significant reduction in molluscicidal activity of A. attenuata and A. filifera against B. alexandrina. Thus, only 20% mortality of treated snails was recorded for LC[50] of A.attenuata in the presence of sandy soil, while no death was observed at alluvial soil. TLC analysis reveled only three bands for A. alt enuata mixed with sandy or alluvial soil compared to 6 bands for the crude plant. For A filifera only two bands appeared by mixing with sandy soil, whereas with alluvial soil no bands appeared