Determination of the Levels of Some Heavy Metals in Three Locally Available Commercial Brands of Bottled Orange Juice Obtained from Supermarkets in Harar and Dire Dawa Towns Advisor: Tesfahun Kebede (Ph D) By: Alemayehu Nima ABSTRACT In the present work , the contents of some heavy metals including Zn, Cu, Fe, Cr, Cd and Pb in three Brands of Orange Juice samples obtained from Local supermarkets found in Harar and Dire Dawa Towns were analysed by FAAS after digestion of all samples with optimum amounts of mixtures of concentrated HNO3 and 30%H2O2 solutions. The mean (±SD) concentrations of Zn, Cu, Fe, Cr, Cd and Pb in the analyzed samples were found to be , 2.761±0.056, 2.680±0.061 ,1.730±0.017 , 0.346±0.025 , 0.241±0.031 and 0.463±0.034 ppm, respectively. The values were compared with the WHO Recommended Dietary Allowance (RDA) as well as with values reported in the available literature for the same metals on similar studies heavy metal contents of fruit juice. The concentrations of some of the heavy metals found in orange juice were above the safe limit recommended by WHO. The recoveries of metals were in the range 86% - 100%. And the relative standard deviations for most metals in the samples were less than 10%. A statistical analysis of variance (ANOVA) at 95% confidence level was used to test whether the variation between the mineral content of three sample means were significant or not. Key Words: Orange juice, FAAS, Heavy Metals, Dietary Intake, Toxicity of Heavy Metal
Abstract: This study demonstrated the application of biomaterial for the removal of hexavalent chromium (Cr(VI)).in the primary work of this study; the determination of Cr(VI) in an aqueous solution was conducted by direct UV-visible spectro-photometry. The effects of different parameters such as pH, contact time, adsorbent dose and initial concentration of an adsorbate on the adsorption of Cr(VI) were investigated. Equilibrium isotherm data were analyzed and indicated that adsorption process favored on Langmuir isotherm model. The adsorption kinetic data were described very well by the pseudo-second order model. The adsorption efficiency of biosorbent lignin on to Cr(VI) was found to be 99.23%. Therefore, lignin, which is an ecofriendly, low cost and ease of access adsorbent is expected to be feasible adsorbent for the removal of Cr(VI). Keywords: determination, hexavalent chromium, Adsorption, Lignin
Abstract The aim of this study was to analyse the distribution and abundance of benthic macroinvertebrates in the Upper Awash River. The study was conducted for three months from January 2018 to March2018, and macroinvertebrates were collected from five sites using a standard hand net. Physicochemical parameters that can affect the distribution and abundance of benthic macroinvertebrates due to water pollution were measured and analysed. A total of 14,465 individuals belonging to 33 families of aquatic insects, 5 families of the non-insect group were identified. Among all taxa, Diptera was the most abundant and diversified animals in the study area. Macroinvertebrates among the five sites showed variation in species richness, evenness and Shannon Diversity Index. The highly impacted downstream site (UAW4) had the relatively highest H-FBI index (5.15), followed by UAW5 (5.08) indicating that UAW4 and UAW5 were poorer in benthic faunal diversity than other sites. In addition, as habitat and water quality degradation increased, the number and percentage of Ephemeroptera, Plecoptera, and Trichoptera (EPT) decreased. Furthermore, as perturbation increased, species diversity, ETHbios index, Average Score per Taxon , and family richness were decreased, while the percentage of Chironomidae, Diptera, Dominant Taxa and Hilsenhoff Family-Level Biotic Index were increased indicating that tolerant species become abundant in UAW4 and UAW5. Based on the current study, we recommend that sustainable management of the Upper Awash River by environmental protection agencies of governmental and non-governmental organizations should take strict remedy to tackle anthropogenic activities resulting in water pollution.