College of Natural and Computational Sciences

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The College of Natural and Computational Sciences advances education, research, and innovation in natural sciences, mathematics, statistics, and computational disciplines.

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Subject: search.filters.subject.Heavy metal

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    ATOMIC ABSORPTION SPECTROSCOPIC ANALYSIS OF HEAVY METAL CONTENTS OF MALT BEVERAGES CONSUMED IN ETHIOPIA
    (HAWASSA UNIVERSITY, 2024-06) MARISHET TESSEMA TAMIRU
    This study was designed to detect the levels of some heavy metals such as, nickel, cobalt, chromium, lead, and copper in five different brands of malt beverages commonly consumed in Ethiopia (Sinq, Sofi, Nigus, Malta Guinness and Bertat), using flame atomic absorption spectrometry (FAAS). The heavy metal contents obtained using FAAS shows slight differences among the five malt beverages. Generally in all brands of malt beverages, the concentration of Cu is the highest and Ni has the lowest concentrations. The order of abundance of these heavy metals is: Cu > Co > Cr > Ni. The levels of Ni and Cr show very small variations among the different brands of malt beverages. On the other hand, concentrations determined for Cu, Co shows slightly higher variations among the different brands. The level of Cobalt (Co) concentrations are in the range between 0.048 mg/L and 0.073 mg/L, which is above the maximum limit that has set by WHO (0.01 mg/L) in five malt beverages. The Ni level obtained in the beverages range between 0.015 mg/L and 0.029 mg/L, which is above the maximum limit set by WHO (0.02 mg/L) except the Bertat that has concentration range 0.015mg/L. The concentration of Cu is in the range from 0.4 mg/L to 0.68 mg/L, while the maximum allowed value set by WHO has 2.0. Therefore the levels of Cu in all the samples are within the acceptable limit. The level of Cr in the samples range between 0.032 and 0.047 which is again below the maximum allowed limit set by WHO (0.05 mg/L). In all samples, the level of Pb is below the detection limit of the instrument. In general, few malt drinks, the level of some heavy metals are slightly above the maximum limit set by the national and international organizations. Therefore, I suggested that malt beverage producing companies should pay attention to continuous monitoring of the sources of these heavy metals in malt beverages. The experimental results are validated in terms of accuracy, precession, linearity and method of detection limit. The accuracy was determined by spiking experiment and an accepted percentage recovery was obtained in the range of 97%-98%.
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    INVESTIGATION OF LEVELS OF SOME HEAVY METAL PRESENTS IN LIVESTIKE‟S WATER AND RAW MILK IN EAST GUJI ZONE, ETHIOPIA USING ATOMIC ABSORPTION SPECTROSCOPY
    (HAWASSA UNIVERSITY, 2024-10) DEBELE NEDI AREDO
    In this work heavy metal concentration in row cow milk and live stock water in east Guji Zone were studied using FAAS. The Raw Cow’s milk and water were collected from six farms of Liben bulb, Liben, mugayo, Goro Dola Daraara, Goro Dola Haraqalo and, Wadera Lagu, Wadera Calo site Guji zone, Ethiopia and HNO3 was used in the optimal microwave digestion process to break down the milk and water samples. The heavy metal contents obtained using FAAS show slight different among six samples in cow milk and water. The concentration of Pb, Ni, Co, Cr and Cu were determined by using AAS. Pb, Ni, Co, Cr, and Cu were found in every sample of milk and water. The concentration of Pb, Ni, Co, Cr and Cu, 0.046 - 0.084 mg\L , 0.17 - 0.245, 0.0035 -0.097mg\L, 0.045 - 0.104 mg and 0.161 -0.473 mg\Lin milk and WHO of the above elements 0.04, 0.07, 0.05),0.05,2.0)in cow milk and the concentration of Pb ,Ni,Cr,Cu andCu,0.034- 0.084mg\L,0.134-0.344,0.034-0.295,0.045-0.104and0.026-0.094in water and The WHO above element, 0.01, 0.02, 2.0, 0.05, and 0.05 in water. The concentration Cu and Ni are more than Co, Cr, and Pb in both milk and water, concentrations are generally the lowest in milk and water.
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    REMOVAL OF SELECTED TRACE METALS FROM WASTE WATER USING SOURSOP (ANNONA MURICATA L.) SEED
    (Hawassa University, 2025-03) WONDIMAGEGN BIRHANU
    The effective removal of heavy metals from industrial wastewater is among the most important issues for many industrialized countries. Removal of lead (II), nickel (Ni) and copper (II) from aqueous solutions were studied using adsorbent prepared from soursop (annonamuricata l. Seed. The surface groups present on the adsorbrnt surface were determined by the Fourier Transform Infrared Spectroscopy (FTIR) analysis. Batch adsorption experiments were performed as a function of pH, contact time, initial concentration, temperature and adsorbent dose. The optimum pH required for maximum adsorption was found to be 6,6 and 5 for lead (II), nickel (Ni) and copper (II) respectively. The maximum contact time for the equilibrium condition is 90 min at the sorbent dose rate of 0.16 g. The maximum efficiencies of lead, Nickel and copper removal by adsorbent were 92%, 93 % and 94 %, respectively. Thermodynamic investigation stated endothermic and spontaneous nature of the system with the participation of a chemical adsorption process. Equilibrium data were represented better by the Freundlich model than the Langmuir model by which describes multilayer adsorptions. The linear regression analysis of kinetic data confirmed that pseudo-second order rate expression.
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    THE EFFECT OF IRRIGATION AROUND ZIWAY ON HEAVY METAL CONTENT OF MAIZE GRAIN AND SOIL
    (Hawassa University, 2024-11) SILESHI TEFERRA
    The aim of the current study was to determine the metallic concentration of maize of irrigated versus rain fed and soil of irrigated versus rain fed and the water used for irrigation. This is to investigate the influence of irrigation on the concentration of heavy metals in the maize grains and soil. This was done by comparing with rain fed farms. The concentrations of copper (Cu), zinc (Zn), chromium (Cr), nickel (Ni), and lead (Pb) in acid digested sample were determined using flame atomic absorption spectrometry. A composite purposive sampling method was used to collect samples from sample site of ziway city, Ethiopia. Microsoft Excel was used for Descriptive statistical analysis of the results and one way ANOVA was employed to compare the mean difference of heavy metals concentration between irrigated and rain fed. In maize samples (rain fed and irrigated maize) the mean concentrations of Pb, Cr, Ni, Cu and Zn were (0.42 – 1.25) for rain fed and irrigate maize, (not detected (nd) – 0.42) for rain fed and irrigated maize, (0.62 –0.93) for rain fed and irrigated maize, (10.8 – 12.3) for rain fed and irrigated maize and (20.23 – 24.3) for rain fed and irrigated maize. In soil samples mean concentration of Pb, Cr, Ni, Cu and Zn were in the range of (9.46 – 12.36) for rain fed and irrigated, (4.4 – 5.36) for rain fed and irrigated, (4.3 – 6.4) for rain fed and irrigated, (56.4 – 66.3) for rain fed and irrigated and (74.26 – 86. 35) for rain fed and irrigated. The mean concentrations of metals in water used for irrigation were (mg/L) of Pb (0.24), Cr (0.065), Ni (0.051), Cu (1.23) and Zn (0.92) in the irrigated water samples were above the limit set by US EPA (2004). The study show that irrigated (maize and soil) contained higher concentration of heavy metals and were above the limit set by US EPA which show that it was contaminated and would be unsave for human consumption.
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    DETERMINATION OF SELECTED HEAVY METALS (Cu, Cr, Pb. Ni, Mn AND Co) IN SOIL SAMPLES AROUND MIDROC GOLD MINING IN SHAKISO DISTRICT, GUJI ZONE, OROMIA REGION ETHIOPIA.
    (2025-06) DEJENE GENENE ASHENAFI
    Soil supports all terrestrial life, and it is a medium in which nearly all food-producing crops grow. However, soil pollution, mainly due to anthropogenic origin, is a significant problem worldwide, affecting soil fertility, plant growth, and human health. Heavy metal contamination of soils is mostly due to mining and smelting of metal ores. Therefore, in this study, soil samples were taken from three sampling sites, such as Dadola, Reji, and Legedembi, around the MIDROC gold mining company to assess the levels of heavy metal contamination of the sampling sites. The soils samples (0 to 15 cm deep) were collected from across 9 sites within three selected areas by using stainless steel applying a random sampling technique. After proper samples pretreatment of dried, crushed and homogenized, known weight of Soils sample was wet digested using 3:2mL of HNO3, of HClO4 for 2:00 hr at 250 oC and Soil samples were prepared through an optimized wet digestion procedure is a material to ensure safety and accurany., and the concentrations of the selected heavy metals (Cu, Cr, Co, Pb, Mn, and Ni) were determined by using FAAS. All these heavy metals statically analyzed by using one way ANOVA are significantly difference (p<0.05). The average concentrations of the heavy metals were found to be in the range of Cu (161.5–312) mg/kg, Cr (127–276.66) mg/kg, Mn (446.27–644.44) mg/kg, Pb (52–77) mg/kg, Ni (25.5–42.83) mg/kg, and Co (13.18–18) mg/kg. The levels of the heavy metals in the soil samples were found in the decreasing order Mn > Cu > Cr > Pb > Ni > Co, and the concentrations of Cu, Cr, Pb, and Mn were above the WHO-recommended limits. This result showed the sampling sites were polluted with heavy metals, and this could affect soil quality, the environment, and human health. Therefore, the concerned bodies should take necessary measures to reduce the effect of soil pollution from MIDROC gold mining companies in the host community.