Master of Science in Chemistry

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    Phytochemical Analysis, Antibacterial and Antifungal Activity of Compounds of Alstonia Boonei Stem Bark
    (Kampala International University, 2023-08-03) Ivan, Byaruhanga
    The aim of this study was to investigate the bioactive compounds present in the stem bark of Alstoniaboonei. The plant was selected on the basis of its wide spread use in traditional herbal medicine for the treatment of various ailments like malaria, urinary tract infections, fever, sleeplessness, chronic diarrhea, rheumatic aches and typhoid. The stem bark of Alstoniabooneiplant was collected from Mabira Forest, with the help of a plant taxonomist from the Department of Botany Makerere University. A voucher specimen was deposited at the Herbarium, Department of Botany, Makerere University, for future reference. The collected plant was air-dried under shade, ground into powder and extracted using Dichloromethane:Methanol (1:1) for 24 hours, with occasional stirring, at room temperature. The resulting extract was filtered using cotton wool, followed by Whatman (number 1) filter paper and then dried on a rotatory evaporator to obtain a crude extract. The crude extract was subjected to various chromatographic separations, isolation and purification to yield three pure compounds. Structure elucidation of the isolated pure compounds was achieved by a combination of spectroscopic techniques including 1H NMR, 13C NMR, HMBC, HSQC and COSY. This was done in Germany and the compounds were identified as triterpeneslupeol(1) (3β)-Lup-20(29)-en-3-ol, di-butyl phthalate (2) butyl phthalic acid and β-amyrin ((3beta)-olean-12-en-3-ol) (3). The crude extract and the isolated pure compounds were tested for their antimicrobial properties against Candida albicans,Aspergillusfumigatus, Staphylococcus aureus, Escherichia coli, Enterobacteraerogenes, Pseudomonas aeruginosa and Salmonella enterica. Compounds 1, 2, 3 showed moderate mean zones of inhibition of (8.4±1.2) mm, (5.0±2.5) mmand (8.3±1.4) mm respectively. The crude extract showed very high zones of inhibition of (9.4±0.7) mm. Furthermore, compounds 1and 3 showed high zones of inhibition against Candida Albicans and Arspegillusfumigatus of 12.6±0.2 mm and 12.3±0.7 mm respectively; compound 2 showed moderate mean zone of inhibition of (9±0.4) mm while the crude extract showed the highest zones of inhibition of 13.1±0.2 mm which proves the use of Alstoniaboonei stem bark in treatment of both bacterial and fungal infections. .
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    Assessment of heavy metal pollution in pece channelized stream water Gulu town, northern-Uganda
    (Kampala International University, Colleges of Humanities and Social sciences, 2013-09) Otieno, Ochieng’ Moses
    Water quality monitoring in developing countries is inadequate, especially in stream water affected by urban effluents and runoff. The purpose of this study was to investigate heavy metal contaminants in the Pece Stream water in Gulu Municipality, Northern-Uganda. Water samples were collected along the channel of Pece stream and other samples from Nakaseke River which served as a control site. Selected heavy metals (Zinc, Copper, Lead and Cadmium) were determined using Atomic Absorption Spectrophotometry. Sampling of water was done during the dry and the wet seasons of the years 2011 and 2012, respectively. Physicochemical parameters were also determined for Electrical conductivity, pH, hardness of water, Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD). Results indicate that heavy metal concentrations in Pece stream water were significant. The mean concentration of Zinc ranged between 0.64 } 0.0040 and 0.78 } 0.0095. Copper gave mean total concentrations between O.0880 }0.0054mg1’ and 0.0420 }0.0072mg/i during the two consecutive years of the study. All these values obtained for Zn and Cu were within the maximum permissible limits of WHO (2008), NEMA (2006) and USEPA (2005). The total lead concentrations in the samples were <0.003 mg/l, this was below the permissible limits of WHO (2008), NEMA (2006) and FMENV (1991). Cadmium was detected at a very low level in all the samples with the highest Mean concentration being 0.005 } 0.002 1 mgl’ and the lowest 0.003 } 0.0002 mgl’ which is below the water quality standards. The average pH of the filtered water samples at 25°C was between 7.04 } 0.0011 and 7.24 } 0.0008. Electric conductivities were comparatively high, with average values ranging between 226.3 } 0.0352 and 232.5 } 0.0048, more than 200-fold that of pure distilled deionised water. The levels of average hardness were between 95.8 } 0.0125 and 103.3 } 0.1106 compared with the FMENV (1991)100 mgl’, WHO (2008)100 mgl’ and USEPA (2005) 100 mgF’ permissible limits. The levels of the Total suspended solids (TSS) were in the range of 0.074 } 0.0051 to 0.077 } 0.0037 mgl’ in the both the wet and dry seasons, these values were within WHO/USEPA, 2005 (0 -5 mgl’) and FMENV, 1991 (30 mgI’) limits. The values of COD ranged from 107.5 } 0.7820 to 134.3 } 4.634 mg (O2)l’ the values obtained were above the maximum permissible limits according to WHO (2008) 10 - 20 mg ’and USEPA (2005)10 Even though the heavy metal pollution were within the maximum permissible limits of NEMA(2004), USEPA (2005), WHO (2008) and FMENV (1991), they are toxic even at very low concentration. Special attention should be paid to mitigate pollution from these sources as their effects may become significant during seasons and years of low water flow in the stream. Therefore, constant monitoring of the Pece stream water quality is needed to record any alteration in the quality and mitigate outbreak of health disorders and the detrimental impacts on the aquatic ecosystem.
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    Assessment of heavy metal concentrations in food crops from Pece wet land in Gulu Township, Northern Uganda
    (Kampala International University, School of Engineering Science, 2013-11) Twinamatsiko, Richard
    The present study is aimed at assessing the concentrations of heavy metals in food crops from pece wet land Gulu town ship. The study investigated heavy metals which include Copper, Zinc, Lead, and Cadmium in the soil and in selected crops which were banana fruit, sugar cane, coco yam and green vegetables (Amaranthus dubius). Metals are essential for maintaining human health throughout life however, at high concentrations they become poisonous. In Gulu town ship, waste disposal and management is still a challenge, wastes are dumped anywhere and when it rains they are taken by runoffs into pece wet land which is also used as a dumping site and on the other hand utilized for agriculture. Intake of heavy metal contaminated crops may pose a risk to the human health. Plants take in minerals from soil media or air through their roots or foliage. Understanding the distribution of some trace metals in some common food crops is important for establishing baseline concentrations from which anthropogenic effects can be measured. This will provide a basis for encouraging people to undertake proper care in the handling and disposal of solid wastes in addition to providing analytical data for further research. Soil and plant samples were collected from Pece wet land Gulu Township which was used as a dumping site and other samples from Katikamwe wet land in Bushenyi district which served as a control site. The samples from both sites were transported to the laboratory well prepared, soil parameters pH and electrical conductivity determined using a pH meter and a conductivity meter bridge respectively Samples were digested using acids and the concentrations of heavy metals Cadmium, Copper, Lead and Zinc determined using Atomic Absorption Spectrophotometer. The results showed that the soils in municipal waste dump sites are higher in heavy metals: Cd (1.35 ± 0.44)mg/kg, Cu (36.23 ± 4.04)mg/kg, Pb (46.23 ± 1.68) mg/kg and Zn (151.36 ± 2.22)mg/kg compared to those of the control site Cd (0.65 ± 0.0l)mg/kg, Cu (18.22 ± 3.22)mg/kg, Pb (12.56 + 3.36)mg/kg, and Zn (7.50 ± 2.76)mg/kg, suggesting possible mobility of metals from dumpsites to farmlands through leaching and runoffs. Soils from Gulu town ship had higher pH and EC values than the control site 6.35±0.07 compared to 5.47±0.09 and 167 ± 6 compared to 143 ± 3 respectively.
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    Toxicological studies on organic manures derived from municipal solid waste in Makindye, Rubaga and Kawempe divisions of Kampala, Uganda
    (Kampala International University, School of Engineering, 2019-04) Bello, Imrana
    The study was carried out to estimate the levels of contamination and marketability of organic compost manures, derived from Kampala municipal solid wastes (MSW), sold along roads in the various suburbs of Kampala. The organic composts were sampled from five locations: Kawempe (KWP); Bwaise (BWS); Kitebi (KTB); Wankulukuku (WKK) and Ggaba-Kansanga (GGK~. The overall quality of the compost manures was determined by investigating selected physicochemical, trace metals and fertilizing properties, via standard methods. The pH of the manure was found to be within the range of 5.27-8.30. The electrical conductivity (EC) of manure samples ranged from 3.07 to 7.13 ~is/c1m A strong negative correlation was found between pH and both EC and trace metals in such manures. The study was found out that, apart from Cu and Zn which were within the permissible limits, the concentration of Pb, Cd, and Cr in all five areas were higher than the permissible limits set by UNBS, 2017. The results of ANOVA (F: 5, 0.05) showed that the there was significant difference in the manure samples collected from the various locations (p < 0.05). The study results indicated that majority of these manures had medium fertilizing potential but did not meet certain control guidelines set by standard agencies and may pose specific risks to the environment. Composts of KTB, BWS, KWP, GKK and were of medium quality (Class D) and had medium fertilizing potential. They could be conveniently applied in small scale farms and gardens. However, WKK, which did not comply for heavy metals should not be allowed into the market. It may only be used for developing lawns/gardens (with single application) or for the rehabilitation of degraded land. Post-treatment of these compost manures was recommended to improve their quality before being utilized for agricultural purposes.
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    Potentially toxic elements in food crops grown on urban waste dump-sites: a case study of Wakaliga Dump-site, Kampala City, Uganda
    (Kampala International University, School of Engineering and Applied Science, 2018-06) Nura, Tasiu
    This study aimed at investigating the seasonal variation in the levels of contamination in soils, food crops, and domestic spring water samples from Wakaliga dumpsite in Kampala. Potentially Toxic Elements (PTE) and physicochemical properties were analyzed during the dry season (May-July 2017) and the wet season (September-November 2017) and the results compared to standard limits set by international and local agencies. The results obtained indicated that some of the elements were found in concentration levels within permissible limits, while others were above permissible set limits in the soil, crops and domestic (spring) water samples. Zinc maximum levels of 3.41±0.01 mg/kg and 3.3 1±0.04 mg/kg d.w. were found in dry-season picked spinach and sugarcane, respectively, while the lowest concentrations of 0.98±0.02 mg/kg d.w. were found in wet-season cocoyam. Copper was found to exist below permissible limits for all the crops, soil and water; concentrations of lead in spinach were found to be within a permissible limit 2.31±0.005 mg/kg d.w. while all the others were below the permissible limits. Negligible amounts of cadmium were found in all the samples. All the soil samples indicated results below permissible levels of toxic metals in the arable soils as indicated by ‘~ATHO (1996). The physiochemical parameters were all within acceptable limits for drinking water, as set by WHO and NEMA; Cadmium was not detected in the domestic water. The findings of this research indicated the presence of potentially toxic elements whose levels could be on the increase and found out that zinc concentrations were higher in both crops and soil for both the two harvesting seasons. This was followed by lead, which is attributable to the availability of discarded substances containing these elements in the environment. Proper waste management, control and disposal methods should be put in place to minimize exposure of toxic containing substances into the environment.