Thesis and dissertation


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Now showing 1 - 5 of 45
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    Persistent Organic Pollutants in Human Milk From Wesha Coastal Community in Pemba - Tanzania
    (SUZA, 2022-12-01) ADAM, Nahija Haji
    Human milk is considered to be vital for health development of infant as it provide infants with well-balanced nutrition and protection against infectious pathogens. The milk also offers psychological and social benefits to breastfed infants. Being very rich in Lipid fat, various Persistent Organic Pollutants (POPs) dissolve and accumulate in the milk to the level that can pose serious health risks to breast-fed infants. The levels of persistent organic pollutants (POPs) in human milk from Wesha coastal community in Pemba were analyzed using GC-ECD and GC-MS. The determined levels were assessed for their composition, variations and the associated health risks to breast-infants. A total of 31 POPs belonging to organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) categories were identified in the analyzed human milk. OCPs were predominated by DDTs while all PCBs were dominated by ortho-congeners. Composition of DDTs revealed highest contribution of the parent p’p-DDT followed closely by p’p-DDE while HCHs had highest contribution of γ–HCH followed by α-HCH indicating combination of both continuous exposures of new and aged sources of pollutants. The levels of DDTs were much higher than the levels reported elsewhere with the exception of those reported in human milk from South Africa. In contrary, PCBs in this study were much lower than many reported levels from other parts of the world. ΣDDTS and ΣPCBs showed positive association and both of them increased significantly with lipid contents indicating that the two groups of POPs are originated from the same sources of exposure and are highly lipophilic in nature. On the other hand ΣHCHs gave strong negative associations with ΣDDTs and ΣPCBs and decreased with lipid content because of its relatively lower lipophilic nature compared to ΣDDTs and ΣPCBs. In contrary, DDTs and PCBs decreased significantly with lactation period, maternal age and parity whereas the HCHs depicted increased trend with lactation period, maternal age and parity proving that the first-born babies are exposed with the highest pollutant load from their mothers. Health risks assessment using both HQ and HI revealed possibility of potential health hazard to breast-fed infants. The follow-up study focusing on assessment of dietary intake of Wesha community is recommended to reveal the potential sources of POPs exposure in human
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    Evaluation of Biosorption Potentials of Bambara Ground Nut (Vigna Subterranea) and Sour Sop Seeds (Annona Muricata) Powder For The Selected Heavy Metals From Aqueous Solution
    (SUZA, 2022-12-01) MWINYI, Khadija Ali
    Heavy metals have increased a greater consideration to environmental chemists due to their toxic nature. They are persistent in nature and cannot be degraded. Heavy metals can deteriorate the environment resulting in a variety of illness and disorders when entering the living tissue. This study aims at investigating the adsorption capacity of biosorbent (bambara groundnut powder; BGP, and soursop powder; SSSP) on toxic metals from synthetically prepared waste water. The adsorbents were used to examine their respective efficiency on selected metal; cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), and thallium (Tl) from the prepared contaminated water. The samples were analysed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). 0.2 g of (BGP) was added to 50 mL of ultra-pure water. Then separately known concentrations of the analyzed parameter were added to the solution of BGP and SSSP. The results of adsorption efficiency were: 100% each for Cd2+, Tl2+ and Pb2+; 94% for Cu2+; 81% for Zn 2+; 68% for Co2+; 64% for Mn2+; 46% Fe2+; and 07% for In2+ . The results revealed that, the metal ions were removed in the following order: Cd2+ = Tl2+ = Pb2+ ˃ Cu2+ ˃ Zn 2+ ˃ Co2+ ˃ Mn2+ ˃ Fe2+ ˃ In2+ . With the same conditions as applied in bambara ground nut powder the adsorption efficiency of the soursop seed powder were: for 100% for Cd2+; Cu2+; Tl2+and Pb2+; 83% for Zn 2+; 62% for Co2+; 49% for Fe2+; 21% for In2+; and 0% for Mn2+ with an order of (Cd2+ = Cu2+ = Tl2+ = Pb2+) ˃ Zn 2+ ˃ Co2+ ˃ Fe2+ ˃ In2+ ˃ Mn2+ . The analysis showed that both BGP and SSSP have remarkable adsorption capacity on selected metals. Suggestively, the BGP and SSSP are preferable low cost and eco-friendly alternative adsorption materials for toxic metals ions. It is therefore recommended to the society to increase the consumption of bambara ground nut and soursop as well as its seeds being an important way of getting rid of toxic chemicals from the body.
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    Quantification of Lycopene and Β-Carotene in Coloured Sweet Potatoes (Ipomoea Batatas L.) From Donge Zanzibar
    (SUZA, 2022-12-01) MLEKWA, Mosi Juma
    Coloured fruits, vegetables and tuber crops contain important food carotenoids such as lycopene and β-carotene that play significant nutritional values to human body. While lycopene is a well-known antioxidant agent β-carotene is considered as a potential source of vitamin A. It is unfortunate that these crops are neglected and their nutritional values are rarely documented. This study aimed to characterize and quantify lycopene and β-carotene present in available coloured sweet potatoes found in Donge, Zanzibar. The study employed gravitational methods and UV-VIS spectrophotometer techniques to quantify and identify lycopene and β-carotene respectively in the three common sweet potato varieties farmed in Zanzibar to assess their composition and nutritional values. The results revealed presence of maximum peaks for β-carotene and lycopene at wavelength range of 375nm to 475nm. Both lycopene and β-carotene were found in deep orange flesh (Mataya) and light orange flesh (Jowel) varieties while yellow flesh variety contained β-carotene only without lycopene. The levels of carotenoids were significantly higher in deep orange flesh (mean = 3285.45 µg/g) variety followed by light orange (mean = 2811.43 µg/g) and yellow flesh variety (mean 1015.38 µg/g). This carotenoids content trend is directly related to the colour intensity of the sweet potato varieties. Compositional analysis of carotenoids showed slight dominance of lycopene over β-carotene in Deep Orange Flesh and Light Orange Flesh but not in yellow flesh that was entirely dominated by β-carotene only. In general level of carotenoids content reveals the nutritional significant of all three varieties, however the highest levels of both lycopene over β-carotene in deep orange flesh make the varieties more suitable in addressing vitamin A deficiency (VAD) and problem of chronic diseases associated with oxidant stresses
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    Occurrence and Distribution of Antifouling Biocide (Diuron) Along the Coastal Areas of Zanzibar: The Case Study of Unguja Island.
    (SUZA, 2022-12-01) ALI, Fatma Khamis
    Diuron (N-(3,4-dichlorophenyl)-N,N-dimethylurea) is one amongst the booster biocides presented to substitute tributyltin (TBT) as an antifouling agent. It has continued to be used ever since, though little is known about their levels in the maritime setting of Zanzibar. This thesis details the occurrence and distribution of Diuron around the coastline area of Unguja Island. Total of 33 samples from 11 sampling sites with different characteristics and activities such as tourisms, dockyards, fishing, coral reef areas, cargo and passengers‘ ports were collected. Samples were prepared and extracted automatically using Solid Phase Extraction (SPE) technique. Finally, Diuron was analyzed using High Performance Liquid Chromatography HPLC (an Agilent Technologies series 1260 infinity II, USA) equipped with DAD (G1315D). The concentrations of diuron in water ranged from Below Detection Limit (BDL) to 1321ng/L maximum were detected. The average concentration observed in harbor and ports (commercial and fisheries) (mean ± SD) were 1006.67 ± 90.6 ng/L (Malindi), 1321.67 ± 52.3 ng/L (Bwawani), BDL (Mtoni). Average concentration results observed in small isles and sand sandbanks were 263.67 ± 4.0 ng/L (Bawe), 1047.33 ± 45.4 ng/L (Pange), BDL (Kwale). The average concentration observed in coastal area is 449.33 ± 91.2 ng/L (Kizimkazi). Average concentration results from Coral reef islands were 1126.33 ± 31.1 ng/L (Chapwani), 620.33 ± 5.7 ng/L (Mnemba) while the results from Chumbe and Murongo were below detection limit (BDL). Majority of the sites showed higher levels of Diuron above the maximum permissible concentration (MPC) of 430 ng/L as restricted by the Dutch Authorities for marine organisms except Bawe (263.67ng/L). Average concentration between all sites and permissible concentration showed significant difference (p<0.05). In general the results of this study suggest that the long term future studies on the antifouling biocides particularly on long term monitoring, chronic exposure, risk assessment, organisms' responses and pollution models would add special value towards better understanding the mechanisms and sustainable marine ecosystem health.
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    Characterization and Identification of Salinity Sources in Groundwater of Some Areas of Zanzibar
    (SUZA, 2022-12-01) ALI, Neema Ashkina
    The coastal areas of Zanzibar are mostly vulnerable to elevated groundwater salinization. The groundwater salinity could be associated with cardiovascular diseases and gestational hypertension. The current study was aimed to characterize and identify the groundwater salinity sources at urban Unguja selected areas. These areas were Mjimkongwe, Chukwani, Magomeni and Bububu. The samples of groundwater were collected in 500 ml new plastic bottles. The chemical analysis was performed using Atomic Absorption Spectroscopy (AAS) for Na+ , K+ and Al3+ , UV- spectrophotometer for SO4 2- , Iron meter for NO3 -and F- where by titration for Mg2+, Ca2+, HCO3 - and Cl- . Fourth (40) samples of groundwater were analyzed for salinity, temperature, pH, DO, EC together with cations and anions that mentioned above. Groundwater types through piper diagram were determined as Na-HCO3, Na-Cl, Ca-HCO3, Mg-HCO3, and Ca-Cl whereby more than 45% of all water samples were belongs to Na-Cl water types. Electrical conductivity (EC) values varied from 334μS/cm to 12631μS/cm with an average of 1856.86μS/cm. The concentration of chloride ions was between 56.73mg/L to 3091mg/L with its average of 360.88mg/L. Also high nitrate concentrations were found at Magomeni and Mjimkongwe with its mean values of 179.21mg/L and 135.61mg/L respectively. Na/Cl ratio values of Mjimkongwe and Chukwani were closely related to that of seawater (0.86). In addition, the existence of strong correlation of Cl with EC and Na 0.982 and 0.996 respectively. Seawater intrusion is mostly occurred in the groundwater samples from Mjimkongwe and Chukwani. Hence, the origin of groundwater salinization in the study area was recognized to seawater intrusion and nitrate contamination. The results from this research showed that significant quantities required to raising awareness about the health risks. Therefore, it is important to develop inexpensive methods to produce water resources with low salt content in order to control this emerging threat to consumer