Browsing by Author "Spyrou, Nicholas M."

Now showing 1 - 6 of 6
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    Assessment of the Lake Gendabi salt for trace elements and toxic heavy metals by energy dispersive X-ray fluorescence spectrometry
    (Springer Netherlands, 2012-08) Lugendo, Innocent; Mohammed, Najat K.; Mussa, L. M.; Spyrou, Nicholas M.
    This study has analyzed samples of salts from Lake Gendabi, located in the northern part of Tanzania for metal contamination using the EDXRF spectrometry. The aim of the study was to assess the suitability of the salt from Lake Gendabi for human consumption. Seventy-five samples of salt were collected from the Lake Gendabi floor and grouped into five grades (G1, G2, G3, G4 and G5) depending on the position of the salt from the lake shore. In addition to Na and Cl, concentrations of 17 more elements were determined in all five grades of salt. These included seven toxic metals which are Al, Ni, Cr, Cd, Pb as well as Th and U which are both toxic and radioactive. The concentrations of all toxic elements found in the samples were higher than their Maximum tolerable limits set by international organizations. As this salt is used in many parts of Tanzania, it is proposed that the salt should be thoroughly purified before entering the market. Further research to include salt samples from other salt production areas in Tanzania is recommended.
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    The elemental analysis of staple foods for children in Tanzania as a step to the improvement of their nutrition and health
    (Elsevier, 2008) Mohammed, Najat K.; Spyrou, Nicholas M.
    The objective of this study was to evaluate the contents of essential elements in the two staple foods (rice and maize flour) consumed by children in Tanzania as a possible selection measure for high nutrient foods in order to combat malnutrition. Samples were analysed using proton-induced X-ray emission (PIXE) at the University of Surrey Ion Beam Centre. The mean concentrations of elements determined in the two staple foods are presented and compared with the mean concentrations published in the literature.
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    Elemental contents in hair of children from Zanzibar in Tanzania as bio-indicator of their nutritional status
    (Springer Netherlands, 2008-04) Mohammed, Najat K.; Mizera, Jiri; Spyrou, Nicholas M.
    Nutritional status and toxic elements body burden were evaluated in hair of children living in Zanzibar. 18 samples were collected from Zanzibar town and 19 samples from Nungwi village, which is approximately 64 km from Zanzibar town. The analysis was carried out using instrumental neutron activation analysis (INAA). The concentration ranges obtained in this study overlap with the published elemental values of healthy children of the same age group. The concentration levels of K, Zn, Cu, As and Co in hair of children from Zanzibar town were higher than from Nungwi whereas levels of Mn, Br and Sr were lower.
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    Radioactivity levels of staple foodstuffs and dose estimates for most of the Tanzanian population
    (iopscience, 2008-01) Mlwilo, N. A.; Mohammed, Najat K.; Spyrou, Nicholas M.
    Levels of natural radioactivity in staple food products (maize and rice) from various localities of Tanzania have been studied. The average activity concentrations of 40K, 232Th and 238U in maize were 48.79 ± 0.11, 4.08 ± 0.01 and 13.23 ± 0.10 Bq kg−1, respectively. In rice the concentrations of 40K, 232Th and 238U were 24.67 ± 0.03, 3.82 ± 0.02 and 5.02 ± 0.02 Bq kg−1, respectively. 137Cs was detected in only one sample collected in Zanzibar. The sample, with activity concentration of 5.57 ± 0.01 Bq kg−1, had been imported from Thailand. The relatively high average concentrations of the radionuclides in maize compared to rice may be attributed to the extensive use of phosphate fertilizers in maize production in Tanzania. Total annual committed effective doses due to total 232Th and 238U intakes as a result of consumption of staple foodstuffs for infants, children and adults were 0.16, 0.29 and 0.36 mSv y−1, respectively, which are lower than the annual dose guideline for the general public.
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    Trace elemental analysis of rice grown in two regions of Tanzania
    (Springer Netherlands, 2009-06) Mohammed, Najat K.; Spyrou, Nicholas M.
    The concentrations of elements in rice, locally cultivated in two regions of Tanzania (Mbeya and Morogoro), were determined using Instrumental Neutron Activation Analysis (INAA) for Na, Mg, Al, Cl, K, Ca, V, Mn, Cu and Br, and Particle-Induced X-Ray Emission (PIXE) for P, Fe and Zn. There were no statistical differences in concentrations of the essential elements Fe, Zn, Cu and P in rice from both regions. There was also no significant correlation between grain P and Fe content, suggesting the possibility of growing Tanzanian rice with low phytic acid and high Fe contents.
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    Trace Elements in Hair from Tanzanian Children: Effect of Dietary Factor
    (Springer Netherlands, 2009-04) Mohammed, Najat K.; Spyrou, Nicholas M.
    Trace elements in certain amounts are essential for childrens' health, because they are present in tissues participating in metabolic reactions of organisms. Deficiency of the essential elements may result in malnutrition, impaired body immunity, and poor resistance to disease. These conditions might be enhanced against a background of additional adverse environmental factors such as toxic elements. The analysis of elements in childrens' hair will give information on the deficiency of essential elements and excess of toxic elements in relation to their diet. In this study, 141 hair samples from children (girls and boys) living in two regions of Tanzanian mainland (Dar es Salaam and Moshi) and the island of Zanzibar have been analysed for trace elements in relation to food consumption habits. The analysis was carried out using long and short irradiation instrumental neutron activation analysis (INAA) of the Nuclear Physics Institute at Rez, Czech Republic. Arithmetic and geometric means with their respective standard deviations are presented for 19 elements. Subgroups were formed according to age, gender, and geographic regions from which the samples were collected. Differences in concentrations for the groups and with other childhood populations were explored and discussed.