Browsing by Author "Makundi, Ismael"

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    ASSESSMENT OF INDOOR RADON-222 CONCENTRATIONS IN THE VICINITY OF MANYONI URANIUM DEPOSIT, SINGIDA
    (Tanzania Journal of Science, 2018-05-23) Mlay, Germana; Makundi, Ismael
    This study aimed to assess indoor radon concentrations in the vicinity of the Manyoni Uranium Deposit in Singida. The concentrations were measured for two months in 32 houses in the vicinity of Manyoni Uranium Deposit and 9 houses at Manyoni town using a portable radon gas monitor (Alpha –GUARDTM). The radon concentrations ranged from 27±3 to 518±28 Bq/m3with the overall mean of 166±12 Bq/m3 which is above recommended values of 100 Bq/m3 and 148 Bq/m3 set by WHO (World Health Organization) and EPA (Environmental Protection Agency's), respectively. The overall mean of indoor radon concentrations from each village were Kipondoda (169±13 Bq/m3), Muhalala (177±16 Bq/m3), Mwanzi, (287±13 Bq/m3), Mitoo (325±21 Bq/m3) and Majengo (377±23 Bq/m3) which exceed the limit set by WHO (World Health Organization) and EPA (Environmental Protection Agency). The value of 325±21 Bq/m3 and 377±23 Bq/m3 from Mitoo and Majengo respectively, exceed the limit of 300 Bq/m3 recommended by ICRP (International Commission on Radiation Protection). Thus there is a non-negligible probability of incurring stochastic effects for people living in the vicinity of Manyoni Uranium mine. It is recommended that human activities should be controlled near the uranium deposits and dwelings should be well ventilated.
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    A Mössbauer study of the 61Black colour in early Cypriote and Nubian C-Group black-topped pottery
    (2007-08) Makundi, Ismael; Sperber, A. Waern; Ericsson, T.
    Black-topped pottery is a general term for vessels with a black interior and rim, the lower exterior being brownish red. Such pottery was common through millennia in the Nile valley. but it is also known elsewhere. In Cyprus there are bowls and other objects from the Early Bronze Age and the periods immediately before and after. In the Nile valley the Nubian C-Group bowls are similar to the Cypriote bowls in shape and colour. These wares are roughly contemporary occurring from the latter part of the third millennium B.C., but the Nubian C-Group, overlapping the former in time, prevailed further into the second millennium. In black-topped pottery the colours generally penetrate below the surface into the core. Also the surface border line dividing the differently coloured areas is not as straight and sharp as would be expected if it had been made by a painter's brush. Therefore the colouration seems to have been achieved in the firing process. The exact method used by the ancient potters and the chemical explanation of the change in colours have been discussed for about a century without a complete understanding having been reached yet. The black has been considered due either to carbon or to ferrous iron, the views being summarized in a preliminary study (Waern-Sperber 1988). By Mossbauer spectroscopy it was found that red or pink colour coincides with Fe3+ and black or grey colour coincides with Fe". indicating that iron might be essential for the colouration in the Early Cypriote black-topped samples examined. Several authors using Mossbauer spectroscopy have found such a correlation in ceramic materials (Hess and Perlman 1974, Bouchez et al. 1974, Eissa et al. 1979, Longworth and Tite 1979, Riederer et al. 1979, Lazzarini et al. 1980, Maggetti et al. 1981, Tite et al. 1982). Other possible reasons for the black colour in pottery are carbon and manganese (Noll 1982). Only trace amounts of the latter were found in the preliminary study. zyxwvu
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    A study of heavy metal pollution in Lake Victoria sediments by Energy Dispersive X-Ray Fluorescence
    (2001-02) Makundi, Ismael
    Sources of heavy metal pollution of Lake Victoria is of interest due to its economic and domestic implication in East Africa. Sediments from the shore of Lake Victoria and from some streams flowing into the lake have been analyzed for their heavy metal content using Energy Dispersive X-Ray Fluorescence (EDXRF) analysis. The samples were collected from seventeen different locations around the Municipality of Mwanza divided into three zones according to their activities. The results show that sediments from Mwanza North, which is least in anthropogenic activities, contains Cr and Co in addition to metals of terrestrial origin (K, Ca, Ti, Mn, Fe, Rb, Sr, Y, and Zr), samples from Mwanza Central, which is the town center, contains high concentrations of V, Cu, Zn and Pb, and samples collected from Mwanza South, which is the industrial area, contains the highest concentrations of V, Cu, Zn, As and Pb. It is concluded that the industrial and sewage wastes discharged into the lake are the main sources of the heavy metal contamination of Lake Victoria. Further studies will be required to assess detriments of these pollutants to human and aquatic life before policy for the factories responsible is put in place.
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    A survey of background radiation dose rates and radioactivity in Tanzania
    (2002-02) Banzi, Firmi B.; Msaki, P.; Makundi, Ismael
    Potential terrestrial sources of naturally occurring elevated radiation levels have been identified in Tanzania. Thus, efforts are currently being undertaken to create a natural radiation database, in the form of a radiation level map of natural radioactivity, to be used to assess the associated radiation risk to public and workers. Background radiation dose rate was determined with thermoluminescent dosimeters for 7 y (1993-1999) in five stations. The average background radiation dose rates for these stations were as follows: Tropical Pesticides Research Institute (TPRI) (102 +/- 7 nGy h(-1)), Same (98 +/- 2 nGy h(-1)), Namanga (98 +/- 5 nGy h(-1)), University of Dar Es Salaam (99 +/- 2 nGy h(-1)), and Kilimanjaro Christian Medical Center (121 +/- 3 nGy h(-1)). These stations were found convenient from an economic point of view since the project has no funds to cover wider and/or more remote areas in Tanzania. For the sake of comparison, similar measurements were made for the same period at Minjingu phosphate mine. The mine was one of the suspected areas with elevated levels of natural radioactivity. The radiation dose rate measured in this mine was about fourteen times higher (1,415 +/- 28 nGy h(-1)) than the average value obtained in northern Tanzania (98 nGy h(-1)). The high average activity levels of phosphate (5760 +/- 107 Bq kg(-1) for 261Ra, 497 +/- 5 Bq kg(-1) for 228Ra, 350 +/- 6 Bq kg(-1) for 228Th, and 280 +/- 5 Bq kg(-1) for 40K) and radiation dose rate recorded show that Minjingu phosphate mine has higher values than the highest radioactivity in phosphate compiled by the United Nations Scientific Committee on the Effect of Atomic Radiation. In view of these findings, a comprehensive risk-management strategy for reduction of radiation risk to the public and mine workers should be put in place. Efforts are currently being made to seek support to improve the background radiation database for subsequent assessment of radiation risk to miners and the societies in the