Browsing by Author "Petro, Phares Maximilian Doyi"

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    Levels and distribution of heavy metals in soil maize and rice within the vicinity Of Buzwagi gold mine Kahama Tanzania
    (University of Dar es salaam, 2019) Petro, Phares Maximilian Doyi
    This dissertation reports on the levels and spatial distribution of Cd, Fe, Co, Cu, Pb, Zn and Hg in maize, rice and soil in the vicinity of Buzwagi gold mine, Kahama, Tanzania. The concentrations of heavy metals were compared with FAO/WHO and/or TBS standards. The methods involved random and systematic sampling, extraction by using wet acid digestion and determination of the levels of heavy metals by AAS, with the exception of mercury which was analyzed using a Direct Mercury Analyzer (DMA). Analysis of variance ( ANOVA) and t-test using Graphpad Instant Demo software were employed for data analysis. The mean levels of Cd, Fe, Co, Cu, Pb, Zn and Hg at Mwime village in mg/kg were 9.34, 122969, 22.2, 79.6, 20.80, 38.9 and 0.02 in soil BD L 57, 15.1, 14.7, BDL, 21.1 and 0.16 in maize and BDL, 96.82, BDL, 5.53, BDL, 16.37 and 0.295 in rice, respectively. The mean levels of Cd, Fe, Co, Cu, Pb, Zn and Hg at Chapulwa in mg/kg were 13.6, 134913, 27.1, 54.1, 23.2, 22.01 and 0.036 in Soil, BDL, 34.77, BDL, 1.7, BDL, 17.4 and 0.03 in maize and BDL,26.50, BDL,4.70, BDL,16.03 and 0.37, in rice respectively. In addition the mean levels of Cd, Fe, Co, Cu, Pb, Zn, and Hg at Mwendakulima in mg/kg were BDL, 1782600, 26.3, 72.6, 18.3, 39.1 and 0.03 in soil, BDL 64.10, BDL, BDL, 5.53, BDL, 16.3 and 0.04 in maize and bdl, 88.21, BDL, 2.46, BDL, 16.03 and 0.04 in rice respectively. The study has shown that levels of Cu, Zu, and Hg in rice at Mwime, Chapulwa and Mwendakulima villages are above FAO/ WHO (2001) limits. In addition, Fe in rice at Mwime and Mwendakulima Villages has been found to be above FAO/WHO (2001) set limits. For maize, analysis results have shown that Zn and Hg are above FAO/WHO (2001) limits. Furthermore, Fe at Mwime and Mwendakulima villages and Co at Mwime village have also been found to be above FAO/ WHO limits. Likewise, Fe in soil at Mwine, Chapulwa and Mwendakulima villages have been found to be above FAO/WHO (2001) limits, and Cd at mwime and Chapulwa villages also recorded above FAO/WHO (2001) set limits. The level of heavy metals increased with increase in distance from Buzwagi gold mine through Mwime village whereas it is decreased with increase in distance from Buzwagi gold mine through Chapulwa and Mwendakulima villages. In the determination of the transfer factors (TF), the results have shown that about 70% of Hg uptake by maize and rice are above 100% and therefore people in the vicinity are susceptible to health risks.