Browsing by Author "Mganga, Nyatwere"

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    CLASSIFICATION OF PLANTS ACCORDING TO THEIR HEAVY METAL CONTENT AROUND NORTH MARA GOLD MINE, TANZANIA: IMPLICATION FOR PHYTOREMEDIATION
    (AJOL, 2011) Mganga, Nyatwere; Manoko, Mkabwa; Rulangaranga, Zachariah
    Plants like other living organisms respond differently under different environmental conditions. An elevated level of heavy metals is one of the stresses which results into three classes of plants depending on their heavy metal content. The classes of plant species according to their accumulated heavy metals around North Mara Gold Mine were not known. To study such classes, a line transect of 700m long was established opposite the gold mine wastes. A total of eight sampling points were systematically established each after every 100m in that transect. Fifteen plant species were sampled; at least one species per sampling point. Approximately 5g of the root and shoot portions of the plants were separately collected from each plant. Three soil samples were also collected at each sampling point where vegetations were previously sampled. The soils and vegetations were analyzed for heavy metals (copper, lead, chromium, zinc, cadmium and nickel) by AAS. Of 15 plant species; 10, 6, 6 were hyperaccumulators, excluders and indicators for heavy metals respectively. Detailed studies on the agronomical requirements, optimizations, growth rates and the incidence of pests and diseases are required on the identified heavy metal hyperaccumulator plants for possible future remediation of the study area.
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    Distribution patterns of plant species around North Mara Gold Mine in Tanzania
    (International Academic Journals, 2012-03) Mganga, Nyatwere; Manoko, Mkabwa L.K.M.; Rulangaranga, Zachariah K.R.
    Elevated heavy metals are toxic to many plants. There are many known edaphic factors affecting alteration of vegetation patterns. This study aimed to determine the relationship between bioavailable heavy metals and distribution patterns of plant species. Three parallel line transects of 3500 m long and 100 m apart were established opposite the mine wastes. Sampling was done at every 100 m up to 700 m and from the last 500 m. Numbers of plant species were systematically recorded using nested quadrats per transect and soil samples were collected at each point. The soil samples were analyzed for evidence of bioavailable heavy metals (copper, lead, chromium, zinc, cadmium and nickel) using an Atomic Absorption Spectrophotometer. Canonical Correspondence Analysis showed that levels of lead, chromium, cadmium and nickel negatively influenced distribution patterns of the plants. However, the Monte Carlo Permutation test showed that the measured metals did not have a significant influence on distribution patterns of the plants. It is likely that distribution patterns of the plants were also influenced by some other factors that were not currently investigated in this research. In terms of conservation as the main priority, waiting for evidence of the influence of heavy metals to have an obvious and significant effect on plant patterns may mean that an ecosystem has already undergone serious damage.