Mekonnen, Bekele (2008) Determination of Heavy Metals Concentration in the Sediment Cores, Waterhyaciths and Water of Aba Samuel Lake. Masters thesis, Addis Ababa University.
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Abstract
In this work the concentration of selected trace metals (Cu, Co, Cr, Cd, Ni, Mn and Zn) were determined in the water, water hyacinth plant and sediment core samples from Aba Samuel reservoir - artificial lake, 37 km south of Addis Ababa. The maximum concentrations of dissolved metals in the water of the reservoir were found to be, 0.037, 0.022, 0.12, 0.023, 0.594, 0.045, 0.166 mg/L for Cu, Co, Cr, Cd, Mn, Ni and Zn, respectively. The levels of dissolved metals in the water were found to be below the WHO and South African TWQR for drinking water for Cu, Co, Ni, and Zn, while the respective guideline values are surpassed for Cr, Cd and Mn. The study has revealed that conc. of the metals to be many folds higher in the tissues of the water hyacinth (Echhornia Crassipus) plants than in the ambient water of the lake. The ratio of average concentration of the metals in the root of the plants to that in the water of the lake was calculated to be 442, 1647, 1546, 121, 275, 1684, and 1501 for Cu, Co, Cr, Cd, Mn, Ni and Zn, respectively. Moreover, analyses of correlation between level of dissolved metal and the level of the metals in plants tissues (roots and leaves) revealed that there exists strong correlation between the two. This could be an indicator of the fact that the water hyacinths absorb the metals mainly from the lake water. The depth profile Constructed for the trace metal contaminants from analysis of the sediment core sections showed an increasing trend for most of the metal in the recent (upper) sections of the sediment cores. Some irregularities are observed in the depth profile of the metals. For example, sub-surfacial maxima were observed for some metals which could be due to occasional increased metal load at the time corresponding to that particular sediment core section. Comparison of the level of the metals in the upper section of the sediment core with the Canadian interim and EPA fresh water SQG revealed that the levels of Cd, Cr, and Ni has already surpassed their maximum advisable levels which is recommended as a safe level for protection of aquatic system. The rest of the metals have levels which are below their respective maximum permissible values that are recommended by the Canadian EPA to protect aquatic life.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | G Geography. Anthropology. Recreation > GE Environmental Sciences G Geography. Anthropology. Recreation > GF Human ecology. Anthropogeography Q Science > QD Chemistry |
| Divisions: | Africana |
| Depositing User: | Selom Ghislain |
| Date Deposited: | 25 May 2018 13:34 |
| Last Modified: | 25 May 2018 13:34 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/4131 |
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