Environmental Monitoring of the Effects of Conventional and Artisanal Gold Mining on Water Quality in Ngwabalozi River, Southern Zimbabwe
International Journal of Environmental Monitoring and Analysis
Volume 2, Issue 2, April 2014, Pages: 123-127
Received: Apr. 10, 2014;
Accepted: Apr. 22, 2014;
Published: May 10, 2014
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Simbarashe Mudyazhezha, Department of Soil Science and Agricultural Engineering, University of Zimbabwe, Mt Pleasant, Harare, Zimbabwe
Reginald Kanhukamwe, Department of Soil Science and Agricultural Engineering, University of Zimbabwe, Mt Pleasant, Harare, Zimbabwe
Mineral extraction contributes positive to the socioeconomic fabric of many African countries but has also contributed to the deterioration of environmental quality. It has been branded the most destructive industry in the world. This study sought to assess the effects of conventional gold mining which use cyanide for gold extraction and artisanal gold mining which uses mercury amalgamation on water quality in Ngwabalozi River. Along the river, there are gold panning activities upstream and a conventional mine downstream. Water samples were collected at four sampling points: 1) upstream of the gold panning activities; 2) just downstream of gold panning area; 3) upstream of the conventional mine; 4) downstream of the conventional mine. Benthic macro-invertebrates were also collected at the name four points, identified to family level and counted. Water samples were analyzed for mercury, iron, arsenic, sulphates and turbidity. There were significant differences (p = 0.000) in the measurements of mercury, arsenic, sulphates, taxa richness, total count of individuals, Shannon-Weiner index, evenness index and average tolerance scores among the four sampling sites. Gold panning activities were found to pollute Ngwabalozi River with mercury while the conventional mine polluted the river with sulphates. Gold panning activities also feed a lot of sand into the river resulting in high turbidity. Gold mining reduced the taxa richness, total count of individual and the diversity of benthic macro-invertebrate community in the river. There was pollution induced succession in the river as pollution sensitive species were replaced by pollution tolerant ones.
Environmental Monitoring of the Effects of Conventional and Artisanal Gold Mining on Water Quality in Ngwabalozi River, Southern Zimbabwe, International Journal of Environmental Monitoring and Analysis.
Vol. 2, No. 2,
2014, pp. 123-127.
Baird, C. 1999. Environmental Chemistry. 2nd Ed. W.H. Freeman
Chenje, M. (Ed.), 2000. State of the Environment Zambezi Basin 2000. SADC/IUCN/ZRA/SARDC, Mas-eru/Lusaka/Harare.
Chutter, F.M. (1994), The rapid biological assessment of streams and rivers water quality by means of the macroinvertebrate community in South Africa In: Uys, M (ed) (1997), Classification of rivers and environmental health indicators. WRC Report No. TT 63/94.
Hilson, G. (2000). Barriers to implementing cleaner technologies and cleaner production (CP) practices in the mining industry: A case study of the Americas. Minerals Engi-neering, 13(7), 699-717.
Hilson, G. 2002. Small-Scale Mining in Africa: Tackling Pressing Environmental Problems With Improved Strategy. The Journal of Environment Development 2002 11: 149-174.
Hilson, G., and van der Vorst, R. 2002. Technology, Managerial, and Policy Initiatives for Improving Environmental Performance in Small-Scale Gold Mining Industry. Envi-ronmental Management Vol. 30, No. 6: 764–777
Maponga, O. (1997). Small scale mining and the environment in Zimbabwe: The case of alluvial gold panning and chromite mining. In A. K. Ghose (Ed.), Small/medium scale mining (pp. 186-211). Calcutta, India: Oxford & IBH Publishing Co. PVT Ltd.
Maponga, O., and C.F., Ngorima. 2003. Overcoming environmental problems in the gold panning sector through legislation and education: the Zimbabwean experience. Journal of Cleaner Production 11: 147–157.
Mondlane S., Shoko DSM., 2002 – The socio-economic and environmental impacts of artisanal and small scale mining in Mozambique. In Gavin H( ed). The socio- economic impacts of Artisanal and small Scale mining in Developing Countries. Rotterdam, The Netherland: Blackwell Publishers.
Pereira, A. 2009. Environmental Impact of Artisanal Gold Mining in the Pungwe River Basin. Freiberg Online Geology. Volume 24: 45-49.
Ravengai, S., Love, D., Love, I., Gratwicke, B., Mandingaisa, O. and Owen, R. 2005. Impact of Iron Duke Pyrite Mine on water chemistry and aquatic life – Mazowe valley, Zimbabwe. Water SA, 31, 219-228.
Sasmaz, A., Obek, E. and Hasar, H, 2008. The accumulation of heavy metals in Typha latifolia L. grown in a stream carrying secondary effluent. Ecological Engineering 33: 278-284.
Shoko, M., Maviya, J.,& Bachs, A. (1993). Mines and envi-ronment in Zimbabwe. Gweru, Zimbabwe: Department of Natural Resources.
Shoko, D.S.M., Love, D., 2005. Gold panning legislation in Zimbabwe –what potentials for sustainable management of river resources. In: Mathew, K., Nhapi, I. (Eds.), Water and Wastewater Man-agement for Development Countries, IWAWater and Environmental Management Series. IWA Publishing, London, pp. 499–512.
van Straaten, P. 2000. Mercury contamination asso-ciated with small-scale gold mining in Tanzania and Zimbabwe. The Science of the Total Environ-ment 259: 105-113.
World Bank. (1995). Staff appraisal report, republic of Ghana, mining sector development and environmental project (World Bank Report No. 13881-GH). Africa: World Bank, Industry and Energy Operations, West Central Africa Department, Africa Re-gion.
Zwane, N., Love, D., Hoko, Z., Shoko, D. 2006. Managing the impact of gold panning activities within the context of integrated water resources management planning in the Lower Manyame Sub-Catchment, Zambezi Basin, Zimbabwe. Physics and Chemistry of the Earth 31: 848–856.