Geochemical assessment of an old uchi tailing dump in Kitwe, Zambia.
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Date
2024
Authors
Muma, Stephen
Journal Title
Journal ISSN
Volume Title
Publisher
The University of Zambia
Abstract
This study investigates the characteristics of soil from an old Uchi Tailing Dump in Kitwe, Zambia, through field sampling and analysis. Soil samples were systematically collected using a grid
sampling techniques to inform future environmentally responsible restoration strategies. Particle size distribution was assessed through sieve analysis while X-ray diffraction (XRD) provided
insights into the soil's crystalline structure. Results from these techniques, along with elemental quantification using flame atomic absorption spectrometry, revealed a hierarchy of element
concentrations in the Uchi Tailing Dump samples: Fe>Cu>Ca>Mn>Co>Zn, with pH ranging from 5.5 to 7.5. Notably, copper (0.56%) and cobalt (0.15%) levels were particularly high. Cuprite was
identified as a significant source of copper while iron oxide contributed to elevated iron levels. XRD analysis highlighted quartz, kaolinite and dolomite as the predominant phases, with montmorillonite aiding in pH stability. The study also attributed high calcium content to calcite. Spatial distribution analysis revealed distinct patterns, with elevated copper in the northwest and
increased cobalt in the northeast. Both topsoil and subsurface samples exhibited contamination, likely due to anthropogenic influences. The soil was predominantly fine sand (86% sand, 13% clay and 1.4% silt) with a gap-graded particle size distribution. The simulation results from PHREEQC revealed distinct saturation levels for various mineral phases within the tailings, with cupric ferrite (CuFe2O4) at 10.72, cuprite (Cu2O) at 3.08, zincate (ZnSO4: H2O) at -9.54, gypsum (CaSO4: 2H2O) at -4.85 and hematite (Fe2O3) at 13.10. The Geo-Accumulation Index (Igeo) confirmed contamination, particularly in copper (Igeo=5), cobalt (Igeo=2.5), iron (Igeo=0.5) and zinc (Igeo<0). Dust emissions, acid mine drainage, soil degradation and a reduction in biodiversity in
the Uchi Stream are significant hazards associated with the Uchi Tailing Dump. In summary, the study underscores the significant pollution and environmental risks associated with the Uchi
Tailing Dump, emphasizing the need for ongoing monitoring and remediation efforts to protect the ecosystem and community health in the area. In conclusion, this study highlights significant
pollution and environmental risks at the Uchi Tailing Dump, emphasizing the necessity for continued monitoring and remediation efforts to safeguard the ecosystem and community health
in the area.
Description
Thesis of Master of Science Degree in Integrated Water Resources Management