[01] Mwanamuchende Trevor, Department of Geology & Survey, Copperbelt University, Kitwe, Zambia. [02] Mukube Pumulo, Department of Geology & Survey, Copperbelt University, Kitwe, Zambia. [03] Nyirenda Kenny, Department of Geology & Survey, Copperbelt University, Kitwe, Zambia. [04] Okello Nicholas, Department of Geology & Survey, Copperbelt University, Kitwe, Zambia. [05] Ziwa Gabriel, Department of Geology & Survey, Copperbelt University, Kitwe, Zambia. [06] Mwape Annie, Department of Environmental Engineering, Copperbelt University, Kitwe, Zambia.

The objective of this study was to assess the heavy metal contamination of soils in three residential areas of Kitwe district namely Nkana East, Nkana West and Wusakile and to determine the spatial distribution of the metals within the soils of the residential areas using geochemical maps. Soil samples were collected in the aforementioned areas and analyzed for Cu, Zn, Pb and Co contents using Atomic Absorption Spectrometry (AAS). The results of the analysis were used to generate geochemical maps using the Inverse Distance Weighting (IDW) interpolation technique in ArcGIS and to calculate the geo-accumulation index (I_geo), Enrichment Factor (EF) and Pollution Load Index (PLI). The I_geo, EF and PLI were used to assess the soil contamination levels of the four heavy metals. In Nkana West, the I_geo for Cu ranged between 1-2 and the EF between 5-20, whereas the I_geo and EF values for Co ranged between 0-1 and 2-5 respectively. The I_geo values for Cu indicated that the soils were moderately contaminated with Cu while the EF indicated severe enrichment. For Co, the I_geo showed moderate contamination while the EF indicated moderate enrichment. In Wusakile, the I_geo for Cu was recorded as 0.52 while the EF was recorded as 4.91. These values indicated that the soils in Wusakile were moderately contaminated with Cu. Similar results were recorded for Co although the EF for Co indicated that the soils in Wusakile were severely enriched with the metal. The results for Zn and Pb across all the study areas showed that I_geo<0 and EF<2, indicating that the soils were uncontaminated with these heavy metals. Both Cu and Co recorded a PLI >1 across all the study areas, indicating that the soils were contaminated with these metals. Statistical analyses across all the study areas showed that Nkana West and Wusakile had the highest mean concentrations of Cu and Co recorded as 1068.96 mg/kg and 343.96 mg/kg respectively, standard deviations recorded as 1666.21 mg/kg and 222.22 mg/kg respectively and Coefficient of Variation (COV) recorded as 1.56 and 1.87 respectively. Spatial analysis revealed that the highest concentration of heavy metals was near active mining areas. Of all the residential areas considered, Nkana West and Wusakile recorded the highest statistical variability and were therefore, the most contaminated areas due to their proximity to Nkana mine site.

Heavy Metal, Soil Contamination, Spatial Distribution, Geo-accumulation Index, Enrichment Factor, Pollution Load Index, Kitwe District

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