Distribution of copper, lead, cadmium and zinc concentrations in soils around Kabwe town in Zambia

Abstract

The extent of pollution of the environment as a result of mining activities in Kabwe, the provincial capital of Central province in Zambia has not yet been evaluated. Mining of lead and zinc were the core activities of Kabwe mine while cadmium and silver were produced as by-products. The smelting processes produced a significant amount of copper. The spatial distribution of four heavy metals in soils in the northern, eastern, southern and western directions of the mine was analyzed using atomic absorption spectrometry (AAS). Samples were collected up to 20 km in each direction from the mine. Results were consistent with the wind flow patterns in the town. Results ranged between 0.08 and 28 mg kg −1 (Cd); 0.20 and 0.61 mg kg −1 (Cu); 0.10 and 758 mg kg −1 (Pb) and 0.40 and 234 mg kg −1 (Zn) suggesting high precipitation of metals from the core mining activities. These concentrations were for only the fractions of metals extractable by 0.5 M nitric acid and that could be available for plant uptake in the environment. The distribution of metals indicated a decrease of metal concentrations with distance from the mine, which confirmed that precipitation due to mining activities was the main cause of soil contamination.