Multidisciplinary field research in Kabwe, Zambia, towards better understanding of lead contamination of the city - A short report from a field survey

Abstract

Heavy metal contamination is a serious issue in many post-mining regions around the world. Kabwe town, Zambia, is known as one of the most polluted cities in the world, where high lead (Pb) levels have been reported in soils, plants, animals and human blood. Multidisciplinary approaches are critically needed to understand the current situation and to remediate the polluted area. In the current research, a large-scale preliminary field survey was performed to understand the current situation in Kabwe and to plan future mitigation approaches. Three aspects were mainly observed; 1) plant communities during the dry season in Kabwe city, 2) spectral images of the land surfaces in various locations in Kabwe and 3) Pb concentrations in soils and water. Overall, >15 different plant species were observed and many of them maintained their green colour even during the dry season. Some tree species, for example, Caesalpiniaceae and Fabaceae families may be utilised as phytostabilization approaches although their impacts on the soil Pb mobility should be further studied. For the spectral images, we used a handmade portable spectrometer, and our obtained spectral images showed typical curves observed from soils. These data may be used to understand the distribution of different soil types in this area, using aboveground images such as satellite images. For Pb concentrations in soils, extremely high total Pb levels (>1,000 ppm) was observed only within 2 km from the mining site. There was a weak but a positive correlation between the total and soluble Pb thus further study should also focus on the mobility of Pb from soils to plant ecosystems.