Zero Hunger (SDG 2), Good Health & Well-being (SDG 3)
Characterisation of factors controlling the speciation of zinc, cadmium and lead in an environmental compartment impacted by mining activities Festus Shafodino * , Julien Lusilao & Marius Mutorwa Department of Biology, Chemistry and Physics, Namibia University of Science and Technology, Windhoek, Namibia E-mail: shafodino12@gmail.com The toxicological impacts of heavy metals depend on their chemical forms, making it crucial to characterise the factors controlling their speciation. In this work, the speciation of zinc, cadmium, and lead was characterised in soils from Berg Aukas, a closed mine in the North of Namibia. The soils were analysed for physicochemical parameters and for anions content using IC. The metal(loid) concentrations and chemical association were determined by ICP-OES analysis. The results revealed high concentrations of the target heavy metals, consistent with the pollution indices. These metals were mainly associated with the oxidizable fraction and distributed among the non-residual fractions. Both the total concentrations and the percentages of Zn, Cd, and Pb in the mobile fraction of the BCR procedure showed increasing patterns with sampling depth, suggesting long term pollution or the mobility of the metals at the site. Co-existing metal(loid)s, phosphate anion, sulfur, OM, TOC, EC, TDS, and pH were the most important factors controlling the speciation of Zn, Cd, and Pb, with pH affecting Cd and Pb but not Zn. The use of advanced speciation techniques in future studies may be necessary to further elucidate the mechanisms driving heavy metal speciation and fates in the target environment. Key words: Berg Aukas, Mining activities, Heavy metals, Pollution, Speciation References 1. Nijeje, E., Senyonjo, A., Sahan, S. J., Byamugisha, D., & Ntambi, E. (2023). Speciation of Selected Heavy Metals in Bottom Sediments of River Rwizi, Mbarara City, Uganda. Water, Air, and Soil Pollution , 234(3). https://doi.org/10.1007/s11270-023- 06184-0 2. Singh, N., & Gadi, R. (2009). Biological methods for speciation of heavy metals: Different approaches Different Approaches. Critical Reviews in Biotechnology , 29(4), 307–312. https://doi.org/10.3109/07388550903284462 3. Zhang, J., Liu, Y., Hong, S., Wen, M., Zheng, C., & Liu, P. (2023). Speciation Analysis and Pollution Assessment of Heavy Metals in Farmland Soil of a Typical Mining Area: A Case Study of Dachang Tin Polymetallic Ore, Guangxi. Applied Sciences 2023, Vol. 13, Page 708, 13(2), 708. https://doi.org/10.3390/APP13020708
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