Citation: Sadiki, B.; Ilunga, F.; Shengo, M. Dispersal Mechanisms of Trace Metal Elements in the Environment: The Case of Mineral Wastes Stored in Tshamilemba District of the City of Lubumbashi, DR Congo. Sustainability 2023, 15, 4476. https://doi.org/10.3390/ su15054476 Academic Editor: Guannan Liu Received: 22 January 2023 Revised: 17 February 2023 Accepted: 21 February 2023 Published: 2 March 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Dispersal Mechanisms of Trace Metal Elements in the Environment: The Case of Mineral Wastes Stored in Tshamilemba District of the City of Lubumbashi, DR Congo Ben Sadiki 1 , Fabien Ilunga 2 and Michel Shengo 2, * 1 Applied Chemistry and Metallurgy Department, Higher School of Applied Techniques in Lubumbashi (ISTA-LU), 1896 M’Siri Boulevard, Lubumbashi P.O. Box 2099, Democratic Republic of the Congo 2 Inorganic Chemistry Unit, Chemistry Department, Faculty of the Sciences, University of Lubumbashi, Lubumbashi P.O. Box 1825, Democratic Republic of the Congo * Correspondence: shengolutandulamichel@yahoo.fr Abstract: Since 2001, the Tshamilemba quarter, located in the City of Lubumbashi (DRC), has been home to copper- and cobalt-producing plants, which generate great amounts of mineral waste, the storage of which has resulted in environmental pollution. Previous studies conducted in the Tshamilemba district have identified the weathering process of stored mineral wastes as the main source of trace metal elements (TMEs) involved in the contamination of soil and well water, and have highlighted the population exposure to cobalt. This study strives to identify or establish the dispersal mechanisms of pollutants in the environment that contaminate soil, surface water and edible plants. This study measured major physicochemical parameters, determined TME concentrations in samples (soil, water and edible plants) and established, based on data from soil sample analysis mathematically processed using Matlab 7.1 software, the spatial distributions of TMEs, in both the upper and deep soil (20 cm). The soil sample analysis revealed an average pH of 7.69 and a value of 9.1 for the near-white crusts collected at some spots. In the soil, TMEs were present in upper layers (Co, Cu, Zn and Fe) and the deep layers (Co, Cu, Pb, Zn and Fe) at phytotoxic concentrations. TMEs were observed in water samples at concentrations (Cu, Co, Mn, Zn and Pb) surpassing the quality standards for drinking water. This also applies to edible plant samples of Saccharum officinarum (Co, Cd, Ni, Mg and Pb) and Musa acuminate (Cd, Co, Pb, Zn, Mn and Ni). TMEs disperse in the environment as airborne particles from aerial erosion and as dissolved species in run-off water, mixed with acidic, metal-rich waters spreading from the weathering of stored mineral waste. TMEs contaminate the surrounding soil near to the surface water and build up in edible plants. Therefore, fear among the population about the environment pollution in Tshamilemba is well justified. Understanding the dispersal mechanisms of TMEs is of paramount importance to better control and to contain mineral pollution and design strategies for minimizing the effects on human health. Keywords: mining industry; mineral waste storage; trace metal element spread; environment pollution 1. Introduction Mining is one of the industrial activities that leads to the most serious environmental issues, experienced in many regions of the world [1–9]. This is exemplified by the im- proper management of mineral waste and wastewaters generated due to mining activities over many years in the DRC. This practice has resulted in the pollution of soil and water resources in the former Katanga region, including in the Tshamilemba district which is studied in this paper [4,10–14]. Indeed, the environmental footprint of mining activities conducted in the Katanga region is such that TMEs have contaminated arable soils with a serious threat to wildlife and human health [4,15,16]. This situation has mainly resulted from the fact that the vast majority of mineral processing and hydrometallurgical plants in the Katanga region have not always had an appropriate management system for mineral Sustainability 2023, 15, 4476. https://doi.org/10.3390/su15054476 https://www.mdpi.com/journal/sustainability