Occurrence and levels of potentially harmful elements (PHEs) in natural waters of the gold mining areas of the Kette-Batouri region of Eastern Cameroon

Arsenic pollution in Quaternary sediments and water near a former gold mine

Contamination of water and sediments with arsenic and heavy metals is a global issue affecting human health. Regions covered with Quaternary deposits have received little attention from the point of view of the flux of arsenic and heavy metals from sediments to surface water. This study aims to determine the flux of arsenic and other heavy metals from Quaternary sediments to surface waters in an area affected by the former Złoty Stok gold and arsenic mine. Contamination in surface waters and sediments was caused by arsenic, whereas concentrations of metals were usually within water quality standards. Arsenic contamination of surface water increased in the lower part of the basin covered by Quaternary sediments, and exceeded water quality standards by 2 orders of magnitude. Arsenic mass flux exceeded 8 kg/day near the confluence of the Trująca River with the Nysa Kłodzka, a main tributary of the Oder River. An increase in arsenic concentration in the lower part of the basin is related to mine tailings and preferential flow of groundwater through Quaternary sediments. In future, water resources scarcity may lead to an increase in arsenic contamination in surface and groundwater.

Evaluation of Cleaner Production for Gold Mines Employing a Hybrid Multi-Criteria Decision Making Approach

Implementing cleaner production (CP) is effective to resolve the contradiction between economic growth and environmental crisis. To avoid destroying the ecological environment in the exploitation process of mineral resources, CP has been developed in many gold mines to achieve the goal of sustainable development. Thus, this paper aims to propose a favorable approach to assess CP for gold mines. First, according to the specific characteristics of gold mines, an evaluation criteria system of CP is established. Meanwhile, considering the diversity of evaluation information, crisp numbers and probabilistic linguistic term sets (PLTSs) are adopted to indicate the quantitative and qualitative information, respectively. Subsequently, a modified experts grading method based on PLTSs is proposed to calculate the sub-criteria weights’ values. Following this, an extended Tomada de Decisão Interativa Multicritério (TODIM) method with hybrid evaluation values is presented to obtain the ranking order. Finally, the hybrid multi-criteria decision making (MCDM) approach is applied to a case of assessing CP for gold mines to demonstrate its feasibility. Furthermore, the robustness and advantages of this approach are justified by sensitivity and comparison analyses. The results show that the proposed approach is feasible to solve such kinds of evaluation problems with hybrid decision making information and can provide some managerial suggestions for government and enterprises.