A systematic review of the risk management frameworks for potentially toxic chemical elements

In the last 50 years, various frameworks have been used to control and manage potentially toxic chemical risks; however, these chemicals continue to negatively impact environmental and human health. This work was intended to provide a systematic review of the literature on essential aspects of current risk management frameworks for potentially toxic chemicals. The frameworks were reviewed using Organisation for Economic Co-operation and Development (OECD) principles that focus on elements, successes, shortcomings, similarities, and dissimilarities premised on the experiences of many countries. Keywords such as heavy metals, health risk, industrial chemicals, potentially toxic elements, chemical pollutants, and risk management framework were utilised to search the literature from databases and other sources. Ten risk framework documents selected from an initial yield of 1349 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow processes met the inclusion criteria. The key elements of risk frameworks that were identified included the risk assessment paradigm, iteration, tiered approach, weight of evidence, uncertainty analysis, and multi-criteria decision analysis among others. Notable gaps in risk frameworks that required improvements to effectively manage health risks posed by potentially toxic chemicals were identified. While existing risk frameworks have made significant contributions to human health and environmental protection, new and comprehensive frameworks are needed to address the novel and dynamic risks posed by toxic industrial chemicals. Also, there is a need to promote the use of risk management frameworks in developing countries through technology transfer and the provision of financial assistance to improve environmental and public health protection from toxic chemicals.

The impact of artisanal mining on rehabilitation efforts of abandoned mine shafts in Sutherland goldfield, South Africa

Abandoned gold mine sites are generally characterised by severe environmental problems and physical hazards. Because of socio-economic problems confronting communities around abandoned mine sites, historic and abandoned gold mines have become hot-spots for artisanal and small-scale miners. These mining activities at times thwart the efforts of rehabilitation at these sites. This article details how artisanal mining operations have frustrated rehabilitation efforts of abandoned mine shafts in the Sutherland goldfield. The field investigation of abandoned shafts and analysis of the nature of artisanal mining operations in the Sutherland goldfield revealed that artisanal mining involving digging around collars of sealed shafts is a major threat to the stability of the shafts and their sealing structures. In addition, artisanal mining operations have increased the safety risks of the abandoned shafts in the area. This has also been worsened by the fact that a large number of people, especially women and children, are exposed to the hazards of the abandoned mine sites. This article emphasises an urgent need for the development of holistic and cohesive strategies for dealing with the problems of abandoned gold mine shafts wherever they exist in the country as opposed to simply closing them up.

Geochemical fractionation of metals and metalloids in tailings and appraisal of environmental pollution in the abandoned Musina Copper Mine, South Africa

The economic benefits of mining industry have often overshadowed the serious challenges posed to the environments through huge volume of tailings generated and disposed in tailings dumps. Some of these challenges include the surface and groundwater contamination, dust, and inability to utilize the land for developmental purposes. The abandoned copper mine tailings in Musina (Limpopo province, South Africa) was investigated for particle size distribution, mineralogy, physicochemical properties using arrays of granulometric, X-ray diffraction, and X-ray fluorescence analyses. A modified Community Bureau of Reference (BCR) sequential chemical extraction method followed by inductively coupled plasma mass spectrometry/atomic emission spectrometry (ICP-MS/AES) technique was employed to assess bioavailability of metals. Principal component analysis was performed on the sequential extraction data to reveal different loadings and mobilities of metals in samples collected at various depths. The pH ranged between 7.5 and 8.5 (average ≈ 8.0) indicating alkaline medium. Samples composed mostly of poorly grated sands (i.e. 50% fine sand) with an average permeability of about 387.6 m/s. Samples have SiO₂/Al₂O₃ and Na₂O/(Al₂O₃ + SiO₂) ratios and low plastic index (i.e. PI ≈ 2.79) suggesting non-plastic and very low dry strength. Major minerals were comprised of quartz, epidote, and chlorite while the order of relative abundance of minerals in minor quantities is plagioclase > muscovite > hornblende > calcite > haematite. The largest percentage of elements such as As, Cd and Cr was strongly bound to less extractable fractions. Results showed high concentration and easily extractable Cu in the Musina Copper Mine tailings, which indicates bioavailability and poses environmental risk and potential health risk of human exposure. Principal component analysis revealed Fe-oxide/hydroxides, carbonate and clay components, and copper ore process are controlling the elements distribution.

Potential implications of mine dusts on human health: A case study of Mukula Mine, Limpopo Province, South Africa

Objective: The purpose of this study was to estimate the levels of Suspended Particulate Matter (SPM) in ambient air within Mukula mine and the potential risks to mineworkers and inhabitants of the adjoining Mukula community’s health.

Methods: An SPM was used to measure the levels of particulate matter (PM₁₀) in and around the mining site. One-way Analysis of Variance (ANOVA) was used to determine significance level of PM₁₀ in ambient air.

Results: Suspended particulate matter in the air ranged from 60.25 to 1820.45 µg/m³. The lowest value of SPM was more than four times the required World Health Organisation’s allowable level in ambient air, which the mine workers and locals would be inhaling.

Conclusion: Continuous inhalation of mine dusts by mine workers and locals could result in pulmonary fibrosis, silicosis and lung cancer. The findings from this study support the need to have in place the necessary control measures that will drastically reduce SPM in the air. Such measure includes wet drilling and blasting, sprinkling of water on the mine roads and planting of vegetation around the mines and neighbouring communities.