Toxicology Department, National Institute for Occupational Health, Johannesburg, South Africa.
Haematology and Molecular Medicine Department, University of the Witwatersrand, Johannesburg, South Africa.
Inhal Toxicol. 2020 Sep-Oct;32(11-12):431-445. doi: 10.1080/08958378.2020.1836092. Epub 2020 Oct 23.
Decades of mining in South Africa has given rise to hundreds of tailings storage facilities (TSFs) and several tonnes of waste. These TSFs have contributed to air pollution due to the lack of proper rehabilitation measures. Currently, it is not known whether tailings emissions could be the cause of respiratory-related ill effects. In addition, the physicochemical properties that may govern their toxicity have not yet been identified.
The aim of this research was to determine the toxicity of tailings dust and identify the physicochemical properties likely to govern toxicity.
Dust samples were collected from five TSFs in the Gauteng and North West Provinces of South Africa and sieved to enrich the airborne particle fraction more likely to be inhaled. Thereafter, their physicochemical characteristics were assessed i.e. size distribution, specific surface area, shape, surface elemental composition, mineral composition, total elemental composition and surface activity. In addition, the toxicity and cellular internalization of the particles were assessed using the BEAS-2B epithelial and U937 monocytic-macrophage cell lines.
The results showed that all tailings dusts showed toxicity, particularly in the BEAS-2B cell line. This toxicity could have been governed by either their elemental composition, e.g. high transition elements e.g. Fe, Cu, Cr and V in the dusts from TSF 4, or a combination of other physicochemical properties, e.g. higher quartz content, lower size and higher surface area in the dusts from TSF 1.
These results provide mechanistic evidence to support future epidemiological studies attempting to link tailings dust exposure to adverse health effects.
在南非，数十年来的采矿活动产生了数百个尾矿储存设施（TSF）和数吨废物。由于缺乏适当的修复措施，这些 TSF 导致了空气污染。目前，尚不清楚尾矿排放是否是导致与呼吸相关的不良影响的原因。此外，可能控制其毒性的物理化学特性尚未确定。
本研究的目的是确定尾矿粉尘的毒性，并确定可能控制毒性的物理化学特性。
从南非豪登省和西北省的五个 TSF 中采集粉尘样品，并进行筛分以富集更有可能被吸入的空气传播颗粒。然后，评估它们的物理化学特性，例如粒径分布、比表面积、形状、表面元素组成、矿物组成、总元素组成和表面活性。此外，使用 BEAS-2B 上皮细胞和 U937 单核细胞-巨噬细胞细胞系评估颗粒的毒性和细胞内吞作用。
结果表明，所有尾矿粉尘均显示出毒性，特别是在 BEAS-2B 细胞系中。这种毒性可能是由其元素组成决定的，例如 TSF 4 中的高过渡元素，例如 Fe、Cu、Cr 和 V，或者是由其他物理化学特性决定的，例如 TSF 1 中的石英含量较高、粒径较小和比表面积较大。
这些结果为试图将尾矿粉尘暴露与不良健康影响联系起来的未来流行病学研究提供了机制证据。
