Kicińska Alicja, Pomykała Radosław
Faculty of Geology, Geophysics and Environmental Protection, Department of Environmental Protection, AGH University of Krakow, Mickiewicza 30 Av., 30-059, Kraków, Poland.
Faculty of Mining and Geoengineering, Department of Environmental Engineering, AGH University of Krakow, Mickiewicza 30 Av., 30-059, Kraków, Poland.
Sci Rep. 2023 Dec 18;13(1):22519. doi: 10.1038/s41598-023-50143-y.
The paper analyzes the process of incongruent dissolution of silicates taking place in close proximity to a talc mine. The chemical and phase composition as well as the concentrations and mobility of potentially toxic elements (PTE) in research material with varying levels of weathering were determined using instrumental (XRF, XRD) and chemical methods (extractions: BCR, aqua regia, water leaching, 0.05 M EDTA). It was demonstrated that the predominant minerals in the weathering crust include weathering-resistant minerals (i.e. quartz and muscovite) and secondary minerals (kaolinite, illite and interstratified minerals, vermiculite/chlorite) and that the predominant processes are hydrolysis and oxidation. The weathering process has an impact on the complexity of the chemical and mineral composition and the diverse structure of the weathering crust. A layer of Fe and Al oxides and hydroxides forms in the upper part of the weathering crust, while the amount of silica decreases. Low-mobility elements (i.e. Si, Al and Fe) react on the phase separation surface, causing the formation of clay minerals (i.e. vermiculite, montmorillonite) or Al and Fe hydroxides (e.g. goethite). The duration of weathering causes an increase in the content of PTEs in solid materials: multifold in the case of Cr (15), Ba (9), Pb (7), Zn (6) and considerably lower in the case of V (1.3), Sr (0.8) and Co (0.4). It was demonstrated that PTEs co-occur in several chemical fractions in the weathering crust and that the highest share of their total concentration are cations incorporated in the crystal lattice of minerals and bound by strong crystalline bonds (F4 46%). The lowest share was observed for the reducible fraction (9%) and the share of the oxidizable fraction was 29% The most mobile cations connected by the weakest bonds comprised only 16% of the total concentration. Based on the content of the readily soluble fraction of PTEs, it was concluded that the degree of weathering does not increase the environmental risk, but actually reduces it for Cr, Cr and Pb. The obtained Ecological Risk Index (ERI) values indicate that the ecological risk associated with the elements tested is low for the entire area, which means that natural weathering processes do not have any impact on environmental pollution.
本文分析了滑石矿附近发生的硅酸盐不一致溶解过程。使用仪器分析方法（XRF、XRD）和化学方法（萃取：BCR法、王水法、水浸提法、0.05M EDTA法）测定了不同风化程度研究材料中的化学和相组成以及潜在有毒元素（PTE）的浓度和迁移率。结果表明，风化壳中的主要矿物包括抗风化矿物（即石英和白云母）和次生矿物（高岭石、伊利石和间层矿物、蛭石/绿泥石），主要过程是水解和氧化。风化过程对化学和矿物组成的复杂性以及风化壳的多样结构有影响。在风化壳上部形成一层铁和铝的氧化物及氢氧化物，而二氧化硅的含量减少。低迁移率元素（即硅、铝和铁）在相分离表面发生反应，导致形成粘土矿物（即蛭石、蒙脱石）或铝和铁的氢氧化物（如针铁矿）。风化持续时间导致固体材料中PTEs含量增加：铬增加了15倍，钡增加了9倍，铅增加了7倍，锌增加了6倍，而钒增加了1.3倍，锶增加了0.8倍，钴增加了0.4倍，增加幅度相对较小。结果表明，PTEs在风化壳中以几种化学形态共存，其总浓度中最高比例是结合在矿物晶格中并通过强晶体键结合的阳离子（F4为46%）。可还原态的比例最低（9%），可氧化态的比例为29%，通过最弱键连接的最易迁移阳离子仅占总浓度的16%。基于PTEs易溶态的含量，得出结论：风化程度并未增加环境风险，实际上对于铬、镉和铅而言，反而降低了环境风险。获得的生态风险指数（ERI）值表明，整个区域与所测试元素相关的生态风险较低，这意味着自然风化过程对环境污染没有任何影响。
