Museo Nacional de Ciencias Naturales (MNCN, CSIC), C/ José Gutiérrez Abascal 2, 28026 Madrid, Spain; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland.
Museo Nacional de Ciencias Naturales (MNCN, CSIC), C/ José Gutiérrez Abascal 2, 28026 Madrid, Spain.
Sci Total Environ. 2020 May 15;717:137162. doi: 10.1016/j.scitotenv.2020.137162. Epub 2020 Feb 6.
Thallium (Tl) is a hazardous trace metal that can harm human and environmental health. Tl pollution can result from the mining and smelting of Tl-bearing minerals, but also the natural weathering of Tl-bearing sulfide minerals may induce Tl release to the environment. In this study, hydrothermal deposits hosted in dolostone rocks sited along fossil thermal springs in the Lodares region (Soria province, central Spain) were studied. In this hydrothermal mineralization zone, Tl association with primary minerals, identified Tl-bearing secondary products resulting from natural weathering of primary minerals, as well as the dispersion from its natural source along a seasonal small streambed were explored. Samples were analyzed by chemical, microscopic and spectroscopic techniques and epithermal pyrite, sphalerite, galena and barite and secondary gypsum, jarosite, scorodite, anglesite, goethite, epsomite and elemental sulfur produced by both inorganic and bacterial processes were found. The highest Tl contents were found in hydrothermal pyrite (188 mg kg), jarosite (142 mg kg), Mn-oxides (27 mg kg) or kerogen (13 mg kg). Feldspar was identified by electron probe microanalysis as potential host phase of Tl. XANES results confirmed the association of Tl(I) with metal sulfides in pyrite-rich samples and highlighted the role of jarosite-like minerals for Tl(I) sequestration upon pyrite oxidation, even in carbonate-rich samples at near-neutral pH. In addition to micaceous minerals, jarosite-group minerals and K-feldspars may contribute to the natural attenuation of Tl in soils and sediments.
铊（Tl）是一种有害的痕量金属，会危害人类和环境健康。Tl 污染可能是由含 Tl 矿物的开采和冶炼造成的，但含 Tl 硫化物矿物的自然风化也可能导致 Tl 释放到环境中。本研究对位于西班牙中部索里亚省 Lodares 地区的化石温泉沿线白云岩岩石中赋存的热水矿床进行了研究。在这个热液矿化带中，研究了 Tl 与原生矿物的结合，鉴定了原生矿物自然风化产生的含 Tl 次生产物，以及其从自然源沿季节性小溪床的分散。通过化学、微观和光谱技术对样品进行了分析，发现了热液黄铁矿、闪锌矿、方铅矿和重晶石以及次生石膏、水铁矾、硫锑铜矿、硬石膏、针铁矿、泻利盐和元素硫，这些都是由无机和细菌过程产生的。黄铁矿（188 mg kg）、水铁矾（142 mg kg）、Mn 氧化物（27 mg kg）或干酪根（13 mg kg）中 Tl 含量最高。电子探针微分析鉴定出长石是 Tl 的潜在宿主相。XANES 结果证实了 Tl(I)与富含黄铁矿样品中金属硫化物的结合，并强调了在黄铁矿氧化过程中，即使在近中性 pH 值的碳酸盐丰富的样品中，类水铁矾矿物对 Tl(I)的固定作用。除了云母状矿物外，类水铁矾矿物和 K 长石可能有助于土壤和沉积物中 Tl 的自然衰减。
