Thallium and co-genetic trace elements in hydrothermal Fe-Mn deposits of Central Spain
Thallium (Tl) is a hazardous trace metal that may potentially be harmful to human and environmental health. Tl pollution is mainly derived from mining and smelting of Tl-bearing minerals but natural weathering of Tl-bearing sulfides minerals may also induce Tl release to the environment. In this stu...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/200618 |
| Acceso en línea: | http://hdl.handle.net/10261/200618 |
| Access Level: | acceso abierto |
| Palabra clave: | Thallium Pyrite Jarosite Kerogen Thallium XANES Soil pollution |
| Sumario: | Thallium (Tl) is a hazardous trace metal that may potentially be harmful to human and environmental health. Tl pollution is mainly derived from mining and smelting of Tl-bearing minerals but natural weathering of Tl-bearing sulfides minerals may also 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−1), jarosite (142 mg kg−1), Mn-oxides (27 mg kg−1) or kerogen (13 mg kg−1). 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. Both jarosite-like and K-feldspars mineral phases as well as other clay minerals such as illite may be the unique natural alternative to minimize Tl pollution of the water and soil system. |
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