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Título del libro: Water-Rock Interaction - Proceedings Of The 13th International Conference On Water-Rock Interaction, Wri-13
Título del capítulo: Chromium contamination in León valley, Guanajuato, México: A Cr stable isotope perspective

Autores UNAM:
MARIA AURORA ARMIENTA HERNANDEZ; OFELIA MORTON BERMEA;
Autores externos:

Idioma:
Inglés
Año de publicación:
2010
Palabras clave:

Anthropogenic sources; Chromium contamination; Cr concentration; Cr isotopes; Cr reductions; Isotopic data; Isotopic values; Me-xico; Reductants; Stable isotopes; Superficial water; Ultramafic rocks; Aquifers; Chromates; Chromium; Groundwater pollution; Groundwater resources; Isotopes; Rocks; Weathering


Resumen:

The León valley, Guanajuato, Mexico, has a long history (30+ years) of Cr contamination of groundwater and surface water. Cr(VI) is more mobile and toxic than Cr(III), thus Cr(VI) to Cr(III) reduction is a remediation technique frequently employed. Cr isotopes are used to monitor Cr reduction. We present Cr concentration and isotopic data from two sites: Buenavista (anthropogenic source) and San Juan de Otates (weathering of ultramafic rocks). In Buenavista, a chromate factory and its waste materials are the main source of Cr. Our results are consistent with historic monitoring data showing a general decrease in Cr(VI) concentrations. Cr isotope values show minimal reduction in Buenavista, where the high Cr(VI) concentrations seemingly have overwhelmed natural reductants in the aquifer directly under the factory. In San Juan de Otates, the sub ppb plume remains under normative values for Cr and the isotopic values show that reduction is occurring in the superficial waters. © 2010 Taylor & Francis Group, London.


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