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Evidencia de complejidad de hierro, cobre y zinc como grupos de sulfuro multinuclear en ríos óxidos
1College of Marine Studies, University of Delaware, 19958, USA. trozan@udel.edu
Nature
|September 6, 2000
Resumen
Los sulfuros metálicos disueltos, previamente pasados por alto, se encuentran en los ríos. Estas estructuras estables y complejas de sulfuros metálicos pueden regular la toxicidad de los metales traza en los ecosistemas de agua dulce.
Área de la Ciencia:
- Química del medio ambiente Química del medio ambiente
- La geoquímica es la geoquímica.
- Química acuática Química acuática es la química acuática.
Sus antecedentes:
- La biodisponibilidad de metales traza y la toxicidad en agua dulce están influenciadas por la complejación con materia orgánica disuelta.
- El papel de los sulfuros inorgánicos en la unión de metales traza es a menudo ignorado debido a su baja persistencia en aguas oxigenadas.
Objetivo del estudio:
- Investigar la presencia y la naturaleza de los sulfuros inorgánicos disueltos en los sistemas fluviales.
- Determinar hasta qué punto los sulfuros son complejos con metales traza clave como el cobre, el hierro y el zinc.
Principales métodos:
- Análisis de concentraciones de sulfuro disuelto en muestras de agua de ríos de Connecticut y Maryland.
- Cuantificación de los complejos metal-sulfuro utilizando la espectrometría de masas de la transformación de Fourier (FTMS).
Principales resultados:
- Se detectaron concentraciones nanomolares de sulfuros disueltos, con más del 90% complejo por cobre, hierro y zinc.
- Estos complejos metal-sulfuro constituían una fracción significativa del total de metales disueltos (hasta el 20% para Fe/Zn, el 45% para Cu).
- El FTMS identificó grupos de sulfuro no protonados de orden superior (por ejemplo, M3S3, M4S6) en lugar de especies simples protonadas.
Conclusiones:
- Los sulfuros metálicos disueltos existen en los sistemas fluviales óxidos y forman estructuras estables y complejas.
- Estos complejos estables de sulfuros metálicos pueden desempeñar un papel crucial en el control de la biodisponibilidad y la toxicidad de los metales traza, incluidos los altamente tóxicos como la plata, el cadmio y el mercurio.
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