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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: Manganese mobilization from quarries and tailings in four watersheds of the Molango Mining District, Mexico

Autores UNAM:
CHRISTINA DESIREE SIEBE GRABACH; SILKE CRAM HEYDRICH;
Autores externos:

Idioma:
Inglés
Año de publicación:
2010
Palabras clave:

Aquatic biota; Environmental hazards; Human settlements; Me-xico; Mining activities; Mining district; Mn content; Point sources; Potential risks; Pyrite oxidation; Reducing conditions; River systems; Sediment samples; Soluble mn; Erosion; Manganese; Ore deposits; Quarries; Sedimentology; Sediments; Watersheds; Manganese removal (water treatment)


Resumen:

In the Sierra Madre Oriental Mn ore deposits are mined since the 1960s. Intense rainfalls promote erosion and disseminate Mn rich sediments from quarries and tailings into river systems. In four watersheds we studied water and sediment samples before and after point sources of mining activities to assess their contribution to Mn in sediments and surface water and to evaluate potential environmental hazards. Results show a clear contribution of discharges and erosion on Mn contents in sediments of up to 250 g kg -1. Locally at quarries, pyrite oxidation acidifies the water and increases soluble Mn concentrations to up to 4.5 mg L -1. Nevertheless, the imbedding limestone neutralizes the water and MnCO 3 precipitates few 100 m downstream. Close to human settlements along the river, Mn solubility increases again locally to 2.8 mg L -1. Organic matter inputs through domestic discharges seem to provide reducing conditions and mobilize Mn, which poses a potential risk for aquatic biota and humans. © 2010 Taylor & Francis Group, London.


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