IBIGEO   22622
INSTITUTO DE BIO Y GEOCIENCIAS DEL NOA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Arsenic solid speciation in tailings of the abandoned Pan de Azúcar mine, Northwestern Argentina
Autor/es:
MURRAY, J.; GARCÍA M. G; BORGNINO L; MENDEZ GUIMARAES, E.; KIRSCHBAUM, A.
Lugar:
Buenos Aires
Reunión:
Congreso; V International Congress of Arsenic in the Environment.; 2014
Resumen:
In the Argentina Puna region there are several metal sulfide mines that ceased their activity twenty years ago without a proper closure plan. The exposure of the waste rocks and tailing impoundments to weathering led to sulfide oxidation and generation of highly acid solutions rich in metal(oid)s, that react with the unaltered waste rocks, partitioning into different solid phases. The As speciation along a 120 cm depth oxidation profile described in the Pan de Azucar mine tailings was studied by standarized sequential extraction procedures. Results show that the highest As concentration remain in the bottom unaltered layer mainly associated with primary and secondary sulfides. In the upper layers, the total As concentrations are 40 to 70% lower than that of the bottom layer, and most As is associated with amorphous and cristalline oxides. More bioavailable forms of As (exchangeable and soluble) account for less than 1.5% of the total As concentration.