Factors controlling the release of arsenic from mining tailings

Abstract

Some mine tailings pools in the Mine District of Guanajuato, Mexico, present a varied distribution and temporal and spatial concentration of elements that are potentially toxic, such as manganese, cadmium and zinc. These elements were detected in majority concentrations, and arsenic was present in the two major oxidation states As(III) and As(V). The highest arsenic concentration in the surrounding surface water reservoirs was detected when a rainy seasons occurred, which in turn is mainly a function of pH and the presence of bicarbonate ions. The conceptual model to describe the mobilization of arsenic from mining tailings towards the aqueous systems proposes a scenario where oxidation, the neutralization of acid drainage by carbonates, and arsenic desorption by bicarbonates takes place in different steps and at different times.

Mobilization of arsenic from contaminated sediment by anionic and nonionic surfactants

“…The introduction of OH − could increase the replacement of arsenic from sediment. Increase of pH could also enhance the negative charge of the sediment particle surface, which could enhance the repulsion between arsenic species in the solution and the sediment surface (Rodríguez-Cruz et al, 2005;Rubinos et al, 2010;Rubio-Campos et al, 2010;Shen, 2000;Sugihara et al, 2008). However, previous research has reported that the increase of pH had a negative effect on the adsorption of anionic surfactants due to the reversion of the surface charge (Camacho et al, 1996;Huang and Van Benschoten, 2000;Li et al, 2012;Mushtaq et al, 2015).…”