The fate of arsenic in groundwater depends largely on its interaction with mineral surfaces. We investigated the kinetics of As(III) oxidation by aquifer materials collected from the USGS research site at Cape Cod, MA, USA, by conducting laboratory experiments. Five different solid samples with similar specific surface areas (0.6–0.9 m g ) and reductively extractable iron contents (18– 26 lmol ...

The objective of this study was to evaluate the possible effects of manganese (Mn) exposure on variations of cortisol levels in Garra gotyla gotyla. LC50 value of manganese after 96 hours was found to be 3.2mg/l for Garra gotyla gotyla. Three replicates of 10 fishes were subjected to three sub-lethal concentrations of manganese i.e. 0.64mg/l, 1.28mg/l and 1.92mg/l (20%, 40% and 60% respectively...

Rock varnish is generally understood to be a 5-500 micrometer thick nanostratigraphic coating consisting of approximately 70% clay glued together by 30% iron and manganese oxides, which forms on the surfaces of rocks in most semi-arid to hyper-arid climates. Many investigators believe that manganese exists in rock varnish mainly as birnessite, and that varnish has at least a partial biological ...

The crucial role of manganese(III) species in the oxidative and catalytic reactivity manganese oxides have been widely reported. However, direct activation radical precursors by Mn(III) is still a matter discussion. In this work, ability Mn(III)-bearing oxide (Mn2O3) for peroxydisulfate (PS) peroxymonosulfate (PMS) was evaluated compared using caffeine (CAF) as model pollutant. Complete CAF rem...

Chromite is a mineral with low solubility and is thus resistant to dissolution. The exception is when manganese oxides are available, since they are the only known naturally occurring oxidants for chromite. In the presence of Mn(IV) oxides, Cr(III) will oxidise to Cr(VI), which is more soluble than Cr(III), and thus easier to be removed. Here we report of chromite phenocrysts that are replaced ...