Selective extraction techniques were used to assay the importance of specific solid phases in Pb binding by heterogeneous surface coating materials (biofilms) in Cayuga Lake, NY. Hydroxylamine hydrochloride (NH(2)OH.HC1) was used to extract easily reducible Mn oxides, and sodium dithionite (Na(2)S(2)O(4)) was used to extract Mn and Fe oxides in two sets of biofilm samples retrieved from the lak...

Iron (Fe) and manganese (Mn) are the two most common redox-active elements in the Earth's crust and are well known to influence mineral formation and dissolution, trace metal sequestration, and contaminant transformations in soils and sediments. Here, we characterized the reaction of aqueous Fe(II) with pyrolusite (β-MnO2) using electron microscopy, X-ray diffraction, aqueous Fe and Mn analyses...

The microstructure and local mechanical characteristics of thermal spray ferrous coatings have been determined. The emphasis has been on coatings made by the high velocity oxyfuel (HVOF) process, especially the role of Al alloy additives. The oxide phase present in the material and preferred pathways for local cracking and separation have been determined. Thin intersplat oxide layers emerge as ...

Sorption and desorption experiments were performed by the batch method on the B horizons of five natural soils: Umbric Cambisol, Endoleptic Luvisol, Mollic Umbrisol, Dystric Umbrisol, and Dystric Fluvisol. Individual and competitive sorption and desorption capacity and hysteresis were determined. The results showed that Pb2+ was sorbed and retained in a greater quantity than Cd2+ and that the h...

Aquifer sediment samples obtained from the anaerobic part of a landfill leachate plume in Vejen, Denmark, were suspended in groundwater or in an artificial medium and incubated. The strictly anaerobic suspensions were tested for reduction of ferric iron [Fe(III)] oxides, which was measured as an increase in the concentration of dissolved Fe(II). Iron reduction did not occur when the medium was ...

The adsorption of DNA by an andosol was much greater than that by a fluvisol or acrisol. The decrease in soil organic matter on treatment with hydrogen peroxide (H(2)O(2)) little affected DNA adsorption per weight of the particles, implying that the organic matter is not involved in the adsorption. The acid oxalate treatment of the H(2)O(2)-treated soils decreased DNA adsorption. Among soil con...

The adsorption of DNA by an andosol was much greater than that by a fluvisol or acrisol. The decrease in soil organic matter on treatment with hydrogen peroxide (H2O2) little affected DNA adsorption per weight of the particles, implying that the organic matter is not involved in the adsorption. The acid oxalate treatment of the H2O2-treated soils decreased DNA adsorption. Among soil constituent...

Dissolved organic matter (DOM) is implicated in arsenic (As) and iron (Fe) mobilization via microbial metabolic processes. The Ganges Delta Plain is a key area where As contamination of groundwater constitutes a human catastrophe. The delta plain geomorphology comprises a large number of abandoned meander bends, or oxbow lakes (Donselaar et al., 2017) characterized by an anoxic environment in t...

X-ray fluorescence spectra obtained by the MESSENGER spacecraft orbiting Mercury indicate that the planet's surface differs in composition from those of other terrestrial planets. Relatively high Mg/Si and low Al/Si and Ca/Si ratios rule out a lunarlike feldspar-rich crust. The sulfur abundance is at least 10 times higher than that of the silicate portion of Earth or the Moon, and this observat...

Ancient rocks record the redox conditions of the oceanatmosphere system through the distribution of iron (Fe) between oxidised and reduced minerals, which can be formulated into a suite of Fe palaeoredox proxies. The balance between Fe and S in a given system reflects the variance in a range of highand low-temperature sources and sinks. Iron can be delivered by hydrothermal, diagenetic or clast...