Arsenic mineralogy and mobility in the arsenic-rich historical mine waste dump.

A more than 250 year-old mine dump was studied to document the products of long-term arsenopyrite oxidation under natural conditions in a coarse-grained mine waste dump and to evaluate the environmental hazards associated with this material. Using complementary mineralogical and chemical approaches (SEM/EDS/WDS, XRD, micro-Raman spectroscopy, pore water analysis, chemical extraction techniques and thermodynamic PHREEQC-2 modeling), we documented the mineralogical/geochemical characteristics of the dumped arsenopyrite-rich material and environmental stability of the newly formed secondary minerals. A distinct mineralogical zonation was found (listed based on the distance from the decomposed arsenopyrite): scorodite (locally associated with native sulfur pseudomorphs) plus amorphous ferric arsenate (AFA/pitticite), kaňkite, As-bearing ferric (hydr)oxides and jarosite.

Natural attenuation of arsenic in soils near a highly contaminated historical mine waste dump.

Arsenic-contaminated soils near historical As-rich mine waste in Jáchymov (Czech Rep.), resulting from the smelting and seepage of the mine waste pore water, were studied to examine As partitioning between solid phases and pore waters. Mineralogical and geochemical analyses showed that As is exclusively associated with unidentified amorphous Fe oxyhydroxides, poorly crystalline goethite and hematite as adsorbed and coprecipitated species (with up to 3.

Secondary arsenic minerals in the environment: a review.

Information on arsenic (As) speciation in solid materials is critical for many environmental studies concerned with As stability and/or mobility in natural As-impacted soils and mining or industrial sites contaminated by As. The investigation of these systems has provided evidence for a number of secondary As minerals that have often played a significant role in As mobility in the solid phase-water system. This paper presents a list of environmentally important secondary As minerals in contaminated soil and waste systems, summarizes the information about their origin, occurrence, environmental stability and thermodynamics, and proposes several important avenues for further investigation.

Raman microspectroscopy as a valuable additional method to X-ray diffraction and electron microscope/microprobe analysis in the study of iron arsenates in environmental samples.

In this paper, we demonstrate that combined application of X-ray diffraction (XRD), electron microscope/microprobe analysis (EMPA), and Raman microspectroscopy is an available and powerful approach for identification and characterization of iron arsenate minerals in complex environmental samples. Arsenic-rich material from the medieval mining dump close to the Giftkies mine in the Jáchymov ore district (Czech Republic) has been studied. Scorodite, kankite, amorphous iron arsenate (pitticite), and, to a lesser extent, native sulfur were determined in the studied samples as products of low-temperature arsenopyrite weathering.

Mineralogical and geochemical controls of arsenic speciation and mobility under different redox conditions in soil, sediment and water at the Mokrsko-West gold deposit, Czech Republic.

Naturally contaminated soil, sediment and water at the Mokrsko-West gold deposit, Central Bohemia, have been studied in order to determine the processes that lead to release of As into water and to control its speciation under various redox conditions. In soils, As is bonded mainly to secondary arseniosiderite, pharmacosiderite and Fe oxyhydroxides and, rarely, to scorodite; in sediments, As is bonded mainly to Fe oxyhydroxides and rarely to arsenate minerals. The highest concentrations of dissolved As were found in groundwater (up to 1141 microg L(-1)), which mostly represented a redox transition zone where neither sulphide minerals nor Fe oxyhydroxide are stable.

Oxidation of the arsenic-rich concentrate at the Prebuz abandoned mine (Erzgebirge Mts., CZ): mineralogical evolution.

Ore concentrate with up to 65 wt.% of arsenic (by-product of cassiterite extraction) exposed to climatic conditions was studied from the mineralogical point of view. Detailed sampling, X-ray diffraction analyses, energy-dispersive microanalysis (EDAX) and especially scanning electron microscopy (SEM) were applied to study the arsenopyrite-löllingite-concentrate weathering.