Investigations on Iron Precipitates accumulating from underground workings and Mud Lake at South Bay

In pyritic mining wastes, the release and subsequent oxidation of Fe(II) from mining sites may produce non-negligible amounts of high sulfate and extremely low pH waters. The resulting acid mine drainage (AMD) may be divided into three types: • iron sulfide oxidation, • dissolution of soluble iron sulfate minerals, and • the dissolution of less soluble sulfate minerals of the alunite-jarosite series. The oxidation of iron sulfide minerals such as pyrite (FeS2) and pyrrhotite is responsible for the majority of acid production from mining wastes. In addition to metals, acid, sulfate is also released to ground and surface water. If sulfate is present in higher concentrations a variety of iron minerals may form, i.e.: jarosite (XFe3(SO4)2(OH)6, (X being a monovalent cation) • Schwertmannite (Fe8O8(OH)6SO4). These secondary minerals are not stable and the release of sulfate by dissolution of these minerals may result in the formation of Fe(III) hydroxides with subsequent acid (H+ ) release. Secondary mineral formation, with hydrogen-ion generation leading to pH values as low as pH 1, was reported in stored South Bay tailings pore water. Investigations on the secondary mineral phases, along with microbial investigations, were carried out and Schwertmannite minerals were detected as reported in Kalin, 2003, "The acid generation potential of iron precipitates and their sludge in Decommissioning with Ecological Engineering". This is a matter of some concern, given the high number of hydrogen ions, generated by the formation of Schwertmannite, The natural precipitation of stable, iron-hydroxide sludge, which is not a source of acidity, is an important component of the Ecological Engineering decommissioning approach. Thus Schwertmannite formation is undesirable, and the conditions under which it occurs must well understood. Samples of sludge were collected from relevant locations at the South Bay site for an investigation into the formation of this secondary mineral

Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine

Remediation of former uranium mining sites represents one of the biggest challenges worldwide that have to be solved in this century. During the last years, the search of alternative strategies involving environmentally sustainable treatments has started. Bioremediation, the use of microorganisms to clean up polluted sites in the environment, is considered one the best alternative. By means of culture-dependent methods, we isolated an indigenous yeast strain, KS5 (Rhodosporidium toruloides), directly from the flooding water of a former uranium mining site and investigated its interactions with uranium. Our results highlight distinct adaptive mechanisms towards high uranium concentrations on the one hand, and complex interaction mechanisms on the other. The cells of the strain KS5 exhibit high a uranium tolerance, being able to grow at 6 mM, and also a high ability to accumulate this radionuclide (350 mg uranium/g dry biomass, 48 h). The removal of uranium by KS5 displays a temperature- and cell viability-dependent process, indicating that metabolic activity could be involved. By STEM (scanning transmission electron microscopy) investigations, we observed that uranium was removed by two mechanisms, active bioaccumulation and inactive biosorption. This study highlights the potential of KS5 as a representative of indigenous species within the flooding water of a former uranium mine, which may play a key role in bioremediation of uranium contaminated sites.This work was supported by the Bundesministerium für Bildung und Forschung grand nº 02NUK030F (TransAqua). Further support took place by the ERDF-co-financed Grants CGL2012-36505 and 315 CGL2014-59616R, Ministerio de Ciencia e Innovación, Spain

Dissociating the effects of alternative early-life feeding schedules on the development of adult depression-like phenotypes

Neville, V., Andrews, C., Nettle, D. and M. Bateson (2017). Dissociating the effects of alternative early-life feeding schedules on the development of adult depression-like phenotypes. Scientific Reports 7: 14832

Carbonat-Komplexierung des dreiwertigen Americiums unter Grundwasserbedingungen

Available from TIB Hannover: DW 5075 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman