Thallium and co-genetic trace elements in hydrothermal Fe-Mn deposits of Central Spain.

Thallium (Tl) is a hazardous trace metal that can harm human and environmental health. Tl pollution can result from the mining and smelting of Tl-bearing minerals, but also the natural weathering of Tl-bearing sulfide minerals may induce Tl release to the environment. In this study, hydrothermal deposits hosted in dolostone rocks sited along fossil thermal springs in the Lodares region (Soria province, central Spain) were studied.

Radiation effect on cathodoluminescence and thermoluminescence emission of Ca-rich oxalates from the human body.

The radiation effect of luminescence emission of Ca-rich oxalate biogenic materials (gallbladder and renal calculi) and a commercial standard sample (CaC O ·H O) is reported. The samples were characterized by environmental scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric and differential thermal analyses, display complex cathodoluminescence (CL) and thermoluminescence (TL) glow emissions. CL spectra (in the UV-infrared range) displayed non-well defined peaks, and exhibited emission at: (i) higher energies (300-490 nm) mainly associated with non-bridging oxygen hole centers, oxygen-deficient centers and peroxy intrinsic defects, regardless of the sample; and (ii) higher, narrow and sharp wavebands, in the red region, probably induced by the presence of traces of Sm ( G → H transition) and/or Tb ( D → F transition) only for mineral-like materials in the human body.

Historical roasting of thallium- and arsenic-bearing pyrite: Current Tl pollution in the Riotinto mine area.

Samples of an open-air pyrite roasting heap from the 19th century in the Riotinto mine area (SW Spain) and surrounding sediments and soil along a seasonal surface runoff channel were analyzed to study thallium (Tl) phase transformations during historical roasting of Tl-bearing arsenian pyrite, secondary weathering processes, Tl dispersion and current environmental pollution. Results from Electron Probe Microanalyses (EPMA) indicate an even distribution of Tl in pyrite grains of an ore sample (22 mg kg total Tl), suggesting that Tl is incorporated in the pyrite structure rather than in discrete Tl-sulfide microparticles. The roasting residue (122 mg kg total Tl) consists mainly of hematite.

Iron oxide - clay composite vectors on long-distance transport of arsenic and toxic metals in mining-affected areas.

Mine wastes from abandoned exploitations are sources of high concentrations of hazardous metal(oid)s. Although these contaminants can be attenuated by sorbing to secondary minerals, in this work we identified a mechanism for long-distance dispersion of arsenic and metals through their association to mobile colloids. We characterize the colloids and their sorbed contaminants using spectrometric and physicochemical fractionation techniques.

Chemistry and phase evolution during roasting of toxic thallium-bearing pyrite.

In the frame of a research project on microscopic distribution and speciation of geogenic thallium (Tl) from contaminated mine soils, Tl-bearing pyrite ore samples from Riotinto mining district (Huelva, SW Spain) were experimentally fired to simulate a roasting process. Concentration and volatility behavior of Tl and other toxic heavy metals was determined by quantitative ICP-MS, whereas semi-quantitative mineral phase transitions were identified by in situ thermo X-Ray Diffraction (HT-XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) analyses after each firing temperature. Sample with initial highest amount of quartz (higher Si content), lowest quantity of pyrite and traces of jarosite (lower S content) developed hematite and concentrated Tl (from 10 up to 72 mg kg) after roasting at 900 °C in an oxidizing atmosphere.

Spectral cathodoluminescence analysis of hymenopteran mandibles with different levels of zinc enrichment in their teeth.

The inclusion of Zn in insect mandibles affects their hardness and is functional to their use during feeding or reproducing. However, little is known on the chemical/structural base of Zn enrichment. Here, we found that cathodoluminescence (CL) technique revealed two different types of CL spectra in the mandibles of Hymenoptera, depending on the Zn enrichment level assessed by Energy Dispersive X-ray Spectroscopy (EDS).

Combining single-particle inductively coupled plasma mass spectrometry and X-ray absorption spectroscopy to evaluate the release of colloidal arsenic from environmental samples.

Detection and sizing of natural colloids involved in the release and transport of toxic metals and metalloids is essential to understand and model their environmental effects. Single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS) was applied for the detection of arsenic-bearing particles released from mine wastes. Arsenic-bearing particles were detected in leachates from mine wastes, with a mass-per-particle detection limit of 0.

Colloidal mobilization of arsenic from mining-affected soils by surface runoff.

Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond.

Studies on luminescence from a cerium-doped strontium stannate phosphor.

The crystal structure and morphology of Ce(3+) -doped SrSnO3 materials prepared using the solid-state reaction method were extensively characterized using experimental techniques. X-Ray diffraction results show that the cerium substitution of strontium does not change the structure of the strontium stannate. Raman spectroscopy was used to investigate the microstructures and lattice vibrations.

Composition and spectra of copper-carotenoid sediments from a pyrite mine stream in Spain.

Mine drainages of La Poderosa (El Campillo, Huelva, Spain), located in the Rio Tinto Basin (Iberian Pyrite Belt) generate carotenoid complexes mixed with copper sulfates presenting good natural models for the production of carotenoids from microorganisms. The environmental conditions of Rio Tinto Basin include important environmental stresses to force the microorganisms to accumulate carotenoids. Here we show as carotenoid compounds in sediments can be analyzed directly in the solid state by Raman and Luminescence spectroscopy techniques to identify solid carotenoid, avoiding dissolution and pre-concentration treatments, since the hydrous copper-salted paragenesis do not mask the Raman emission of carotenoids.

Non-destructive analyses on a meteorite fragment that fell in the Madrid city centre in 1896.

The historical Madrid meteorite chondrite fell in 1896 showing thin melt veins with a 65% of brecciated forsterite fragments surrounded by a fine grained matrix formed by troilite, chromite and Fe-Ni blebs. It exhibits a delicate iron infill, neo-formation of troilite in pockets and shock veins and neo-formation of Na-feldspar formed at high temperature and fast quenching. The semi-quantitative mineral determinations were performed with IMAGEJ freeware and chemical mappings resulting in the following approximated compositions: olivine (~55%); augite (~10%); enstatite (~10%); plagioclase (~10%); chromite (~2%); troilite (~4%), kamacite-taenite α-γ-(Fe, Ni) (~7%) and merrillite (~7%).

Study of coal and graphite specimens by means of Raman and cathodoluminescence.

The weak luminescence shown by coals has been attributed to accessorial minerals and poly-nuclear aromatic hydrocarbons, such as exinite, vitrinite or inertinite, while the luminescence quenching has been found in asphaltenes produced by coal hydrogenation or in pyridine extracts. Nowadays, the spatial resolution and the improved luminescence efficiency of the modern spectrometers allow some details of the luminescent emission centers to be explained. We have selected museum historical coal specimens with different rank, i.

Ossification vesicles with calcium phosphate in the eyes of the insect Copium teucrii (Hemiptera: Tingidae).

Arthropod eyes are built of repeating units named ommatidia. Each single ommatidium unit contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The insect Copium eye ommatidia include additional calcium-phosphate deposits, not described in insects to date, which can be examined today using a combined set of modern microscopy and spectroscopy techniques.

Byzantine wall paintings from Kastoria, northern Greece: spectroscopic study of pigments and efflorescing salts.

This study concerns the investigation of pigments and efflorescence phenomena on the wall paintings of Kastoria, a rural, non-metropolitan Byzantine town. A large number of representative samples were collected from the murals of three churches, dated to post-Byzantine era (14th-17th c. AD).

Influence of accumulation of heaps of steel slag on the environment: determination of heavy metals content in the soils.

The presence of high level of heavy metals involves a human healthy risk that could induce chronic diseases. This work reports on the metal contamination due to heaps of steel-slag accumulated during more than 40 years in allotments and industrial areas in the southern part of Madrid (Spain). Several slag and soil samples were collected in an area of 10 km(2) and characterized by different conventional (XRD and XRF) and no so common methods (ESEM, thermoluminescence and EDS-WDS).

An anamorph of the white-rot fungus Bjerkandera adusta capable of colonizing and degrading compact disc components.

A Geotrichum-like fungus isolated from a biodeteriorated compact disc (CD) was able to degrade in vitro the components of different CD types. The fungal hyphae inside the CD fragments grew through the aluminium layer and produced the solubilization of this metal. Furthermore, examination of CDs by scanning electron microscopy showed that the fungus was able to destroy the pits and lands structures grooved in the polycarbonate layer, confirming degradation of this aromatic polymer.

Low-magnesium uranium-calcite with high degree of crystallinity and gigantic luminescence emission.

Cabrera (Madrid) low-Mg calcites exhibit: (i) an unusual twofold elevation in X-ray diffraction pattern intensity; (ii) a 60-fold elevation of luminescence emission, compared to six common natural calcites selected for comparison purposes; (iii) a natural relatively high radiation level of circa 200 nSvh(-1) not detected in 1300 other calcites from the Natural History Museum of Madrid. Calcites were analysed by the X-ray diffraction powder method (XRD), cathodo-luminescence spectroscopy in scanning electron microscopy (CL-SEM), thermoluminescence (TL), differential thermal analysis (DTA), X-ray fluorescence spectrometry (XRF) and particle size distribution (PSD). The Cabrera calcite study shows: (i) helicoidally distributed steps along the (0001) orientation; (ii) protuberance defects onto the (0001) surface, observed by SEM; (iii) XRF chemical contents of 0.