Radon-222, a radioactive noble gas with a half-life of 3.8 days produced by radium-226, is a health hazard in caves, but also a powerful tracer of atmospheric dynamics. Here we show how airborne radon-222 can be analysed in a cave with multiple openings, the Pech Merle Cave in South-West France.
View Article and Find Full Text PDFMaghemite (γ-FeO) nanoparticles (MNPs) were functionalized with 3-aminopropyltriethoxysilane (APTES) to give APTES@FeO (AMNP) which was then reacted with diethylenetriamine-pentaacetic acid (DTPA) to give a nanohybrid DTPA-APTES@FeO (DAMNP). Nano-isothermal titration calorimetry shows that DTPA complexation with uranyl ions in water is exothermic and has a stoichiometry of two DTPA to three uranyl ions. Density functional theory calculations indicate the possibility of several complexes between DTPA and UO with different stoichiometries.
View Article and Find Full Text PDFEnvironmental pollution caused by heavy metals constitutes a serious public health problem. In the case of uranium depletion, amidoxime groups are important because of their high affinity for uranium(VI). New series of bis(amidoxime)s with catechol-derived anchor groups were tested (b-AMD-1 and b-AMD-2).
View Article and Find Full Text PDFThe aim of this study was to determine the mobilization capability of Ni, Co, and Mn contained in New Caledonian ultramafic soils. Two series of soils were sampled: bare-surface mining soils in a Ni-mining context (n = 10), and forest soils, either in the vicinity of mine-working areas (n = 3) or far away from any known mining activity (n = 2). We focused on the < 100 μm soil fraction, because of its sensitivity to wind erosion, and its possible dissemination toward urbanized areas.
View Article and Find Full Text PDFThe atmospheric dispersion atmospheric plume of the metropolitan region and neighborhoods of the city of Rio de Janeiro was investigated through elemental analyzes (Na, K, Al, Mn, Pb, Ni, Cr) and stable lead isotopes in two epiphytes; the lichen Parmotrema crinitum (Ach.) and the bromeliad Tillandsia usneoides (L.).
View Article and Find Full Text PDFThroughout history, ancient human societies exploited mineral resources all over the world, even in areas that are now protected and considered to be relatively pristine. Here, we show that past mining still has an impact on wildlife in some French protected areas. We measured cadmium, copper, lead, and zinc concentrations in topsoils and wood mouse kidneys from sites located in the Cévennes and the Morvan.
View Article and Find Full Text PDFThe aim of this study is to explore the use of lichens as biomonitors of the impact of nickel mining and ore treatment on the atmosphere in the New Caledonian archipelago (South Pacific Ocean); both activities emitting also Co, Cr and possibly Fe. Metal contents were analysed in thirty-four epiphytic lichens, collected in the vicinity of the potential sources, and in places free from known historical mining. The highest Ni, Co, and Cr concentrations were, as expected, observed in lichens collected near ore deposits or treatment areas.
View Article and Find Full Text PDFA simple new device for dry separation of fine particulate matter from bulk soil samples is presented here. It consists of a stainless steel tube along which a nitrogen flow is imposed, resulting in the displacement of particles. Taking into account particle transport, fluid mechanics, and soil sample composition, a tube 6-m long, with a 0.
View Article and Find Full Text PDFBackground: Targeting nanoobjects via the iron-acquisition pathway is always reported slower than the transferrin/receptor endocytosis. Is there a remedy?
Methods: Maghemite superparamagnetic and theragnostic nanoparticles (diameter 8.6nm) were synthesized, coated with 3-aminopropyltriethoxysilane (NP) and coupled to four holotransferrin (TFe2) by amide bonds (TFe2-NP).
The synthesis of bimetallic alloy nanocrystals with a well-controlled relative composition is a real challenge and requires chemical analysis techniques with high accuracy. A new chemical route has been used to synthesize cobalt-platinum nanocrystals of 2-nm diameter in a wide range of relative stoichiometry. A study of the elemental composition of the nanoalloy was carried out by X-ray fluorescence (XRF) spectroscopy and energy-dispersive X-ray analysis.
View Article and Find Full Text PDFAtmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed.
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