The largest range in MDF is obsd. The largest pos. MIF of Hg isotopes odd-mass excess is caused by photochem. This signature is retained through the food web and measured in all freshwater and marine fish. The largest neg. MIF of Hg isotopes odd-mass deficit is caused by photochem. Hg and has been obsd. More than a decade of research demonstrates that Hg isotopes can be used to trace sources, biogeochem.
Isotope fractionation of mercury during its photochemical reduction by low-molecular-weight organic compounds J. LMWOC was studied to evaluate the effect of specific functional groups that are typically encountered in natural dissolved org. The nuclear field shift effect was also obsd. These isotope effects are related to specific functional groups and redn. Isotopic composition and fractionation of mercury in Great Lakes precipitation and ambient air Environ.
Hg stable isotope geochem. To examine the atm. Hg isotopic compn. Significant pos.
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MIF of Hg up to 0. Such MIF of an even-mass Hg isotope was not previously reported for natural samples. Results contrast with recent predictions of the isotopic compn. Hg and suggest that, in addn. Unusual fractionation of both odd and even mercury isotopes in precipitation from Peterborough, ON, Canada Geochim. Once released into the atm. Though impressive progress has been made in understanding all aspects of Hg behavior in the atm.
Hg remain unidentified and source attribution is still an enormous challenge. The isotopic compn. All pptn. Results may suggest that photoredn. Mercury isotopes in a forested ecosystem: Implications for air-surface exchange dynamics and the global mercury cycle Global Biogeochem. Forests mediate the biogeochem. Our objectives in this study were to characterize Hg isotopic compn.
We quantified the stable Hg isotopic compn. The effect of increased atm. CO2 and O3 concns. Uptake of THg g by foliage resulted in a large Mercury isotopes distinguished geogenic sources of Hg and atm. Hg inputs. Mercury evasion from the forest floor may have arisen from air-surface exchange of atm.
THg g , but was not the emission of legacy Hg from soils, nor re-emission of wet-deposition. This implies that there was net atm. THg g deposition to the forest soils. Furthermore, MDF of Hg isotopes during foliar uptake and air-surface exchange of atm. THg g resulted in the release of Hg with very pos. Unique Hg stable isotope signatures of compact fluorescent lamp-sourced Hg Environ. The recent widespread adoption of compact fluorescent lamps CFL has increased their importance as a source of environmental Hg.
Stable isotope anal. This fractionation is large vs. The fractionation process described may also explain anomalous fractionation of Hg isotopes in pptn. Isotopic abundance variations of selected elements Pure Appl. Coplen, T. International Union of Pure and Applied Chemistry. Documented variations in the isotopic compns. This report summarizes reported variations in the isotopic compns. For 2 elements Cr and Tl , recently reported isotope-abundance variations potentially are large enough to result in future expansion of their at. For 7 elements Mg, Ca, Fe, Zn, Mo, Pd, and Te , documented isotope variations in materials of natural terrestrial origin are too small to have a significant effect on their std.
This compilation indicates the extent to which the at.
For most elements given above, data are graphically illustrated by a diagram in which the materials are specified in the ordinate and the compositional ranges are plotted along the abscissa in scales of 1 at. Geological Society of America. The Hg isotopic compns. The Hg isotope compns. These differences probably resulted from the combination of boiling of the hydrothermal fluid, oxidn.
BY G.W. SEPTIMUS PIESSE,
The natural variation in Hg isotopic compns. Stable isotope geology. Exploration potential of Cu isotope fractionation in porphyry copper deposits J. We examd. Cu-sulfides, secondary low temp. Cu-sulfides and Cu-oxides as well as Fe-oxides in the leach cap, which represent the weathered remains of a spectrum of Cu mineralization, from nine porphyry copper deposits.
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The overall isotopic variability measured in these samples range from - Distinct Cu isotopic reservoirs exist for high temp. Chalcopyrite from high temp. Leach cap minerals dominated by Fe-oxides jarosite, hematite and goethite are relatively light ranging from - 9.
The pattern could be used as a tool for exploration geol. Stable isotopes of Cr and Se as tracers of redox processes in Earth surface environments. We explored Cr isotope systematics at 11 sites in the Czech Republic and Poland.
Geogenic Cr pollution was assocd. Cr VI concn. At the industrial sites, this pos. Small-scale studies of roasted ore waste reveal extreme ranges of stable mercury isotope signatures Geochim. Smith, Robin S.
Chemical causes (toxics / biocides)
Active and closed Hg mines are significant sources of Hg contamination to the environment, mainly due to large vols. The application of Hg isotopes as source tracer from such contaminated sites requires knowledge of the Hg isotope signatures of different materials potentially released to the environment.
Previous work has shown that calcine, the waste residue of the on-site ore roasting process, can exhibit distinct Hg isotope signatures compared with the primary ore. Significant Fe, S, and Hg concn. Isotopic analyses revealed an extreme variation with pronounced isotopic gradients across the internal layered features.
Our results demonstrate that the incomplete roasting of HgS ores in Hg mines can cause extreme mass-dependent Hg isotope fractionations at the scale of individual calcine pieces with enrichments in both light and heavy Hg isotopes relative to the primary ore signatures.
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This finding has important implications for the application of Hg isotopes as potential source tracers for Hg released to the environment from closed Hg mines and highlights the need for detailed source signature identification. We report a method for the chem. Double-spiking of samples was carried out prior to digestion and chem. Samples were digested using a NiS fire assay method, which pre-concs.
Pt into a metallic bead that is readily dissolved in acid in prepn. Pt was recovered from anion-exchange resin in concd. HNO3 acid after elution of matrix elements, including the other platinum group elements PGE , in dil.
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HCl and HNO3 acids. The sepn.
source url Using this chem. Pt from 11 international geol. Pt concns. This anal. Creech et al. The reproducibility in natural samples is evaluated by processing multiple replicates of four std. Pt stable isotope data for the full set of ref.