In practice, stable Cd isotope ratios are being applied to trace pollution sources in the natural environment. However, Cd isotope fractionation during weathering processes is not yet fully understood. We investigated Cd isotope fractionation of PbZn ore in leaching experiments and in the environment under natural weathering processes. Our leaching experiments demonstrated that the leachate was enriched with heavy Cd isotopes, relative to initial and residual samples (Δ(114/110)Cdleachate - initial state = 0.40-0.50‰, Δ(114/110)Cdleachate -residual state = 0.36-0.53‰). For natural samples, δ(114/110)Cd values of stream sediments were higher than those of the corresponding soil samples collected from the riverbank, Δ(114/110)Cdstream sediment -soil can be up to 0.50‰. This observation is consistent with our leaching experiments, which indicate significant Cd isotope fractionation during natural weathering processes. Therefore, natural contributions should be considered when using Cd isotopes to trace anthropogenic pollution in water and sediment systems.
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http://dx.doi.org/10.1016/j.envpol.2016.04.060 | DOI Listing |
ACS Earth Space Chem
January 2025
Department of Earth Sciences, Utrecht University, 3584 CB Utrecht, The Netherlands.
Chemical weathering processes play a key role in regulating the global climate over geological time scales. Lithium (Li) isotope compositions have proven to be a robust proxy for tracing weathering processes that produce secondary minerals, such as clays and oxides, with a focus often placed on Li adsorption to, or incorporation into, clay minerals. In addition, the interaction between Li and Fe-oxides has long been assumed and discussed based on field observations, but experimental constraints on this process are lacking.
View Article and Find Full Text PDFEnviron Pollut
January 2025
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Natural attenuation represents a significant ecosystem function for mitigating the quantity and toxicity of polycyclic aromatic hydrocarbons (PAHs) through both abiotic and biotic dissipation processes. This study systematically investigated abiotic and biotic dissipation of phenanthrene (Phe) and benzo[a]pyrene (BaP) in four soils over 360 days, using CSIA to quantitatively analyze δ³C changes and demonstrate biodegradation. The results indicated that extractable Phe was primarily attenuated via biodegradation (65% - 81%), as revealed by CSIA, with the δ³C changes ranging from 2.
View Article and Find Full Text PDFAnal Chem
January 2025
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, China.
A novel method has been developed for the simultaneous online determination of the isotopic compositions of different antimony (Sb) species in a single analytical run using high-performance liquid chromatography (HPLC) coupled with multicollector inductively coupled plasma mass spectrometry (MC-ICPMS), with hydride generation (HG) serving as the interface. Various parameters affecting the precision of Sb isotope analysis including HG conditions, transient signal processing methods and peak integration windows, were optimized. The linear regression slope method and a 100% peak integration window provided the optimal precision.
View Article and Find Full Text PDFSci Total Environ
January 2025
Laboratorio de Limnología, Unidad de Ecología y Sistemática (UNESIS), Departamento de Biología, Pontificia Universidad Javeriana, Bogotá, Colombia.
In this study, we focused on Lake Tota (Colombia) as a model for investigating the impact of anthropogenic activities on lake productivity. Two sediment cores collected from the two main basins of the lake (Lago Grande and Lago Chico) were dated using alpha spectrometry for Pb. Changes in organic matter, carbon and nitrogen isotope ratios, C:N ratios, diatoms and elemental fractions were examined as indicators of productivity.
View Article and Find Full Text PDFJ Nutr
January 2025
Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA.
Background: Retinol isotope dilution (RID) equations are used to predict vitamin A total body stores (TBS). Including population-based ("super-subject") modeling with RID provides group-specific values for the equation coefficients.
Objectives: Objective was to test an approach that would accommodate a limited super-subject sample size without compromising accuracy in RID predictions of TBS.
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