Cadmium isotope fractionation during sorption to soil minerals: Lab evidence and field implication

Unraveling the nuclear isotope tapestry: Applications, challenges, and future horizons in a dynamic landscape

“…Factors such as soil type, pH, organic matter content, and moisture levels influence the mobility and binding affinity of these isotopes [ 90 ]. In many instances, isotopes can bind strongly to soil particles, reducing their immediate mobility but posing long-term contamination risks [ 91 ]. In contrast, in aquatic sediments, the interplay of water currents, sediment composition, and biological activity can influence the distribution and concentration of these radioactive materials.…”

Cadmium Isotope Fractionation during Adsorption onto Edge Sites and Vacancies in Phyllomanganate

“…From a practical point of view, reconstruction of the isotope fractionation of solids by using the two end members may be used to assess the relative proportions of Cd 2+ adsorbed onto birnessite edge sites and vacancies, which is currently challenging. The present results also suggest that these birnessite-like minerals may affect Cd isotope fractionation to a larger extent than other active components, such as Fe/Al (hydr)­oxides, clay minerals, calcite, quartz, or humic acids. − , In addition to birnessite structural characteristics, such as the relative proportions of vacancy and edge sites, different binding modes of Cd 2+ adsorption onto Mn (hydr)­oxides (e.g., tectomanganates with different tunnel sizes), and under contrasting environmental conditions (e.g., presence and nature of inorganic and organic ligands, temperature), may influence Cd isotope fractionation further. ,,, Additional studies are thus needed to fully elucidate the intrinsic mechanisms and influencing factors of the directions and magnitudes of Cd isotopic fractionation during its interaction with environmentally relevant Mn (hydr)­oxides.…”

“…Adsorption of heavy metals onto solid surfaces can induce isotope fractionation. − Previous studies have demonstrated that light Cd isotopes are preferentially adsorbed onto soil active minerals (e.g., Fe/Mn/Al (hydr)­oxides, clay minerals, calcite, and quartz). ,− However, fractionation mechanisms during such interface reactions are not clearly constrained. Our previous study on Cd isotope fractionation during adsorption onto Fe (hydr)­oxides revealed that the isotope offsets were independent of reaction conditions, such as ionic strength, initial Cd concentration, and pH, as well as mineral type, but were attributed only to the strong distortion of CdO 6 octahedra formed at mineral surfaces .…”

Isotope Evidence for Rice Accumulation of Newly Deposited and Soil Legacy Cadmium: A Three-Year Field Study

“…In the last two decades, significant advancement in multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) analysis of nontraditional stable isotopes has introduced Cd isotope analysis as a powerful tool for source identification in various fields and may elucidate uptake pathways for Cd in cereal plants . The isotopic composition of Cd has been determined in meteorites, rocks, ores, soils, sediments, aquatic organisms, and plant samples. ,− Several studies have relied on mass-dependent fractionation or differences in Cd isotopic ratios from the original substance for soil source identification and fingerprinting. − However, identifying the source of Cd in plants poses significant challenges due to the fractionation of Cd isotopes during biological uptake . Fortunately, Cd isotope fractionation occurs during industrial processes at high temperatures, resulting in a heavy isotopic signature in slag and a light signature in dust released into the atmosphere .…”