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Isotope technology is an ideal tool for tracing the sources of certain pollutants or providing insights into environmental processes. In recent years, the advent of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has enabled the precise measurement of various metal stable isotopes. Due to the presence of "fingerprint" properties in various environmental samples, metal stable isotopes have been applied to distinguish the source of contaminants effectively and further understand the corresponding environmental processes. The environmental fate of metal elements is strongly controlled by adsorption, an essential process for the distribution of elements between the dissolved and particulate phases. The adsorption of metal elements on mineral and organic surfaces significantly affects their biogeochemical cycles in the environment. Therefore, it is crucial to elucidate the fractionation characteristics of stable metal isotopes during the adsorption process. In this review, three typical transitional metal elements were selected, considering Mo as the representative of anionic species and Fe and Zn as the representative of cationic species. For Mo, the heavier Mo isotope is preferentially adsorbed in the solution phase, pH has a more significant influence on isotope fractionation, and temperature and ionic strength are relatively insensitive. Differences in coordination environments between dissolved and adsorbed Mo during adsorption, i.e., attachment mode (inner- or outer-sphere) or molecular symmetry (e.g., coordination number and magnitude of distortion), are likely responsible for isotopic fractionation. For Fe, The study of equilibrium/kinetic Fe isotopic fractionation in aqueous Fe(II)-mineral is not simple. The interaction between aqueous Fe(II) and Fe (hydroxyl) oxides is complex and dynamic. The isotope effect is due to coupled electron and atom exchange between adsorbed Fe(II), aqueous Fe(II), and reactive Fe(III) on the surface of Fe (hydroxyl) oxide. For Zn, the heavier Fe isotope preferentially adsorbs on the solid phase, and pH and ionic strength are essential influencing factors. The difference in coordination environment may be the cause of isotope fractionation. [Display omitted] • The analytical techniques of Mo, Fe, and Zn stable isotopes were systematically summarized. • The characteristics and mechanism of Mo, Fe, and Zn stable isotopes fractionation during adsorption process were elaborated. • The prospects for future research issues related to stable metal isotopes were provided. [ABSTRACT FROM AUTHOR]

The Yili Block is one of the major Precambrian microcontinents of the Central Asian Orogenic Belt (CAOB). Detrital zircon U-Pb ages and Hf isotopic data of the Meso-Neoproterozoic (meta)-sedimentary units within the Yili Block constrain the tectonic affinity and early history of the block. Detrital zircon U-Pb ages, in combination with related magmatic age data, indicate that the Tekesi and Kusitai groups were deposited during the latest Mesoproterozoic-earliest Neoproterozoic (1040–960 Ma) and early Neoproterozoic (<926 Ma), respectively. Zircons from the Kusitai Group yield major age groups at 941–910 Ma and 1887–1122 Ma, whereas the Tekesi Group have a dominant age group at ca. 2.0–1.1 Ga with age peaks at ca. 1.9 Ga, 1.8 Ga, 1.75–1.70 Ga, 1.58 Ga, 1.5 Ga, 1.47–1.43 Ga and 1.27–1.20 Ga. A minor age peak of ca. 2.5 Ga is also recognized in the middle part of the Tekesi Group. Early Neoproterozoic detrital zircons with relatively uniform ε Hf (t) values (+0.7 to +3.2) were mainly derived from contemporaneous magmatic rocks in the Yili Block. The Central Tianshan Block provides a likely source for detritus with ages of ca. 1.7–1.4 and 2.5 Ga. The predominant late Paleoproterozoic to latest Mesoproterozoic detrital zircons with positive ε Hf (t) values (+0.5 to +12.0) in the Yili Block were probably derived primarily from regions exhumed during collisional assembly of Rodinia. These populations are consistent with those from the late Mesoproterozoic-early Neoproterozoic (meta)-sedimentary successions in the Central Tianshan, Kokchetav-North Tianshan and Erementau-Niyaz blocks, and Southeast Siberia and northeastern Laurentia cratons. The Yili Block, together with the Precambrian microcontinents in the southwestern Central Asian Orogenic Belt, was likely located at the margin of Rodinia supercontinent, between the southeast Siberia and northeast Laurentia during the early Neoproterozoic. Unlabelled Image • The Tekesi Group in Yili Block was deposited at ca. 1040–960 Ma. • The Yili Block contains detritus sourced from the Grenville Orogen. • The Yili Block was likely connected with the northeast Laurentia. [ABSTRACT FROM AUTHOR]

To clarify the mechanisms of uranium distribution in river sediment and its speciation in river water near a phosphate mining region, the sediment and river water in the Mianyuan River in China were investigated. Using linear correlation analysis, it was determined that uranium distribution in upstream sediment is mainly controlled by the adsorption of organic compounds ( R TOC-U 2 = 0.848 ), whereas distribution is controlled by physical deposition of albite ( R Na-U 2 = 0.773 ) in downstream sediment. In addition, it was determined that Se and As had strong and positive linear correlations with uranium in sediment, regardless of whether it was upstream or downstream sediment. This type of relationship was also found in phosphate ores, which suggests that the ore is the common source of U, Se and As in the sediment. The results of speciation-solubility modelling suggest that no precipitation of uranium minerals occurred in river water and the dominant uranium species in river water included: UO 2 (HPO 4 ) 2 2− , Ca 2 UO 2 (CO 3 ) 3 and UO 2 (CO 3 ) 3 4− . In addition, our modelling indicated the relative species distribution was mainly affected by the pH and the total phosphate concentration. [ABSTRACT FROM AUTHOR]