Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025111403
Sediments from the Hengyang reach of the Xiangjiang River were analyzed for concentrations, chemical fractions, and sources of 14 heavy metals (As, Se, Cd, Sb, Pb, Tl, Bi, Co, Ni, Mn, Zn, V, Cr, Cu). Mean concentrations of As, Se, Cd, Sb, Pb, Tl, and Bi exceeded local background values, with Cd, Se, Bi, and As showing pronounced enrichment. Spatial heterogeneity was marked, with higher levels downstream; overall concentrations were lower than previously reported. Sequential extraction revealed that Sb, Bi, Se, Tl, Cu, As, V, Cr, and Ni were predominantly in the residual fraction (F4), while Zn, Cd, Pb, and Mn had higher extractable fractions (F1+F2+F3), with bioavailable fractions generally elevated downstream. Geo-accumulation index (Igeo) indicated no contamination by Co, Zn, V, or Cr, but varying degrees of contamination by Mn, Ni, As, Se, Cd, Sb, Pb, Tl, Bi, and Cu, with pollution severity order: Se>Cd>Bi>As>Sb>Pb>Tl>Ni>Cu>Mn>Zn>Cr>Co>V. Enrichment factors showed significant enrichment for Cd, Sb, and Bi, moderate for Pb, and low for others. Potential ecological risk index (RI) revealed Cd as the primary contributor (87.49% of total risk), with overall moderate risk at downstream sites and slight risk across the entire section. Source apportionment using PCA and PMF identified three sources: industrial and traffic mixed source (57.60%), natural source (16.00%), and industrial-natural mixed source (26.40%). These findings enhance understanding of heavy metal pollution mechanisms in the Hengyang section and recommend priority control of industrial and traffic emissions, with focus on Cd mobility, to support sediment remediation strategies.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4029-4
Chemical sensing technology is pivotal in modern industry and daily life, with sensor performance critically reliant on nanomaterials. While sensors based on traditional nanomaterials, such as inorganic semiconductors and organic conductive polymers, have achieved commercialization, they face persistent challenges. As an emerging subclass, conductive metal-organic frameworks (c-MOFs) not only inherit the core advantages of traditional MOFs—high specific surface area, porosity, and tunable composition/structure—but also offer adjustable electrical conductivity, rendering them ideal for sensing applications. This review systematically elucidates the construction and properties of c-MOFs across microscopic crystalline and macroscopic micro-nano structural scales. Special emphasis is placed on the structural design and regulation of c-MOFs for analytical sensing, and the intrinsic structure-performance relationship is clarified to achieve higher sensitivity, selectivity, response speed, and long-term stability, as well as other performance metrics. Finally, we comprehensively summarize the typical applications of c-MOFs-based sensors, covering environmental and safety monitoring, photoelectric detection, and health monitoring and diagnosis. At the same time, the key challenges existing in this field, such as the controllable preparation of high-quality single-crystal materials, the theoretical analysis of intrinsic electrically conductive mechanisms, and the balance between macroscopic material stability and the processing performance of devices, were evaluated. The future research directions should focus on developing new ligands and metal combinations to optimize the band structure, deepening the exploration of the mechanisms of emerging physical effects such as piezoelectricity, and promoting the integration and application of materials in practical scenarios such as flexible electronics and wearable devices.