Mar Pollut Bull. 2026 Mar 30;228:119654. doi: 10.1016/j.marpolbul.2026.119654. Online ahead of print.
ABSTRACT
Understanding how vegetation and sediment regimes jointly shape trace metal risks in deltaic tidal wetlands is pivotal for targeted monitoring and restoration. Here we propose a vegetation-sediment indicator framework to diagnose the distribution and ecological risk of six trace metals (Cu, Zn, Cr, As, Cd, Pb) in the tidal flat wetlands of the Yellow River Estuary (YRE). A total of 18 sampling sites were established, covering five vegetation types (mudflat, Suaeda salsa, Phragmites australis, Suaeda salsa & Tamarix chinensis, Suaeda salsa & Phragmites australis) and three soil depth layers (0-10 cm, 10-20 cm, 20-30 cm). Multi-dimensional evidence was obtained through analyses of spatial distribution, pollution assessment, and statistical modeling. Redundancy analysis (RDA), linear fitting, and partial least squares regression (PLS) confirmed that hydrodynamic-driven grain size differentiation laid the foundation framework for metal distribution. Grain-size differentiation driven by local hydrodynamics emerged as the first-order control, setting a “risk template” in which fine-sediment zones show higher metal accumulation and risk than coarse-grained areas. Vegetation further amplified the spatial heterogeneity of metal distribution through “grain size regulation” and “rhizosphere chemistry” effects: Phragmites australis zones emerged as metal enrichment hotspots, while Suaeda salsa zones exhibited a distinct “buffering” capacity. Vertical differentiation across 0-30 cm soil profile was weak, which favored the formation of horizontally structured metal hotspots. This study advances a generalizable, management-oriented indicator set-vegetation type plus sediment grain-size characteristics-to support targeted surveillance, early warning, and restoration prioritization in deltaic tidal wetlands.
PMID:41915933 | DOI:10.1016/j.marpolbul.2026.119654
