Significant microplastic accumulation and burial in the intertidal sedimentary environments of the Yellow River Delta

Xiaoxuan Di; Tao Sun; Ming Hu; Dawei Wang; Hui Zhang

doi:10.1016/j.jhazmat.2025.137134

Significant microplastic accumulation and burial in the intertidal sedimentary environments of the Yellow River Delta

J Hazard Mater. 2025 Jan 4:487:137134. doi: 10.1016/j.jhazmat.2025.137134. Online ahead of print.

Authors

Xiaoxuan Di¹, Tao Sun², Ming Hu³, Dawei Wang⁴, Hui Zhang⁵

Affiliations

¹ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: dixiaoxuan@mail.bnu.edu.cn.
² State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: suntao@bnu.edu.cn.
³ Command Center of Natural Resources Comprehensive Survey, China Geological Survey, Beijing 100055, China.
⁴ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
⁵ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: zhanghui@bnu.edu.cn.

PMID: 39787922
DOI: 10.1016/j.jhazmat.2025.137134

Abstract

Estuarine intertidal habitats provide a dynamic and distinctive environment for the transport of microplastics, yet their migration and accumulation in these areas remain poorly understood. Herein, the spatial distribution patterns of microplastics in the estuarine sedimentary environment of the Yellow River Delta were investigated across elevation and depth gradients. Compared to the subtidal and supratidal zones, the estuarine intertidal zone exhibited the highest microplastic abundance in sediment (1027 ± 29 items/kg). Sediment cores revealed that the highest microplastic abundance occurred at a depth of 5-10 cm. The evolution of microplastic size and morphology characteristics with sediment depth indicates vertical transport of microplastics in estuarine sediments. The strong correlations between organic matter, silt content, and microplastics abundance in estuarine sediments suggested significant impacts of tidal hydrodynamics and sediment characteristics on microplastic migration processes. Estimates indicated that microplastic burial in the deeper sediments (638.7 tons in the 5-30 cm layer) was 1.96 times greater than that in the upper layers. Distinct variations in the carbonyl index across habitats suggested that tidal-induced dynamic redox conditions in the intertidal zone promoted both biotic and abiotic aging processes of microplastics. This study provides new insights into the environmental behavior and long-term fate of microplastics in estuarine intertidal sedimentary environments.

Keywords: Aging; Estuarine intertidal sediment; Microplastics; Migration; Spatial distribution.