中山大学学报（自然科学版）（中英文）2026，Vol.65Issue(2)：56-65,10.DOI:10.11714/acta.snus.ZR20250183
淇澳岛红树林沉积物镉的空间分布特征和固定-再移动机制
Spatial distribution and immobilization-remobilization mechanisms of cadmium in mangrove sediments of the Qi'ao Island
摘要
Abstract
With the acceleration of industrialization and urbanization,cadmium(Cd)poses a serious threat to estuarine ecosystems and human health due to its high toxicity.As a typical estuarine wetland,the intertidal mangrove zone provides a pivotal place for the geochemical cycle of heavy metals,yet,the mechanisms regulating Cd migration and transformation in its sediments remain poorly understood.Focusing on the intertidal zone of Qi'ao Island in the Pearl River Estuary,this study systematically analyzed the spatial distribution of total Cd and its geochemical fractions in sediments.We applied the diffusive gradients in thin films(DGT)technique to investigate the seasonal variations of labile Cd across the overlying water-sediment interface,aiming to clarify the spatial pattern and the underlying geochemical mechanisms of Cd fixation and remobilization,thereby providing scientific guidance for regional pollution control.The results show that the total Cd concentrations in mangrove sediments are significantly higher than those in tidal flats(P<0.05).Cd is predominantly present in the acid-soluble fraction(37%-50%),which exhibits high remobilization potential and bioavailability.In winter,the reductive dissolution of Mn oxides is identified as the primary driver for the significantly elevated DGT labile Cd concentration in surface sediments(1.07±0.16)μg/L.In contrast,under high-temperature conditions in summer,the mineralization of organic matter promotes sulfate reduction,leading to the formation of CdS precipitates as the primary control on the decrease in labile Cd concentration(0.07±0.02)μg/L.Moreover,mangrove roots retain suspended particles,and the associated organic-rich,weakly acidic environment facilitates Cd accumulation while suppressing its remobilization.This study provides a scientific basis and theoretical support for controlling sediment Cd pollution and formulating mangrove restoration rstrategies in the Pearl River Estuary.关键词
镉/红树林/沉积物/薄膜扩散梯度技术(DGT)/时空分布/再移动机制Key words
cadmium/mangrove/sediment/diffusive gradients in thin films(DGT)/spatiotemporal distribution/remobilization mechanism分类
资源环境引用本文复制引用
泽林,李睿,伍祺瑞,杨再智,田帝,梁作兵,李绍恒,高磊,陈建耀..淇澳岛红树林沉积物镉的空间分布特征和固定-再移动机制[J].中山大学学报（自然科学版）（中英文）,2026,65(2):56-65,10.基金项目
国家自然科学基金(42577083) （42577083）
广东省基础与应用基础研究基金(2024B1515020030) （2024B1515020030）
中国科学院青年创新促进会会员(2022352) （2022352）
国家重点研发计划(2023YFC3709005,2023YFC3709002) （2023YFC3709005,2023YFC3709002）
