地球学报2026，Vol.47Issue(3)：454-468,15.DOI:10.3975/cagsb.2025.101101
沉积物的粒度分布特征及砷的次生富集机制
Characteristics of Sediment Grain Size Distribution and the Mechanism of Arsenic Secondary Enrichment
摘要
Abstract
The differential distribution of sediment grain size is a key factor controlling the spatial heterogeneity of arsenic(As)distribution in sediments and is the most sensitive indicator for reconstructing sedimentary environments and tracing the sources of As in sediments.Studying the particle size distribution of sediments as well as the distribution of As in different grain size fractions helps trace the source-sink relationship and release-migration processes of As.This study focused on 68 sediment samples from seven boreholes with different sedimentary facies in the Baoding Plain.The grain size distribution and geochemical characteristics of the sediments were analyzed,and the factors controlling the heterogeneous distribution of the sediment chemical composition were clarified.The main carriers of As in the sediments were identified,and the sources of As in the sediments were elucidated using the As/Fe ratios.The results showed that the grain size distribution of the sediment samples was mainly controlled by lithology,with little difference in grain size distribution among sediments of the same lithology in different sedimentary facies.The heterogeneous distribution of the chemical composition of the sediment was strongly controlled by hydrodynamic sorting.The fine fraction(grain size<0.062 mm)in the fine-grained(clay to silty sand)and coarse-grained sediments(fine sand to gravel)accounted for(85±12)%and(22±5)%,respectively.The proportion of the fine sediment fraction was significantly positively correlated with the total organic carbon(TOC),total As,and HCl-extractable As/Fe/Mn.The As content in the sediments ranged from 0.5 to 29.5 mg/kg,with an average of(7.6±4.7)mg/kg.The As sediments were primarily derived from the lithosphere,with secondary Fe/Mn oxides as the main carriers.This mobilizable Fe/Mn oxide-loaded As poses a high risk of As release into groundwater.关键词
钻孔沉积物/粒径分布/砷/富集机制/保定平原Key words
borehole sediment/grain size/arsenic/enrichment/Baoding Plain分类
天文与地球科学引用本文复制引用
段艳华,杨羽霞,郭文思,马云杰,曹文庚,郑焰..沉积物的粒度分布特征及砷的次生富集机制[J].地球学报,2026,47(3):454-468,15.基金项目
本文由国家重点研发计划项目(编号:2021YFA0715900)、广东省基础与应用基础研究基金(编号:2024A1515030174)、河北省中央引导地方科技发展资金项目(编号:246Z3601G)和河北省自然科学基金杰青基金项目(编号:D2023504030)联合资助.为中国地质科学院 2024 年度十大科技进展第七名的成果之一. This study was supported by the National Key Research and Development Program of China(No.2021YFA0715900),the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515030174),the Central Government Guidance Funds for Local Science and Technology Development of Hebei Prov-ince(No.246Z3601G),and the Natural Science Foun-dation of Hebei Province(No.D2023504030). （编号:2021YFA0715900）
