摘要：Compositions of dissolved organic matter (DOM) in high-arsenic groundwater are usually sourced from the recharged groundwater DOM and the in-situ mobilized organic matter (OM) from aquifer sediments. However, relative importance of the two sources in DOM remains unclear. To quantify sources of DOM, Fourier transform ion cyclotron resonance mass spectrometry was used to analyze molecular characteristics of groundwater DOM and water-soluble organic matter (WSOM) in sediments along an inferred groundwater flow path in the Hetao Basin, China. Results showed that dissolved arsenic concentrations gradually increased from 1.92 to 402 mu g/L along the flow path, being mainly due to the DOM degradation-triggered Fe(III) oxide reduction. The DOM molecules being unique to the background groundwater represented the in-situ mobilized OM, which showed the similar abundance to the DOM molecules being common to its depth-matched WSOM. An increasing trend of the relative abundance of the in-situ mobilized OM to the total DOM molecules along the flow path was recognized (from 0 % to 44.5 %). This suggests that the relative contribution of the in-situ mobilized OM to the groundwater DOM increased along with dissolved arsenic concentration. Furthermore, the biodegradable pool among the in situ mobilized OM was significantly positively correlated with dissolved arsenic, indicating that this in-situ mobilized OM exhibited a dominant role in groundwater arsenic enrichment. The study provides novel insights into contribution of the in-situ mobilized OM to DOM and arsenic mobility in groundwater systems.

关键字：Arsenic; FT-ICR MS; Groundwater DOM sources; Relative contribution; WSOM

ISSN号：0022-1694

卷、期、页：卷626子辑B

发表日期：2023-11-01

期刊分区（SCI为中科院分区）：一区

收录情况：SCI（科学引文索引印刷版）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：JOURNAL OF HYDROLOGY

参与作者：乔雯,高志鹏,韩双宝,郭华明

第一作者：何晨,史权

论文类型：期刊论文

论文概要：乔雯,高志鹏,何晨,史权,韩双宝,郭华明，Molecule-based quantification of dissolved organic matter sources in high-arsenic groundwater，JOURNAL OF HYDROLOGY，2023，卷626子辑B

论文题目：Molecule-based quantification of dissolved organic matter sources in high-arsenic groundwater