Peak Chromium Pollution in Summer and Winter Caused by High Mobility of Chromium in Sediment of a Eutrophic Lake: In Situ Evidence from High Spatiotemporal Sampling

Xianfang Fan, Shiming Ding, Musong Chen, Shuaishuai Gao, Zhen Fu, Mengdan Gong, Daniel C.W. Tsang, Yan Wang, Chaosheng Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

14 Citations (Scopus)

Abstract

To study the mechanisms of chromium (Cr) mobilization in sediments of eutrophic lakes, monthly sampling was performed in the Meiliang Bay of Lake Taihu, China, combined with laboratory experiments. High-resolution dialysis and diffusive gradients in thin film (DGT) sampling techniques were used. Results indicated that in July 2016 and January 2017, the concentrations of soluble Cr and DGT-labile Cr(VI) in the overlying water exceeded both drinking and fishery water quality standards, resulting from the high mobility of Cr in sediments. In July (summer), the high concentration of soluble Cr (134.04 ± 7.20 μg/L) detected in the anaerobic sediments was primarily caused by the complexation of Cr(III) with dissolved organic matter (DOM). This mechanism was supported by an observed simultaneous increase of soluble Cr and DOM under simulated anaerobic conditions. In January (winter), the high concentrations of soluble Cr (97.55 ± 9.65 μg/L) and DGT-labile Cr(VI) (25.83 ± 1.25 μg/L) in aerobic sediments were primarily caused by reoxidation of Cr(III) by Mn(III/IV) oxides as evidenced by the lowest concentrations of soluble and DGT-labile Mn(II). This study sheds light on the full-year variation and mechanisms of Cr mobilization in eutrophic lake sediments and suggests the urgent need for remediation of Cr pollution especially for winter.

Original languageEnglish
Pages (from-to)4755-4764
Number of pages10
JournalEnvironmental Science and Technology
Volume53
Issue number9
DOIs
Publication statusPublished - 7 May 2019

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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