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Article

The Long-Term Effects of Dredging on Chromium Pollution in the Sediment of Meiliang Bay, Lake Taihu, China

1
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
2
General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, Beijing 100053, China
3
Department of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
*
Author to whom correspondence should be addressed.
Academic Editors: Rolf D. Vogt and Matthias Zessner
Water 2021, 13(3), 327; https://doi.org/10.3390/w13030327
Received: 3 December 2020 / Revised: 26 January 2021 / Accepted: 26 January 2021 / Published: 28 January 2021
(This article belongs to the Section Water Quality and Contamination)
Sediment dredging is a common remediation tool for polluted water bodies. However, the long-term effects of dredging on chromium (Cr) contamination remain unclear. This study was conducted to evaluate the long-term effects of sediment dredging on Cr contamination in Lake Taihu, six years after dredging was performed. In this study, high-resolution equilibrium dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) sampling techniques were used for sampling total dissolved Cr and DGT-labile Cr(VI) at the sediment water interface. The results show that the vertical averaged concentrations of total dissolved Cr in summer (112.6 ± 28.8 μg/L) and winter (115.3 ± 29.9 μg/L) in the non-dredged site were above the fisheries water quality standard (AEPC, 2002). They were 38% lower in overlying water and 20% lower in sediment pore water in the dredged site in winter, while in summer the reduction was not evident. The concentration of total dissolved Cr in the dredged site was significantly higher in spring and autumn than those in the non-dredged site, which was probably caused by the large rainfall and river discharge during the two seasons. The vertically averaged concentrations of DGT-labile Cr(VI) in both the non-dredged and dredged sites did not exceed the drinking water quality standard requirements (WHO, 1993). Modeling of DGT-induced fluxes from sediment into overlying water showed a higher response time (Tc) and lower adsorption rate (k1) and desorption rate (k−1) in the dredged site except in summer, indicating that sediment dredging decreased Cr mobility in sediments. Overall, these results confirm that sediment dredging decreased the risk of Cr contamination in winter in Lake Taihu. View Full-Text
Keywords: sediment dredging; chromium; diffusive gradients in thin films (DGT); high-resolution equilibrium dialysis (HR-Peeper) sediment dredging; chromium; diffusive gradients in thin films (DGT); high-resolution equilibrium dialysis (HR-Peeper)
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MDPI and ACS Style

Gao, S.; Xing, X.; Ding, S.; Fan, X. The Long-Term Effects of Dredging on Chromium Pollution in the Sediment of Meiliang Bay, Lake Taihu, China. Water 2021, 13, 327. https://doi.org/10.3390/w13030327

AMA Style

Gao S, Xing X, Ding S, Fan X. The Long-Term Effects of Dredging on Chromium Pollution in the Sediment of Meiliang Bay, Lake Taihu, China. Water. 2021; 13(3):327. https://doi.org/10.3390/w13030327

Chicago/Turabian Style

Gao, Shuaishuai, Xigang Xing, Shiming Ding, and Xianfang Fan. 2021. "The Long-Term Effects of Dredging on Chromium Pollution in the Sediment of Meiliang Bay, Lake Taihu, China" Water 13, no. 3: 327. https://doi.org/10.3390/w13030327

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