TY - JOUR
T1 - High cadmium pollution from sediments in a eutrophic lake caused by dissolved organic matter complexation and reduction of manganese oxide
AU - Chen, Musong
AU - Ding, Shiming
AU - Li, Cai
AU - Tang, Yazhou
AU - Fan, Xianfang
AU - Xu, Huacheng
AU - Tsang, Daniel C.W.
AU - Zhang, Chaosheng
N1 - Funding Information:
This work was financially supported by the National Key R&D Program of China (2019YFD0901100), the National Natural Science Foundation of China (41621002, 41701568 and 41877492), the Natural Science Foundation of Jiangsu Province (BK20171518), the Research Instrument and Equipment, and Development Project of the Chinese Academy of Sciences (YJKYYQ20170016), and the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering (2018nkms01). We thank Wei He (China University of Geosciences (Beijing)) for his help in the DOM analysis, and the Taihu Laboratory for Lake Ecosystem Research, Chinese Ecosystem Research Network (CERN TLLER) for providing the monitoring data.
Funding Information:
This work was financially supported by the National Key R&D Program of China ( 2019YFD0901100 ), the National Natural Science Foundation of China ( 41621002 , 41701568 and 41877492 ), the Natural Science Foundation of Jiangsu Province (BK20171518), the Research Instrument and Equipment, and Development Project of the Chinese Academy of Sciences (YJKYYQ20170016), and the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering (2018nkms01). We thank Wei He (China University of Geosciences (Beijing)) for his help in the DOM analysis, and the Taihu Laboratory for Lake Ecosystem Research, Chinese Ecosystem Research Network (CERN TLLER) for providing the monitoring data.
Publisher Copyright:
© 2020
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2021/2/15
Y1 - 2021/2/15
N2 - Eutrophication and metal pollution are global environmental problems. The risk of metal pollution is high in the eutrophic lakes because of high mobility of metal in sediments. However, the mechanism of cadmium (Cd) mobility in sediments is still unclear. Here we study the mobilization of Cd in sediments from the eutrophic Lake Taihu via monthly field monitoring of mobile Cd using diffusive gradient in thin films (DGT) and high resolution dialysis (HR-Peeper) techniques. We found a high mobility of Cd in sediments in February and March, resulting from reductive dissolution of Mn oxide mediation by high microbial activities, as shown by the similarities in distribution patterns of DGT-labile Cd and Mn. A two orders of magnitude increase in dissolved Cd concentrations (about 28 μg L−1) was observed in May and June, with dissolved Cd concentrations in overlying water about 110 times higher than the criteria continuous concentration set by Environmental Protection Agency. Hourly changes were found to coincide and correlate between dissolved Cd and dissolved organic matter (DOM) under simulated anaerobic conditions, strongly suggesting that the sudden outbreak of Cd pollution observed in the field resulted from the complexation of DOM with Cd in sediments. This was further supported by the NICA-Donnan model that more than 71% of dissolved Cd in the pore water in May and June was present as Cd-DOM complexes. Three components of DOM including humic-, tryptophan-, and tyrosine-like components in the sediments in June was identified using the fluorescence excitation emission matrix-parallel factor analysis. We found that Cd was stable complexed with tyrosine-like component. The Fourier transform infrared and two-dimensional correlation spectroscopy further revealed that Cd was bound to phenolic O–H, alkene C[dbnd]C, alcoholic C–O, aromatic C–H, and alkene [dbnd]CH groups. Our study effectively promotes the understanding of Cd mobilization in sediments and highlights the risk of sudden Cd pollution events in the eutrophic lakes.
AB - Eutrophication and metal pollution are global environmental problems. The risk of metal pollution is high in the eutrophic lakes because of high mobility of metal in sediments. However, the mechanism of cadmium (Cd) mobility in sediments is still unclear. Here we study the mobilization of Cd in sediments from the eutrophic Lake Taihu via monthly field monitoring of mobile Cd using diffusive gradient in thin films (DGT) and high resolution dialysis (HR-Peeper) techniques. We found a high mobility of Cd in sediments in February and March, resulting from reductive dissolution of Mn oxide mediation by high microbial activities, as shown by the similarities in distribution patterns of DGT-labile Cd and Mn. A two orders of magnitude increase in dissolved Cd concentrations (about 28 μg L−1) was observed in May and June, with dissolved Cd concentrations in overlying water about 110 times higher than the criteria continuous concentration set by Environmental Protection Agency. Hourly changes were found to coincide and correlate between dissolved Cd and dissolved organic matter (DOM) under simulated anaerobic conditions, strongly suggesting that the sudden outbreak of Cd pollution observed in the field resulted from the complexation of DOM with Cd in sediments. This was further supported by the NICA-Donnan model that more than 71% of dissolved Cd in the pore water in May and June was present as Cd-DOM complexes. Three components of DOM including humic-, tryptophan-, and tyrosine-like components in the sediments in June was identified using the fluorescence excitation emission matrix-parallel factor analysis. We found that Cd was stable complexed with tyrosine-like component. The Fourier transform infrared and two-dimensional correlation spectroscopy further revealed that Cd was bound to phenolic O–H, alkene C[dbnd]C, alcoholic C–O, aromatic C–H, and alkene [dbnd]CH groups. Our study effectively promotes the understanding of Cd mobilization in sediments and highlights the risk of sudden Cd pollution events in the eutrophic lakes.
KW - Cadmium pollution
KW - Dissolved organic matter
KW - Eutrophication
KW - High-resolution sampling
KW - Spatio-temporal analysis
UR - http://www.scopus.com/inward/record.url?scp=85097252527&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2020.116711
DO - 10.1016/j.watres.2020.116711
M3 - Journal article
C2 - 33296734
AN - SCOPUS:85097252527
SN - 0043-1354
VL - 190
JO - Water Research
JF - Water Research
M1 - 116711
ER -