Colloidal toxic trace metals in urban riverine and estuarine waters of Yantai City, southern coast of North Yellow Sea

Yuxi Lu; Xuelu Gao; Jinming Song; Chen-Tung Arthur Chen; Jinling Chu

doi:10.1016/j.scitotenv.2019.135265

Colloidal toxic trace metals in urban riverine and estuarine waters of Yantai City, southern coast of North Yellow Sea

Sci Total Environ. 2020 May 15:717:135265. doi: 10.1016/j.scitotenv.2019.135265. Epub 2019 Nov 21.

Authors

Yuxi Lu¹, Xuelu Gao², Jinming Song³, Chen-Tung Arthur Chen⁴, Jinling Chu⁵

Affiliations

¹ CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: xlgao@yic.ac.cn.
³ University of Chinese Academy of Sciences, Beijing 100049, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071, China; Function Laboratory of Marine Ecology and Environmental Sciences, Qingdao National Laboratory of Marine Science and Technology, Qingdao, Shandong 266237, China.
⁴ Department of Oceanography, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
⁵ CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China.

PMID: 31839287
DOI: 10.1016/j.scitotenv.2019.135265

Abstract

The environmental characteristics of colloidal toxic trace metals Cd, Cu and Pb in riverine and estuarine waters collected from two urban rivers of Yantai City in eastern China, the Guangdang and Xin'an Rivers, were investigated using a modified centrifugal ultrafiltration (CUF) method in conjunction with acid extraction and inductively coupled plasma mass spectrometry. The target metals in dissolved pool were divided into four CUF fractions, i.e. <1 kDa, 1-3 kDa, 3-10 kDa and 10 kDa-0.2 μm, and the results showed that colloidal Cd, Cu and Pb were dominated by 1-10 kDa (1-3 and 3-10 kDa), 1-3 kDa and 10 kDa-0.2 μm fractions, respectively. The coagulation/flocculation of low-molecular-weight (1-10 kDa) colloidal Cd and Cu in the estuaries was obvious and strong, while the enrichment of dissolved Pb in the 10 kDa-0.2 μm fraction may be mainly related to its biogeochemical interactions with Fe-oxides, which is easy to occur in macromolecular colloids. In addition, the actual molecular weight cutoffs (MWCOs) of the three used CUF units with nominal MWCOs of 1, 3 and 10 kDa were determined to be 4.9, 8.5 and 33.9 kDa, respectively, indicating that membrane calibration is essential for explaining the actual fraction of dissolved trace metals and verifying the integrity of ultrafiltration membrane. Overall, the results in this study provide a further understanding of the heterogeneity in biogeochemical features, migration and fate of toxic trace metals in aquatic ecosystems, especially that of the river-sea mixing zone.

Keywords: Aquatic environment; Centrifugal ultrafiltration; Dissolved trace metal; Geochemical features; Membrane calibration.