title: Effects of riverine suspended particulate matter on post-dredging metal re-contamination across the sediment-water interface.
abstract: Environmental dredging is often used in river mouth areas to remove heavy metals. However, following dredging, high levels of metal-adsorbed suspended particulate matter (SPM) originating from polluted inflowing rivers might adversely affect the sediment-water interface (SWI). Here, we conducted a 360-day-long experiment investigating whether the riverine SPM adversely affects dredging outcome in a bay area of Lake Chaohu, China. We found that the heavy metal concentrations in the post-dredging surface sediment increased to pre-dredging levels for all metals studied (As, Cd, Cr, Cu, Ni, Pb, and Zn) after the addition of SPM. In addition, the increased concentrations were mostly detected in the relatively bioavailable non-residual fractions. Of the metals studied, the rate of increase was the greatest for Zn and Cd (482.98% and 261.07%, respectively), mostly in the weak acid extractable fraction. These results were probably due to certain characteristics of SPM (fine grain size, and high concentrations of organic matter and heavy metals) and the good oxic conditions of the SWI. Furthermore, As was the only metal for which we observed an increasing trend of diffusive flux across the SWI. However, the flux was still significantly lower than that measured before dredging. In conclusion, the quantity and character of riverine metal-adsorbed SPM affect metal re-contamination across the post-dredging SWI, and this information should be incorporated into the management schemes of dredging projects dedicated to reducing metal contamination in similar areas.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China. Electronic address: cxfan@niglas.ac.cn.
authors.forename: Chengxin
authors.initials: C
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China.
authors.forename: Qiushi
authors.initials: Q
authors.lastname: Shen
authors.affiliation: College of Hydrology and Water Resource, Hohai University, Nanjing, 210098, PR China.
authors.forename: Shiguang
authors.initials: S
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D052638:Particulate Matter / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D052638:Particulate Matter; D014874:Water Pollutants, Chemical; D001151:Arsenic
keywords: Confluence bay area; Heavy metal; Lake Chaohu; Non-residual fraction; Sediment dredging