Zhang Jin, Wang Kun, Yi Qitao, Zhang Tao, Shi Wenqing, Zhou Xuefei
School of Civil Engineering, Yantai University, Yantai, 264005, China.
School of Civil Engineering, Yantai University, Yantai, 264005, China.
Environ Pollut. 2022 Feb 1;294:118668. doi: 10.1016/j.envpol.2021.118668. Epub 2021 Dec 9.
This study showed that metal transport and partitioning are primarily controlled by suspended solids with seasonal flow regimes in plain river networks with sedimentary resuspension. Eight metal species containing iron (Fe), manganese (Mn), cadmium (Cd), chrome (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn), in multiple phases of sediments, suspended solids (>0.7 μm), colloids (1 nm-0.7 μm) and dissolved phase (<1 nm) were analysed to characterize their temporal-spatial patterns, partitioning and transport on a watershed scale. Metal concentrations were associated with suspended solids in the water column and decreased from low flow to high flow. However, metal partitioning between particulate phase (suspended solids) and dissolvable phases (colloids and dissolved phase) was reversed and increased from low flow to high flow with decreased concentration of total suspended solids and median particle size. Partition coefficients (k) showed differences among metal species, with higher values for Pb (354.3-649.0 L/g) and Cr (54.2-223.7 L/g) and lower values for Zn (2.5-25.2 L/g) and Cd (17.3-21.0 L/g). Metal concentrations in sediments increased by factors of 1.2-3.0 from upstream to downstream in watersheds impacted by urbanization. The behaviours of metals in rivers provide deeper insight into the ecological risks they pose for downstream lakes, where increased redox potential and organic matter may increase metal mobility due to algal blooms. Areas with heavy pollution of metals and the transport routines of metals in the river networks were also revealed in our research.
本研究表明，在存在沉积物再悬浮现象的平原河网中，金属的迁移和分配主要受具有季节性水流状态的悬浮固体控制。分析了沉积物、悬浮固体（>0.7μm）、胶体（1nm - 0.7μm）和溶解相（<1nm）多相中包含铁（Fe）、锰（Mn）、镉（Cd）、铬（Cr）、铜（Cu）、镍（Ni）、铅（Pb）和锌（Zn）的8种金属物种，以表征它们在流域尺度上的时空格局、分配和迁移。金属浓度与水柱中的悬浮固体相关，并且从低流量到高流量逐渐降低。然而，颗粒相（悬浮固体）和可溶相（胶体和溶解相）之间的金属分配发生了逆转，随着总悬浮固体浓度和中值粒径的降低，从低流量到高流量增加。分配系数（k）在金属物种之间存在差异，Pb（354.3 - 649.0 L/g）和Cr（54.2 - 223.7 L/g）的值较高，而Zn（2.5 - 25.2 L/g）和Cd（17.3 - 21.0 L/g）的值较低。在受城市化影响的流域中，沉积物中的金属浓度从上游到下游增加了1.2 - 3.0倍。河流中金属的行为为它们对下游湖泊造成的生态风险提供了更深入的见解，在下游湖泊中，氧化还原电位和有机物的增加可能由于藻华而增加金属的迁移性。我们的研究还揭示了金属污染严重的区域以及河网中金属的迁移路径。
