摘要:基于2016年汛前和汛后获取的黄河尾闾河道与河口区（低盐区）表层和底层水体和悬浮颗粒物样品，研究了水体和悬浮颗粒物中重金属（Cr、Ni、Cu、Zn、Pb、Cd）和As含量的沿程分布特征，并评估了其生态风险。结果表明，汛前尾闾河道表层水体中仅Cd的平均含量高于河口区，而底层水体中As、Cr、Cu、Ni和Pb的平均含量均高于河口区；汛后尾闾河道表层水体中仅Ni的平均含量低于河口区，而底层水体中6种重金属和As的平均含量均高于河口区。汛前尾闾河道表层悬浮颗粒物中As、Cd、Cu、Ni、Pb和Zn的平均含量均低于河口区，而底层悬浮颗粒物中6种重金属和As的平均含量均低于河口区；汛后尾闾河道表层悬浮颗粒物中6种重金属和As的平均含量均高于河口区，而底层悬浮颗粒物中As、Cd、Cr、Cu和Pb的平均含量均高于河口区。汛前和汛后尾闾河道及河口区表层和底层水体中重金属和As污染较轻，其值大多分别低于地表水环境质量Ⅰ类标准和海水水质Ⅰ类标准限值。相对于汛前，汛后尾闾河道及河口区表层或底层悬浮颗粒物中As和6种重金属的毒性单位之和（∑TUs）和平均PEL商数值均降低，说明汛期调水调沙工程的实施可降低汛后悬浮颗粒物中上述元素综合作用所产生潜在生态毒性风险。



Abstract:The concentrations of heavy metals (Cr, Ni, Cu, Zn, Pb, Cd) and arsenic (As) in the water and suspended particulate matter (SPM) of different layers of the tail reaches of the river and estuary (low-salinity area) of the Yellow River were sampled in the pre-flood (April) and post-flood (October) seasons of 2016 to investigate their distributions in a seaward direction. The ecological risk of heavy metals and As in the water and SPM of different depth layers were evaluated. The results showed that in the pre-flood season, only the mean level of Cd in the surface layer was higher in the tail reaches than in the low-salinity area, whereas the average concentrations of As, Cr, Cu, Ni, and Pb in the bottom layer water were higher in the tail reaches than in the low-salinity area. In the post-flood season, the average level of Ni in the surface water layer was lower in the tail reaches than in the low-salinity area, while the average concentrations of the six heavy metals and As in the bottom layer were higher than those in the low-salinity area. Moreover, in the pre-flood season, the average concentrations of As, Cd, Cu, Ni, Pb, and Zn in SPM in the surface layer were lower in the tail reaches than in the low-salinity area and the average levels of six heavy metals and As in SPM in the bottom layer of tail reaches were all lower than those in low-salinity areas. In the post-flood season, the average concentrations of six heavy metals and As in SPM of the surface layer of tail reaches were higher than those in low-salinity areas; the average levels of As, Cd, Cr, Cu, and Pb in SPM of the bottom layer were higher in tail reaches than in low-salinity areas. As and metal pollution in the water of surface and bottom layers of tail reaches and low-salinity areas was not serious, and was generally in accordance with the Class I Criteria of Environmental Quality of Surface Water in China and the Class I Criteria of Seawater Quality in China, respectively. Compared with the pre-flood season, the sum of toxic units (ΣTUs) and the mean probable effects level (PEL) quotient of As and metals in the SPM of the surface and/or bottom layers of tail reaches and low-salinity areas decreased greatly in the post-flood season, indicating that the implementation of a Flow-Sediment Regulation Scheme during the flooding season could reduce the potential ecological toxicity risk caused by the combined effects of these elements in suspended particles.





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