Ji Fang-ying, Wang Tu-jin, Hu Xue-bin, He Qiang, Ye Jiang-yu, Li Si, Cao Lin
Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, Chongqing University, Chongqing 400045, China.
Huan Jing Ke Xue. 2009 Dec;30(12):3481-7.
According to the off-season regulation model for Three Gorges Reservoir, the characteristic of movement and transformation of Cu, Pb, Cd and Cr in sediment of water-level-fluctuating zone of Three Gorge Reservoir Area was investigated. The results indicated that the chemical fraction composition characteristics of heavy metals are different. Cu mainly existed in organic/sulphidic fraction and residual fraction; Pb mainly existed in carbonates, Fe-Mn oxides and residual fraction; Cd mainly existed in carbonates and Fe-Mn oxides fraction; Cr mainly existed in residual fraction. In flood season, the exposure of sediment from river bottom to atmosphere caused the decrease of TOC, AVS and pH and increase of ORP, and lowered the amount of extractable heavy metals. Heavy metals have the tendency to release to water body. The migration rates of Cu, Pb, Cd and Cr were 30.50%, 26.10%, 33.50%, and 11.77% respectively, the migration ability of heavy metals followed: Cd > Cu > Pb > Cr. The contributions of extractable fractions of Cu, Pb, Cd and Cr to the migrated heavy metals were 77.15%, 86.09%, 94.86%, and 32.34% respectively, extractable fraction was the mainly part of the migrated heavy metals. The off-season regulation model for Three Gorges Reservoir lowered the ecological harm of heavy metals, the concentrations of Cu, Pb, Cr, Cd in the study areas were low.
依据三峡水库的非汛期调度模型，对三峡库区消落带沉积物中铜、铅、镉和铬的迁移转化特征进行了研究。结果表明，重金属的化学形态组成特征各异。铜主要存在于有机/硫化物态和残渣态中；铅主要存在于碳酸盐态、铁锰氧化物态和残渣态中；镉主要存在于碳酸盐态和铁锰氧化物态中；铬主要存在于残渣态中。汛期时，河底沉积物暴露于大气中导致总有机碳（TOC）、酸挥发性硫化物（AVS）含量降低，pH值下降，氧化还原电位（ORP）升高，可提取重金属含量减少。重金属有向水体释放的趋势。铜、铅、镉和铬的迁移率分别为30.50%、26.10%、33.50%和11.77%，重金属的迁移能力顺序为：镉＞铜＞铅＞铬。铜、铅、镉和铬的可提取态对迁移重金属的贡献率分别为77.15%、86.09%、94.86%和32.34%，可提取态是迁移重金属的主要组成部分。三峡水库的非汛期调度模型降低了重金属的生态危害，研究区域内铜、铅、铬、镉的浓度较低。
