Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Tianshui South Road 222, Lanzhou 730000, Gansu, China; Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Tianshui South Road 222, Lanzhou 730000, Gansu, China.
Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Tianshui South Road 222, Lanzhou 730000, Gansu, China; Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Tianshui South Road 222, Lanzhou 730000, Gansu, China.
Chemosphere. 2017 Aug;181:83-91. doi: 10.1016/j.chemosphere.2017.04.070. Epub 2017 Apr 17.
The in situ immobilization of metal-contaminated sediment, using various amendments, has attracted great attention owing to their cost-effectiveness. The present study investigated the effectiveness of Chinese loess on Cu, Zn, Cd and Pb stabilization by decreasing their bioavailability in contaminated sediment. The loess was mixed with the sediment in doses of 0, 0.5, 1, 2, 5, 10 and 20 kg. Approximately 70 d after loess application, the effectiveness was evaluated using the Tessier sequential extraction procedure and single extractants, including ethylenediaminetetraacetic acid disodium salt (EDTA-2Na), diethylenetriaminepentaacetic acid (DTPA), calcium chloride (CaCl) and hydrochloric acid (HCl). The results indicated that the loess can effectively transform Cu from the carbonate fraction into the residual fraction when the loess dose was ≥5 kg. However, loess had little effect on Zn, Cd and Pb immobilization. Correlation analysis showed that these four extractants can provide a good indication of the toxicity of Cu, Zn, Cd and Pb in the amended sediment. Additionally, the organic matter content in the amended sediment decreased by 1.4% for CK, 1.6% for L0.5, 1.7% for L1, 1.5% for L2, 1.5% for L5, 1.9% for L10 and 1.9% for L20 (CK: untreated sediment; L0.5 to L20 represent loess doses of 0.5, 1, 2, 5, 10 and 20 kg, respectively) compared to the initial organic matter content in the unamended sediment, which may increase the atmospheric carbon dioxide owing to the degradation of organic matter.
原位固定受金属污染的沉积物，使用各种改良剂，由于其成本效益而受到极大关注。本研究通过降低污染沉积物中生物有效性来研究黄土对 Cu、Zn、Cd 和 Pb 的稳定效果。将黄土以 0、0.5、1、2、5、10 和 20 kg 的剂量与沉积物混合。黄土施用后约 70 d，采用 Tessier 连续提取程序和单一提取剂（包括乙二胺四乙酸二钠盐（EDTA-2Na）、二乙烯三胺五乙酸（DTPA）、氯化钙（CaCl）和盐酸（HCl））评价其效果。结果表明，当黄土剂量≥5 kg 时，黄土可将 Cu 有效从碳酸盐部分转化为残渣部分。然而，黄土对 Zn、Cd 和 Pb 的固定作用影响较小。相关性分析表明，这四种提取剂可很好地指示改良沉积物中 Cu、Zn、Cd 和 Pb 的毒性。此外，与未改良沉积物相比，改良沉积物中的有机质含量分别降低了 CK（未处理沉积物）的 1.4%、L0.5 的 1.6%、L1 的 1.7%、L2 的 1.5%、L5 的 1.5%、L10 的 1.9%和 L20 的 1.9%，这可能会由于有机质降解而增加大气二氧化碳。
