Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea; School of Natural Resources and Environmental Science, Kangwon National University, Chuncheon 24341, Republic of Korea; Department of Soil Sciences, Faculty of Agriculture, Ain Shams University, Cairo 11241, Egypt.
University of Kafrelsheikh, Faculty of Agriculture, Department of Soil and Water Sciences, 33516 Kafr El-Sheikh, Egypt; University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany.
Sci Total Environ. 2018 May 15;624:1059-1071. doi: 10.1016/j.scitotenv.2017.12.190. Epub 2017 Dec 27.
There is a lack of knowledge on the effects of biochar (BC) on the release dynamics of potentially toxic elements (PTEs) in different phases of soil under systematic change of redox potential (E). We aimed to elucidate the impact of pre-definite E on the release dynamics of dissolved and colloidal concentrations of Cd, Cu, Ni, and Zn as well as their phytoavailability and potential mobility in the solid-phase of a mining soil treated with rice hull biochar (S+BC) compared to non-treated soil (S). The influence of E-dependent changes of soil pH, dissolved organic carbon (DOC), dissolved aromatic carbon (DAC), Fe, Mn, SO, and Cl on the elements release was also determined. The experiment was conducted stepwise from reducing (-30mV in S and -12mV in S+BC) to oxidizing (+218mV in S and +333mV in S+BC) conditions using an automated biogeochemical microcosm system. Biochar-treated soil exhibited a wider range of E and a lower pH than the non-treated soil. Dissolved concentrations of Cd, Cu, Ni, Zn, Fe, Mn, SO, and DAC increased under oxic conditions in the non-treated and biochar-treated-soils, which might be due to the decline of pH, and/or sulfide oxidation. Cadmium was more abundant in the colloidal fraction, while Cu, Mn, and DOC were more abundant in the dissolved fraction. Nickel, Zn, and Fe distributed almost equally in both fractions. Biochar increased the dissolved concentration of Cd, Ni, Zn and in particular Cu under oxic conditions. However, the biochar did not significantly affect the colloidal fraction of Cd, Cu, Ni, and Zn. The phytoavailability of the studied elements was higher than the potential mobility. We conclude that increasing the dissolved concentrations of the elements under oxic conditions might increase their release and transfer into the groundwater and the food chain which should be harmful for the environment.
关于生物炭（BC）对不同氧化还原电位（E）阶段土壤中潜在有毒元素（PTE）释放动力学的影响，人们知之甚少。我们旨在阐明预定义 E 对溶解态和胶体态浓度 Cd、Cu、Ni 和 Zn 释放动力学的影响，以及与未处理土壤（S）相比，用稻壳生物炭（S+BC）处理的采矿土壤中这些元素在固相中的植物可利用性和潜在迁移性。还确定了 E 依赖的土壤 pH 值、溶解有机碳（DOC）、溶解芳香碳（DAC）、Fe、Mn、SO 和 Cl 变化对元素释放的影响。该实验使用自动化生物地球化学微宇宙系统逐步从还原（S 中为-30mV，S+BC 中为-12mV）到氧化（S 中为+218mV，S+BC 中为+333mV）条件进行。与未处理土壤相比，生物炭处理过的土壤表现出更宽的 E 范围和更低的 pH 值。在未处理和生物炭处理土壤中，氧化条件下溶解态 Cd、Cu、Ni、Zn、Fe、Mn、SO 和 DAC 浓度增加，这可能是由于 pH 值下降和/或硫化物氧化所致。Cd 在胶体部分更丰富，而 Cu、Mn 和 DOC 在溶解部分更丰富。Ni、Zn 和 Fe 在两个部分中分布几乎相等。在氧化条件下，生物炭增加了 Cd、Ni、Zn 特别是 Cu 的溶解浓度。然而，生物炭对 Cd、Cu、Ni 和 Zn 的胶体部分没有显著影响。研究元素的植物可利用性高于潜在迁移性。我们得出结论，在氧化条件下增加元素的溶解浓度可能会增加它们向地下水和食物链的释放和转移，这对环境可能是有害的。
