Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea; Department of Soil Sciences, Faculty of Agriculture, Ain Shams University, Cairo 11241, 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.
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; University of Kafrelsheikh, Faculty of Agriculture, Department of Soil and Water Sciences, Kafr El-Sheikh, 33516, Egypt.
Sci Total Environ. 2019 Mar 20;657:686-695. doi: 10.1016/j.scitotenv.2018.12.026. Epub 2018 Dec 5.
This study assessed the impact of pre-definite redox potential (E) on the release dynamics and distribution of As, Co, and Mo between the dissolved and colloidal phases as well as their potential mobility and phytoavailability in the sediment phase of a mining soil treated with rice hull biochar (BC). The experiment was conducted from controlled moderately-reducing to oxidizing conditions using an automated biogeochemical microcosm system. Arsenic and Mo were more abundant in the dissolved phase due to their predominant in potential mobile fractions, while Co was more abundant in the colloidal phase due to its association with Fe-(hydr)oxides. Biochar increased the dissolved and colloidal concentrations of As, the dissolved concentration of Co, and the colloidal concentration of Mo under oxidizing condition. On the other hand, the application of BC decreased the dissolved concentration of Mo and the colloidal concentration of Co in the first redox cycle under reducing-acidic condition, due to lower pH values, and chemistry of sulfide-sulfate and Fe/Mn oxides. The phytoavailability of As and Co were higher than their potential mobility in the sediment phase, while the same trend was not discerned for Mo. The potential mobility and phytoavailability of As and Co were high under oxic-acidic conditions. The potential mobility and phytoavailability of Mo might be increased under oxic condition due to the dissolution of Fe and Mn oxides under lower pH conditions, especially in the BC treated soil. Application of such rice hull BC to soil might stimulate the release of As, Co, and Mo under flooding conditions, which might increase the environmental and health risks in such wetland ecosystems.
本研究评估了预限定氧化还原电位 (E) 对生物炭处理矿区土壤中砷、钴和钼在溶解相和胶体相之间的释放动力学和分布的影响，以及它们在沉淀相中的潜在迁移性和植物可利用性。该实验使用自动化生物地球化学微宇宙系统，从受控的适度还原条件到氧化条件进行。由于其主要处于潜在可迁移的分数中，砷和钼在溶解相中更丰富，而钴在胶体相中更丰富，因为其与 Fe-(水合)氧化物有关。在氧化条件下，生物炭增加了砷的溶解和胶体浓度、钴的溶解浓度和钼的胶体浓度。另一方面，在还原-酸性条件下，由于较低的 pH 值和硫化物-硫酸盐和 Fe/Mn 氧化物的化学性质，BC 的应用降低了第一个氧化还原循环中钼的溶解浓度和钴的胶体浓度。砷和钴在沉淀相中具有较高的植物可利用性，高于其潜在的迁移性，而钼则没有表现出相同的趋势。在有氧酸性条件下，砷和钴的潜在迁移性和植物可利用性较高。在较低 pH 条件下，Fe 和 Mn 氧化物的溶解可能会增加钼的潜在迁移性和植物可利用性，尤其是在添加生物炭的土壤中。在淹水条件下，将这种稻壳生物炭应用于土壤可能会刺激砷、钴和钼的释放，这可能会增加湿地生态系统中的环境和健康风险。
