Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou 570228, China; College of Ecology and Environment, Hainan University, Haikou City 570100, China.
Environmental Science Center, Qatar University, Doha, Qatar.
Sci Total Environ. 2022 Jun 20;826:154043. doi: 10.1016/j.scitotenv.2022.154043. Epub 2022 Feb 21.
Fishpond sediments are rich in organic carbon and nutrients; thus, they can be used as potential fertilizers and soil conditioners. However, sediments can be contaminated with toxic elements (TEs), which have to be immobilized to allow sediment reutilization. Addition of biochars (BCs) to contaminated sediments may enhance their nutrient content and stabilize TEs, which valorize its reutilization. Consequently, this study evaluated the performance of BCs derived from Taraxacum mongolicum Hand-Mazz (TMBC), Tribulus terrestris (TTBC), and rice straw (RSBC) for Cu, Cr, and Zn stabilization and for the enhancement of nutrient content in the fishpond sediments from San Jiang (SJ) and Tan Niu (TN), China. All BCs, particularly TMBC, reduced significantly the average concentrations of Cr, Cu, and Zn in the overlying water (up to 51% for Cr, 71% for Cu, and 68% for Zn) and in the sediments pore water (up to 77% for Cr, 76% for Cu, and 50% for Zn), and also reduced metal leachability (up to 47% for Cr, 60% for Cu, and 62% for Zn), as compared to the control. The acid soluble fraction accounted for the highest portion of the total content of Cr (43-44%), Cu (38-43%), and Zn (42-45%), followed by the reducible, oxidizable, and the residual fraction; this indicates the high potential risk. As compared with the control, TMBC was more effective in reducing the average concentrations of the acid soluble Cr (15-22%), Cu (35-53%), and Zn (21-39%). Added BCs altered the metals acid soluble fraction by shifting it to the oxidizable and residual fractions. Moreover, TMBC improved the macronutrient status in both sediments. This work provides a pathway for TEs remediation of sediments and gives novel insights into the utilization of BC-treated fishpond sediments as fertilizers for crop production.
鱼塘沉积物富含有机碳和养分；因此，它们可用作潜在的肥料和土壤改良剂。然而，沉积物可能受到有毒元素 (TEs) 的污染，这些元素必须被固定化才能允许沉积物再利用。向受污染的沉积物中添加生物炭 (BC) 可以提高其养分含量并稳定 TEs，从而实现其再利用的价值。因此，本研究评估了源自蒲公英 (TMBC)、蒺藜 (TTBC) 和稻草 (RSBC) 的 BC 对 Cu、Cr 和 Zn 的固定化效果，以及对中国三江 (SJ) 和滩牛 (TN) 鱼塘沉积物中养分含量的提高作用。所有 BC，特别是 TMBC，显著降低了上覆水（Cr 降低 51%，Cu 降低 71%，Zn 降低 68%）和沉积物孔隙水中（Cr 降低 77%，Cu 降低 76%，Zn 降低 50%）的 Cr、Cu 和 Zn 的平均浓度，也降低了金属的浸出性（Cr 降低 47%，Cu 降低 60%，Zn 降低 62%），与对照相比。酸可溶部分占 Cr（43-44%）、Cu（38-43%）和 Zn（42-45%）总含量的比例最高，其次是可还原、可氧化和残留部分；这表明存在较高的潜在风险。与对照相比，TMBC 更有效地降低了酸可溶 Cr（15-22%）、Cu（35-53%）和 Zn（21-39%）的平均浓度。添加的 BC 通过将金属的酸可溶部分转移到可氧化和残留部分来改变其酸可溶部分。此外，TMBC 改善了两种沉积物中的大量营养元素状况。这项工作为沉积物中 TEs 的修复提供了一种途径，并为将经过 BC 处理的鱼塘沉积物用作作物生产的肥料提供了新的见解。
