Abstract

Agricultural soil contaminated with potentially toxic metals poses great health risk to humans and it requires long-term remediation. Here, we investigate the remediation of metal-polluted agricultural soil by combining chemical washing with repeated phytoextraction. The polluted field was initially washed with 40 mmol L⁻¹ FeCl₃ (F) or 20 mmol L⁻¹ FeCl₃ + 40 mmol L⁻¹ citric acid (F + C). After the application of organic fertilizer (O), lime (L), and sepiolite (S), Sedum plumbizincicola was cultivated for three successive crops from 2017 to 2019. Results showed that the soil washed with FeCl₃ had high removal efficiencies of Cd (35.2%), Pb (24.3%), and Zn (26.6%). Although the shoot biomass and metal concentrations of S. plumbizincicola decreased significantly in the first crop, there were no significant differences in the subsequent two crops. Throughout the remediation process, the higher total removal efficiencies of Cd, Pb, and Zn were conducted in F + OLS treatment which observed in 71.0, 34.0, and 47.7%, respectively. The results, therefore, conclusively indicated that combining chemical washing with repeated phytoextraction showed considerable potential for the remediation of agricultural soils polluted with multiple metals. However, further studies are required to focus on the amelioration of the degraded soil quality and safe agricultural production.

摘要

被潜在有毒金属污染的农业土壤对人类构成极大的健康风险，需要长期的补救措施。在这里，我们研究通过化学洗涤与重复植物提取相结合的方法修复金属污染的农业土壤。最初用40 mmol L ^-1 FeCl ₃（F）或20 mmol L ^-1 FeCl ₃ + 40 mmol L ^-1柠檬酸（F + C）洗涤被污染的田地。在施用有机肥料（O），石灰（L）和海泡石（S）后，从2017年至2019年连续种植了3种作物的景天（Sedum plumbizincicola）。结果表明，用FeCl ₃洗涤过的土壤Cd（35.2％），Pb（24.3％）和Zn（26.6％）的去除效率很高。尽管第一批作物的李子链霉菌的茎生物量和金属浓度显着降低，但随后的两种作物没有显着差异。在整个修复过程中，F + OLS处理的Cd，Pb和Zn的总去除效率更高，分别为71.0、34.0和47.7％。因此，结果最终表明，化学洗涤与重复的植物提取相结合显示出修复被多种金属污染的农业土壤的巨大潜力。但是，需要进一步研究以改善退化的土壤质量和安全的农业生产为重点。