Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China.
Chemosphere. 2018 Aug;204:390-397. doi: 10.1016/j.chemosphere.2018.04.061. Epub 2018 Apr 13.
Biochars and hyperaccumulators have been widely used for the remediation of trace metal contaminated soils through immobilization and phytoextraction. These two options have rarely been used simultaneously despite their potential to achieve a greater decline in trace metal availability and higher removal efficiency in polluted soils. This study investigated the combined effects of biochar and the cadmium/zinc (Cd/Zn) hyperaccumulator Sedum plumbizincicola in a pot experiment and examined the effect of an antibiotic (oxytetracycline, OTC) in an acid soil spiked with Cd/Zn alone and with OTC. Biochar amendment alone significantly decreased soil CaCl-extractable Cd and Zn by 22.7 and 43.1%, respectively. Growing S. plumbizincicola alone resulted in 11.3% Cd and 3.88% Zn removal after ten weeks of phytoextraction. Growing S. plumbizincicola with biochar resulted in higher decreases in extractable Cd and Zn by 60.0% and 53.2%, respectively, and more than three times Cd and Zn removal efficiencies compared to growing S. plumbizincicola without biochar. The results indicate that biochar addition promoted plant growth and increased shoot trace metal concentrations, consequently increasing the removal efficiency and that soil trace metal removal by the hyperaccumulator further reduced the extractable trace metals in addition to immobilization by biochar. Biochar amendment decreased plant OTC concentrations. However, OTC showed no effect on trace metal phytoextraction. Results indicate that the simultaneous use of biochar and the hyperaccumulator can give high Cd/Zn phytoextraction efficiency in terms of both soil total and available trace metal concentrations in acid soils highly contaminated with trace metals or trace metals and OTC.
生物炭和超积累植物已被广泛应用于通过固定化和植物提取来修复痕量金属污染土壤。尽管这两种方法都有可能降低痕量金属的生物有效性并提高污染土壤的去除效率，但它们很少同时使用。本研究通过盆栽实验研究了生物炭和镉/锌（Cd/Zn）超积累植物垂盆草（Sedum plumbizincicola）联合修复作用，并在添加 Cd/Zn 的酸性土壤中单独添加抗生素（土霉素，OTC）和添加 OTC 两种情况下，考察了抗生素的影响。单独添加生物炭可使土壤中氯化钙可提取态 Cd 和 Zn 分别降低 22.7%和 43.1%。单独种植垂盆草 10 周后，可去除 11.3%的 Cd 和 3.88%的 Zn。与不添加生物炭相比，添加生物炭后，垂盆草种植区土壤中可提取态 Cd 和 Zn 分别降低 60.0%和 53.2%，Cd 和 Zn 的去除效率提高了三倍以上。结果表明，添加生物炭促进了植物的生长，增加了地上部痕量金属的浓度，从而提高了去除效率，而超积累植物的生长进一步降低了土壤痕量金属的生物有效性，除了生物炭的固定化作用。生物炭添加降低了植物 OTC 浓度。然而，OTC 对痕量金属的植物提取没有影响。结果表明，在同时添加生物炭和超积累植物的情况下，在高度污染的酸性土壤中，可同时实现总痕量金属和有效态痕量金属的高效去除。
