College of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
College of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
Ecotoxicol Environ Saf. 2021 Aug;219:112332. doi: 10.1016/j.ecoenv.2021.112332. Epub 2021 May 25.
Cadmium (Cd) due to its strong toxicity and high mobility, which poses a considerable threat to soil environment and human health, has aroused widespread concern. Biochar has been used for remediating Cd-contaminated soil recently, however this method has the risk of fixed-Cd re-release. Phytoremediation can make up for its shortcoming. In this study, a pot experiment was carried out, where Bidens pilosa L. (B.pilosa) was as the tested plant and biochars (maize straw biochar and wheat straw biochar with two particle sizes) were as amendments. The mechanism of how biochars promoted B.pilosa Cd accumulation in Cd-contaminated farmland soil was explored. Results showed that the application of 5% wheat straw fine biochar (WF), wheat straw coarse biochar (WC), maize straw fine biochar (MF) and maize straw coarse biochar (MC) increased the total Cd accumulation of B.pilosa to 251.57%, 217.41%, 321.64% and 349.66%, respectively. Biochars amendment significantly promoted B.pilosa growth and increased Cd accumulation by improving soil physical properties, nutrient levels (available nitrogen, available phosphorus (AP), available potassium (AK) and organic matter (OM)) and microbial activity, and changing the nutrients distribution in B.pilosa organs although tissues although DTPA-Cd reduced to some extent. The effect of MF on AP increase was better than MC, while the effect of WF on AK increase was better than WC. Fine-particle was superior to coarse-particle in increasing B.pilosa biomass of aboveground, OM and microbial activity in soil. The changes of N, P and K concentrations in B.pilsosa roots, stems and leaves were closely related to the changes of AN, AP and AK in soil after biochars application. The results indicated that the combination of straw biochars and hyperaccumulators had the synergistic effect. This study can provide data support and meaningful reference values for remediating actual Cd-contaminated soil.
镉（Cd）由于其强毒性和高迁移性，对土壤环境和人类健康构成了相当大的威胁，引起了广泛关注。生物炭最近被用于修复镉污染土壤，但这种方法存在固定态 Cd 再次释放的风险。植物修复可以弥补这一不足。在这项研究中，进行了盆栽实验，其中鬼针草（B.pilosa）作为受试植物，生物炭（玉米秸秆生物炭和两种粒径的小麦秸秆生物炭）作为改良剂。探讨了生物炭促进镉污染农田土壤中鬼针草 Cd 积累的机制。结果表明，应用 5%的小麦秸秆细生物炭（WF）、小麦秸秆粗生物炭（WC）、玉米秸秆细生物炭（MF）和玉米秸秆粗生物炭（MC）分别使鬼针草的总 Cd 积累量增加了 251.57%、217.41%、321.64%和 349.66%。生物炭改良剂通过改善土壤物理性质、养分水平（有效氮、有效磷（AP）、有效钾（AK）和有机质（OM））和微生物活性，以及改变鬼针草器官中养分的分布，尽管 DTPA-Cd 有所降低，从而显著促进了鬼针草的生长和 Cd 积累。MF 对 AP 增加的效果优于 MC，而 WF 对 AK 增加的效果优于 WC。在增加地上部生物量、OM 和土壤微生物活性方面，细颗粒优于粗颗粒。鬼针草根、茎、叶中 N、P、K 浓度的变化与生物炭施用后土壤中 AN、AP、AK 的变化密切相关。结果表明，秸秆生物炭与超积累植物的结合具有协同作用。本研究可为实际镉污染土壤的修复提供数据支持和有意义的参考价值。
