College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Chengdu Geological Survey Center, China Geological Survey, Chengdu, 610081, China.
Ecotoxicol Environ Saf. 2021 Jan 15;208:111441. doi: 10.1016/j.ecoenv.2020.111441. Epub 2020 Oct 7.
Soil heavy metal contamination is an increasingly urgent problem throughout the world. Phytoremediation is a cost-effective and ecologically friendly in situ method for the remediation of heavy metal contaminated soils. Rice has the potential for use in soil remediation due to its high biomass production, however, risks related to food safety and low accumulation potential exist. Therefore, in the current study, rice stubble was used as the adsorbent in a modified rice-fish system (MRFS) to assess its accumulation capacity in a model paddy field dosed with 0-40.0 mg kg Cd. The weighted mean concentration (WMC) of Cd in rice stubble increased from 0.498 to 36.365 mg kg to 1.038-71.180 mg kg from 0 to 60 days post-harvest (dph), and the corresponding increment rate was 107.68%, 117.42%, 157.77% and 95.73%, respectively. Sixty-days post-harvest, removal rate of Cd from contaminated soils was 1.11-1.40%, which was greater than that of the Cd-hyperaccumulator Thlaspi caerulescens. The WMC of the heavy metals Cd, Zn, Pb, Cr and Cu in rice stubble increased 51.11-97.50%, and removal rate was 1.93-2.66%. Overall, rice stubble had a high capacity of heavy metal accumulation, mainly benefiting from the synthesis effects of MRFS and the changes of accumulation mechanism within the plant from being alive until death. Notably, this study also provides a new idea for in situ, herbage-based phytoremediation of heavy metal-contaminated soils.
土壤重金属污染是全世界日益紧迫的问题。植物修复是一种经济有效且生态友好的原位方法，可用于修复重金属污染土壤。由于水稻具有高生物量生产的潜力，因此具有用于土壤修复的潜力，然而，存在与食品安全和低积累潜力相关的风险。因此，在当前的研究中，利用稻草作为改良的稻-鱼系统（MRFS）中的吸附剂，评估其在施用量为 0-40.0mgkg 的模型稻田中对镉的积累能力。收获后 60 天内，稻草中镉的加权平均浓度（WMC）从 0.498 增加到 36.365mgkg 至 1.038-71.180mgkg，相应的增长率分别为 107.68%、117.42%、157.77%和 95.73%。收获后 60 天，从污染土壤中去除镉的去除率为 1.11-1.40%，大于超积累植物堇菜的去除率。稻草中重金属 Cd、Zn、Pb、Cr 和 Cu 的 WMC 分别增加了 51.11-97.50%，去除率为 1.93-2.66%。总体而言，稻草具有很高的重金属积累能力，主要受益于 MRFS 的合成作用以及植物从存活到死亡过程中积累机制的变化。值得注意的是，本研究还为原位、基于草料的重金属污染土壤植物修复提供了新的思路。
