Li Yang, Liang Xuefeng, Huang Qingqing, Xu Yingming, Yang Fang
College of Earth Science, Chengdu University of Technology Chengdu 610059 PR China.
Chengdu Hydrogeological and Engineering Geological Team Chengdu 610072 PR China.
RSC Adv. 2019 Nov 1;9(61):35539-35548. doi: 10.1039/c9ra07137g. eCollection 2019 Oct 31.
The accumulation of heavy metals in soils and crops jeopardizes human health, and thus remedying soil and ensuring food safety have attracted wide concern. In this study, composite silicate was employed as an amendment to inhibit cadmium (Cd) accumulation in the grains of wheat and rice in an upland/paddy rotation mode in field-scale remediation. The composite silicate amendment (CSA) at a dosage of 0.2-0.8% decreased the Cd concentration in wheat grains in the first growing season of upland mode by 7.5-58.3% compared with CK, and decreased the Cd concentration in brown rice by 38.7-58.1% in the second season of paddy mode. The minimum values satisfy the Chinese National and International Standards. The results confirmed the inhibitory effect of CSA on the accumulation of Cd in crop grains. CSA increased the soil pH obviously and enhanced the sorption of Cd on soil particles by 14.6-56.2%, and declined the DTPA- and HCl-extractable Cd concentrations in the soil by 16.2-49.5% and 23.8-75.6%, respectively. Furthermore, CSA decreased the exchangeable Cd fraction by 21.5-41.6% in the sequential extraction. The immobilization effect was retained in both growing seasons in terms of Cd concentration in the crop grains and extractable Cd concentration in the soil. CSA had a negligible effect on the normal growth of wheat and rice and the available Zn and Cu concentration in the soil, indicating its environmental friendliness. Considering its low cost and abundant reserves, CSA can be recommended as an immobilization amendment for Cd-polluted paddy soil in wheat/rice rotation mode.
土壤和农作物中重金属的积累危害人类健康，因此修复土壤和确保食品安全引起了广泛关注。在本研究中，复合硅酸盐被用作改良剂，以田间规模修复的旱田/水田轮作模式抑制小麦和水稻籽粒中的镉（Cd）积累。剂量为0.2-0.8%的复合硅酸盐改良剂（CSA）使旱田模式第一季小麦籽粒中的Cd浓度与对照相比降低了7.5-58.3%，使水田模式第二季糙米中的Cd浓度降低了38.7-58.1%。最小值符合中国国家标准和国际标准。结果证实了CSA对作物籽粒中Cd积累的抑制作用。CSA显著提高了土壤pH值，增强了土壤颗粒对Cd的吸附，增幅为14.6-56.2%，并使土壤中DTPA和HCl可提取的Cd浓度分别下降了16.2-49.5%和23.8-75.6%。此外，在连续提取中，CSA使可交换Cd组分降低了21.5-41.6%。就作物籽粒中的Cd浓度和土壤中可提取的Cd浓度而言，固定化效果在两个生长季节均得以保持。CSA对小麦和水稻的正常生长以及土壤中有效锌和铜的浓度影响可忽略不计，表明其具有环境友好性。考虑到其低成本和丰富的储量，CSA可被推荐作为小麦/水稻轮作模式下Cd污染水田土壤的固定化改良剂。
