Effects of Water Management on the Transformation of Iron Oxide Forms in Paddy Soils and Its Coupling with Changes in Cadmium Activity

被引：3
作者：
Li M.-Y. [1 ,2 ]
Zhang X.-T. [1 ,2 ]
Liu H.-Y. [1 ,2 ]
Wei S.-Q. [1 ,2 ]
机构：
[1] College of Resources and Environment, Southwest University, Chongqing
[2] Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing
来源：
Huanjing Kexue/Environmental Science | 2022年 / 43卷 / 08期
关键词：
bioavailability; cadmium (Cd); farmland soil; iron oxide; water management;
D O I：
10.13227/j.hjkx.202111108
中图分类号：
学科分类号：
摘要：
The transformation of iron oxide forms in the process of soil water management in paddy fields has an important impact on soil cadmium (Cd) activity and accumulation in rice. The test soil for this experiment was purple paddy soil in southwest China contaminated with exogenously added Cd. Through indoor cultivation experiments, the effects of water management (continuous flooding, CW; alternating wet and dry, DW) combined with iron oxide application (goethite, G-Fe; iron powder, Fe) on the pH, redox state (Eh, pe+pH), iron oxide form conversion, and Cd bioavailability changes in Cd-contaminated soil were studied. Meanwhile, the coupling relationship between the transformation of iron oxide form and the evolution of soil Cd activity driven by water management were also analyzed. The results showed that DTPA-Cd content was decreased by 17.7%-39.2% after 93 days of flooding, indicating that CW could significantly reduce soil Cd bioavailability. CW combined with Fe or G-Fe application significantly enhanced the passivating effect on soil Cd. Among them, the DTPA-Cd content of G-Fe application was reduced by 24.3% compared with that of the CK after 14 d of flooding; thus, G-Fe was effective in short-term passivation. The reduction in DTPA-Cd content of Fe application was 39.2% after 93 d of flooding, so Fe was able to passivate soil Cd continuously. It was also found that the application of iron oxides under alternating wet and dry conditions had no passivating effect on soil Cd. Furthermore, based on correlation analysis, the formation of amorphous iron (Feo) (P<0. 01) was verified as the main reason for the change in Cd bioavailability of Cd in the soil: firstly, the soil pH gradually declined to 7.4, and the soil was kept at reduction conditions under CW, which promoted the morphology transformation from the crystalline state (Fec) to Feo. This transformation subsequently pushed the Cd transformation from the exchangeable state to the iron-manganese combined state and thus resulted in the significant decrease in Cd bioavailability. Meanwhile, the content and proportion of Feo were also significantly increased by the application of CW combined with Fe or G-Fe, thus further enhancing its Cd passivating effect on the soil. This research provides a scientific basis for the optimal water management and the application of iron-containing passivation agent in the safe use of Cd-contaminated paddy soils. © 2022 Science Press. All rights reserved.
引用
收藏
页码：4301 / 4312
页数：11
相关论文
共 46 条
  • [1] Moulis J M, Thevenod F., New perspectives in cadmium toxicity: an introduction, BioMetals, 23, 5, pp. 763-768, (2010)
  • [2] Li K, Cao C L, Ma Y B, Et al., Identification of cadmium bioaccumulation in rice (Oryza sativa L.) by the soil-plant transfer model and species sensitivity distribution, Science of the Total Environment, 692, pp. 1022-1028, (2019)
  • [3] Chen X H, Shen G X, Bai Y J, Et al., Accumulation of Cd in different crops and screening of low-Cd accumulation cultivars, Environmental Science, 40, 10, pp. 4647-4653, (2019)
  • [4] Song B, Wang F P, Zhou L, Et al., Cd content characteristics and ecological risk assessment of paddy Soil in high cadmium anomaly area of Guangxi, Environmental Science, 40, 5, pp. 2443-2452, (2019)
  • [5] Yang Q Q, Li Z Y, Lu X N, Et al., A review of soil heavy metal pollution from industrial and agricultural regions in China: pollution and risk assessment [ J ], Science of the Total Environment, 642, pp. 690-700, (2018)
  • [6] Wang R, Hu X L, Zhang Y W, Et al., Bioavailability and influencing factors of soil Cd in the major farming areas of Chongqing[ J ], Environmental Science, 41, 4, pp. 1864-1870, (2020)
  • [7] Cao S Z, Mu Y, Cui J X, Et al., Cd pollution and safe planting zoning in paddy soils: a case study in a district of Chongqing, Environmental Science, 42, 11, pp. 5535-5544, (2021)
  • [8] Gao Z Q, Fu W J, Zhang M J, Et al., Potentially hazardous metals contamination in soil-rice system and it's spatial variation in Shengzhou City, China [ J ], Journal of Geochemical Exploration, 167, pp. 62-69, (2016)
  • [9] Tian T, Lei M, Zhou H, Et al., Effects of two amendments on remedying garden soil complexly contaminated with Pb, Cd and As, Environmental Science, 38, 6, pp. 2553-2560, (2017)
  • [10] Wang X Y, Han H., Effects of heavy metal-immobilizing bacteria on reducing wheat uptake Cd by regulation soil iron oxides, Environmental Science, 41, 11, pp. 5160-5167, (2020)
12345