修复剂对镉污染盐渍化土壤植物修复效率的影响

目前,重金属污染盐渍化土壤已成为世界性的环境问题,利用盐生植物进行修复具有良好的环境与经济效益,但如何提高盐生植物修复效率的研究尚较少.采用盆栽试验方法,通过向土壤中施加氯化钠和氯化镉溶液分别模拟无污染非盐渍化土壤(Cd0S0)、NaCl型盐渍化土壤(Cd0S4)、重金属Cd污染土壤(Cd3S0)、重金属Cd污染NaC...

Effects of Soil Remediation Agents on the Phytoremediation Efficiency of Cadmium-Polluted Salinized Soil

[Objective] With accelerated urbanization, industrial development and excessive utilization of agricultural chemicals, the globe has witnessed soils in a number of regions or areas being salinized and polluted with heavy metals simultaneously. At present, heavy metal-polluted salinized soil has become a worldwide environmental problem. Phytoremediation of heavy metal-polluted salinized soil with halophytes demonstrates benign environmental and good economic benefits. However, little can be found in the literature about how to improve the efficiency of soil remediation with halophytes. The present research is to investigate effects of two remediation agents on remediation of heavy metal-polluted salinized soil with halophytes.[Method] A pot experiment was carried out in greenhouse under natural light. Halophyte Suaeda Salsa was selected as the test plant in the experiment. Four types of soils were simulated by amending the soil with sodium chloride and cadmium chloride solutions separately into 1) soil Cd0S0(0 mg·kg^-1Cd and 0 g·kg^-1NaCl); 2)Soil Cd0S4(0 mg·kg^-1Cd and 4 g·kg^-1NaCl); 3)Soil Cd3S0 (3 mg·kg^-1Cd and 0 g·kg^-1NaCl)and 4)Soil Cd3S4(3 mg·kg^-1Cd and 4 g·kg^-1NaCl). The experiment was laid out in a 2×2×3-factor randomized complete block design(0 and 3 mg·kg^-1Cd; 0 and 4 g·kg^-1NaCl; 0 and 4 mmol·kg^-1 Ethylene Diamine Tetraacetic Acid (EDTA) and 15 g·kg^-1biochar). The aim of the experiment was to investigate effects of EDTA and biochar on growth, ion balance, and Cd and Na⁺ uptake and accumulation of the Suaeda salsa grown in cadmium-polluted sodium chloride salinized soil.[Result] Results show that dry weight of Suaeda salsa shoot was 115.5%-341.7% higher in Treatment Cd0S4 than in Treatment Cd0S0, but 62.8%-84.4% lower in Treatment Cd3S4 than in Treatment Cd0S4. With application of biochar, total dry weight of the Suaeda salsa increased significantly by 328.6% in Treatment Cd3S0. K⁺/Na⁺, Ca²⁺/Na⁺ and P/Na⁺ ratios in shoot and root of the Suaeda salsa decreased significantly in Treatments Cd0S4 and Cd3S4 as compared to that in Treatment Cd0S0 or Cd3S0. Application of biochar increased significantly P/Na⁺ ratio in shoot and K⁺/Na⁺ and P/Na⁺ ratios in root of the Suaeda salsa in Treatment Cd3S0. Na⁺ concentration in shoot and root of the Suaeda salsa increased significantly by 32.5%-94.5%, while Na⁺ content in shoot and root of the Suaeda salsa decreased significantly by 21.3%-90.9% in Treatment Cd3S4 as compared to that in Treatment Cd0S4. Cd concentration and content in shoot of the Suaeda salsa increased significantly by 135.8%-223.6% and 132.4%-471.5%, respectively, in Treatment Cd3S4 compared to that in Treatment Cd3S0. Application of EDTA and biochar increased significantly Na⁺ concentration by 38.6% and 56.0%, Na⁺ content by 199.6% and 289.3%, and Cd content by 133.4% and 173.4% in shoot of the Suaeda salsa in Treatment Cd3S4, respectively.[Conclusion] Results suggest that applications of EDTA and biochar significantly promote uptake and accumulation of Cd and Na⁺ in shoot of the Suaeda salsa grown in cadmium-polluted sodium chloride salinizd soil and improve efficiency of the phytoremediation of heavy metal-polluted salinized soil. All the findings in the research may provide certain basic data and a scientific basis for remediation of heavy metal-polluted salinized soil.