交流电场和水分对褪色柳-东南景天混栽修复镉污染土壤的影响

Effects of AC electric field and soil moisture on phytoremediation of cadmium contaminated soil by mixed planting of Salix discolor and Sedum alfredii

【目的】研究交流电场和土壤水分对褪色柳Salix discolor-东南景天Sedum alfredii混栽模式下镉污染土壤修复效率的影响。【方法】通过土壤盆栽试验,研究不同水分[湿润(60%土壤田间持水量)、高水分(100%土壤田间持水量)]和不同交流电场(0和0.5 V·cm^(-1))的组合处理,对土壤镉活性、褪色柳和东南景天生长及镉吸收与积累的影响。【结果】交流电场显著提高土壤有效态镉质量分数、促进褪色柳和东南景天地上部对镉的积累,与对照相比,有效态镉质量分数显著提高16.13%(P<0.05),柳叶、东南景天地上部镉积累量分别提高12.61%、22.50%;高水分+电场处理有利于提高土壤pH、碱解氮质量分数,以及残渣态镉所占比例,与对照相比分别提高6.47%、12.09%、22.89%(P<0.05),但会影响褪色柳、东南景天积累重金属镉,与对照相比,柳叶、东南景天地上部镉积累量分别降低95.60%(P<0.05)、18.02%。【结论】土壤湿润条件下施加电场有利于褪色柳-东南景天修复镉污染土壤,褪色柳和东南景天地上部镉总积累量分别是其他处理的1.13~1.93倍。表4参40。

[Objective] This study is aimed to examine the effects of alternating current(AC) electric field and soil moisture on the remediation efficiency of cadmium(Cd) contaminated soil via the mixed planting of Salix discolor and Sedum alfredii. [Method] With a soil pot experiment, an investigation is conducted of the effects of 2 soil water treatments(moist, keeping 60% of the soil field capacity, and high water content, equivalent to paddy field condition, flooding) combined with 2 AC electric field gradients(0, 0.5 V·cm^(-1)) on soil Cd availability and plant growth of S. discolor and S. alfredii. [Result] The application of 0.5 V·cm^(-1) AC electric field significantly increased soil available Cd concentration [by 16.13%(P<0.05)], and promoted the absorption and accumulation of Cd in S. discolor and S. afredii, the soil available Cd and Cd accumulation in leaves of S.discolor and the above-ground parts of S. afredii were significantly higher(by 12.61% and 22.50% respectively)than those of the control. The integrated application of high moisture and electric field contributed to the increase of soil pH, alkali-hydrolysable nitrogen concentration and the proportion of residual cadmium by 6.47%, 12.09% and 22.89%(P<0.05) compared with those of the control. This integrated application reduced the accumulation of Cd in S. discolor and S. afredii, the accumulation of Cd in leaves of S. discolor and the above-ground parts of S. afredii were lower than that of the control by 95.60%(P<0.05) and 18.02% respectively.[Conclusion] Under moist condition, the AC electric field was beneficial to the phytoremediation of Cd contaminated soil via the mixed planting of S. discolor and S. afredii. And the Cd accumulated in the aboveground parts of S. discolor and S. afredii was 1.13-1.93 times of that achieved with other treatments. [Ch, 4 tab.40 ref.]