钝化剂对中碱性农田土壤重金属镉及其在小麦中累积的影响

    The Effect of Soil Passivator on Heavy Metal Cadmium in Alkaline Farmland Soil and Its Accumulation in Wheat

    • 摘要: 通过田间实验探讨了钝化剂对中碱性农田土壤中镉含量及其在小麦不同生长期镉累积的影响。结果显示, 钝化剂能降低中碱性农田土壤有效态镉含量。在有效态镉含量为1.24 mg·kg-1的新乡农田土壤中, 添加w=0.20%的钝化剂, 60~240 d后土壤二乙烯三胺五乙酸(DTPA)有效态镉含量较对照(CK)降低28.09%~53.15%, 140 d后小麦根、茎、叶镉含量较对照分别降低43.20%、53.00%、53.00%, 200 d后分别降低48.92%、53.82%、39.20%, 240 d后分别降低47.92%、29.46%、21.41%, 说明钝化剂能降低土壤中有效态镉含量和小麦中镉含量, 使小麦不同生长期各部位镉累积量降低, 小麦籽粒镉含量从0.22降低至0.09 mg·kg-1, 满足GB 2762-2017《食品安全国家标准食品中污染物限量》要求。

       

      Abstract: Field experiments were performed to investigate the effect of passivator on heavy metal cadmium in alkaline farmland soil and its accumulation in different growing period of wheat. The results show that the addition of passivator could decrease the available Cd in alkaline farmland soil. In Cd contaminated soil collected from Xinxiang (DTPA-Cd 1.24 mg·kg-1), compared with the control experiment. By adding 0.20% (mass fraction) of the passivator, the available Cd content of the soil reduced by 28.09%-53.15% after 60-240 days; the Cd contents of the wheat root, stem and leaf were reduced by 43.20%, 53.00% and 53.00% after 140 days, respectively; the Cd contents of the wheat root, stem and leaf were reduced by 48.92%, 53.82% and 39.20% after 200 days, respectively; and the Cd contents of the wheat root, stem, leaf, and grain were reduced by 47.92%, 29.46% and 21.41% after 240 days, respectively. The results show that the passivator could decrease the available Cd content of soil and wheat, thus the Cd accumulation in different parts and different growing periods of wheat could be reduced. The contents of cadmium in wheat grain decreased from 0.22 to 0.09 mg·kg-1, which meets with the national standard (GB 2762-2017). It indicates that the passivator is a potential material for the remediation of heavy metal contaminated alkaline farmland soil.

       

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