Phytoextraction repairing method for heavy metal cadmium contaminated calcicolous farmland soil

Abstract

The invention discloses a phytoextraction repairing method for heavy metal cadmium contaminated calcicolous farmland soil, and belongs to the technical field of phytoremediation for contaminated soil. The phytoextraction repairing method for the heavy metal cadmium contaminated calcicolous farmland soil particularly comprises the following steps that S1, hyperaccumulators of which the enrichment coefficient and transfer coefficient meet the standards are planted in the heavy metal cadmium contaminated calcicolous farmland soil; S2, a chelating agent is added to improve biological effectiveness of heavy metals; S3, growth conditions of plants are periodically observed; and S4, sampling is conducted on the plants, and the content of metal chromium at different positions of the plants is analyzed. The phytoextraction repairing method for the heavy metal cadmium contaminated calcicolous farmland soil belongs to an in-situ remediation technology, disturbance to the environment is small, landscape ecology cannot be destroyed, the environment can be greened, operation is easy, and the phytoextraction repairing method has a wide application prospect in environmental protection. According to the phytoextraction repairing method, soil fertility and ecological structure cannot be destroyed in the soil repairing process, and other crops can be planted without secondary treatment.

Description

technical field [0001] The invention relates to the technical field of phytoremediation of polluted soil, in particular to a method for phytoextraction and remediation of heavy metal cadmium polluted calcareous farmland soil. Background technique [0002] Cadmium is a dangerous environmental pollution element. When cadmium enters plants and accumulates to a certain extent, it will produce toxic symptoms, such as growth inhibition, plant dwarfism, chlorosis, and yield decline. Its impact on plants includes two aspects: one affects its growth and yield, such as reducing the photosynthetic intensity of rice in the physiological and biochemical process, reducing the chlorophyll content, resulting in chlorosis, delayed turning green tillering, and lack of root system; the other affects quality, The cadmium content in crops is significantly positively correlated with the soluble cadmium content in soil. For example, the correlation coefficient between rice cadmium and soil soluble...

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Problems solved by technology

At present, heavy metal pollution in soil is mainly improved by engineering treatment and chemical treatment. The engineering treatment method refers to the use of physical or physical and chemical principles to control heavy metal pollution in soil. The physical methods mainly include foreign soil, soil replacement, topsoil removal and deep plowing. Measures such as tilling the soil, the guest soil method refers to adding a large amount of clean soil to the polluted soil, covering the surface layer and mixing evenly, so as to reduce the concentration of pollutants below the harmful concentration or reduce the contact between pollutants and plant roots, so as to reduce the harm. Purpose: The method of exchanging soil is to take away the polluted soil and replace it with new, clean soil. This method has a more obvious treatment effect on soils with small areas, serious pollution, radioactive pollutants, easy to diffuse, and difficult to decompose. The method of turning the soil is to turn the soil deeply, so that the pollutants accumulated on the surface can be dispersed to a deeper layer to achieve the purpose of diluting the pollutants. The loss of soil nutrient reduction; and the chemical treatment method is to put amendments and inhibitors into the soil to increase the organic matter, cation exchange capacity and clay content of the soil, so that it can change the acidity and alkalinity of the soil, soil redox conditions or The composition of ions in the soil will affect the adsorption, redox, antagonism or precipitation of heavy metals, and finally reduce the pollution of heavy metals. However, these treatment methods cost a lot in the early stage and the treatment effect is not obvious. , we proposed a method of phytoextraction and remediation of heavy metal cadmium polluted calcareous farmland soil to solve the pollution of cadmium in farmland soil

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