Mercury mining area soil pollution treatment agent as well as preparation method and application thereof

Abstract

The invention discloses a mercury mining area soil pollution abatement agent and a preparation method and application thereof, and particularly relates to the technical field of soil remediation agents. The treatment agent comprises an organic matrix containing arbuscular fungi, humic acid and mercury-tolerant plants, wherein the ratio of the organic matrix containing the arbuscular fungi to the humic acid is (1-3): 1. The arbuscular fungi and the humic acid are jointly applied to the mercury-contaminated soil, the infection rate of the arbuscular fungi can be greatly increased, and the biomass, the mercury tolerance concentration and the mercury extraction amount of mercury remediation plants are increased. The mercury pollution treatment effect and the phytoremediation effect are better than those of single application of humic acid or arbuscular fungi.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation agents, and in particular to a mercury mining area soil pollution control agent, a preparation method and applications thereof. Background Art

[0002] Mercury, a major global pollutant, is highly toxic and easily migrated. It not only poses a significant threat to human health but also harms the growth and development of many plants. Mercury contamination of soil in mercury mine tailings areas is severe, posing a significant risk of mercury release into the environment and requiring pollution control. This also limits the restoration of vegetation in these areas. Therefore, there is an urgent need for technologies to reclaim and restore tailings areas and mercury-contaminated soils.

[0003] The existing methods for soil pollution control in mercury mining areas mainly include physical, chemical and biological methods.

[0004] Physical methods primarily include the imported soil method and thermal desorption technology. The imported soil method involves excavating the contaminated soil and replacing it with clean soil. Chinese patent CN113000574A describes a method for remediating mercury-contaminated acidic soil in mines. The method includes the following steps: pretreatment of the contaminated soil area to be remediated, in-situ solidification / stabilization remediation, barrier and anti-seepage measures, construction of retaining walls, covering with imported soil, construction of drainage ditches, and restoration of vegetation. However, this method requires the addition of other remediation agents and is labor-intensive, requiring large quantities of clean soil. Furthermore, it can only treat surface soil and is ineffective against mercury contamination in deeper soil layers. Furthermore, improper handling of the excavated contaminated soil can cause secondary pollution.

[0005] Thermal desorption technology can volatilize mercury from soil. Chinese patent CN116851431A discloses an ex situ thermal desorption device and method for mercury-contaminated soil, comprising: a preheating feed system for preheating the pretreated contaminated soil and feeding it into a thermal treatment system; a thermal treatment system for electrically heating the contaminated soil; a heat exchange system for initially cooling the flue gas generated by the thermal treatment system; wherein the cooling fluid in the heat exchange system, after heat exchange, is used to preheat the contaminated soil in the preheating feed system; and a flue gas treatment system for treating the flue gas after the initial cooling. However, this patent requires specialized equipment, resulting in high energy consumption, expensive equipment, and high processing costs. Furthermore, the mercury volatilization process requires a comprehensive gas collection system, otherwise mercury vapor leakage is likely to occur, polluting the atmospheric environment.

[0006] Among chemical methods, Chinese patent CN106433649A, a chemical eluent for remediating mercury-contaminated soil and its application method, falls within the contaminated soil remediation technology area. The eluent consists of two separate agents: Agent A, which includes hydrochloric acid, potassium iodide, and sodium thiosulfate solution, and Agent B, which includes sodium hydroxide and sodium hypochlorite solution. The application method comprises the following steps: (1) soil pretreatment, crushing, and picking out debris and stones; (2) adding eluent A and mercury-contaminated soil, maintaining the ratio of contaminated soil to eluent at 1:10-1:20, and stirring continuously or intermittently for 4-8 hours; (3) after solid-liquid separation, adding water to the residual soil for clean elution; (4) adding eluent B to the soil after clean elution in step (3), and continuing to stir continuously or intermittently for 4-8 hours; (5) after solid-liquid separation, adding water to the residual soil for clean elution, and then backfilling can be directly carried out. However, the eluent combination of agent A composed of hydrochloric acid, potassium iodide and sodium thiosulfate solution and agent B composed of sodium hydroxide and sodium hypochlorite solution can improve the elution efficiency of soil mercury by step elution, but the strong acidity of hydrochloric acid will destroy the physical and chemical properties of the soil, and sodium thiosulfate will react with strong acid to reduce the elution effect.

[0007] Biological remediation of mercury-contaminated soil offers the advantages of low cost and environmental friendliness. Using microorganisms or plants, remediation can be performed in situ without disrupting the soil structure. This reduces the risk of secondary contamination and is effective for low-concentration mercury contamination, contributing to ecologically sustainable soil remediation.

[0008] Chinese patent CN110484275A, a method and reagent for remediating mercury and chromium deep contaminated soil using anaerobic sulfate-reducing bacteria in collaboration with iron-based materials. The mercury and chromium contaminated soil remediation reagent includes an iron-based material and an anaerobic sulfate-reducing bacteria solution; the iron-based material is obtained by reacting iron-containing silicate minerals with oxalic acid in an aqueous medium. However, anaerobic sulfate-reducing bacteria is a microorganism, and its growth and metabolic activities are very sensitive to environmental conditions. In actual deep contaminated soil environments, factors such as temperature, pH value, and soil texture may vary greatly at different depths. Although the oxygen content in the deep soil is low, if there are local ventilation channels or if oxygen enters due to interference from external factors during the remediation process, it will be toxic to anaerobic microorganisms, interfere with their normal metabolism, and reduce remediation efficiency.

[0009] Phytoremediation techniques can both extract mercury from the soil and restore vegetation in mining areas. However, current restoration efforts in mercury mining areas are significantly limited by high mercury concentrations and nutrient-poor soils. Although some restoration projects have utilized mercury-tolerant plants such as poplar and smilax china, these plants have low biomass, necessitating year-round replanting. Even after years of artificial planting, these plants struggle to maintain a stable, self-sustaining ecosystem. Summary of the Invention

[0010] To this end, the present invention provides a mercury mining area soil pollution control agent and its preparation method and application to solve the above problems.

[0011] In order to achieve the above object, the present invention provides the following technical solutions: According to the first aspect of the present invention, a mercury mining area soil pollution control agent is provided, which includes an organic matrix containing arbuscular fungi, humic acid and mercury-resistant plants. The ratio of the organic matrix of the arbuscular fungi to the humic acid is (1-3):1; as an example, the ratio of the organic matrix of the arbuscular fungi to the humic acid is preferably 1:0.5.

[0012] Furthermore, the organic matrix of arbuscular fungi is prepared by mixing a mixed bacterial agent of Piperacium mosseae and Rhizocystis radicifolium with an organic breeding matrix, and then sowing alfalfa seeds. After breeding, the vegetation and main roots are removed, and the organic matrix that is expanded and rich in arbuscular fungi is collected and sieved to obtain the organic matrix containing arbuscular fungi.

[0013] Furthermore, the ratio of the fungus Sphaerotheca mosseae to the fungus Sphaerotheca radicifolia is 1:(0.5-1.5).

[0014] Furthermore, the weight ratio of the mixed bacterial agent to the organic breeding matrix is ​​1:100-200.

[0015] As an example, the arbuscular fungi are a mixture of Piperacium mosseae and Rhizocystis radicifolia (at a spore ratio of 1:1) and an organic breeding matrix, with an inoculation ratio of the fungus to the matrix of 1:150 by weight; the mixture is placed in a breeding tray, alfalfa seeds are sown, and the seedlings are grown in a greenhouse for 60 days; the above-ground vegetation and main roots are removed, and the organic matrix rich in arbuscular fungi is collected and sieved through a 2 mm sieve for later use.

[0016] According to a second aspect of the present invention, a method for preparing any of the above-mentioned mercury mining area soil pollution control agents is provided, comprising weighing the raw materials of the control agent in proportion and mixing them uniformly to obtain the agent.

[0017] According to a third aspect of the present invention, a method for treating contaminated soil in a mining area using any of the above mercury mining area soil pollution treatment agents is provided, the method comprising: Step 1: Level the land, mix the mercury mine soil pollution control agent with clay and surface soil, spread it on the surface, lay out the sprinkler irrigation network, and water it steadily; Step 2: Arrange mercury-resistant plants according to the "grass-shrub" pattern, cover with thin soil and water after planting.

[0018] As an example, the application rate of organic substrate for propagating fungi is: 0.5-1.5 kg / m 2 The application amount of humic acid is: 0.2-0.8kg / m 2 , the application rate of clay is 1-2kg / m2 More preferably, the application rate of the organic matrix for propagating fungi is: 1kg / m 2 , the application amount of humic acid is: 0.5kg / m 2 , the application rate of clay is 1.5kg / m 2 .

[0019] Furthermore, in step 1, the surface soil refers to the soil within 20 cm of the surface.

[0020] Furthermore, in step 1, the watering stabilization time is 1-3 weeks.

[0021] Furthermore, in the step 2, the mercury-resistant plant configuration method according to the "grass-shrub" method is to sow herbaceous plants on the flat surface soil, such as ramie and centipede grass; cover with a thin layer of soil and water; and then transplant shrubs such as big-leaf Buddleja and honeysuckle.

[0022] As an example, it is preferred to transplant shrubs 2 months after the herbaceous plants are planted.

[0023] Furthermore, in step 2, the herbaceous plants are planted at a density of 100-150 plants / m 2 ; The shrub planting density is about 1-2 plants / m 2 .

[0024] The present invention has the following advantages: The mercury mining soil pollution control agent of the present invention contains humic acid, which is beneficial to increasing the organic matter content of the mining soil. Humic acid can combine with mercury to fix mercury and reduce the bioavailability of mercury, and can also enhance the mercury absorption capacity of mercury remediation plants, which is beneficial to using plant remediation to control mercury pollution in mining soil.

[0025] The organic matrix of arbuscular fungi in the mercury mine soil pollution control agent of the present invention is beneficial to increasing the organic matter in the poor soil of the mining area, providing nutrients for mercury remediation plants; covering the mining area with the organic matrix is ​​beneficial to wind protection and water conservation, while conserving the soil and reducing mercury output in the mining area; arbuscular fungi can help mercury-contaminated plants improve their drought resistance, adapt to low-nutrient environments, and enhance mercury tolerance.

[0026] The combined application of arbuscular fungi and humic acid in mercury-contaminated soil significantly increases the infection rate of arbuscular fungi, boosting the biomass, mercury tolerance, and mercury extraction of mercury-remediation plants. The resulting mercury pollution control and phytoremediation effects surpass those achieved by applying humic acid or arbuscular fungi alone. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0028] The structures, proportions, sizes, etc. illustrated in this specification are intended only to complement the contents disclosed herein and to facilitate understanding and reading by persons familiar with the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall still fall within the scope of the technical contents disclosed herein.

[0029] Figure 1 This is a graph showing the effects of humic acid and arbuscular fungi on the infection rate of arbuscular fungi provided in Example 5 of the present invention; Figure 2 Effects of humic acid and arbuscular fungi on mercury extraction from mercury-tolerant plants provided in Example 6 of the present invention; Figure 3 The soil pollution control agent for mercury mines provided in Example 7 of the present invention has a soil control effect on mercury mines; Figure 4 This is the plant restoration effect of the mercury mine soil pollution control agent provided in Example 8 of the present invention on the mercury mine area. DETAILED DESCRIPTION

[0030] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0031] The described Pipecystis mosseae and Rhizocystis radicifolia were purchased from China National Center for Microbiological Collection, and the national microbial resource platform numbers were: 1511C0001BGCAM0060 and 1511C0001BGCAM0042, respectively.

[0032] Example 1 This embodiment provides a mercury mining area soil pollution control agent: 1 part organic substrate for arbuscular fungi, 0.5 part humic acid and mercury-tolerant plants (herbs: ramie and centipede grass; the ratio is 1:1, and the herb planting density is about 150 plants / m 2Shrubs: Buddleja macrophylla and Honeysuckle, the ratio is 1:1, and the shrub planting density is about 2 plants / m 2 ).

[0033] Organic substrate for arbuscular fungi: Mix a mixture of Pipestomyces mosseae and Rhizocystis radicifolia (spore ratio 1:1) with an organic substrate, using a 1:150 ratio by weight. Place the mixture in seed trays, sow alfalfa seeds, and grow the seedlings in a greenhouse for 60 days. Remove aboveground vegetation and taproots, collect the organic substrate enriched with arbuscular fungi, and pass it through a 2mm sieve for later use.

[0034] Example 2 This embodiment provides a mercury mining area soil pollution control agent: 1 part organic substrate for arbuscular fungi, 1 part humic acid and mercury-tolerant plants (herbs: ramie and centipede grass, the ratio is 1:1, the herb planting density is about 100 plants / m 2 Shrubs: Buddleja macrophylla and Honeysuckle, the ratio is 1:1, and the shrub planting density is about 1 plant / m 2 ).

[0035] Organic substrate for arbuscular fungi: Mix a mixture of Pipestomyces mosseae and Rhizocystis radicifolia (spore ratio of 1:0.5) with the organic substrate, using a 1:100 weight ratio. Place the inoculum in seed trays, sow alfalfa seeds, and grow the seedlings in a greenhouse for 60 days. Remove aboveground vegetation and taproots, collect the organic substrate enriched with arbuscular fungi, and pass it through a 2mm sieve for later use.

[0036] Example 3 This embodiment provides a mercury mining area soil pollution control agent: 3 parts of organic substrate for arbuscular fungi, 1 part of humic acid and mercury-tolerant plants (herbs: ramie and centipede grass, the ratio is 1:1, and the herb planting density is about 120 plants / m 2 Shrubs: Buddleja macrophylla and Honeysuckle, with a ratio of 1:1 and a shrub planting density of approximately 1.5 plants / m 2 ).

[0037] Organic substrate for arbuscular fungi: Mix a mixture of Pipestomyces mosseae and Rhizocystis radicifolia (spore ratio of 1:1.5) with an organic substrate, using a 1:200 ratio by weight. Place the inoculum in seed trays, sow alfalfa seeds, and grow the seedlings in a greenhouse for 60 days. Remove aboveground vegetation and taproots, collect the organic substrate enriched with arbuscular fungi, and pass it through a 2mm sieve for later use.

[0038] Example 4 This embodiment provides a method for treating soil pollution in a mercury mine area using the mercury mine area soil pollution treatment agent of Examples 1-3: Step 1: Remove large rocks from the ground, crush small rocks and level the ground. Mix the organic matrix for the fungus propagation, humic acid and clay with the top 20cm of soil and spread it flat on the ground. The application rate of the organic matrix for the fungus propagation is: 0.5-1.5kg / m 2 The application amount of humic acid is: 0.2-0.8kg / m 2 , the application rate of clay is 1-2kg / m 2 More preferably (subsequent experiments will use more preferred dosages), the application rate of organic substrate for propagating fungi is: 1kg / m 2 , the application amount of humic acid is: 0.5kg / m 2 , the application rate of clay is 1.5kg / m 2 After the soil layer is flattened, the sprinkler network is laid out and watering is carried out steadily for 2 weeks.

[0039] Step 2: Configure mercury-resistant plants according to the "grass-shrub" pattern, and mainly select native plant species with high biomass. In the early stages of vegetation recovery, appropriately densely plant herbs and shrubs. First, sow ramie and centipede grass seeds at a ratio of 1:1 on the surface of the mixed soil in step 1, cover with a thin layer of soil and water. The grass seeds should be disinfected with potassium permanganate solution before use. The planting density of herbaceous plants is about 100-150 plants / m 2 2 months after planting, transplant two shrubs, Buddleja macrophylla and Honeysuckle, with a ratio of 1:1. The shrub planting density is about 1-2 plants / m 2 .

[0040] Example 5 To investigate the effects of combined application of humic acid and arbuscular fungi on the root systems of mercury-remediated plants, a cultivation experiment of Cyperus rotundus was conducted in the laboratory using contaminated soil from the mercury mining area in Guizhou (total mercury content of 34.26 mg / kg).

[0041] Four treatments were set up: a blank control group (no humic acid or arbuscular fungi added); control group 1 (humic acid added alone); control group 2 (arbuscular fungi added alone); and an experimental group (the mercury mine soil contamination control agent from Example 1, combined with humic acid and arbuscular fungi). The remediation method from Example 4 was used. Each group had five replicates. Rhizosphere soil was collected two months after the smilax china plantation, and the infection rate was determined using trypan blue staining.

[0042] The results showed that the control group only achieved an arbuscular fungal infection rate of 22.98% ± 1.53%, while the addition of humic acid or arbuscular fungi alone could increase the arbuscular fungal infection rate to 31.67% and 48.29%, respectively (e.g. Figure 1The combined application of humic acid and arbuscular fungi significantly increased the arbuscular fungus infection rate of the roots of P. cyrthospermum to 68.38%, which may help improve P. cyrthospermum's tolerance to mercury and increase its absorption of mercury in the soil.

[0043] Example 6 In order to verify the effect of the combined application of humic acid and arbuscular fungi on the mercury extraction ability of mercury-tolerant plants, a cultivation experiment of Cyperus rotundus was carried out in the laboratory using contaminated soil from a mercury mine in Guizhou (total mercury content of 34.26 mg / kg). Two treatments were set up: a control group (without the addition of humic acid and arbuscular fungi) and an experimental group: the mercury mine soil pollution control agent with the addition of humic acid and arbuscular fungi as described in Example 1. The remediation method of Example 4 was used. Each group was set up with 5 parallels. After 2 months of planting, the aboveground parts and roots were collected respectively. The mercury content in Cyperus rotundus was determined by atomic fluorescence spectrometry after digestion with aqua regia, and the absorption of mercury by Cyperus rotundus was calculated. The results showed that the combined application of humic acid and arbuscular fungi significantly increased the mercury content in the aboveground parts and roots, and at the same time increased the biomass of Cyperus rotundus, which indicated that the application of humic acid and arbuscular fungi improved Cyperus rotundus's tolerance to mercury (such as Figure 2 Further calculations of the total mercury content of each plant revealed that mercury uptake by both the shoots and roots of the plants treated with humic acid and arbuscular fungi was significantly higher than that of the control group. This suggests that the combined application of humic acid and arbuscular fungi can significantly enhance the mercury extraction capacity of mercury-tolerant plants.

[0044] Example 7 In order to verify the therapeutic effect of the combined application of humic acid and arbuscular fungi on the soil in mercury mining areas (the remediation agent of Example 1 + the remediation method of Example 4), a field test was conducted in a mercury mining area in Guizhou. The area of ​​the plot is 10×10m, and the mercury content in the soil is as high as 1526.75mg / kg. According to the specific methods described in this technology, the propagation of arbuscular fungi, the surface preparation of the mining area, the application of humic acid and arbuscular fungi, and the configuration and planting of mercury remediation plants were carried out respectively. Before and after 2 years of treatment, surface mixed soil samples (0-20cm) were taken, and the soil organic matter and nitrogen content were determined by elemental analyzer, the total mercury content in the soil was determined by aqua regia digestion-atomic fluorescence spectrometry, and the water-soluble mercury and exchangeable mercury in the soil were determined by Tisser grouping method to calculate the biologically available mercury content. The results showed that after the combined application of humic acid and arbuscular fungi and the planting of mercury remediation plants for treatment, the organic matter and total nitrogen in the soil of the mercury mining area increased significantly, which shows that the combined application of humic acid and arbuscular fungi improved the soil and provided a nutrient basis for mercury remediation plants. After two years of treatment, Figure 3As shown in the results, total mercury and bioavailable mercury in the soil decreased from 1526.75 mg / kg and 59.53 μg / kg to 934.86 mg / kg and 26.78 μg / kg, respectively, with removal rates as high as 39.77% and 55.02%. These results indicate that the combined application of humic acid and arbuscular fungi is effective in treating soils with high mercury concentrations in mercury mining areas.

[0045] Example 8 In order to verify the therapeutic effect of the combined application of humic acid and arbuscular fungi on the soil in mercury mining areas, a field experiment was conducted in a mercury mining area in Guizhou. The area of ​​the plot is 10 m×10 m, and the mercury content in the soil is as high as 1526.75 mg / kg. According to the specific methods described in this technology, the propagation of arbuscular fungi, the surface preparation of the mining area, the application of humic acid and arbuscular fungi, and the configuration and planting of mercury remediation plants were carried out respectively. Before and after 2 years of treatment, a 0.5 m×0.5 m sample frame was laid out to measure the vegetation coverage, height and aboveground biomass. The results are as follows Figure 4 As shown in the figure, the combined application of humic acid and arbuscular fungi reduced the aboveground biomass, height and cover of vegetation from 4.89 g / m 2 , 2.41cm and 10% increased to 397.26g / m after treatment 2 , 58.9 cm and 85%. This shows that the combined application of humic acid and arbuscular fungi has a good restoration effect on vegetation restoration in mercury mining areas.

[0046] In summary, the mercury mining soil pollution control agent of the present invention contains humic acid, which is beneficial to increasing the organic matter content of the mining soil; humic acid can combine with mercury to fix mercury and reduce the bioavailability of mercury, and can also enhance the mercury absorption capacity of mercury remediation plants, which is beneficial to the use of plant remediation to control mercury pollution in mining soil.

[0047] The organic matrix of arbuscular fungi in the mercury mine soil pollution control agent of the present invention is beneficial to increasing the organic matter in the poor soil of the mining area, providing nutrients for mercury remediation plants; covering the mining area with the organic matrix is ​​beneficial to wind protection and water conservation, while conserving the soil and reducing mercury output in the mining area; arbuscular fungi can help mercury-contaminated plants improve their drought resistance, adapt to low-nutrient environments, and enhance mercury tolerance.

[0048] The combined application of arbuscular fungi and humic acid in mercury-contaminated soil significantly increases the infection rate of arbuscular fungi, boosting the biomass, mercury tolerance, and mercury extraction of mercury-remediation plants. The resulting mercury pollution control and phytoremediation effects surpass those achieved by applying humic acid or arbuscular fungi alone.

[0049] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A mercury mining area soil pollution control agent, characterized in that: The treatment agent comprises an organic matrix containing arbuscular fungi, humic acid and mercury-resistant plants, wherein the ratio of the organic matrix containing arbuscular fungi to the humic acid is (1-3):

1.

2. The mercury mining area soil pollution control agent according to claim 1, characterized in that: The organic matrix of arbuscular fungi is prepared by mixing a mixed bacterial agent of Pipe Sphaerotheca mosseae and Rhizocystis radix with an organic breeding matrix, sowing alfalfa seeds, removing vegetation and main roots after breeding, collecting the organic matrix rich in arbuscular fungi, and sieving to obtain the organic matrix containing arbuscular fungi.

3. The mercury mining area soil pollution control agent according to claim 2, characterized in that: The ratio of the mossea cysts to the root cysts is 1:(0.5-1.5).

4. The mercury mining area soil pollution control agent according to claim 2, characterized in that: The weight ratio of the mixed bacterial agent to the organic breeding matrix is ​​1:100-200.

5. A method for preparing a mercury mining area soil pollution control agent according to any one of claims 1 to 4, characterized in that: The method comprises weighing the raw materials of the treatment agent in proportion and mixing them evenly to obtain the treatment agent.

6. A method for treating polluted soil in a mining area using any mercury mining area soil pollution treatment agent according to any one of claims 1 to 4, characterized in that: The method comprises: Step 1: Level the land, mix the mercury mine soil pollution control agent with clay and surface soil, spread it on the surface, lay out the sprinkler irrigation network, and water it steadily; Step 2: Arrange mercury-resistant plants according to the "herb-shrub" combination, cover with a thin layer of soil and water after planting.

7. The method for treating contaminated soil in mining areas according to claim 6, characterized in that: In step 1, the surface soil refers to the soil within 20 cm of the surface.

8. The method for treating contaminated soil in mining areas according to claim 6, characterized in that: In the step 1, the watering stabilization time is 1-3 weeks.

9. The method for treating contaminated soil in mining areas according to claim 6, characterized in that: In the step 2, the method of configuring mercury-resistant plants according to the "grass-shrub" method is to sow herbaceous plants, such as ramie and centipede grass, on the flat topsoil; cover with a thin layer of soil and water; and then transplant shrubs such as big-leaf Buddleja and honeysuckle.

10. The method for treating contaminated soil in mining areas according to claim 9, characterized in that: In the step 2, the herbaceous plants are planted at a density of 100-150 plants / m 2 ; The shrub planting density is about 1-2 plants / m 2 .

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