CN1303014C - Method for treating soil and aquatic lead, zinc, cadmium pollution by cone south mustard - Google Patents

Abstract

The present invention relates to a method for repairing zinc and cadmium single or composite pollution of soil and water bodies by using arabis paniculata as a polymetallic over-enriched plant. The method mainly utilizes plumbum, zinc and cadmium polymetallic over-enriched plant, namely the arabis paniculata to enrich plumbum, zinc and cadmium in polluted soil or water bodies, and simultaneously upward transfer the zinc, the plumbum and the cadmium to an overground part, when the overground part of thearabis paniculata forms certain biomass, the overground part is periodically harvested (the overground part is harvested twice one year in the soil and thrice one year in the water bodies; or when the height of the varabis paniculata is from 20cm to 30cm, the overground part is harvested once), the underground part is remained, and stalks of 3cm to 5cm are remained when the overground part is harvested so as to be continuously extracted. The present invention establishes a continuous extraction mode, can continuously transfer a great amount of plumbum, zinc and cadmium in the polluted soil or the polluted water bodies until the contents of plumbum, the zinc and the cadmium in the soil or the water bodies reach the standards of environmental safety.

Description

The method of using A. paniculata to control the pollution of lead, zinc and cadmium in soil and water

technical field

The invention relates to a method for using Arabis Paniculata to remediate single or combined pollution of lead, zinc and cadmium in soil and water.

Background technique

Soil and water pollution with toxic heavy metals (lead, zinc, cadmium, etc.) poses a major environmental and human health concern. my country is rich in lead, zinc, and cadmium mineral resources. Due to the natural weathering of ore bodies rich in lead, zinc, and cadmium, the corresponding open-pit mining, smelting and other mining activities, as well as the extensive use of chemical fertilizers, pesticides and other chemical products, my country's large-scale Heavy metals such as lead, zinc, and cadmium pollute the soil and water bodies of the entire area, especially in areas around mines and smelters. Excessive exposure of lead, zinc, and cadmium directly threatens the living environment and food safety. The above three metals, which are ingested in large quantities through drinking water and food, have carcinogenic, teratogenic, mutagenic, and hormone-endocrine-interfering effects, endangering the health of residents and the safety of livestock. .

At present, the methods available to control heavy metal pollution in soil or water are mainly physical and chemical remediation and bioremediation.

Physical and chemical methods include guest soil (exchange soil) method, precipitation method, leaching method, electrochemical method, and magnetization method. These physical or chemical methods have their own advantages, but generally there are problems such as high cost, large amount of engineering, and easy to cause secondary pollution.

Biological methods include microbial and phytoremediation methods. The local success of microbial bioremediation is limited to the degradation of some organic pollutants.

Treatment of metal contaminants, especially in soil, is not effective. Phytoremediation is an emerging in situ green remediation technology for heavy metal pollution. As one of its core technologies, phytoextraction has developed into a research and application hotspot in the field of environmental science, and has attracted attention. The government, academia and business circles attach great importance to it.

Judging from the current research and practical progress of plant extraction technology at home and abroad, the following problems still exist and need to be solved: (1) There are few plant species that can be selected to enrich heavy metals lead, zinc and cadmium, especially those that can enrich heavy metals at the same time. There are very few plants with more than two kinds of metals; (2) hyperaccumulators, which are recommended for priority use, generally have low biomass, low overall removal efficiency of heavy metals, and there are also problems such as climate adaptation in different places; (3) ) The bioavailability of heavy metals in contaminated soil needs to be improved; (4) In terms of application, some phytoremediation technologies in developed countries have been put into practical application and have achieved good environmental, economic and social benefits, while China has not It is in its infancy, and related technologies are still in the laboratory or pilot stage.

Contents of the invention

The purpose of the present invention is to provide a kind of method utilizing Arabis Paniculata to remediate lead, zinc, cadmium pollution of soil or water body.

The present invention continuously extracts and activates lead, zinc, and cadmium in soil or water by planting A. paniculata, and at the same time transfers them upwards to the aboveground part. After a certain amount of biomass is formed in the aboveground part, the aboveground part is regularly harvested and the underground part is kept. Carry out continuous extraction, and continuously transfer a large amount of lead, zinc, and cadmium in the soil or water body, so as to remove lead, zinc, and cadmium pollution from the soil or water body after a certain extraction cycle.

Concrete steps of the method of the present invention include:

(1) Select Arabis Paniculata (Arabis Paniculata) that naturally grows in the Jinding lead-zinc mining area of Lanping County, Yunnan Province, my country, and collect its seeds for conventional seedling cultivation;

When raising seedlings with seeds, the conditions for seed germination and seedling cultivation are generally: soak the seeds of A. paniculata in Hoagland nutrient solution for imbibition for 2-3 hours, place them in a dark place to germinate for 3-5 days, and grow seedlings in normal soil in the greenhouse. Relative humidity 50-60%, temperature 22-25 ℃;

(2) Control the pH of the soil or water between 5 and 7; depending on the actual pH of the growth medium, adjust it by applying acidic or alkaline fertilizers (or lime);

(3) Transplant the above-mentioned A. paniculata seedlings cultivated by seeds that have grown to 3-5 cm (or grow for 4-5 weeks) into the soil or compound polluted by lead, zinc, and cadmium whose pH has been adjusted according to the aforementioned requirements. In the water body; the treatment for the growth support of A. paniculata in the water body is: implant A. paniculata into the floating bed, and the roots directly contact the polluted water body through the small holes drilled on the floating bed, and add sponge or absorbent cotton in the small holes to stabilize the plants in the early stage of growth. ;

(4) Harvest the aboveground part regularly, twice a year in the soil, three times a year in the water body, or harvest once when A. paniculata grows to a height of 20-30cm; leave 3-5cm stubble when harvesting the above-ground part; let A. paniculata Continue to grow and harvest the shoots of A. paniculata until the lead, zinc, and cadmium in the soil or water reach the safety standards. Harvested aerial parts of A. paniculata can be disposed of uniformly, such as safe landfill or incineration in landfill areas.

The lead, zinc and cadmium super-enrichment plant Arabis Paniculata used in the present invention is a plant of the genus Arabidopsis thaliana, which grows naturally in Jinding lead-zinc mining area, Lanping County, Yunnan Province, my country, and can be collected all year round. Its seeds are also easier to germinate and reproduce.

The polymetallic enrichment characteristics under natural conditions are as follows:

The average contents of lead, zinc and cadmium in the aerial parts of A. paniculata were 2484, 20749 and 457 mg/kg (dry weight, the same below), and the average contents of lead, zinc and cadmium in the underground were 1578, 18149 and 452 mg/kg, respectively. The contents in the aboveground parts were greater than those in the underground parts, and the enrichment index reached the super-enrichment level.

The present invention has the following outstanding effects:

1. The selected Arabidopsis paniculata in the present invention can hyper-accumulate heavy metals lead, zinc and cadmium, and can be applied to phytoremediation of lead, zinc and cadmium in polluted soil or water bodies, with low cost, environmental friendliness, high repair efficiency and potential considerable economic benefits;

2. the selected Arabidopsis paniculata of the present invention has characteristics such as easy reproduction, can tolerate and enrich multiple heavy metals (mainly lead, zinc, cadmium), resistance to diseases and insect pests, and perennial growth, and is suitable for polluting soil or water bodies Lead, zinc, cadmium plant extraction;

3. According to the continuous extraction mode of the method of the present invention, the procedure for remediating soil or water body lead, zinc, and cadmium pollution is simplified, which is suitable for popularization and application;

4. The restoration mode established by the present invention is green in-situ restoration, and the harvested above-ground parts are safely buried or incinerated, which will not cause secondary pollution. At the same time, the restoration process will not damage the soil or water body ecological environment, and contribute to Improve soil degradation and productivity decline caused by heavy metal pollution, restore and increase soil biodiversity, and restore water bodies can significantly improve water quality.

Detailed ways

The present invention will be further described below through embodiment.

Example 1: Soil Remediation

Seeds of A. paniculata were imbibed in Hoagland nutrient solution for 3 hours, placed in a dark place for 4 days to germinate, and then cultivated in normal soil in a greenhouse with a relative air humidity of 60% and a temperature of 25°C. When the seedlings of A. paniculata grow to 3-5cm, transplant them into heavy metal-contaminated soil. The background content of heavy metals in the soil: lead> 500mg/kg, zinc> 1000mg/kg, cadmium> 10mg/kg, apply lime to adjust the pH to 6-7 , row spacing 15cm, plant spacing 10cm. Harvest the aboveground part after 6 months of growth, and leave stubble of 4 to 5 cm. For the first harvest of A. paniculata, the content of heavy metals in the dry weight of the aboveground part was determined as follows: Pb>100mg/kg, zinc>3000mg/kg, cadmium>100mg/kg; A. paniculata continues to grow and continuously extracts soil lead and zinc , cadmium, continuous harvesting of the shoots of A. paniculata, the content of lead, zinc, and cadmium in the soil continued to decrease, until the content of lead, zinc, and cadmium in the polluted soil decreased to the normal soil level, and the pollution of soil lead, zinc, and cadmium was eliminated.

Example 2: Water restoration

The seedlings transplanted in the field are cultivated in the normal soil of the greenhouse, the relative air humidity is 60%, and the temperature is 25°C. After the seedlings grow to 3-5cm, they are transplanted into the floating bed set in the heavy metal polluted water body, and the roots pass through the small holes drilled on the floating bed. Hole, directly in contact with polluted water, add sponge in the small hole to stabilize the plant in the early stage of growth; the background content of heavy metals in the water: lead> 20mg/L, zinc> 100mg/L, cadmium> 10mg/L, add lime to adjust the pH to 6~ 7; row spacing 15cm, plant spacing 15cm. Harvest the aboveground part after growing for four months, leaving 3 to 4 cm stubble. After determination, the content of heavy metals in the dry weight of the harvested A. paniculata: lead > 2000mg/kg, zinc > 5000mg/kg, cadmium > 100mg/kg; continuous extraction of lead, zinc and cadmium from A. paniculata, continuous harvesting of its aboveground Ministry, the content of lead, zinc and cadmium in the water body is continuously reduced until the content of lead, zinc and cadmium in the polluted water body is reduced to the level of the normal water body, and the pollution of lead, zinc and cadmium in the water body is eliminated.

Claims (4)

1. a method utilizing A. paniculata to remediate soil or water body lead, zinc and cadmium pollution, it is characterized in that the step of the method comprises: (1) Select A. paniculata that grows naturally in the Jinding lead-zinc mining area of Lanping County, Yunnan Province, my country, and collect its seeds for conventional seedling cultivation; (2) Control the pH of the soil or water between 5 and 7; (3) Transplant A. paniculata seedlings cultivated by seeds to 3-5 cm or 4-5 weeks into the soil or compound polluted by lead, zinc and cadmium that has adjusted the pH according to the requirements of step (2). In the water body; the supporting treatment for the growth of A. paniculata in the water body is as follows: plant A. paniculata into the floating bed, and the roots directly contact the polluted water body through the small holes drilled on the floating bed, and add sponge or absorbent cotton in the small holes in the early stage of growth to stabilize plant; (4) Harvest the aboveground part regularly, twice a year in the soil, three times a year in the water body, or harvest once when A. paniculata grows to a height of 20-30cm; leave 3-5cm stubble when harvesting the above-ground part; let A. paniculata Continue to grow and harvest the shoots of A. paniculata until the soil or water body lead, zinc and cadmium meet the safety standards. 2. according to the method for claim 1, it is characterized in that when using seed seedling cultivation in the step (1), seed germination and seedling greenhouse cultivation condition are: with A. paniculata seed imbibition 2-3 hour in Hoagland nutrient solution, After germinating in a dark place for 3-5 days, grow seedlings in normal soil in a greenhouse with a relative air humidity of 50-60% and a temperature of 22-25°C. 3. according to the described method of claim 1 or 2, it is characterized in that in the step (2) by applying acidic or alkaline fertilizer to regulate the pH of soil or water body. 4. according to the described method of claim 1 or 2, it is characterized in that in the step (2), adjust the pH of soil or water body by applying lime.