CN1397390A

CN1397390A - Method for treating As polluted soil

Info

Publication number: CN1397390A
Application number: CN 01120519
Authority: CN
Inventors: 陈同斌; 韦朝阳
Original assignee: Institute of Geographic Sciences and Natural Resources of CAS
Current assignee: Institute of Geographic Sciences and Natural Resources of CAS
Priority date: 2001-07-18
Filing date: 2001-07-18
Publication date: 2003-02-19

Abstract

A method for treating the As-polluted soil features that the Chinese brake herbs are planted in said soil for absorbing the As from the soil and the their leaves are removed periodically (5-6 months). For acid soil, the lime or alkaline fertilizer can be applied to increase its pH value.

Description

A kind of method of administering As polluted soil

Technical field

This method relates to a kind of method of administering As polluted soil.

Background technology

Arsenic contamination is a very general and unusual serious environmental problem.Many mining areas of China and western high arsenic area also exist large-area arsenic contamination and arsenic poisoning problem, and people's lives and industrial and agricultural production are caused very big harm.Since 19th century, arsenic is widely used in industrial and agricultural production always.Matter containing arsenic is commonly used for the raw material of pesticide, bactericide, herbicide, defoliant, male gametocide, anticorrisive agent, coating, softening agents, chemical industry and semiconductor production etc., make near the soil many orchards, farmland, art material processing factory and the factory be subjected to serious arsenic contamination, have in addition exceed thousands of times than the arsenic content of natural soils.Be exposed to for a long time in the environment that contains arsenic and can cause carcinoma of urinary bladder, liver cancer and cutaneum carcinoma, the energetic supersession that the arsenic of high dose can interference cell, thus cause the death of organism.

At present, the method for improvement heavy metal pollution of soil mainly contains the precipitation method, elution method, antagonism method, electrochemical process, magnetization method.These physics or chemical method respectively have its advantage, and quantities is big, expense is high but generally all exist, and also cause secondary pollution easily simultaneously and cause secondary ecological problems such as soil texture destruction and soil fertility degeneration.

As everyone knows, natural plant can both absorb the arsenic in the soil more or less, but manually have the arsenic content of the common plant of purpose cultivation generally to be no more than 0.5mg/kg, for example: China beans is 0.02～0.56mg/kg, and greengrocery is 0.001～0.04mg/kg.Arsenic has very strong toxicity to plant, the ability of common plant absorbing arsenic generally all very a little less than, therefore plant common plant and then be difficult to reach the effect of administering and repairing As polluted soil.

Summary of the invention

Purpose of the present invention is providing a kind of method of administering As polluted soil, this method small investment, maintenance cost is low, quantities is little, administrative skill is less demanding, do not destroy soil physico-chemical property, do not produce secondary pollution, and to water and soil conservation, fixing soil with beautify landscape environment and all have good effect.

For achieving the above object, the root system of the present invention by ciliate desert-grass absorbs the arsenic in the soil in a large number, and upwards carries and be transported to overground part, and the harvesting overground part is also removed it, then can from soil, take away a large amount of arsenic, thereby reach the purpose of from contaminated soil, removing the arsenic contamination thing fast.

A kind of method of administering As polluted soil provided by the invention comprises:

The control soil pH is between neutrality and the meta-alkalescence, then regulates by using alkaline matter such as lime or alkaline fertilizer for acid ground.

Regularly or look the ciliate desert-grass growing height and gather in, and it is transferred to other places focus on.

Gather in overground part first and carry out in the time of individual month, gathered in once in later every growth 4-5 month, or when ciliate desert-grass grows into 50～80cm height, gather in once at the 5-6 that grows.

Toothing 5～10cm height during the harvesting overground part.

Ciliate desert-grass is different with general plant, it has extremely strong patience to the arsenic poison, even can be in containing the arsenic poison ring border of arsenic 24000mg/kg normal growth, its overground part not only can a large amount of arsenic (reaching as high as 8000mg/kg) of enrichment, its arsenic content is higher 10,000 times to tens thousand of times than common plant, its speed of growth is also very fast, and biomass is very big.Under the field condition, its overground part fresh weight can reach 36t/ha and (contain arsenic about 10～20kg/ha).And ciliate desert-grass can reach 80 at arsenic content less than the biological concentration coefficient on the soil of 1000mg/kg, especially in the artificial cultivation environment, and the easier overground part that is enriched to of arsenic.Even under low arsenic concentration, ciliate desert-grass is enrichment arsenic in a large number also, so it also can be used to repair the soil of serious pollution and slight pollution.Absorb arsenic in a large number by the plantation ciliate desert-grass, provide a good technical approach for solving the arsenic contamination problem undoubtedly.

Ciliate desert-grass can be grown in the soil of pH4.5～8.5, no matter is in southern red soil, and still in the cinnamon soil in the north, growth conditions is all very good, so ciliate desert-grass is very wide to the accommodation of soil.Just the acid-base value of soil absorbs arsenic to ciliate desert-grass certain influence, and ciliate desert-grass is more prone to absorb and enrichment arsenic under neutral and alkali condition.Therefore,, quicken reparation and the improvement speed of ciliate desert-grass, less than 6 acid ground, can use alkaline matter such as lime or alkaline fertilizer in right amount, to improve pH in soil for pH to the dirty soil of arsenic in order further to improve the absorption efficiency of plant to arsenic.

Along with the prolongation of implantation time, not only ciliate desert-grass the upperground part biomass constantly increases, and the arsenic content of its blade also significantly increases.When just transplanting, because the arsenic that the ciliate desert-grass early growth is slow and absorb is less, therefore should after transplanting, just gather in overground part in individual month by 5-6, harvesting in then every later on growth 4-5 month is once, or when growing into 50～80cm height, ciliate desert-grass gathers in once equal toothing 5-10cm height when at every turn gathering in.Therefore, when utilizing ciliate desert-grass to repair and administering As polluted soil, the time of harvesting should be grasped, overground part can not be gathered in prematurely, otherwise the effect that can reduce its reparation and administer As polluted soil.

Harvested ciliate desert-grass then should be transferred in other environment that can not cause secondary pollution and focus on (as refuse landfill or burning).

Comparing with traditional contaminated soil improvement method, by plantation ciliate desert-grass repairing polluted soil, mainly is to utilize that ciliate desert-grass absorbs from soil environment in a large number, enrichment arsenic, when its upperground part biomass of harvesting then can be taken away a large amount of arsenic from soil.In acid ground, should improve the pH of contaminated soil by means such as limings, so that bring into play special absorption, the enrichment function of super enriching plant ciliate desert-grass better to arsenic.This method has small investment and maintenance cost is low, quantities is little, administrative skill is less demanding, do not destroy soil physico-chemical property, do not produce secondary pollution, and to water and soil conservation, fixing soil with beautify landscape environment and all have good effect, be that a kind of usage range is wide, investment and low, the easy maintenance of operating cost, contaminated environment " green recovery technique " simple to operate.The invention solves the reparation and the governing problem of As polluted soil, have good benefits in environment, social benefit and economic benefit, have huge application potential aspect the reparation of As polluted soil and the improvement.

Description of drawings

Fig. 1 is the result of the test of the embodiment of the invention 2.

The specific embodiment

Exemplify embodiment below, be used for illustrating feasibility of the present invention and good effect.

Embodiment 1:

Transplant the ciliate desert-grass seedling in the As polluted soil that contains arsenic 209mg/kg, the management method according to common crops behind plant survival manages, and gathers in overground part after 6 months.After measured, total arsenic amount that this moment, the ciliate desert-grass overground part absorbed from soil is 3140mg/kg, and the soil arsenic content then is reduced to 177mg/kg by original 209mg/kg, is equivalent to make the total arsenic in the soil to reduce 15.0%.Later on then gathered in overground part continuously in 4-5 month when the ciliate desert-grass growth, the content of arsenic will constantly reduce in the soil, and it is flat finally to make the arsenic content of contaminated soil be reduced to the arsenic-containing water of normal soil, eliminates the purpose that arsenic in soil pollutes to reach.

Embodiment 2:

As can be seen from Figure 1, plant after 6 months, the arsenic content of its blade is increased to 5070mg/kg by original 1850mg/kg.The ciliate desert-grass overground part contains so a large amount of arsenic, then the arsenic in a large amount of soil can be taken away by the results overground part, reaches the effect of removing arsenic contamination.

Claims

1, a kind of method of administering As polluted soil comprises, is transplanted in the As polluted soil with the ciliate desert-grass directly transplanting or by a minute seedling mode, it is characterized in that:

The control soil pH is between neutrality and the meta-alkalescence;

2, the method for improvement As polluted soil according to claim 1 is characterized in that: slant acidity soil application alkaline matter is regulated.

3, the method for improvement As polluted soil according to claim 1 is characterized in that: described alkaline matter is lime or alkaline fertilizer.

4, the method for improvement As polluted soil according to claim 1 is characterized in that: described periodical reaping is, gathers in overground part first and carries out in the time of 5-6 month in growth, gathers in once in later every growth 4-5 month.

5, the method for improvement As polluted soil according to claim 1 is characterized in that: described periodical reaping is that ciliate desert-grass grows into 50～80cm when height harvesting once.

6, the method for improvement As polluted soil according to claim 1 is characterized in that: toothing 5～10cm height during described harvesting overground part.