CN110412165A - An In Situ Method for Characterizing the Bioavailability of Hydrophobic Organic Pollutants in Soil Microdomains - Google Patents

Abstract

The invention discloses a kind of methods of hydrophobic organic pollutant biological effectiveness in micro- domain of in-situ characterization soil, belong to Environmental Science and Engineering technical field.Minute yardstick dimethyl silicone polymer probe is placed in soil media by the method, is enriched with by way of Culture in situ to the hydrophobic organic pollutant in soil, then the hydrophobic organic pollutant in probe is extracted and measured.The method of the present invention utilizes the minute yardstick and strong-hydrophobicity feature of dimethyl silicone polymer probe, it can not interfere in situ and and simulate enrichment of the biology to hydrophobic organic pollutant in soil on the basis of the distribution of hydrophobic organic pollutant, the in-situ characterization for realizing hydrophobic organic pollutant biological effectiveness in the micro- domain of soil, provides technical support further to verify migration, conversion and the degradation mechanism of the micro- domain interface hydrophobic organic pollutant of animal activity/root system of plant-soil.

Description

An in situ characterization of the bioavailability of hydrophobic organic pollutants in soil microdomains method

technical field

The invention relates to the field of environmental science and engineering technology, more specifically, to a method for in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains.

Background technique

With the rapid development of society, the interference of human activities such as the synthesis and use of a large number of chemicals, the discharge of industrial wastes, the incomplete combustion of coal and oil, etc., the environment has been polluted to varying degrees on a global scale, which seriously threatens and endangers the ecology. Safety. Among them, hydrophobic organic pollutants have attracted much attention due to their persistence, long-distance migration, bioaccumulation, and three effects (carcinogenic, teratogenic, and mutagenic), and have become the top priority of research and governance. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls and phthalates have been listed as priority pollutants by the environmental protection department. According to reports, domestic surface soil has been polluted to varying degrees, and the scope and level are still increasing sharply. Organisms in the soil are often primary organisms in the food chain. Due to biological activities, hydrophobic organic pollutants will be enriched by plants or animals and enter the food chain, endangering the safety of higher organisms. Therefore, in order to ensure ecological security and human health, risk assessment of hydrophobic organic pollutants in soil is very necessary.

After hydrophobic organic pollutants enter the environment, only some of them enter the food chain through the enrichment of microorganisms, animals, and plants through complex interactions. This part of hydrophobic organic pollutants (bioavailability) is often used in environmental risk assessment. In order to accurately evaluate the bioavailability of hydrophobic organic pollutants in soil, in recent years, researchers have developed a variety of methods for the determination of the bioavailability of hydrophobic organic pollutants in soil, most of which are solid-phase extraction, mild solvent Extraction methods, etc., are all ex-situ methods, and there are fewer in-situ determination methods.

After searching, relevant applications are disclosed in the prior art, such as Chinese patent application number 2017104216600, the application published on September 29, 2017 discloses a method for predicting the bioavailability of polycyclic aromatic hydrocarbons in soil, Including the following steps: the first step: the preparation of polycaprolactone (PCL) film, the method selects PCL particles with a degree of polymerization of 80,000 as a raw material, and prepares a 10% (M:V) mixed solution. Under the condition of spinning for 2 hours, a PCL membrane containing 1-10 μm pores was prepared for use; the second step: the preparation of the PCL semi-permeable membrane passive sampling device (SPMD), and the prepared PCL membrane was cut into 1cm×1.5 cm uniform specification, sealed with a heat sealer, and set aside; the third step: PCL-SPMD for the prediction of the bioavailability of polycyclic aromatic hydrocarbons in soil, take 1 PCL-SPMD, a certain volume of background solution and phenanthrene stock solution in 60mL In the EPA sample bottle, the concentration of phenanthrene is 0.1 ~ 1mg/L, and the enrichment kinetics of phenanthrene in water is studied; take 3 PCL-SPMDs and place them in a beaker containing 100g of soil, and the concentration of phenanthrene is 50mg/kg, and conduct soil analysis. Enrichment kinetics of phenanthrene in PCL-SPMD (soil-water ratio=5:2); after enrichment, measure the concentration of phenanthrene in PCL-SPMD, determine the concentration of phenanthrene in PCL-SPMD after enrichment balance, and compare with biological enrichment Correlation analysis was carried out on the concentration of phenanthrene in earthworms in the experiment.

The method of this application uses a semi-permeable membrane passive sampling device for the determination of the bioavailability of polycyclic aromatic hydrocarbons in soil. However, the above-mentioned device has a large volume, length x width = 1cm x 1.5cm, and it is difficult to realize the soil micro-domain in terms of size. Bioavailability Characterization of Hydrophobic Organic Pollutants in Millimeter-Scale Spatial Regions in the Environment. According to common knowledge, soil animal’s surface absorption of pollutants and plant root activity interface are all completed in the millimeter or even micron space, and the key process for pollutants to enter the food chain from the soil lies in the interaction between soil pollutants and organisms in this tiny area. interaction, the large-volume sampling device not only cannot accurately reflect the micro-domain space process, but also the large-volume enrichment device itself and the large enrichment amount will interfere with the original distribution of hydrophobic organic pollutants in the soil and the pollutants in the soil. The distribution process of the soil-liquid and soil-biological interface affects the accuracy of the measurement. In addition, the fitting equation of the above method is R ² =0.77, indicating that the accuracy of the method needs to be improved.

Therefore, based on the defects of the prior art, it is urgent to invent a simple, efficient, and highly accurate method for in situ determination of the bioavailability of hydrophobic organic pollutants in soil microdomains.

Contents of the invention

1. The technical problem to be solved by the invention

Aiming at the problem that the prior art cannot characterize the bioavailability of hydrophobic organic matter in soil micro-domains, the present invention adopts the method of in-situ culture of micron-scale, strongly hydrophobic polydimethylsiloxane probes to analyze the bioavailability of hydrophobic organic matter in soil micro-scale The distribution and enrichment of hydrophobic organic pollutants can realize the in-situ accurate characterization of hydrophobic organic pollutants in soil micro-domains.

2. Technical solution

In order to solve the problems of the technologies described above, technical scheme of the present invention is as follows:

The invention provides a method for in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains. In the method, a polydimethylsiloxane probe is placed in the soil, and the soil is treated by in-situ cultivation. The hydrophobic organic pollutants in the probe are enriched, and then the hydrophobic organic pollutants in the probe are extracted and determined.

As a further improvement of the present invention, the hydrophobic organic pollutants include polycyclic aromatic hydrocarbons.

As a further improvement of the present invention, the polycyclic aromatic hydrocarbons include one or more of phenanthrene, pyrene, benzo(a)pyrene or benzo(ghi)pyrene.

As a further improvement of the present invention, the mass ratio of the polydimethylsiloxane probe to the soil is less than one thousandth.

As a further improvement of the present invention, the method specifically includes the following steps:

1) The polydimethylsiloxane probe is completely covered with soil containing hydrophobic organic pollutants, and the diameter of the polydimethylsiloxane probe is not greater than 110 μm;

2) adding water to the soil to maintain a certain soil humidity, cultivating the probe at room temperature for a period of time, and replenishing water at intervals;

3) Taking out the probe, extracting the hydrophobic organic pollutants in the probe and measuring the concentration.

As a further improvement of the present invention, in the step 1), the depth of the probe in the soil is greater than 1mm.

As a further improvement of the present invention, in the step 2), the soil moisture is kept at 60% of the field water capacity.

As a further improvement of the present invention, in the step 3), the method of extracting the hydrophobic organic pollutants is as follows: after the probe is cut into pieces, an organic reagent is added for ultrasonication.

As a further improvement of the present invention, in the step 3), the probe is shredded to a length less than 1 cm.

As a further improvement of the present invention, the organic reagent includes acetonitrile, and the ultrasonic time is 5-40 min.

As a further improvement of the present invention, the specific operation steps are as follows:

S1) Weigh 5-30 g of soil containing hydrophobic organic pollutants into a 150 mL beaker, vibrate and spread;

S2) Take 3 to 10 polydimethylsiloxane probes with a length of 2 to 4 cm and place them on the upper surface of the soil at the bottom of the beaker;

S3) Weigh again 5-30 g of soil containing hydrophobic organic pollutants on the polydimethylsiloxane probe, oscillate and shake well, and completely cover the polydimethylsiloxane probe;

S4) add deionized water to 60% of field water holding capacity, cultivate at room temperature for 30 days, replenish water at intervals; S5) make

Take out the polydimethylsiloxane probe with tweezers, wipe it with a wet tissue three times repeatedly, and remove the moisture;

S6) Shred the polydimethylsiloxane probe to less than 1 cm, and place it in a 300 μL inner tube;

S7) Add 200 μL of acetonitrile to the inner cannula, sonicate for 5-40 min, transfer the supernatant to another inner cannula, and use high-performance liquid chromatography to measure.

3. Beneficial effect

Compared with the existing known technology, the technical solution provided by the invention has the following remarkable effects:

(1) The method for in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains of the present invention uses probes of polydimethylsiloxane to carry out soil in-situ cultivation, and utilizes polydimethylsiloxane Hydrophobic properties, that is, partitioning enriches hydrophobic organic pollutants. The results show that there is a good linear fit between the concentration of polycyclic aromatic hydrocarbons enriched in in situ culture and the concentration of organic substances enriched in plant roots/animal surfaces relationship, the linear correlation coefficient R can reach more ^than 0.90, the highest can reach 0.99, and the results are stable and reliable. Therefore, the method of the present invention can be used to perform accurate in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains. In the prior art, although there is a certain linear relationship between the concentration of organic matter extracted by conventional butanol extraction of soil samples and the concentration of organic matter enriched on the plant root system/animal body surface, the linear relationship is unstable. , the reference value of biological effectiveness is low, and it is an ectopic operation, and the theoretical accuracy of the experimental results is low.

(2) The method for in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains of the present invention can well simulate the enrichment and distribution state of hydrophobic organics in soil in animals/plants, so the method of the present invention is adopted The characterization of the bioavailability of the method can overcome the defects of poor reproducibility, time-consuming and high cost caused by complex extraction and other processing processes when directly sampling animals/plants. The method of the present invention has simple processing steps and only needs to The collected samples can be shredded and extracted by ultrasonic, which reduces the error caused by the operation, has high reproducibility, short time consumption, and effectively reduces the cost.

(3) The method for in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains of the present invention can simultaneously simulate the enrichment state of hydrophobic organics in animals and plants, and can not only efficiently realize the hydrophobicity in soil micro-domains Bioavailability characterization of sexual organic pollutants, and provides technical support for further exploration of the migration, transformation and degradation mechanisms of hydrophobic organic pollutants in animal activity areas/plant root-soil interfaces.

(4) The method for in-situ characterization of the bioavailability of hydrophobic organic pollutants in soil micro-domains of the present invention uses a small volume of polydimethylsiloxane to cultivate in the soil, and only a small amount of organic reagents need to be added after the cultivation. It can be extracted, and the amount of organic reagents is small. The determination methods in the prior art usually need to collect a large number of soil or biological samples for processing, and also need to use organic reagents to extract hydrophobic organic matter many times, so a large amount of organic reagents need to be added, the process is complicated, time-consuming, and consumes a relatively large amount of organic reagents. big.

Description of drawings

Figure 1 is the linear correlation between the concentration of polycyclic aromatic hydrocarbons extracted from the polydimethylsiloxane probe and Eisenia chinensis in Example 1, where a is the PHE extracted from the probe and Eisenia chinensis The linear regression equation of the concentration, b is the linear regression equation of the concentration of PYR extracted in the probe and the concentration of PYR extracted in the body of Eisenia chinensis; c is the linear regression equation of the concentration of BaP extracted in the probe and in the body of Eisenia chinensis; d is The linear regression equation of the concentration of BPE extracted in the probe and in the body of Eisenia chinensis;

Fig. 2 is the linear correlation of the polycyclic aromatic hydrocarbon concentration extracted in the polydimethylsiloxane probe and the ryegrass root system in embodiment 2, wherein, a is the difference between the PHE concentration extracted in the probe and the ryegrass root system Linear regression equation; b is the linear regression equation of the PYR concentration extracted in the probe and ryegrass root system; c is the linear regression equation of the BaP concentration extracted in the probe and ryegrass root system; d is the linear regression equation of the probe and ryegrass root concentration Linear regression equation for BPE concentration extracted in roots;

Fig. 3 is the multilayer root box schematic diagram in embodiment 3;

Fig. 4 is the bioavailability experimental characterization result of polycyclic aromatic hydrocarbons in the rhizosphere area in embodiment 3, wherein, a is the bioavailability characterization result of the PHE in the rhizosphere area; b is the bioavailability of the PYR in the rhizosphere area characterization results; c is the bioavailability characterization results of BaP in the rhizosphere; d is the bioavailability characterization results of BPE in the rhizosphere.

Detailed ways

Example 1

1) Using the method of the present invention to adopt polydimethylsiloxane probes to in-situ cultivate and enrich polycyclic aromatic hydrocarbons in the soil, and the specific process of detecting the enriched polycyclic aromatic hydrocarbons is as follows:

a) Weigh 5g of polycyclic aromatic hydrocarbon-contaminated red soil in a 150mL transparent beaker, vibrate and lay flat;

b) Take three polydimethylsiloxane probes with a length of 4 cm and place them on the upper surface of the red soil at the bottom of the beaker. The polydimethylsiloxane probes are commercially available from Poly Micro Technologies, Inc., USA The probe, the mass ratio of the polydimethylsiloxane probe to the soil is less than one thousandth, the diameter of the polydimethylsiloxane probe is not greater than 110 μm, and the probe is in the soil The depth is greater than 1mm.

c) Weigh again 5g of PAH-contaminated red soil and place it above the polydimethylsiloxane probe, oscillate to evenly cover the polydimethylsiloxane probe, and add deionized water to the field water holding capacity 60%, replenish water every 5 days;

d) Use tweezers to take out the polydimethylsiloxane probe, wipe it repeatedly three times with a wet tissue, remove the moisture and cut it to 1 cm, put it in a 300 μL inner cannula, add 200 μL of acetonitrile solution, sonicate for 5 minutes, and transfer The supernatant was placed in another inner tube, and high-performance liquid phase-fluorescence chromatography was used for phenanthrene (PHE), pyrene (PYR), benzo(a)pyrene (BaP), benzo(ghi)pyrene (BPE) Four types of representative polycyclic aromatic hydrocarbons (PAHs) concentrations were detected.

Adopt the routine detection method of PAHs in the prior art, select chromatographic column to be LC-PAH (25cm x 4.6mm x 5 μ m) in the present embodiment, column temperature 30 ℃, mobile phase is the mixed solution of acetonitrile and ultrapure water (V acetonitrile /V ultrapure water=9:1); the injection volume was set to 20 μL, and the flow rate was set to 1.5 mL/min.

2) The specific process for in-situ enrichment of polycyclic aromatic hydrocarbons in soil by Eisenia chinensis and the detection of enriched polycyclic aromatic hydrocarbons is as follows:

a) Weigh 100g of polycyclic aromatic hydrocarbon-contaminated soil into a 150mL transparent beaker, add deionized water to 60% of the field water holding capacity, and set aside; select 10 Eisenia chinensis with similar size and weight, and place them in non-polluted red soil, Acclimate in artificial climate incubator for 2 weeks.

b) Take qualitative filter paper, moisten it with deionized water, put it in a 150mL transparent beaker, put Eisenia chinensis domesticated for 2 weeks, seal the beaker with aluminum foil, and punch holes to ensure air flow, and clean the colon in an artificial climate incubator for 48 hours . To ensure the effect of colon cleansing, a filter paper was replaced every 24 hours.

c) Place the Eisenia chinensis after bowel cleansing in the above-mentioned 150mL transparent beaker containing polycyclic aromatic hydrocarbon-contaminated red soil, seal the beaker with aluminum foil, punch holes, and cultivate it in an artificial climate incubator for 15 days, and replenish water every 3 days, Make sure the water content is 60% of the field capacity;

d) After the cultivation is over, take out Eisenia chinensis, grind and pulverize, stir and mix well, take 0.2g of earthworms and appropriate amount of diatomaceous earth and mix well for later use; take a stainless steel extraction tank, add qualitative filter paper gaskets, appropriate amount of quartz sand, earthworms successively Mix with diatomaceous earth, appropriate amount of quartz sand (fill the extraction tank);

e) Place the extraction cell on an accelerated solvent extraction apparatus, use n-hexane/acetone=4:1 (V/V) as the extractant, and extract twice at 100°C and 1500psi to obtain the extract; Transfer to a rotary evaporator and place on a rotary evaporator, concentrate the extract to 2 mL at 50 °C and 380 psi, and then purify it through a solid-phase extraction column to obtain a purified solution, using n-hexane/dichloromethane (9:1 , V/V) The mixed solution rinses the rotary concentration evaporating flask and the solid phase extraction column three times to reduce the loss of PAHs and improve the recovery rate. Concentrate the purified solution to 2mL on a rotary evaporator, add 1mL of acetonitrile, concentrate again to less than 1mL, use acetonitrile to make up to 1mL, store at -20°C, use the same chromatographic detection method as in Example 1, and measure on the machine .

3) Linear fitting:

Linear fitting was carried out on the concentration of PAHs obtained by the enrichment of polydimethylsiloxane probe in step 1) and the concentration of polycyclic aromatic hydrocarbons obtained in step 2) by the enrichment of Eisenia chinensis. In Figure 1, a is the probe and The linear regression equation of the PHE concentration extracted from Eisenia chinensis, the correlation coefficient (R ² ) is 0.9989; b is the linear regression equation of the concentration of PYR extracted from the probe and Eisenia chinensis, the correlation coefficient (R ² ) is 0.9754 ; c is the linear regression equation of the probe and the concentration of BaP extracted from Eisenia chinensis, and the correlation coefficient (R ² ) is 0.9471; d is the linear regression equation of the concentration of BPE extracted from the body of the probe and Eisenia chinensis, and the correlation (R ² ) was 0.9116.

The good linear correlation indicates that earthworms and polydimethylsiloxane probes have a similar and dominant way of enriching hydrophobic organic pollutants (partitioning), further suggesting that polydimethylsiloxane probes can in situ Precise prediction of animal availability of polycyclic aromatic hydrocarbons in soil microdomains.

Example 2

The basic content of this embodiment is the same as embodiment 1, the difference is:

1) Using the method of the present invention to use polydimethylsiloxane probes to in-situ cultivate and enrich polycyclic aromatic hydrocarbons in the soil, and the specific process of detecting the enriched polycyclic aromatic hydrocarbons is basically the same as that of Example 1, except that in:

a) Weigh 30g of polycyclic aromatic hydrocarbon-contaminated red soil in a 150mL transparent beaker, vibrate and lay flat;

b) Take 10 polydimethylsiloxane probes with a length of 4 cm and place them on the upper surface of the red soil at the bottom of the beaker. The polydimethylsiloxane probes are commercially available from Poly Micro Technologies in the United States. the probe;

c) Weigh again 30g of polycyclic aromatic hydrocarbon-contaminated red soil and place it above the polydimethylsiloxane probe, oscillate and shake well, completely cover the polydimethylsiloxane probe, and add deionized water to the field water holding capacity 60%, replenish water every 5 days;

d) Use tweezers to take out the polydimethylsiloxane probe, wipe it repeatedly 3 times with a wet tissue, remove the water and cut it to less than 1cm, put it in a 300μL inner cannula, add 200μL of acetonitrile solution, ultrasonic for 40min, and transfer to the The supernatant was placed in another inner tube, and the same chromatographic conditions as in Example 1 were used to detect the concentrations of PHE, PYR, BaP, and BPE respectively.

2) Using ryegrass to enrich polycyclic aromatic hydrocarbons in the soil in situ, and the specific process of detecting the enriched polycyclic aromatic hydrocarbons is as follows:

a) Weigh 200g of PAHs-contaminated red soil into a 250mL transparent beaker, add deionized water to 60% of the field water holding capacity, and set aside. In order to increase the germination rate, soak the ryegrass seeds in 10% H ₂ O ₂ solution for 30 minutes to sterilize, At the same time, the ryegrass seeds were washed with deionized water to remove residual H ₂ O ₂ on the surface.

b) Place the washed ryegrass seeds in a brown beaker covered with moist gauze at the bottom, and germinate them in an artificial climate incubator (28±1°C), and add water once a day during the germination period. After the ryegrass seeds germinated, they were placed in the 250mL transparent beaker containing the above PAHs-contaminated red soil, cultivated in an artificial climate incubator (28±1°C, light 500μmolphoton/m ² /s), and replenished water every 3 days . Sampling was carried out after 4 weeks, and the above-ground and underground plant samples were cleaned with deionized water, bagged, and ryegrass samples were obtained.

c) The follow-up treatment process of the ryegrass sample is basically the same as that of Eisenia chinensis in Example 1, the difference is that in this example, 0.5 g of ryegrass is mixed with an appropriate amount of diatomaceous earth and stirred.

3) Linear fitting:

Linear fitting was performed on the concentration of PAHs obtained in step 1) enrichment of polydimethylsiloxane probes and the concentration of PAHs obtained in step 2) enrichment in ryegrass in vivo. The linear regression equation of PHE concentration extracted from wheatgrass root system, the correlation coefficient (R ² ) is 0.9905; b is the linear regression equation of the probe and the PYR concentration extracted from ryegrass root system, and the correlation coefficient (R ² ) is 0.9265; c is The linear regression equation between the probe and the BaP concentration extracted from the ryegrass root system, the correlation coefficient (R ² ) is 0.9843; d is the linear regression equation between the probe and the BPE concentration extracted from the ryegrass root system, and the correlation coefficient (R ² ) is 0.9851.

The good linear correlation indicated that ryegrass and the polydimethylsiloxane probe had a similar and dominant way of enriching hydrophobic organic pollutants (partitioning), further suggesting that the polydimethylsiloxane probe could Bit-accurate prediction of phytoavailability of polycyclic aromatic hydrocarbons in soil microdomains.

comparative example

The basic content of this embodiment is the same as that of Example 1, and the difference is that: the relatively mature n-butanol extraction method in the prior art is adopted, and the specific operation is: take 100g of PAHs polluted red soil, and measure PHE, PYR, BaP and BPE. For the initial concentration of the species, add 15mL of n-butanol, vortex for 50s, centrifuge for 10min, remove the n-butanol solution, then measure the remaining concentration of PHE, PYR, BaP and BPE in the soil, and use the subtraction method to determine the concentration of n-butanol in the n-butanol extract. pollutant content.

The concentration of PAHs extracted by butanol was linearly fitted with the concentration of PAHs enriched in ryegrass and Eisenia chinensis. The correlation coefficients (R ² ) were: 0.5454, 0.9616, 0.8619, and 0.8997; the correlation coefficients (R ² ) between the butanol extract and PHE, PYR, BaP, and BPE in the ryegrass root system were: 0.9736, 0.8291, 0.7925, and 0.5250. Table 1 is a linear correlation comparison between n-butanol extraction and the method of the present invention.

Table 1 n-butanol extraction and the linear correlation comparison that the method of the present invention obtains

The results show that the concentration of hydrophobic pollutants extracted by enrichment and extraction of the present invention has a higher linear relationship with the concentration of hydrophobic pollutants extracted from animals/plants, and is more accurate.

Example 3

This example is the specific operation of the bioavailability characterization experiment of polycyclic aromatic hydrocarbons in the rhizosphere area:

1) Weigh 2.5kg of PAHs-contaminated soil (dry weight), divide it into three treatment groups, namely blank (CK), add 1% corn straw charcoal, add 1% wheat straw charcoal, mix well, and put them into the diagram layer by layer. In the root box shown in 3, the width of each layer along the horizontal direction is 1mm, and each layer of soil is covered with seven 4cm polydimethylsiloxane probes according to the method in embodiment 1, and the arrow position is root growth room, as shown in Figure 3, the rhizosphere, the near-rhizosphere and the far-rhizosphere region are all embedded with probes; add water to 60% of the maximum water holding capacity of the soil;

2) Take germinated ryegrass seeds, place them on the surface soil of the root growth room, spread a layer of dry soil, and treat them in the dark for 2 days to germinate; then transfer the multi-layered root boxes to the greenhouse for cultivation, and replenish water every three days, Replenish the nutrient solution every two weeks, and the ryegrass is used to provide the rhizosphere environment;

3) After culturing for 4 weeks, the polydimethylsiloxane probe (PDMS) was collected, washed and measured, and the operation method was basically the same as in Example 1.

Fig. 4 is the bioavailability experimental characterization result of polycyclic aromatic hydrocarbons in the rhizosphere area in embodiment 3, wherein, a is the bioavailability characterization result of the PHE in the rhizosphere area; b is the bioavailability of the PYR in the rhizosphere area characterization results; c is the bioavailability characterization results of BaP in the rhizosphere; d is the bioavailability characterization results of BPE in the rhizosphere.

According to Fig. 3 and Fig. 4, based on the method of the present invention, combined with the multi-layer root box in situ enrichment experiment, the spatial distribution of PAHs bioavailability in micro-domains such as rhizosphere, near-rhizosphere and far-rhizosphere can be clearly characterized. By comparing CK with 1% corn straw charcoal and 1% wheat straw charcoal, the method of the present invention can explore the effect of biochar on the bioavailability of PAHs in each micro-domain of the root system.

The present invention has been described in detail above with reference to specific exemplary embodiments. However, it should be understood that various modifications and changes can be made without departing from the scope of the present invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative only and not restrictive, and any such modifications and variations, if any, are intended to fall within the scope of the invention as described herein. In addition, the background art is intended to illustrate the research and development status and significance of the present technology, and is not intended to limit the present invention or the application and the application field of the present invention.

Claims (10)

1. a kind of method of hydrophobic organic pollutant biological effectiveness in micro- domain of in-situ characterization soil, it is characterised in that: described Dimethyl silicone polymer probe is placed in soil by method, to the organic dirt of hydrophobicity in soil by way of Culture in situ Dye object is enriched with, then the hydrophobic organic pollutant in probe is extracted and measured.

2. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 1, It is characterized by: the hydrophobic organic pollutant includes polycyclic aromatic hydrocarbon type organic.

3. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 2, It is characterized by: the polycyclic aromatic hydrocarbon type organic includes one of phenanthrene, pyrene, benzo (a) pyrene or benzo (ghi) pyrene or several Kind.

4. the side of hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 2 or 3 Method, it is characterised in that: the mass ratio of the dimethyl silicone polymer probe and soil is less than one thousandth.

5. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 4, It is characterized by: the method specifically includes the following steps:

1) dimethyl silicone polymer probe is completely covered using the soil containing hydrophobic organic pollutant, the poly dimethyl silicon The diameter of oxygen alkane probe is not more than 110 μm；

2) moisture is added into soil, keeps certain soil moisture, and the probe is cultivated a period of time at room temperature, interval Time keeps the skin wet；

3) probe is taken out, extract the hydrophobic organic pollutant in probe and carries out concentration mensuration.

6. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 5, It is characterized by: the depth of the probe in the soil is greater than 1mm in the step 1).

7. the side of hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 5 or 6 Method, it is characterised in that: in the step 2), keeping soil moisture is the 60% of field capacity.

8. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 7, It is characterized by: extracting the mode of hydrophobic organic pollutant in the step 3) are as follows: be added after shredding the probe organic Reagent ultrasound.

9. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 8, It is characterized by: the probe is shredded to length and is less than 1cm in the step 3).

10. the method for hydrophobic organic pollutant biological effectiveness in the micro- domain of in-situ characterization soil according to claim 8, It is characterized by: the organic reagent includes acetonitrile, the ultrasonic time is 5~40min.