阅读说明：本技术 基于光谱分析预测土壤中高环PAHs生物有效性的建模方法 (Modeling method for predicting biological effectiveness of high-ring PAHs in soil based on spectral analysis ) 是由 夏天翔 钟名誉 王世杰 贾晓洋 姜昱聪 于 2019-11-08 设计创作，主要内容包括：本发明公开了一种基于光谱分析预测土壤中高环PAHs生物有效性的建模方法,属于多环芳烃的生物有效性预测技术,包括以下步骤：(1)土壤样品收集和前处理,(2)用化学氧化法氧化土壤样品,(3)将原土样以及其对应氧化后的土样进行红外光谱测定,得到各波长红外吸光度占比,(4)建立16种PAHs的浓度与各红外占比的拟合曲线,比较不同环数多环芳烃与不同波长吸光度占比的回归模型,(5)对回归模型进行筛选,获得相关度最佳的回归模型,得到该场地高环多环芳烃与吸光度占比的函数关系；本发明建立了相对精确快速预测污染土壤中PAHs的生物有效性的光谱模型,便于后续对PAHs的生物有效性及其所带来的环境健康风险进行研究。(The invention discloses a modeling method for predicting bioavailability of high-ring PAHs in soil based on spectral analysis, belonging to a polycyclic aromatic hydrocarbon bioavailability prediction technology and comprising the following steps: (1) collecting and pretreating a soil sample, (2) oxidizing the soil sample by using a chemical oxidation method, (3) carrying out infrared spectrum measurement on an original soil sample and the soil sample after corresponding oxidation to obtain infrared absorbance ratios of various wavelengths, (4) establishing a fitting curve of the concentrations of 16 PAHs and the infrared ratios, comparing regression models of polycyclic aromatic hydrocarbons with different ring numbers and the absorbance ratios of different wavelengths, and (5) screening the regression models to obtain a regression model with the best correlation degree to obtain a functional relation between the polycyclic aromatic hydrocarbons with high rings in the field and the absorbance ratios; the invention establishes a spectral model for relatively accurately and rapidly predicting the biological effectiveness of PAHs in the polluted soil, and is convenient for the follow-up research on the biological effectiveness of the PAHs and the environmental health risk brought by the biological effectiveness.)

1. A modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis is characterized in that: the method comprises the following steps:

(1) sample collection and pretreatment: collecting a soil sample to be detected, air-drying, sieving by a 2mm sieve for later use, and freeze-drying to obtain a soil sample;

(2) oxidation of the sample and determination of its biological effectiveness: oxidizing a soil sample by a chemical oxidation method, measuring the contents of 16 PAHs by GC-MS, and calculating the biological effectiveness by using the concentrations of the PAHs before and after oxidation;

(3) and (3) spectral determination: measuring the original soil sample and the soil sample after corresponding oxidation by adopting an infrared spectroscopy to obtain an infrared absorption peak diagram, wherein the absorbance of a main absorption peak is 875-3439cm ^-1The ratio of the sum of the absorbances of the main absorption peaks in the range is called the absorbance ratio;

(4) establishing a regression model: fitting a high-ring PAHs-absorbance ratio curve according to the concentration and the absorbance ratio of the high-ring PAHs of each sample;

(5) high-cyclic PAHs-absorbance ratio function relation: and screening according to the established fitting curve to obtain a curve equation with relatively high correlation.

2. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 1, wherein: the polluted soil in the step (1) is industrial soil seriously polluted by PAHs.

3. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 1, wherein: the method for determining the biological effectiveness in the step (2) is a chemical oxidation method for oxidizing soil using an oxidizing agent.

4. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 3, wherein: the oxidant in the step (2) is an oxidant K ₂S ₂O ₈Solution, oxidizing agent K ₂S ₂O ₈The concentration of the solution was 0.0357g/ml, K ₂S ₂O ₈The addition amount should satisfy S ₂O ₈ ^2-: organic matter =12g/g, oxidation time 3 h.

5. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 1, wherein: the wavelength of the main absorption peak selected in the step (3) is 875-3439cm ^-1And mainly aliphatic, aromatic carbon, alcohol phenol and carboxylic acid.

6. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 1, wherein: and (3) the ratio of the absorbance in the step (3) is the ratio of the absorbance at the wavelength to the sum of all the absorbances of the main absorption peaks in the spectrogram of the sample.

7. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 1, wherein: the high-ring polycyclic aromatic hydrocarbon in the step (4) is 5-6 rings, and is respectively six polycyclic aromatic hydrocarbons of BbF, BkF, BaP, IP, DBA and Bghip.

8. The modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis according to claim 1, wherein: and (5) respectively fitting the function relationship in each wavelength by taking the ratio of absorbance as an abscissa and the biological effectiveness of PAHs as an ordinate, and establishing a final prediction model according to the height and the significance of the correlation coefficient.

Technical Field

The invention belongs to a biological effectiveness prediction technology of polycyclic aromatic hydrocarbons, and relates to a modeling method for predicting biological effectiveness of high-ring PAHs in soil based on spectral analysis.

Background

Polycyclic aromatic hydrocarbons are organic pollutants widely existing in the environment, most of the polycyclic aromatic hydrocarbons have extremely stable properties, are difficult to degrade and can be accumulated in the environment for a long time, and have carcinogenic, teratogenic and mutagenic 'tri-induced effects'. Among them, the burning of fossil fuel is the main source of environmental PAHs, and with the acceleration of the modernization process, the use of more and more fossil fuels leads to more serious pollution of PAHs, especially polycyclic aromatic hydrocarbon pollution in soil, so the pollution and remediation of PAHs in soil are concerned widely.

Degradation of polycyclic aromatic hydrocarbons is mainly dependent on microbial degradation. Different forms (such as a dissolved state, an adsorption state and a blocking state) exist in the polluted soil, and the polluted soil can be divided into a biological effective state and a non-biological effective state based on the existing forms, wherein the biological effective state refers to PAHs adsorbed in soft carbon, and the PAHs is in line adsorption, has low adsorption strength and is easily biodegraded; the non-biological effective state refers to PAHs adsorbed in hard carbon, which is not in line adsorption and has high adsorption strength, so the PAHs is not easy to biodegrade; wherein, compared with the low-ring polycyclic aromatic hydrocarbon, the 5-6 ring high-ring polycyclic aromatic hydrocarbon has stronger toxicity and hydrophobicity and is more closely related to organic matters.

The biological effectiveness of the polycyclic aromatic hydrocarbon refers to a part of the polycyclic aromatic hydrocarbon which can be bioavailable in the environment, and the understanding of the biological effectiveness of the polycyclic aromatic hydrocarbon has a main significance for researching the pollution remediation of the polycyclic aromatic hydrocarbon in soil and evaluating the environmental risk. The traditional biological method for measuring the bioavailability of the polycyclic aromatic hydrocarbon has the defects of long time consumption, high cost and the like, and researches show that the concentration difference of PAHs before and after oxidation of an oxidation reagent K2S2O8 can be used for measuring the bioavailability of the polycyclic aromatic hydrocarbon in soil, so that the time and the cost can be greatly saved, but the relative cost is high. May result in unnecessary waste during the repair process. Therefore, an intuitive and quick model is urgently needed to be established as a means for evaluating the biological effectiveness and health risk of the polycyclic aromatic hydrocarbon.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a regression model establishing method for predicting the bioavailability of polycyclic aromatic hydrocarbon accurately and rapidly according to the spectral absorbance ratio, and provides reference for the environmental risk assessment and repair of polycyclic aromatic hydrocarbon.

The technical scheme is as follows: the invention provides a modeling method for predicting the biological effectiveness of high-ring PAHs in soil based on spectral analysis, which comprises the following steps:

(1) sample collection and pretreatment: collecting a soil sample to be detected, air-drying, sieving by a 2mm sieve for later use, and freeze-drying to obtain a soil sample;

(2) oxidation of the sample and determination of its biological effectiveness: oxidizing a soil sample by a chemical oxidation method, measuring the contents of 16 PAHs by GC-MS, and calculating the biological effectiveness by using the concentrations of the PAHs before and after oxidation;

(3) and (3) spectral determination: measuring the original soil sample and the soil sample after corresponding oxidation by adopting an infrared spectroscopy to obtain an infrared absorption peak diagram, wherein the absorbance of a main absorption peak is 875-3439cm ^-1Ratio of the sum of the absorbances of the major absorption peaks in the range. This is called the absorbance ratio;

(4) establishing a regression model: fitting a high-ring PAHs-absorbance ratio curve according to the concentration and the absorbance ratio of the high-ring PAHs of each sample;

(5) high-ring PAHs-correlation ratio functional relationship: and screening according to the established fitting curve to obtain a curve equation with relatively high correlation.

Further, the contaminated soil in the step (1) is collected after the removal of a certain large-scale steel plant in Beijing. With the compression of steel activities and the increase of urban environmental protection, the factory is moved, site environment investigation and evaluation work is started for factors such as health risks, environmental safety and the like in the re-development process of the land, and results show that surface soil of the site is seriously polluted by PAHs, so that the plant is one of key factors restricting the development of the site. Therefore, research work of PAHs is needed to be carried out on the site, and relevant basis is provided for soil remediation and site development in the later period.

Further, the chemical oxidation method in the step (2) is used for determining the biological effectiveness. Compared with the traditional biological method for measuring the biological effectiveness, the chemical oxidation method has the obvious advantages of short time, simple and convenient operation and the like, and the chemical oxidant is not easy to cause SOM (soil organic matter) expansion and PAHs desorption. Therefore, compared with other methods, the chemical oxidation method adopted here is more suitable for measuring the biological effectiveness.

Further, K used in the chemical oxidation process in the step (2) ₂S ₂O ₈The concentration of the solution is 0.0357g/ml, K ₂S ₂O ₈The addition amount should satisfy S ₂O ₈ ^2-: organic matter =12g/g, oxidation time 3 h. It has been shown by studies that in the range of 70-21 degrees celsius, the residual polycyclic aromatic hydrocarbon concentration, i.e., the n-t relationship, is greatly affected by temperature if the oxidation time is 3 hours or longer. And when the ratio of the oxidant to the organic matter is 3-29g/g, K ₂S ₂O ₈The proportion of the organic matter does not affect the oxidation degree of the polycyclic aromatic hydrocarbon, and the concentration of the polycyclic aromatic hydrocarbon cannot be reduced by repeatedly adding the oxidant (12 g/g). Therefore, the optimal experimental conditions are: oxidation time 3h, oxidation temperature 70 degree centigrade, and S ₂O ₈ ^2-The proportion of the organic matter to the organic matter is 12g/g, and under the condition, the oxidation effect is optimal.

The biological effectiveness of the polycyclic aromatic hydrocarbon calculated in the step (2) is accurate and rapid. Compared with the traditional methods such as a biodegradation method and the like, the chemical oxidation method adopted in the time has the obvious advantages in the aspect of time consumption, can be completed in a short time, and is thorough in oxidation, and the obtained biological effectiveness is more accurate.

Further, the wavelength of the main absorption peak selected in the step (3) is 875-3439cm ^-1And mainly aliphatic and aromatic phenols. The selected wavelengths are 3439cm respectively ^-1、2922 cm ^-1、2852 cm ^-1、1632 cm ^-1、1448cm ^-1、1033 cm ^-1And 875cm ^-1。

Further, the absorbance ratio in the step (3) is the ratio of the absorbance at the wavelength to the sum of all the absorbances of the main absorption peaks of the sample in the infrared spectrum. The structural change of the SOM before and after the sample oxidation is characterized by the correlation ratio (namely at the wavelength of 875 DEG-3439 cm) ^-1Main absorption peak in between).

Further, the high-ring polycyclic aromatic hydrocarbon in the step (4) is 5-6 rings, namely six polycyclic aromatic hydrocarbons of BbF, BkF, BaP, IP, DBA and Bghip. The high-ring polycyclic aromatic hydrocarbon is difficult to degrade, so the stability is high, the high-ring polycyclic aromatic hydrocarbon is closely related to the SOM, and the structural characteristics of the SOM are represented by the relevance ratio.

Further, the function relationship in the step (5) is that the absorbance ratio is used as an abscissa, the bioavailability of the PAHs is used as an ordinate, and the fitting is performed at each wavelength. Linear functions with relatively high correlation are selected. The correlation and regression models under different wavelengths have larger differences, and a large number of models of the correlation and regression models must be screened to ensure the accuracy and the practicability of the models.

Has the advantages that: the method selects the ratio of the polycyclic aromatic hydrocarbon in the soil to the infrared absorbance to analyze the relationship between the polycyclic aromatic hydrocarbon and the infrared absorbance, and performs linear fitting to obtain a functional relationship with high correlation; the established model can quickly and accurately predict the bioavailability of the high-ring polycyclic aromatic hydrocarbon in a certain polluted site, and compared with the traditional polycyclic aromatic hydrocarbon bioavailability determination method, the method disclosed by the invention is wide in application range, can be used for establishing models aiming at different polluted sites, and has the remarkable advantages of short time, low cost and the like.

Drawings

FIG. 1 shows a graph of the wavelength at 875cm ^-1The relation between the lower infrared absorbance ratio and the bioavailability of the high-ring polycyclic aromatic hydrocarbon;

FIG. 2 shows a signal at a wavelength of 1033cm ^-1The relation between the lower infrared absorbance ratio and the bioavailability of the high-ring polycyclic aromatic hydrocarbon;

FIG. 3 shows the wavelength at 1448cm ^-1The relation between the lower infrared absorbance ratio and the bioavailability of the high-ring polycyclic aromatic hydrocarbon;

FIG. 4 shows a spectrum of wavelengths of 1632cm ^-1The relation between the lower infrared absorbance ratio and the bioavailability of the high-ring polycyclic aromatic hydrocarbon;

FIG. 5 shows a signal at a wavelength of 2852cm ^-1The relation between the lower infrared absorbance ratio and the bioavailability of the high-ring polycyclic aromatic hydrocarbon;

FIG. 6 shows a spectrum at a wavelength of 2922cm ^-1The relation between the ratio of the lower infrared absorbance and the bioavailability of the high-ring polycyclic aromatic hydrocarbon.

Detailed Description

The drawings in the embodiments of the invention will be combined; the technical scheme in the embodiment of the invention is clearly and completely described; obviously; the described embodiments are only some of the embodiments of the invention; rather than all embodiments. Based on the embodiments of the invention; all other embodiments obtained by a person skilled in the art without making any inventive step; all fall within the scope of protection of the present invention.

Referring to fig. 1-6, the present example of determining the bioavailability of a high ring polycyclic aromatic hydrocarbon in a coke plant site includes the following steps:

establishment of linearity of ratio of bioavailability and infrared absorbance of mono-and high-ring PAHs

(1) Sample collection and pretreatment: collecting soil samples at the same depth in different areas of the area, naturally drying the soil samples, sieving the soil samples by a 2mm sieve for later use, dividing the soil samples into different groups, and freeze-drying the groups for 24 hours, wherein each group contains 5g of soil samples to be detected;

(2) preparation of oxidizing solution: adding a certain amount of K into ultrapure water ₂S ₂O ₈Use of K ₂S ₂O ₈The solution concentration is 0.0357g/ml, and K is guaranteed ₂S ₂O ₈The addition amount should satisfy S ₂O ₈ ^2-: soil organic matter =12 g/g;

(3) and (3) oxidation: the six samples collected are chemically oxidized by using an oxidant, the prepared oxidant with the same amount is added into each sample, and the samples are oxidized for 3 hours under the water bath oscillation at 70 ℃ (20 r/min).

(4) And (3) measuring the infrared spectrum of the sample and the concentration of 16 polycyclic aromatic hydrocarbons: mixing and grinding the dried soil sample to be detected and potassium bromide (KBr) in an agate mortar in a mass ratio of 1: 100 uniformly, tabletting, measuring the structural composition of SOM by using an infrared spectrometer (VERTEX 70, Bruker company, Germany), processing an infrared spectrum by using OPUS software, wherein the scanning frequency is 32, and the resolution is 4000cm ^－1The scanning range is 600-4000 cm ^－1Correcting the spectrum to remove moisture and CO ₂The influence of (a); the content of 16 PAHs in the original soil sample and the oxidized soil sample is determined by GC-MS according to the standard of US-EPA 8270E-2017. Calculating the biological effectiveness of PAHs by using the concentrations of the PAHs before and after oxidation;

(5) and (3) processing of absorbance ratio and biological effectiveness: measuring the original soil sample and the soil sample after corresponding oxidation to obtain an infrared absorption peak image, and taking the wavelength of 875-3439cm ^-1The sum of absorbances of main absorption peaks within the range of sigma 875-3439cm ^-1Respectively adjusting the absorbance of the main absorption peak to sigma 875-3439cm ^-1The ratio of (a) to (b). This is called the absorbance ratio.

(6) Establishment of a linear relationship: and fitting a high-ring PAHs-infrared ratio curve according to the concentration and the infrared ratio of the high-ring PAHs of each sample, making a functional relation of the high-ring PAHs-absorbance ratio, and screening the established fitting linearity to obtain a prediction regression equation with relatively high correlation. As shown in FIGS. 1-6, wherein the high-ring polycyclic aromatic hydrocarbon is in clay particle O-H (875 cm) ^-1FIG. 1), aliphatic carbon 1 (1448 cm) ^-1FIG. 3) and aliphatic CH2 (2922 cm) ^-1FIG. 6) shows a better linear correlation, wherein the wavelength is 1448cm ^-1The lower significant one is positively correlated, and at 875cm ^-1And 2922cm ^-1Significant negative correlation was made.

The result shows that the biological effectiveness and the infrared absorbance ratio of the polycyclic aromatic hydrocarbons with high rings (5-6 rings) in the 16 polycyclic aromatic hydrocarbons have good linear relationship under specific wavelength. Through the regression model, the ratio of the polycyclic aromatic hydrocarbon in the soil to the infrared absorbance is subjected to model analysis, the fact that the polycyclic aromatic hydrocarbon in the soil and the infrared absorbance have good correlation is found, the fact that the polycyclic aromatic hydrocarbon in the soil and the infrared absorbance have a certain relation is explained to a certain extent, and further, the functional relation can be used for predicting the biological effectiveness of an unknown sample through the ratio of the infrared absorbance. Thereby providing reference for environmental risk assessment and later soil remediation of the site.

Verification of biological effectiveness model examples of each pollutant in high-ring PAHs

(1) Sample collection and pretreatment: collecting soil samples at the same depth in different areas of the area, naturally drying the soil samples, sieving the soil samples by a 2mm sieve for later use, dividing the soil samples into different groups, and freeze-drying the groups for 24 hours, wherein each group contains 5g of soil samples to be detected;

(2) preparation of oxidizing solution: adding a certain amount of K into ultrapure water ₂S ₂O ₈Use of K ₂S ₂O ₈The solution concentration was 0.0357g/ml, the SOM (soil organic matter) content thereof was measured using an elemental analyzer, and K was secured ₂S ₂O ₈The addition amount should satisfy S ₂O ₈ ^2-: soil organic matter =12 g/g.

(3) Sample oxidation: selecting the collected sample with an oxidizing agent K ₂S ₂O ₈And (3) carrying out chemical oxidation, adding the prepared same amount of oxidant into each sample, and oxidizing for 3 hours under the water bath shaking of 70 ℃ (20 r/min).

(4) And (3) measuring the infrared spectrum of the sample and the concentration of 16 polycyclic aromatic hydrocarbons: mixing and grinding the dried soil sample to be detected and potassium bromide (KBr) in an agate mortar in a mass ratio of 1: 100 uniformly, tabletting, measuring the structural composition of SOM by using an infrared spectrometer (VERTEX 70, Bruker company, Germany), processing an infrared spectrum by using OPUS software, wherein the scanning frequency is 32, and the resolution is 4000cm ^－1The scanning range is 600-4000 cm ^－1Correcting the spectrum to remove moisture and CO ₂The influence of (a); the content of 16 PAHs in the original soil sample and the oxidized soil sample is determined by GC-MS according to the standard of US-EPA 8270E-2017. The biological effectiveness of the high-ring polycyclic aromatic hydrocarbons (BbF, BkF, BaP, IP, DBA and Bghip) is respectively calculated by using the concentrations of PAHs before and after oxidation.

(5) And (3) absorbance ratio treatment: measuring the original soil sample and the soil sample after corresponding oxidation to obtain an infrared absorption peak image, and taking the wavelength of 875-3439cm ^-1The sum of absorbances of main absorption peaks within the range of sigma 875-3439cm ^-1Respectively adjusting the absorbance of the main absorption peak to sigma 875-3439cm ^-1The ratio of (a) to (b). This is called the absorbance ratio.

(6) Model prediction: obtaining the best model of the correlation degree (namely the wavelength is 2922 cm) according to the screening ^-1、1448cm ^-1And 875cm ^-1) Calculating absorbance ratio by infrared spectrum, and adjusting wavelength to 2922cm ^-1、1448cm ^-1And 875cm ^-1The absorbance ratio of (A) is substituted into a model to calculate the model value of each high-ring PAHs, the model value is compared with the biological effectiveness calculated by experimental determination, and the relative error is calculated as the following table:

model one: y = -5.3711x + 0.9627, wavelength: 2922cm ^-1。

Model two: y = 8.9144x-1.0021, wavelength: 1448cm ^-1。

And (3) model III: y = -6.0609x + 1.0996, wavelength: 875cm ^-1。

The results show that when the model is used for predicting single pollutants in high-ring PAHs, the relative error is +/-7.11%, and the error is small. The total amount of the high-ring PAHs in the soil and the biological effectiveness of each pollutant can be predicted quickly and accurately through the model, the biological effectiveness can be calculated indirectly through a method for measuring the spectrum, the prediction is quick, the resource waste caused by measuring the content of the PAHs in the soil is reduced, and the cost is greatly saved.

In addition, because the pollution conditions of each site are different, the obtained regression models are not completely consistent, but the positive correlation and the negative correlation of each wavelength are consistent. The regression model of the invention is not only limited to prediction of bioavailability of soil high-ring polycyclic aromatic hydrocarbon in a coking plant, but also can be used for other fields polluted by polycyclic aromatic hydrocarbon.

The above; but are merely preferred embodiments of the invention; the scope of the invention is not limited thereto; any person skilled in the art is within the technical scope of the present disclosure; the technical scheme and the improved concept of the invention are equally replaced or changed; are intended to be covered by the scope of the present invention.