CN110274991B - Evaluation method for phthalate absorption of greenhouse vegetables and application of evaluation method in human health risk prediction - Google Patents

Abstract

The invention discloses an evaluation method for absorbing phthalate by greenhouse vegetables and application of the evaluation method in human health risk prediction; the evaluation method comprises the following steps: s1, sample collection: collecting PAEs in soil, vegetables and air inside and outside a greenhouse, and measuring the content of the PAEs in the samples after pretreatment; s2, according to the contents of the PAEs in the soil and the air inside and outside the greenhouse obtained in the S1, applying a Telap absorption mechanism model, and performing simulation prediction on the contents of the PAEs in the greenhouse vegetables by adopting a balance equation; and S3, evaluating and analyzing the results of the PAEs absorbed by the crops according to the prediction of the model of the S2 Telapr absorption mechanism. On the basis of collecting crop absorption parameters, the concentration of the phthalate of the simulated greenhouse is analyzed by adopting a Transpp absorption mechanism model, and the human health risk is predicted and evaluated, so that the analysis cost of pollutant evaluation is reduced, and the method has great practical significance.

Description

Evaluation method for phthalate absorption of greenhouse vegetables and application of evaluation method in human health risk prediction

Technical Field

The invention relates to the technical field of environmental quality evaluation, in particular to an evaluation method for phthalate absorption of greenhouse vegetables and application of the evaluation method in human health risk prediction.

Background

Phthalate (PAEs) is a typical plasticizer, is widely applied to plastic plasticizers (commonly called plasticizers), and industries such as automobiles, clothes, cosmetics, lubricants, pesticides and the like, largely enters the environment, has semi-volatility and long-distance migration, and becomes a global environmental pollutant. High concentrations of PAE, especially DBP and DEHP, are widely detected in soil and have become a major organic contaminant in the field soil-vegetable system. The greenhouse film of the greenhouse is an important source of PAEs, the PAEs can be accumulated at edible parts of crops, and long-term consumption of agricultural products containing the PAEs can cause low-dose exposure and generate certain risks to human health. The greenhouse is in a semi-closed state all the year round, has the characteristics of high temperature, high humidity, high evaporation capacity, no rainwater leaching and the like, and has the problems of soil property deterioration, further increase of PAEs residues of vegetables and the like after cultivation for a certain period due to long-term large-amount application of chemical fertilizers. With the widespread agricultural use of plastic films and the discharge of large amounts of urban sewage waste to agricultural fields, phthalate contamination in soils and vegetables is also increasing. Therefore, an evaluation method for absorbing PAEs by vegetables in the greenhouse is urgently needed, and a scientific decision basis is provided for further PAEs control technology research and environmental quality standard formulation.

The current models for chemical evaluation include CLEA model in uk, CETOX model in denmark, CSOIL model in the netherlands, CalTOX model in california, germany, UMS model in the european union, but china lacks a model for evaluating chemical analysis. Among these models, plant uptake models are important models for assessing chemical risk, including the Briggs crop uptake factor model, the Paterson and Mackay fugacity model, the restriction assignment model, the neural network model, and the like. Dunshao and the like (2010) disclose that aiming at typical pollutants PCBs existing in a certain electronic waste dismantling place, a trap crop absorption mechanism model is adopted, the content of PCBs in leaf vegetables in the area is simulated and predicted according to the content of PCBs in soil and atmosphere obtained through actual investigation, and is compared with an actual measured value to investigate the advantages and disadvantages of the model (dunshao slope, luoyun, songshing, Teng, Chengyun. application of the trap model in PCBs vegetable absorption and human health risk assessment [ J ]. environmental science, 2010,31(12): 3018-; at present, no evaluation model and evaluation method established for the vegetable absorption of PAEs in a stable closed system (such as a greenhouse) are available.

Meanwhile, human health risk assessment of pollution sites and areas in China is in a starting stage, in recent years, many students try to carry out some human health risk assessment work in typical pollution areas, but most study on environmental medium pollution conditions is mainly carried out, the human health risk assessment is carried out based on the content of pollutants in an actually investigated environmental medium, a large amount of manpower and material resources are consumed, and the human health risk assessment cannot be completely dependent on sampling detection analysis. How to introduce prediction methods such as mathematical models into risk assessment can effectively promote the development of human health risk assessment work.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings of the existing greenhouse vegetable absorption phthalate evaluation mode, on the basis of collecting crop absorption parameters, a Deltapp (Trapp) absorption mechanism model is adopted to analyze and simulate the concentration of the greenhouse phthalate, and human health risk prediction and evaluation are carried out on the greenhouse phthalate, so that the analysis cost of pollutant evaluation is reduced, and the method has great practical significance.

The invention aims to provide a method for evaluating the absorption of phthalate by greenhouse vegetables.

The second purpose of the invention is to provide the application of the evaluation method in human health risk prediction.

The above object of the present invention is achieved by the following technical solutions:

a method for evaluating phthalate absorption of greenhouse vegetables comprises the following steps:

s1, sample collection: collecting PAEs in soil, vegetables and air inside and outside a greenhouse, and measuring the content of the PAEs in the samples after pretreatment;

s2, according to the contents of the PAEs in the soil and the air inside and outside the greenhouse obtained in the S1, applying a Telap absorption mechanism model, and performing simulation prediction on the contents of the PAEs in the greenhouse vegetables by adopting the following equilibrium equation:

dm_L/dt＝d(C_LV_L)/dt＝Q·TSCF·C_w+Ag(C_A-C_L/K_LA)-λ_Em_L (1)，

when the growth is exponential, the ratio A/V_LAnd Q/V_LConcentration over time dC assuming constant_LChange in/dt:

dC_L/dt＝-[Ag/(K_LAV_L)+λ_E+λ_G]C_L+C_W·TSCF·Q/V_L+C_AgA/V_L (2)

equation (2) can be considered as:

dC_L/dt＝-aC_L+b (3)，

wherein a is Ag/(K)_LAV_L)+λ_E+λ_G，b＝C_W·TSCF·Q/V_L+C_AgA/V_L

(3) The solution of formula (la) is:

C_L(t)＝C_L(0)exp(-at)+b/a[1-exp(-at)]

along with the growth of crops, the pollutants in the overground part of the plants and the pollutants around the overground part of the plants reach balance, and when the growth time is infinite, the contents of the pollutants in the plants are as follows:

C_L(∞)＝b/a

the time required for the contaminants in the plant to reach 95% of their steady state is:

t(95％)＝-0.05/a；

and S3, evaluating and analyzing the results of the PAEs absorbed by the crops according to the prediction of the model of the S2 Telapr absorption mechanism.

The parameters in the above equilibrium equation are shown in table 1.

Preferably, the PAEs are DBP and/or DEHP.

Preferably, the determination method of step S1 is GC-MS.

The invention also requests to protect the application of the method in the prediction of the health risks of the PAEs to the human body.

A PAEs human health risk evaluation method comprises the steps of firstly measuring or predicting the concentrations of DBP and DEHP in vegetables, and then calculating according to the following calculation formula:

wherein DI is the content of PAEs (μ g.kg) taken orally^-1d^-1)；C_DBPAnd C_DEHPRepresents the concentration of DBP and DEHP in vegetables (mg^-1dw); w represents the moisture content in the vegetables (92.31%); IR is the daily intake of vegetables (314.47 g.d)^-1) R is the proportion of greenhouse vegetables to the total vegetable consumption (61% in winter), bw is the average weight of a human (children (5-11 years old): 26.15kg, adult: (>18 years): 65.56kg), r_DBPAnd r_DEHPIndicating the rate of absorption of DBP and DEHP from food by the gastrointestinal tract (DBP: 0.685, DEHP: 0.552).

Compared with the prior art, the invention has the following beneficial effects:

(1) the method for evaluating the organic pollutants in the greenhouse vegetable absorption PAEs by applying the TeraPop absorption mechanism model to the evaluation of the vegetable absorption PAEs in the greenhouse for the first time is established, the simulation condition is very stable, the evaluation result is accurate, the analysis cost of pollutant evaluation is reduced, and the method has great practical significance.

(2) When the PAEs are used for predicting and evaluating the human health risk, prediction methods such as mathematical models are introduced into the risk evaluation, and the formula is corrected, so that the result is more accurate.

Drawings

FIG. 1 is a correlation diagram of a crop absorption model and human health risk assessment in accordance with the present invention.

FIG. 2 is a schematic diagram of a plant absorption PAEs model.

FIG. 3 is a sample-by-sample satellite plot.

FIG. 4 shows the PAEs content in greenhouse soil-vegetable-air around a sampling site.

FIG. 5 shows the total content of PAEs in soil and vegetables in China (S represents soil and V represents vegetables).

FIG. 6 shows the comparison of predicted and actual values (vegetable 1-balsam pear, vegetable 2-corn).

FIG. 7 is the time (d) for the leaf to absorb 95% of the stabilization.

FIG. 8 is a graph of leaf area versus PAEs absorption.

FIG. 9 shows the contribution rate of different sources to PAEs in vegetables.

Fig. 10 shows the actual and predicted exposure values for children and adults.

Detailed Description

The invention is further described with reference to the drawings and the following detailed description, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

The method for evaluating the absorption of phthalic acid ester by greenhouse vegetables mainly comprises the following steps: crop absorption model parameters are obtained from potential risk agricultural land, then a crop absorption pollutant model is constructed by using the obtained parameters, then model result calculation and verification are carried out, human health risk assessment is carried out by using the model result, and risk verification is carried out, wherein the process is shown in figure 1.

Example 1 evaluation method for absorbing phthalate by greenhouse vegetables

Method and device

1. Model assumptions

Assuming that the way in which PAEs enter the plant is passive absorption (the way in which most organic substances enter the plant is passive absorption), the process can be described as follows, as shown in fig. 2:

(1) root absorption: root uptake is one of the routes by which PAEs enter the plant body;

(2) transporting from the underground part to the overground part: the plants can transfer the PAEs from the underground part to the overground part through transpiration tension;

(3) blade absorption: PAEs are semi-volatile organic pollutants (SVOCs) that plants can absorb through leaves

(4) Volatilization from the blade: the plants can volatilize the PAEs into the air while absorbing the PAEs;

(5) some metabolic or degradation processes: PAEs undergo some incomplete metabolism in the plant;

(6) biological dilution: as the plant grows and the biomass increases, the concentration of PAEs in the plant body changes.

2. Experimental data collection, literature data collection and analysis

Earlier, the inventors sampled greenhouses near Guangzhou rural academy, as shown in FIG. 3. The soil and vegetable samples in 5 greenhouses are respectively collected, and the soil and vegetable samples comprise bitter gourds (5 samples) in the greenhouses, bitter gourds (5 samples) outside the greenhouses, corns (6 samples) outside the greenhouses and corresponding soil (16 samples). In addition, the concentrations of PAEs in the air outside (3 samples) the greenhouse (5 samples) were also collected. PAEs concentration analysis was determined according to our previous literature methods. The results are shown in FIG. 4, and different types of PAEs are detected in soil-vegetable-air, for example, the content of DiBP in balsam pear reaches 6.5mg/kgDW, and the content of DEHP in soil reaches 1.68 mg/kgDW. Previous statistical results of the inventor show (fig. 5) that DiBP and DEHP are PAEs which are generally detected in a farmland soil-vegetable system, have the highest concentration and the greatest influence on human health, have higher carcinogenic risk, and therefore prediction and risk evaluation are mainly performed on DiBP and DEHP in the following.

3. Model data collection

Model data collection includes two parts: (1) parameters of the absorption model of the terapu plant are shown in table 1; (2) the basic physicochemical properties of PAEs are shown in table 2.

TABLE 1 Telaprp plant absorption model parameter implications

1) fw represents fresh weight;

2) calculating the concentration of the pollutants in the soil aqueous solution C_wcsoil/Kd ≈ csoil/(OC × KOC); in the formula, csoil is the concentration (actually measured) of pollutants in the air-dried soil, OC is the content (actually measured) of organic carbon in the soil, and the distribution coefficient of organic carbon of KOC pollutants;

3)K_LAthe calculation method comprises the following steps: k_LA＝K_LW/K_AWIn the formula K_LWIs a plant-water distribution coefficient, K_LW＝(Wp+Lp·a·Kbow)·_ρp/_ρw, in the formula, Wp: water content in plant (g.g)^-1) (ii) a Lp: lipid content in plants (g.g)^-1)；_ρp、_ρw: plant and water density, kg.m^-3(ii) a b: vegetable fat-octanol coefficient of correction; kow: a contaminant octanol-water partition coefficient; a: coefficient of octanol-water correction, a ═_ρw/_ρo; water density:_ρw＝1000kg·m^-3density of octanol_ρo＝827kg·m^-3(ii) a The values of the parameters are shown in the text; kaw: dimensionless henry constants;

4) the TSCF calculation method comprises the following steps: TSCF is 0.784exp [ - (lgKow-1.78)2/2.44]

TABLE 2 physicochemical Properties of PAEs

	DMP	DEP	DiBP	DOP	DEHP	BBP
							Kow	3.63	295	360000	7400000000	4100000000	3600000
M	194.19	222.24	278.35	390.56	390.56	312
							Pv	0.00419	0.0035	0.00001	0.00014	0.0000002	0.00006
S	5000	896	13	3	0.4	2.9
							Koa	10232930	35481339	346736850	33884415614	33884415614	602559586
Kaw	3.98E-06	9.77E-06	5.37E-05	0.00158	0.00158	8.32E-05
							Koc	17.4	142	170000	3600000000	2000000000	1700

1)K_owThe octanol water partition coefficient of phthalate;

2) m is the molecular mass of the phthalate;

3) pv is the saturated vapor pressure of the phthalate;

4) s: o-benzeneSolubility of diformates μ g. L^-1；

5)K_oaOctanol air partition coefficient of phthalate ester;

6)K_awdimensionless henry constants;

7)K_OCpollutant organic carbon distribution coefficient;

4. model application

The modeling process according to the Telapr model mainly comprises the steps of calculating distribution coefficients in vegetable tissues, calculating root absorption capacity, calculating transpiration flow concentration factors, calculating gas exchange, calculating metabolism and photodegradation, diluting organisms, and finally obtaining a balance equation according to a calculation formula. The telapr mainly provides a plant growth process mechanism-based crop absorption model aiming at hydrophobic pollutants, and considers the processes of material absorption and exchange. The equilibrium equation is set forth above:

dm_L/dt＝d(C_LV_L)/dt＝Q·TSCF·C_w+Ag(C_A-C_L/K_LA)-λ_Em_L(1) the meaning of the parameters is shown in Table 1.

When the growth is exponential, the ratio A/V_LAnd Q/V_LConcentration over time dC assuming constant_LChange in/dt:

dC_L/dt＝-[Ag/(K_LAV_L)+λ_E+λ_G]C_L+C_W·TSCF·Q/V_L+C_AgA/V_L (2)

equation (2) can be considered as:

dC_L/dt＝-aC_L+b (3)，

wherein a is Ag/(K)_LAV_L)+λ_E+λ_G，b＝C_W·TSCF·Q/V_L+C_AgA/V_L

(3) The solution of formula (la) is:

C_L(t)＝C_L(0)exp(-at)+b/a[1-exp(-at)]

along with the growth of crops, the pollutants in the overground part of the plants and the pollutants around the overground part of the plants reach balance, and when the growth time is infinite, the contents of the pollutants in the plants are as follows:

C_L(∞)＝b/a

the time required for the contaminants in the plant to reach 95% of their steady state is:

t(95％)＝-0.05/a

second, prediction result and explanation of PAEs absorbed by crops

1. Average of total DBP and DEHP content of vegetable-soil-air

The average content of total DBP and DEHP of vegetable-soil-air was determined as shown in table 3,

TABLE 3 mean values of the total DBP and DEHP content of vegetable-soil-air

2. Parameter calculation

The predicted values of DBP and DEHP content of the bitter gourd and corn species can be compared with the actual values (fig. 6), while the time for t (95%) is made (fig. 7), the relationship between the leaf area and PAEs absorption is shown in fig. 8, and the atmospheric source coefficient and soil source coefficient are shown in fig. 9. It can be seen that the error between the predicted value and the measured value of the DBP in the vegetables is smaller than that of the DEHP; the stabilization time for absorbing PAEs by vegetables to reach 95 percent is related to the physical and chemical properties of the PAEs and relevant parameters of plants; when the model predicts that the plant absorbs pollutants, the leaf surface area parameter plays a decisive role; PAEs in the air of the greenhouse are important ways for vegetables to absorb the PAEs.

TABLE 4 predicted DBP and DEHP content values for balsam pear and corn species

Model parameters	Bitter gourd DBP	Bitter gourd DEHP	Corn DBP	Corn DEHP
					A	0.7	0.7	0.8	0.8
CL	1.69	1.24	1.31	1.13
					Cw	2.2E-05	3.29E-05	3.74E-05	1.40E-04
CL(0)	0.00E+00	0.00E+00	0.00E+00	0.00E+00
					CA	160000pg/m3	374000pg/m3	160000pg/m3	374000pg/m3
g	9.26E-04	9.26E-04	9.26E-04	9.26E-04
					KLA	9.68E+06	3.28E+05	9.68E+06	3.28E+05
VL	2.00E-03	2.00E-03	3.00E-03	3.00E-03
					Q	1.16E-08	1.16E-08	1.16E-08	1.16E-08
TSCF	6.18E-02	6.18E-02	6.18E-02	6.18E-02
					t	79	24	80	29
IntoE	0	0	0	0
					IntoG	4.05E-07	4.05E-07	4.05E-07	4.05E-07
A	4.65E-02	4.65E-02	4.65E-02	4.65E-02

The telapr mechanism model is mainly used for hydrophobic organic pollutants, is used for absorbing pollutants in an environmental medium based on the growth process of plants, and considers that the plants absorb the pollutants in soil pore water through root systems, the overground part exchanges with atmospheric gaseous pollutants through plant leaves, the pollutants are diluted and the pollutants are degraded. When the Telapr model is applied, pollutants in air and soil need to be measured simultaneously so as to predict the content of the pollutants in plants. In addition, although the terapu model takes plant-atmosphere absorption pathways into consideration, the simulated conditions are stable, and the influence of real natural conditions on the absorption of organic pollutants by plants is not considered. The greenhouse is in a semi-closed state throughout the year, and is less influenced by ventilation, so that the greenhouse is more suitable for the Telap model.

Example 2 evaluation of human health Risk

1. Method of producing a composite material

According to the method proposed in FIG. 1, taking the greenhouse around the Guangzhou farm academy of agricultural sciences as an example, the research area is mainly agricultural and residential land, and more vegetables produced by the greenhouse are eaten by residents in the area; the existing evaluation standard lacks the reference limit value of PAEs in farmland soil and vegetables and lacks a chemical exposure analysis evaluation model. According to the calculation formula proposed by USEPA:

wherein C is PAE concentration (mg/kg) in vegetables, and IR is daily intake (μ g kg-¹d^-1) Bw is body weight (kg), wherein DBP and EDHP are respectively 100, 20 mu g.kg-¹d^-1)。

Because the formula has great limitation on the evaluation of organic pollutants, when the content of PAEs in vegetables is analyzed again, dry weight is adopted, the formula is not embodied, in addition, the proportion of greenhouse vegetables in the total vegetable consumption is required to be calculated, and the absorption coefficient of phthalic acid ester absorbed by intestinal tracts is considered, so the evaluation formula is corrected as follows:

wherein DI is the content of PAEs (μ g.kg) taken orally^-1d^-1)；C_DBPAnd C_DEHPRepresents the concentration of DBP and DEHP in vegetables (mg^-1dw); w represents the moisture content in the vegetables (92.31%); IR is the daily intake of vegetables (314.47 g.d)^-1) R is the proportion of greenhouse vegetables to the total vegetable consumption (61% in winter), bw is the average weight of a human (children (5-11 years old): 26.15kg, adult: (>18 years): 65.56kg), r_DBPAnd r_DEHPIndicating the rate of absorption of DBP and DEHP from food by the gastrointestinal tract (DBP: 0.685, DEHP: 0.552).

2. Results

And predicting according to the formula, wherein the DEHP predicted risk is lower than the calculated risk. The evaluation results were all below the daily intake specified by USEPA. The accuracy of the plant absorption model directly influences the accuracy of risk assessment; human exposure to PAEs can be through not only vegetable but also meat, fish, milk, poultry, fruit, etc. food intake, so we can calculate daily intakes that are lower than realistic.

Claims (3)

1. The evaluation method for the health risks of the PAEs is characterized in that the concentrations of DBP and DEHP in vegetables are measured or predicted, and then the concentrations are calculated according to the following calculation formula:

wherein DI is the content of orally ingested PAEs in units: mu g.kg^-1d^-1；C_DBPAnd C_DEHPRepresents the concentration of DBP and DEHP in vegetables, unit: mg.kg^-1dw; w represents the moisture content in vegetables 92.31%; IR is vegetable daily intake 314.47g.d^-1R is the proportion of greenhouse vegetables accounting for the total vegetable consumption in winter 61%, bw is the average weight of a human: 26.15kg of children aged 5-11 years old,>adult age 18: 65.56 kg; r is_DBPAnd r_DEHPRepresents the rate at which the gastrointestinal tract absorbs DBP and DEHP from food, DBP: 0.685, DEHP: 0.552.

2. the evaluation method according to claim 1, wherein the predicting the concentration of DBP and DEHP in vegetables comprises the steps of:

s1, sample collection: collecting DBP and DEHP in soil, vegetables and air inside and outside a greenhouse, and measuring the DBP and DEHP content in the sample after pretreatment;

s2, according to the content of the DBP and the DEHP in the soil and the air inside and outside the greenhouse obtained in the S1, a Telap absorption mechanism model is applied, and the content of the DBP and the DEHP in the greenhouse vegetables is simulated and predicted by adopting the following equilibrium equation:

dm_L/dt＝d(C_LV_L)/dt＝Q·TSCF·C_w+Ag(C_A-C_L/K_LA)-λ_Em_L，

when the growth is exponential, the ratio A/V_LAnd Q/V_LConcentration over time dC assuming constant_LChange in/dt:

C_L(t)＝C_L(0)exp(-at)+b/a[1-exp(-at)]

wherein a is Ag/(K)_LAV_L)+λ_E+λ_G，b＝C_W·TSCF·Q/V_L+C_AgA/V_L

Along with the growth of crops, the pollutants in the overground part of the plants and the pollutants around the overground part of the plants reach balance, and when the growth time is infinite, the contents of the pollutants in the plants are as follows:

C_L(∞)＝b/a

the time required for the contaminants in the plant to reach 95% of their steady state is:

t(95％)＝-0.05/a；

and S3, evaluating and analyzing the DBP and DEHP results of the crops predicted according to the model of the S2 Telapr absorption mechanism.

3. The method of claim 2, wherein the determination method of step S1 is GC-MS.

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