A method for assessing the risk of siloxane internal and external exposure for different populations

Abstract

The application provides a method for evaluating the exposure risk of siloxane for different populations, and belongs to the technical field of environmental toxicology and human exposure risk evaluation. First, the daily average external exposure of the target population through at least four channels, including skin contact with personal care products, breathing indoor air, oral intake and skin contact with indoor dust, is calculated; second, the chronic reference dose for specific health endpoints and exposure channels is determined, and the risk is evaluated by comparing the external exposure; then, the concentration of siloxane and its degradation products in the internal exposure medium such as human blood and urine is detected, and the correlation between the internal and external exposure is analyzed. The application has the advantages that the exposure risk of siloxane for different populations can be evaluated comprehensively, accurately and scientifically according to the characteristics of the classified populations, and the potential action mechanism of siloxane on human estrogen receptors can be analyzed by using a molecular docking model, so that a scientific basis for formulating protection measures and management policies can be provided.

Description

Technical Field

[0001] This invention belongs to the field of environmental toxicology and human exposure risk assessment technology, specifically relating to a method for assessing the internal and external exposure risks of siloxanes to different population groups. Background Technology

[0002] Siloxanes, especially cyclic methylsiloxanes and phenylmethylsiloxanes, are widely used in various industrial products and daily consumer goods due to their unique physicochemical properties, particularly in personal care products (such as cosmetics, skincare products, and toiletries) and household appliances. Because of their large-scale production and use, siloxanes have become a pervasive pollutant in the environment, detected globally in the atmosphere, water bodies, soil, sediments, and even in organisms in remote polar and high-altitude regions, demonstrating a certain degree of environmental migration and bioaccumulation.

[0003] Studies have shown that the main routes of human exposure to siloxanes are through the use of personal care products, oral exposure to indoor air and dust, and skin contact. Existing toxicological data indicate that some siloxanes are bioaccumulative, persistent, and potentially toxic, with adverse effects on the liver, endocrine system, and reproductive system. They are currently listed in the European Union as persistent, bioaccumulative, and toxic chemicals (PBT) and highly persistent and bioaccumulative chemicals (vPvB).

[0004] Currently, although some studies have conducted preliminary investigations into the pollution levels of siloxanes in the environment, there is a lack of comprehensive assessment methods for exposure routes and risks across multiple population groups and sources. Existing methods generally focus on a single exposure route (such as respiratory or skin exposure) or a single population (such as adults only), making it difficult to comprehensively reflect the true exposure levels of different populations under multiple exposure routes. Furthermore, the assessment mechanisms for how exposure dose translates into intrinsic exposure risk are incomplete, especially lacking in-depth exploration of the potential for endocrine disruption at the molecular level.

[0005] Therefore, there is an urgent need to establish a scientific, systematic, and molecularly toxicologically based exposure risk assessment framework that can comprehensively consider individual characteristics, multi-media exposure pathways, internal and external exposure correlations, and toxicity mechanisms, thereby providing theoretical support and technical tools for the identification and prevention of siloxane exposure risks in different populations. Summary of the Invention

[0006] To address the current lack of systematic and integrated methods for assessing the risk of siloxane exposure in different populations, identifying multiple exposure pathways, and recognizing endocrine disruption potential, this invention provides a comprehensive assessment method for human siloxane exposure risk based on refined segmentation of the exposed population, combining multiple exposure pathways with molecular docking analysis. This method can calculate the average daily exposure amount for different populations under multiple exposure pathways, determine their exposure risk level by combining chronic reference doses, and further improve the accuracy of the assessment by revealing the potential endocrine disruption mechanisms through molecular docking technology.

[0007] To solve the above problems, the present invention adopts the following technical solution: A method for assessing the internal and external exposure risks of siloxanes to different population groups, the method comprising the following steps: S1: Calculate the average daily external exposure to siloxanes among different target populations through four pathways: skin contact with personal care products, inhalation of indoor air, oral ingestion of indoor dust, and skin contact with indoor dust. i ; S2: Determine the chronic reference dose (RfD) of the siloxane for a specific health endpoint and differentiate between different exposure pathways. i The health risk index method was used to assess the risk of different populations under different exposure routes; S3: Detect the concentration of siloxanes and their degradation products in the internal exposure medium of the target population; S4: Calculate daily renal clearance, assess the renal metabolic characteristics of siloxanes in the human body, and assess the accumulation capacity of siloxanes in the human body. S5: Analyze the correlation between the external exposure amount calculated in S1 and the internal exposure concentration detected in S3; S6: Estimate the binding energy of the siloxane to human estrogen receptor α to identify endocrine disruption mechanisms at the molecular level.

[0008] Furthermore, in S1, the target population includes four categories: children aged 1-3 years, women who frequently wear makeup, women who do not frequently wear makeup, and adult men. The personal care products are six categories of adult personal care products and three categories of children's personal care products commonly used by the target population. The adult personal care products include toothpaste, laundry detergent, shampoo and conditioner, moisturizer, sunscreen, and foundation. The children's personal care products include toothpaste, shampoo and conditioner, and moisturizer. The selected siloxanes are cyclic methylsiloxanes D4-D6 and phenylmethylsiloxanes P3 and P4.

[0009] Furthermore, in S1, the daily average external exposure to the siloxanes via the four pathways (ADD) i Including skin contact exposure to personal care products (ADD) dre（PCPs） Indoor dust exposure via oral ingestion (ADD) ingSkin exposure to indoor dust (ADD) dre（dust） Indoor air exposure and respiratory exposure (ADD) inh The skin contact exposure to personal care products ADD dre（PCPs） The calculation formula is: ; Among them, C PCPsi represents the concentration of siloxane in the i-th personal care product; EF represents the exposure frequency, which is 365 days / year for all volunteer groups; ED represents the exposure duration, with exposure duration of 1-3 years for children aged 1-3 years, 4 years for university students, and 2-10 years for adults; F dre A skin absorption factor; A i Fq represents the single-use dosage of the i-th personal care product. i For usage frequency; R i The retention factors were 1 for toothpaste, 0.01 for laundry detergent, 0.01 for shampoo, conditioner, and shower gel, and 1 for face cream, hand cream, lotion, toner, serum, sunscreen, and foundation; BW was body weight; AT was average time, with the average annual exposure time for all volunteer groups being 365 × ED days. The amount of indoor dust exposure via oral ingestion (ADD) ing The calculation formula is: ; Among them, C dust Q represents the concentration of siloxanes in indoor dust. dust This refers to the daily dust intake, with the recommended daily dust intake for children aged 1-3 years being 0.06 g / day and for adults being 0.02 g / day; F ing It is an oral absorption factor; The skin exposure to indoor dust ADD dre（dust） The calculation formula is: ; SA represents the exposed skin surface area, with 0.28 m² for children aged 1-3 years and 0.57 m² for adults; AF represents the mass of dust adhering to a unit area of ​​skin. The indoor air exposure of the respiratory unit ADD inh The calculation formula is: ; Among them, C airThe concentration of siloxanes in indoor air is IR; IR represents the daily respiratory rate, where the daily respiratory rate for girls aged 1-3 years is 8 m³ / day, for boys aged 1-3 years it is 9 m³ / day, for adult males it is 18.7 m³ / day, and for adult females it is 14.6 m³ / day; F inh It is a respiratory absorption factor; The formula for calculating total exposure is: .

[0010] Furthermore, in S2, the chronic reference dose for different exposure routes includes the chronic reference dose RfD for respiratory exposure. inh Chronic reference dose (RfD) for skin contact exposure dre and chronic reference dose RfD via oral exposure ing Based on toxicity data published by the European Union, doses with no observed adverse effects in animal studies were selected. For compounds D6, P3, and P4 for which no toxicological results were available, the doses with no observed adverse effects were calculated using QSAR Toolbox software, and the chronic reference doses for respiratory exposure were obtained by adjusting for uncertainty factors. ; Among them, RfD inh The chronic reference dose for respiratory exposure is given, NOAEL is the dose with no observed adverse effects in animal studies, and UF is the uncertainty factor.

[0011] Furthermore, based on the absorption factors of each exposure route, the chronic reference dose (RfD) for respiratory exposure was determined. inh Calculate the chronic reference dose (RfD) for skin contact exposure. dre and chronic reference dose RfD via oral exposure ing : ; Among them, F inh F dre These represent the proportions of siloxanes that can be absorbed by the human body through inhalation and skin contact, respectively. inh =0.1, F dre =0.05; ; Where F ing F represents the proportion of siloxanes that can be absorbed by the human body through oral exposure. ing =1.0.

[0012] Furthermore, in S2, the formula for calculating the health risk index is: ; Wherein, HI stands for Health Risk Index, and ADD... i RfD represents the external exposure levels for different populations calculated in S1. i The HI is the chronic reference dose calculated in S2 for different routes. When HI < 1, it indicates that the exposure level is lower than the acceptable reference dose, and the risk is considered low or negligible. When HI ≥ 1, it indicates that the exposure level exceeds the reference dose, indicating a potential health risk that cannot be ignored and requires further attention or protective measures.

[0013] Furthermore, in S2, the siloxane is targeted at specific health endpoints including liver toxicity and reproductive toxicity; in S3, the internal exposure medium includes blood and / or urine.

[0014] Furthermore, in S4, the daily renal clearance rate is used to assess the metabolic and excretory behavior of siloxanes in the human body, and its calculation formula is as follows: ; Wherein, CL represents the daily renal clearance rate in adults, and C... urine and C blood These represent the concentrations of siloxanes in urine and blood, respectively; V urine Daily urine output was estimated at 1.20 L for adult women and 1.40 L for adult men, with BW representing the weight of each volunteer.

[0015] Furthermore, in S5, Spearman statistical analysis was used to analyze the correlation between the calculated external exposure values ​​and internal exposure levels obtained in S1 and S3.

[0016] Furthermore, in S6, molecular docking technology is used to simulate the interaction between the siloxane or its isomers and the human estrogen receptor ER-α. By analyzing the binding energy and mode of action, its potential biological activity or toxic mechanism is evaluated. The molecular docking analysis specifically includes the following steps: S601: Obtain the three-dimensional structure of the siloxane, and optimize the small molecule of the organosiloxane by minimizing energy using obminimize software and MMFF94 force field. S602: Use AutoDockTools software to preprocess the human estrogen receptor ER-α and the optimized ligand, define the active site and generate a Quick Vina-compatible docking configuration file. S603: Iterative calculations and local searches are performed using the gradient heuristic algorithm of Quick Vina to select the conformation with the lowest combined free energy as the optimal docking scheme; S604: Visualizing the complex structure and analyzing the ligand-receptor interaction mechanism using PyMOL software.

[0017] S605: Compare the binding stability of siloxanes with different structures, assess their endocrine disruption potential at the molecular level, and use them in conjunction with exposure data for a comprehensive assessment of exposure risk.

[0018] Advantages of this invention: This innovative method integrates respiratory, ingested, and skin-contact exposure pathways, providing a more comprehensive reflection of human exposure levels in real-world scenarios. Compared to existing single-medium or single-population assessment methods, this invention is more systematic and scientific, significantly improving the accuracy of exposure calculation and risk assessment. Furthermore, this method performs correlation analysis between external exposure and the concentration levels of siloxanes measured in human blood and urine samples, and further validates the correlation between internal and external exposure by combining non-target screening of siloxane degradation products in the human body. This enhances the explanatory power and practicality of the assessment method in real-world scenarios. Finally, a molecular docking model is used to analyze internal exposure risk from the perspective of toxicity mechanism. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating the assessment methods for internal and external exposure risks of siloxanes to different population groups; Figure 2 A schematic diagram showing the concentration of siloxanes in environmental media such as air, dust, and personal care products; Figure 3 (a) Schematic diagram of external exposure to cyclic methylsiloxanes in different population groups; Figure 3 (b) Schematic diagram showing the ratio of external exposure to total exposure to cyclic methylsiloxanes in different population groups; Figure 4 (a) Schematic diagram of external exposure to phenylmethylsiloxane in different population groups; Figure 4 (b) Schematic diagram showing the ratio of external exposure to total exposure to phenylmethylsiloxane in different population groups; Figure 5 (a) Schematic diagram of health risk index of siloxane liver toxicity in different population groups; Figure 5 (b) A schematic diagram of the health risk index of reproductive toxicity to different population groups; Figure 6 (a) is a schematic diagram showing the concentration of methylsiloxane in adult blood and urine; Figure 6 (b) is a schematic diagram showing the proportion of methylsiloxanes in total siloxanes in adult blood; Figure 6 (c) is a schematic diagram showing the proportion of methylsiloxanes in total siloxanes in adult urine; Figure 7 (a) is a schematic diagram of the concentration of silanol in adult blood and urine; Figure 7 (b) is a schematic diagram showing the proportion of silanols in total silanols in adult blood; Figure 7 (c) is a schematic diagram showing the proportion of silanols in total silanols in adult urine; Figure 8 A schematic diagram showing the daily renal clearance rate of siloxanes in adults; Figure 9 A heatmap showing the correlation between external and internal exposure levels of siloxanes in adults; Figure 10 (a) is a schematic diagram of the molecular docking results between cyclic methylsiloxane D4 and ER-α; Figure 10 (b) is a schematic diagram of the molecular docking results between cyclic methylsiloxane D5 and ER-α; Figure 10 (c) is a schematic diagram of the molecular docking results between cyclic methylsiloxane D6 and ER-α; Figure 11 (a) is a schematic diagram of the molecular docking results of phenylmethylsiloxane cis-P3 and ER-α; Figure 11 (b) is a schematic diagram of the molecular docking results of phenylmethylsiloxane trans-P3 and ER-α; Figure 11 (c) is a schematic diagram of the molecular docking results of phenylmethylsiloxane cis-P4 and ER-α; Figure 11 (d) is a schematic diagram of the molecular docking results of phenylmethylsiloxane trans-P4a and ER-α; Figure 11 (e) is a schematic diagram of the molecular docking results of phenylmethylsiloxane trans-P4b and ER-α; Figure 11 (f) is a schematic diagram of the molecular docking results of phenylmethylsiloxane trans-P4c and ER-α. Detailed Implementation

[0021] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, the main variations are obvious within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0022] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0023] like Figure 1 As shown, this solution provides a method for assessing the internal and external exposure risks of siloxanes to different population groups, specifically including the following steps: S1: Collect samples of externally exposed media (personal care products, indoor air, and dust) and monitor the concentration levels of target siloxanes in the samples using the established gas chromatography-mass spectrometry (GC-MS) method: octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecylcyclohexasiloxane (D6), 2,4,6-trimethyl-2,4,6-triphenylcyclotrisiloxane (P3), and 2,4,6,8-tetramethyl-2,4,6,8-tetraphenylcyclotetrasiloxane (P4). Calculate the average daily external exposure (ADD) of siloxanes via four pathways for different target populations. i The target population includes children aged 1-3 years, women who frequently wear makeup, women who do not frequently wear makeup, and adult men. Exposure routes include daily external exposure to siloxanes via skin contact, inhalation, and dust ingestion. Personal care products include six categories of adult personal care products and three categories of children's personal care products commonly used by the target population. Adult personal care products include toothpaste, laundry detergent, shampoos and conditioners, moisturizers, sunscreen, and foundation; children's personal care products include toothpaste, shampoos and conditioners, and moisturizers. Indoor air and indoor dust samples were collected from offices, family living rooms, and university dormitories. Basic information and personal care product usage habits of the target population were collected through questionnaires.

[0024] Taking into account four exposure pathways—skin contact exposure from personal care product use, indoor dust exposure through ingestion and skin contact, and indoor air exposure through respiration—external exposure amounts include the average daily external exposure to siloxanes (ADD). i Including skin contact exposure to personal care products (ADD) dre（PCPs） Indoor dust exposure via oral ingestion (ADD) ing Skin exposure to indoor dust (ADD) dre（dust）Indoor air exposure and respiratory exposure (ADD) inh Based on the standard exposure factor, substitute into the corresponding calculation formula below to calculate the average daily total exposure (ADD) for different population groups. total Quantitative analysis of exposure levels in different population groups was conducted to identify significant differences in exposure levels and various exposure routes, providing a data foundation for subsequent exposure risk analysis. The formulas for calculating exposure amounts through different exposure routes are as follows: Skin exposure to personal care products (ADD) dre（PCPs） The calculation formula is: ; Among them, C PCPsi represents the concentration of siloxane in the i-th personal care product (μg / g); EF represents the exposure frequency (day / year), with an exposure frequency of 365 days / year for all volunteer groups; ED represents the exposure duration (year), with exposure duration of 1-3 years for children aged 1-3 years, 4 years for university students, and 2-10 years for adults; F der A is a skin absorption factor (take 0.05); A i Fq represents the single-use dosage of the i-th personal care product (g / event). i Usage frequency (event / day); R i The retention factors were 1 for toothpaste, 0.01 for laundry detergent, 0.01 for shampoo, conditioner, and shower gel, and 1 for face cream, hand cream, lotion, toner, serum, sunscreen, and foundation; BW was body weight (kg); AT was average time (day), with the average annual exposure time for all volunteer groups being 365 × ED days. Indoor dust exposure via oral intake (ADD) ing The calculation formula is: ; Among them, C dust The concentration of siloxanes in indoor dust (μg / g); Q dust The daily dust intake is defined as g / day, with a recommended daily dust intake of 0.06 g / day for children aged 1-3 years and 0.02 g / day for adults; F ing The oral absorption factor is 1.0. Skin exposure to indoor dust (ADD) dre（dust） The calculation formula is: ; SA represents the skin exposed surface area (m²), with 0.28 m² for children aged 1-3 years and 0.57 m² for adults; AF represents the mass of dust adhering to a unit area of ​​skin (g / m²). Indoor air exposure (ADD) inh The calculation formula is: ; Among them, C air The concentration of siloxanes in indoor air (μg / m³); IR represents the daily respiratory rate (m³ / day), where the daily respiratory rate for girls aged 1-3 years is 8 m³ / day, for boys aged 1-3 years is 9 m³ / day, for adult males is 18.7 m³ / day, and for adult females is 14.6 m³ / day; F inh The respiratory absorption factor (taken as 0.1); The formula for calculating total exposure is: .

[0025] S2: Determine specific health endpoints (hepatotoxicity and reproductive toxicity) for siloxanes and differentiate chronic reference doses (RfD) for different exposure routes. i The Health Risk Index (HI) method was used to assess the risk of exposure.

[0026] For compounds D4 and D5, for which no-observed adverse effect dose (NOAEL) data were available based on toxicological studies, the NOAEL was calculated using the results of rat studies conducted by the European Scientific Committee on Consumer Safety. For compounds (D6, P3, and P4) for which no toxicological results were available, the NOAEL was calculated using QSAR Toolbox software, and the chronic reference dose (RfD) for respiratory exposure was obtained by adjusting for uncertainty factor (UF). inh ).

[0027] Considering interspecific and intraspecific differences and the uncertainty factor (UF, usually taken as 1000) of the study period, calculate the chronic reference dose (RfD) of respiratory exposure. inh The calculation formula is as follows: ; Among them, RfD inh The chronic reference dose for respiratory exposure is given; NOAEL is the dose with no observed adverse effects in animal studies; and UF is the uncertainty factor. Based on the absorption factor of each exposure route, the chronic reference dose (RfD) for respiratory exposure is calculated. inh Calculate the chronic reference dose (RfD) for skin contact exposure. dreand chronic reference dose RfD via oral exposure ing : ; Among them, F inh F dre These represent the proportions of siloxanes that can be absorbed by the human body through inhalation and skin contact, respectively. inh =0.1, F dre =0.05; ; Where F ing F represents the proportion of siloxanes that can be absorbed by the human body through oral exposure. ing =1.0; The formula for calculating the health risk index is as follows: ; HI stands for Health Risk Index, and ADD stands for Health Risk Index. i RfD represents the external exposure levels for different populations calculated in S1. i The HI is the chronic reference dose calculated in S2 for different routes. When HI < 1, it indicates that the exposure level is lower than the acceptable reference dose, and the risk is considered low or negligible. When HI ≥ 1, it indicates that the exposure level exceeds the reference dose, indicating a potential health risk that cannot be ignored and requires further attention or protective measures.

[0028] S3: Similarly, the GC-MS quantitative method in S1 was used to analyze the concentration of target siloxanes and their degradation products [dimethylsilanediol Me2Si(OH)2 and trimethylsilanol Me3SiOH] in the blood and urine of adults. In addition, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to screen non-target metabolites of siloxanes in the human body.

[0029] S4: Calculate daily renal clearance (CL), assess the renal metabolic characteristics of siloxanes in adults, and evaluate the ability of siloxanes to accumulate in the human body.

[0030] Daily renal clearance rate is used to assess the metabolic and excretory characteristics of siloxanes in the human body, and its calculation formula is as follows: ; Wherein, CL represents the daily renal clearance rate in adults, and C... urine and C blood These represent the concentrations of siloxanes in urine and blood, respectively; V urine Daily urine output was estimated at 1.20 L for adult women and 1.40 L for adult men, with BW representing the weight of each volunteer.

[0031] S5: Analyze the correlation between the external exposure calculated in S1 and the concentration levels in blood and urine detected in S3, i.e., the internal exposure level. This invention uses Spearman statistical analysis to analyze the correlation between the calculated external exposure values ​​and the internal exposure levels obtained in S1 and S3.

[0032] S6: Estimate the binding energy of siloxanes to human estrogen receptor α (ER-α) to identify the endocrine disruption mechanism of siloxanes at the molecular level.

[0033] The binding energy of the human estrogen receptor ER-α as the target protein for siloxane docking was estimated using a molecular docking model. The crystal structure of the human estrogen receptor ER-α was obtained from protein structure databases (such as RCSB PDB or AlphaFold) and pre-processed conformationally. Molecular docking was performed using AutoDock software, specifically including the following steps: S601: Obtain the three-dimensional structure of siloxanes and optimize the energy minimization of small organosiloxane molecules using obminimize software and MMFF94 force field. S602: The human estrogen receptor ER-α and its optimized ligands were preprocessed using AutoDockTools software to define active sites and generate Quick Vina-compatible docking configuration files. S603: Iterative calculations and local searches are performed using the gradient heuristic algorithm of Quick Vina to select the conformation with the lowest combined free energy as the optimal docking scheme; S604: Visualizing the complex structure and analyzing the ligand-receptor interaction mechanism using PyMOL software.

[0034] S605: Compare the binding stability of siloxanes with different structures, assess their endocrine disruption potential at the molecular level, and use them in conjunction with exposure data for a comprehensive assessment of exposure risk.

[0035] The method will be further explained below with reference to specific embodiments.

[0036] This embodiment provides a method for assessing the risk of exposure to cyclic methylsiloxanes (D4, D5, and D6) and phenylmethylsiloxanes (P3 and P4) in indoor environments for different population groups in Tianjin. The specific steps are as follows: S1: 141 volunteers were recruited from Tianjin to collect information such as age, weight, and personal care product usage habits through questionnaires. The participants were divided into four groups: children aged 1-3 years (n=31), adult men (n=48), women who do not frequently wear makeup (n=31), and women who frequently wear makeup (n=31). Six categories of adult personal care products (toothpaste, laundry detergent, shampoo and conditioner, moisturizer, sunscreen, and foundation, n=102) and three categories of children's personal care products (toothpaste, shampoo and conditioner, and moisturizer, n=30) were collected. Indoor air (n=56) and dust (n=56) samples were collected from offices, family living rooms, and male and female dormitories. GC-MS was used to quantitatively analyze methylsiloxanes D4-D6 and phenylmethylsiloxanes (P3 and P4) in the samples. Results are as follows: Figure 2 The results showed that the concentration of ΣD4-D6 in six categories of adult personal care products was <LOQ - 1.01 × 10⁻⁶. 4 μg / g, with the highest concentrations found in foundation and sunscreen (351-1.01×10 μg / g). 4 In children's personal care products, the concentration of ΣD4-D6 is <LOQ-5.02 μg / g, which is 2-3 orders of magnitude lower than the concentration in adult personal care products. The total concentration of phenylmethylsiloxanes (P3 and P4) in adult personal care products is 1-5 orders of magnitude lower than the concentration of ΣD4-D6. Specifically, the concentrations of P3 and P4 in sunscreens (<LOQ-1.83×10⁻⁶) are significantly lower. -1 μg / g) and liquid foundation (<LOQ-1.08×10 -1 The two types of personal care products with the highest total concentration (μg / g) are still those with the highest concentration, followed by moisturizing products (< LOQ - 1.15 × 10 μg / g). -1 μg / g); phenylmethylsiloxane (ΣP3-P4, <LOQ-1.07×10) was detected only in moisturizing products among children's personal care products. -2 μg / g).

[0037] The concentration of ΣD4-D6 in the indoor air of female dormitories was the highest (air: 21.6-36.2 μg / m³), which was 1.19-9.28 times higher than the concentration in other indoor environments (family living room: 3.90-14.3 μg / m³, office: 5.89-17.0 μg / m³, male dormitory: 7.70-18.1 μg / m³). P3 and P4 were not detected in the indoor air in any of the other environments. The concentration of ΣD4-D6 in dust in female dormitories was the highest (dust: 1.46×10³-9.82×10³ ng / g), which was 1-2 orders of magnitude higher than the concentration in dust in other environments (family living room: <LOQ-535 ng / g, office: 101-436 ng / g, male dormitory: 108-980 ng / g). The concentration levels of ΣP3-P4 in dust were as follows: female dormitory (<LOQ-48.0 ng / g). ng / g), family living room (<LOQ-26.0ng / g), male dormitory (<LOQ-26.0 ng / g), office (<LOQ-20.0 ng / g).

[0038] Based on the obtained concentration data and specific parameters of each population, the average daily external exposure of the four population groups to D4-D6, P3 and P4 is calculated by substituting them into the above formulas 1-5.

[0039] The results are shown in Table 1. Figure 3 , Figure 4 As shown, women who frequently wear makeup have the highest exposure to cyclic methylsiloxanes (ΣD4-D6) and phenylmethylsiloxanes (ΣP3-P4) compared to the other three groups (63.3-83.2 and 0.07-0.10 μg / kg / day, respectively). This is followed by women who do not frequently wear makeup (1.37-2.33 and 0.02-0.04 μg / kg / day, respectively) and adult men (0.29-23.8 and 1.13×10⁻⁶ μg / kg / day, respectively). -5 -5.74×10 -4 μg / kg / day and children aged 1-3 years (0.69-1.06 and 3.42×10 μg / kg / day) -4 -8.03×10 -4 μg / kg / day. Among them, the main route of exposure for cyclic methylsiloxanes in young children was through inhalation of indoor air (accounting for 98.8% of total cyclic methylsiloxane exposure); while for adults, 98.2% of total exposure came from skin contact with personal care products. For children aged 1-3 years (accounting for 90.9% of total exposure) and adults (accounting for 97.9%), the main route of exposure to phenylmethylsiloxanes was skin contact with personal care products.

[0040] Table 1. Siloxane exposure levels (μg / kg / day) in different population groups under different scenarios

[0041]

[0042] S2: For compounds D4 and D5, for which no-observed-adverse-effect dose (NOAEL) data could be obtained based on toxicological experiments, this example uses the results of rat experiments conducted by the European Scientific Committee on Consumer Safety, which determined that their liver toxicity was 150 mg / kg / day and their reproductive toxicity was 300 mg / kg / day (D4) and 160 mg / kg / day (D5), respectively. For compounds (D6, P3, and P4) for which no toxicological results were available, the NOEL was calculated using QSAR Toolbox software, as detailed below: Hepatotoxicity: 262 mg / kg / day (D6), 243 mg / kg / day (P3) and 273 mg / kg / day (P4); NOAEL values ​​for reproductive toxicity: 105 mg / kg / day (D6), 238 mg / kg / day (P3) and 258 mg / kg / day (P4).

[0043] Divide the obtained NOAEL or NOEL value by 1000 times the uncertainty factor and substitute it into formula (6) to obtain the baseline chronic reference dose (RfD). The NOAEL based on rat experiments and the NOEL calculated using QSAR Toolbox software are shown in Table 2 below: Table 2. Chronic reference doses of different siloxanes (μg / kg / day)

[0044] The baseline values ​​obtained based on the absorption ratio are extrapolated to different exposure routes, specifically including: respiratory exposure routes: RfD inh =RfD; skin contact exposure route RfD dre Calculated using formula (7); RfD of oral exposure route ing Calculated using formula (8). The chronic reference dose values ​​for each toxicity endpoint under different exposure routes were determined accordingly. The exposure amounts and RfDs of each population were substituted into formula (9), and the results are as follows: Figure 5 As shown, the obtained HI values ​​are all far below the reference values, indicating that the exposure level is within a safe range.

[0045] S3: Blood and urine samples were collected from 110 pairs of adults. GC-MS was used to quantitatively analyze the cyclic methylsiloxanes D4-D6 and phenylmethylsiloxanes (P3 and P4) and two silanols [dimethylsilanediol Me2Si(OH)2 and trimethylsilanol Me3SiOH] in the samples. The results of the internal exposure detection are as follows: Figure 6 and Figure 7The results of the detection of target substances in the blood and urine samples of volunteers showed that the concentration of ΣD4-D6 in blood (women who frequently wear makeup: 38.5-166 ng / mL, women who rarely wear makeup: 10.2-101 ng / mL, and men: <LOQ-54.5 ng / mL) was 1-2 orders of magnitude higher than that in urine (women who frequently wear makeup: <LOQ-2.32 ng / mL, women who rarely wear makeup: <LOQ-0.42 ng / mL, and men: <LOQ-1.35 ng / mL). Phenylmethylsiloxane was not detected in either human blood or urine. Me2Si(OH)2 (women who frequently wear makeup: 14.0-3.41×10⁻⁶) was detected in the blood of volunteers. 4 ng / mL, for women who do not frequently wear makeup: 1.39×10 4 -3.21×10 4 ng / mL and male: 5.19×10 3 -4.92×10 4 The concentration of siloxane degradation products (C0.0 ng / mL) in blood was 3-4 orders of magnitude higher than that in urine (women who frequently wear makeup: <LOQ-14.0 ng / mL, women who rarely wear makeup: <LOQ-3.87 ng / mL, and men: <LOQ-20.4 ng / mL). Me3SiOH was detected only in male urine (<LOQ-0.87 ng / mL), and not in the blood of either women or men. Simultaneously, non-target screening of metabolites in blood and urine was performed using FT-ICR / MS, identifying 8 new siloxane degradation products. The results are shown in Table 3. Women who frequently wear makeup had the most types and highest concentrations of degradation products in their blood, while only 2 low-concentration degradation products (C0.0) were detected in other low-exposure groups (children aged 1-3 years, women who rarely wear makeup, and adult men). 14 H 18 O5Si2 and C 21 H 26 O4Si3) further validated the consistency of internal and external exposure among different populations.

[0046] Table 3. Intermediate degradation products of siloxanes in human blood and urine

[0047] S4: The calculation results of renal clearance rate are as follows Figure 8As shown, because phenylmethylsiloxane was not detected in human blood and urine, this study only examined the differences in renal clearance rates of the three methylsiloxanes. The renal clearance rates of men on days 5 and 6 (0-2.56 and 0-0.84 mL / day / kg, respectively) were higher than those of women who frequently wore makeup (0-1.90 and 0-0.48 mL / day / kg) and women who did not frequently wear makeup (0-0.27 and 0-0.16 mL / day / kg). The difference in siloxane metabolism between men and women may be attributed to the fact that men typically have a glomerular filtration rate about 10 mL / min higher than women, a higher basal metabolic rate, and a faster rate of fluid loss, among other gender physiological differences. Furthermore, the metabolic differences between different siloxanes may be related to their physicochemical properties, such as hydrophobicity or volatility. For example, the hydrophobicity of different siloxanes differs (e.g., 1g of siloxanes on day 4...). K ow =6.49, lg of D5 K ow =8.03, lg of D6 K ow =9.06), the lower the hydrophobicity, the less likely it is to bind with plasma proteins or fats, thus making it easier for the body to enter the urine through glomerular filtration. Therefore, the renal clearance rate of D5 in women and men (0.259 and 0.255 mL / day / kg, respectively) is higher than that of D6 in men and women (0.081 and 0.143 mL / day / kg). The renal clearance rate of D4 is lower (0.094 and 0.075 mL / day / kg), which is presumably because D4 is more volatile and can be excreted through human respiration.

[0048] S5: Results of the correlation analysis between external exposure and internal exposure levels are as follows: Figure 9 As shown, skin contact exposure levels were positively correlated with the concentrations of D5 and D6 in the blood (r = 0.50–0.56). p <0.05, further confirming that skin contact is an important pathway for the absorption of siloxanes in the human body, while the amount of external exposure is not significantly correlated with D4 in blood and urine (negative correlation). p >0.05), possibly because D4 is highly volatile and thus rapidly cleared through respiration. The correlation between D4 and D6 in the blood (r=0.57-0.74, p The value <0.05 indicates that the human exposure to the three cyclic methylsiloxanes comes from the same source. Furthermore, there is a significant positive correlation between D5 and D6 levels in blood and urine (r=0.41-0.47). pThe value <0.05 indicates that the two pollutants may enter the human body through a common exposure route and that the exposure is persistent. This correlation supports the use of urine as a substitute sample for blood biomonitoring, especially when frequent monitoring is required (such as occupational exposure assessment).

[0049] S6: As Figure 10 , Figure 11 Table 4 shows that the target siloxane was molecularly docked with the human estrogen receptor ER-α (PDB ID: P03372) using Quick Vina. D4 and D5 formed hydrogen bonds with the HIS547 site. The side chain of HIS547 can act as both a hydrogen bond donor and acceptor. Its nitrogen atom can act as a hydrogen bond acceptor, accepting protons from the hydroxyl group or other hydrogen-donating groups in the D4 / D5 molecules. Alternatively, NH can act as a hydrogen bond donor, forming hydrogen bonds with D4 / D5 (binding energies are -4.747 kcal / mol and -4.765 kcal / mol, respectively). The formation of hydrogen bonds allows D4 and D5 to stably bind to the ER-α ligand, inducing conformational changes in the receptor and activating the estrogen signaling pathway, exhibiting certain estrogenic effects. As reported in the literature, D4 ​​exposure may induce typical estrogenic effects such as uterine weight gain, endometrial hyperplasia, and decreased fertility. The model did not reflect the binding mode of D6 with the ER-α ligand, and the estimated binding energy of D6 was -4.304 kcal / mol, slightly lower than that of D4 and D5. This may be because, compared with D4 and D5, D6 has a larger molecular size and stronger hydrophobicity, making it difficult to form hydrogen bonds, suggesting that it does not exert its estrogenic effect by directly activating ER-α. Studies have shown that a binding energy difference of 0.5 kcal / mol can significantly reduce the receptor occupancy of pollutants by 2-3 times, resulting in insufficient binding ratio with estrogen receptors. The binding energies of the P3 and P4 isomers range from -6.040 to -6.637 kcal / mol and -6.350 to -7.165 kcal / mol, respectively. Since phenylmethylsiloxane molecules contain a phenyl group, which is a strongly hydrophobic group, the interaction modes are mainly hydrophobic interactions and non-covalent interactions between benzene rings through complementary electron clouds, forming π-π stacking. Due to the potential shielding effect of the π electron cloud of the benzene ring, P4 does not form hydrogen bonds with ER-α, but forms hydrophobic interactions at multiple sites, further stabilizing the phenyl structure and making it more difficult for the phenyl to participate in hydrogen bond formation. Because the binding energies of P3 and P4 with ER-α are greater than those of D4-D6, it means that P3 and P4 can maintain a high receptor occupancy even at low concentrations. Although the estimated external exposure of phenylmethylsiloxane in this study is significantly lower than that of cyclic methylsiloxane, the stronger lipophilicity of phenylmethylsiloxane may lead to its long-term accumulation in the human body and continuous interference with estrogen. Further investigation into the health risks posed by phenylmethylsiloxane in the future may be necessary.

[0050] Table 4. Results of docking siloxanes with human ER-α molecules

[0051]

[0052] Through the above steps, this embodiment comprehensively assessed the siloxane exposure levels and risks in different populations. The results showed that the exposure levels of all individuals to the target substance were below the chronic reference thresholds for liver and estrogen effects, indicating no significant health risk. However, due to the bioaccumulation of siloxanes, the risk of long-term low-dose exposure may be underestimated, requiring special attention to the health effects under chronic exposure scenarios. The results demonstrate that the method of this invention can effectively characterize the relationship between external and internal exposure levels in a population and can achieve a scientific assessment of potential exposure risks, thus verifying the feasibility of the method.

[0053] The above examples have provided a detailed description of this embodiment, but the content is only a preferred embodiment and should not be considered as limiting the scope of implementation of this embodiment; all equivalent changes and improvements made in accordance with the scope of this embodiment should still fall within the patent coverage of this embodiment.

Claims

1. A method for assessing the internal and external exposure risks of siloxanes to different population groups, characterized in that: The method includes the following steps: S1: Calculate the average daily external exposure to siloxanes among different target populations through four pathways: skin contact with personal care products, inhalation of indoor air, oral ingestion of indoor dust, and skin contact with indoor dust. i ; S2: Determine the chronic reference dose (RfD) of the siloxane for a specific health endpoint and differentiate between different exposure pathways. i The health risk index method was used to assess the risk of different populations under different exposure routes; S3: Detect the concentration of siloxanes and their degradation products in the internal exposure medium of the target population; S4: Calculate daily renal clearance, assess the renal metabolic characteristics of siloxanes in the human body, and assess the accumulation capacity of siloxanes in the human body. S5: Analyze the external exposure amount (ADD) calculated in S1. i Correlation between the internal exposure concentration detected by S3; S6: Estimate the binding energy of the siloxane to human estrogen receptor α to identify endocrine disruption mechanisms at the molecular level.

2. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S1, the target population is divided into four categories: children aged 1-3 years, women who frequently wear makeup, women who do not frequently wear makeup, and adult men. The personal care products include six categories of adult personal care products commonly used by the target population and three categories of children's personal care products. The adult personal care products include toothpaste, laundry detergent, shampoo and conditioner, moisturizer, sunscreen, and foundation. The children's personal care products include toothpaste, shampoo and conditioner, and moisturizer. The selected siloxanes are cyclic methylsiloxanes D4-D6 and phenylmethylsiloxanes P3 and P4.

3. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S1, the daily average external exposure to the siloxanes via the four pathways (ADD) i Including skin contact exposure to personal care products (ADD) dre（PCPs） Indoor dust exposure via oral ingestion (ADD) ing Skin exposure to indoor dust (ADD) dre（dust） Indoor air exposure and respiratory exposure (ADD) inh The skin contact exposure to personal care products ADD dre（PCPs） The calculation formula is: ； Among them, C PCPsi represents the concentration of siloxane in the i-th personal care product; EF represents the exposure frequency, which is 365 days / year for all volunteer groups; ED represents the exposure duration, with exposure duration of 1-3 years for children aged 1-3 years, 4 years for university students, and 2-10 years for adults; F der A skin absorption factor; A i Fq represents the single-use dosage of the i-th personal care product. i For usage frequency; R i The retention factors were 1 for toothpaste, 0.01 for laundry detergent, 0.01 for shampoo, conditioner, and shower gel, and 1 for face cream, hand cream, lotion, toner, serum, sunscreen, and foundation; BW was body weight; AT was average time, with the average annual exposure time for all volunteer groups being 365 × ED days. The amount of indoor dust exposure via oral ingestion (ADD) ing The calculation formula is: ； Among them, C dust Q represents the concentration of siloxanes in indoor dust. dust This refers to the daily dust intake, with the recommended daily dust intake for children aged 1-3 years being 0.06 g / day and for adults being 0.02 g / day; F ing It is an oral absorption factor; The skin exposure to indoor dust ADD dre（dust） The calculation formula is: ； SA represents the exposed skin surface area, with 0.28 m² for children aged 1-3 years and 0.57 m² for adults; AF represents the mass of dust adhering to a unit area of ​​skin. The indoor air exposure of the respiratory unit ADD inh The calculation formula is: ； Among them, C air The concentration of siloxanes in indoor air is IR; IR represents the daily respiratory rate, where the daily respiratory rate for girls aged 1-3 years is 8 m³ / day, for boys aged 1-3 years it is 9 m³ / day, for adult males it is 18.7 m³ / day, and for adult females it is 14.6 m³ / day; F inh It is a respiratory absorption factor; The formula for calculating total exposure is: 。 4. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S2, the chronic reference dose for different exposure routes includes the chronic reference dose RfD for respiratory exposure. inh Chronic reference dose (RfD) for skin contact exposure dre and chronic reference dose RfD via oral exposure ing Based on toxicity data published by the European Union, doses with no observed adverse effects in animal studies were selected. For compounds D6, P3, and P4 for which no toxicological results were available, the doses with no observed adverse effects were calculated using QSAR Toolbox software, and the chronic reference doses for respiratory exposure were obtained by adjusting for uncertainty factors. ； Among them, RfD inh The chronic reference dose for respiratory exposure is given, NOAEL is the dose with no observed adverse effects in animal studies, and UF is the uncertainty factor.

5. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 4, characterized in that: Based on the absorption factor of each exposure route, the chronic reference dose (RfD) for respiratory exposure is calculated. inh Calculate the chronic reference dose (RfD) for skin contact exposure. dre and chronic reference dose RfD via oral exposure ing : ； Among them, F inh F dre These represent the proportions of siloxanes that can be absorbed by the human body through inhalation and skin contact, respectively. inh =0.1, F dre =0.05; ； Where F ing F represents the proportion of siloxanes that can be absorbed by the human body through oral exposure. ing =1.

0.

6. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S2, the formula for calculating the health risk index is: ； Wherein, HI stands for Health Risk Index, and ADD... i RfD represents the external exposure levels for different populations calculated in S1. i The HI is the chronic reference dose calculated in S2 for different routes. When HI < 1, it indicates that the exposure level is lower than the acceptable reference dose, and the risk is considered low or negligible. When HI ≥ 1, it indicates that the exposure level exceeds the reference dose, indicating a potential health risk that cannot be ignored and requires further attention or protective measures.

7. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S2, the siloxane is targeted at specific health endpoints including liver toxicity and reproductive toxicity. In S3, the internal exposure medium includes blood and / or urine.

8. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S4, daily renal clearance was used to assess the metabolic and excretory characteristics of siloxanes in the human body, and its calculation formula is as follows: ； Wherein, CL represents the daily renal clearance rate in adults, and C... urine and C blood These represent the concentrations of siloxanes in urine and blood, respectively; V urine Daily urine output was estimated at 1.20 L for adult women and 1.40 L for adult men, with BW representing the weight of each volunteer.

9. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S5, Spearman statistical analysis was used to analyze the correlation between the calculated external exposure values ​​and internal exposure levels obtained in S1 and S3.

10. The method for assessing the internal and external exposure risks of siloxanes to different population groups according to claim 1, characterized in that: In S6, molecular docking technology is used to simulate the interaction between the siloxane or its isomers and the human estrogen receptor ER-α. By analyzing the binding energy and mode of action, its potential biological activity or toxic mechanism is evaluated. The molecular docking analysis specifically includes the following steps: S601: Obtain the three-dimensional structure of the siloxane, and optimize the small molecule of the organosiloxane by minimizing energy using obminimize software and MMFF94 force field. S602: Use AutoDockTools software to preprocess the human estrogen receptor ER-α and the optimized ligand, define the active site and generate a Quick Vina-compatible docking configuration file. S603: Iterative calculations and local searches are performed using the gradient heuristic algorithm of Quick Vina to select the conformation with the lowest combined free energy as the optimal docking scheme; S604: Visualizing the complex structure and analyzing the ligand-receptor interaction mechanism using PyMOL software; S605: Compare the binding stability of siloxanes with different structures, assess their endocrine disruption potential at the molecular level, and use them in conjunction with exposure data for a comprehensive assessment of exposure risk.

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