A method for evaluating health risk of heavy metals in reclaimed water based on multi-scale evaluation

Abstract

The present application belongs to the technical field of environmental pollution risk assessment and environmental health assessment, and discloses a heavy metal health risk assessment method for reclaimed water based on multi-scale evaluation. By combining heavy metal pollution characteristic detection in reclaimed water, human health risk scale evaluation, ecological risk scale evaluation and typical heavy metal pollutant cytotoxicity response analysis, a multi-scale evaluation system combining pollution exposure, human health risk, ecological risk and biological effect response is constructed, the comprehensive identification and quantitative evaluation of potential risks of heavy metal pollutants in the reclaimed water reuse process are realized, and the scientificity, integrity and reliability of the heavy metal environmental health risk assessment in reclaimed water are improved.

Description

Technical Field

[0001] This invention belongs to the field of environmental pollution risk assessment and environmental health assessment technology, specifically involving a method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation. Background Technology

[0002] With the continuous acceleration of urbanization and the increasingly prominent problem of water shortage, reclaimed water, as an important unconventional water resource, has been widely used in fields such as landscape recreation, urban greening, and road dust suppression.

[0003] Reclaimed water reuse can effectively alleviate the contradiction between regional water supply and demand and improve water resource utilization efficiency, which is of great significance for promoting the recycling of water resources. However, due to the complexity of wastewater sources, existing wastewater treatment processes mainly target the removal of conventional pollutants such as organic pollutants and nutrients. For some trace persistent pollutants, especially heavy metal pollutants, there is still a certain risk of residue, which may enter the ecological environment through different reuse pathways, potentially impacting human health and the ecosystem.

[0004] Heavy metal pollutants are characterized by their reluctance to degrade, strong bioaccumulation, and persistent toxicity, making them a key concern in the safe utilization of reclaimed water. Heavy metals in wastewater primarily originate from industrial production, urban runoff, and human activities. Although wastewater treatment technologies can reduce some heavy metal concentrations, trace amounts may still remain and re-enter the environment through reuse pathways such as landscaping, urban greening, and road dust suppression. Therefore, conducting environmental and health risk assessments of residual heavy metals in reclaimed water is crucial for ensuring its safe utilization.

[0005] Currently, existing methods for assessing the heavy metal risk in reclaimed water still have certain shortcomings. On the one hand, most assessment methods mainly rely on pollutant concentrations and fixed exposure parameters for risk calculation, failing to adequately consider the differences in human exposure under different reuse pathways, and thus making it difficult to comprehensively reflect the health risks in actual reclaimed water utilization scenarios. On the other hand, existing studies often conduct health risk assessment, ecological risk assessment, and pollutant toxicity effects separately, lacking a comprehensive assessment system that combines environmental pollution characteristics, human exposure risk, ecological risk, and biological response, making it difficult to achieve correlation analysis between different assessment scales. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a multi-scale evaluation method for assessing the health risks of heavy metals in reclaimed water. By combining the detection of heavy metal pollution characteristics in reclaimed water, human health risk scale evaluation, ecological risk scale evaluation, and analysis of cytotoxic responses to typical heavy metal pollutants, a multi-scale evaluation system integrating pollution exposure, human health risk, ecological risk, and biological effect response is constructed. This system enables the comprehensive identification and quantitative evaluation of potential risks of heavy metal pollutants during the reuse of reclaimed water, thereby improving the scientific rigor, completeness, and reliability of the environmental health risk assessment of heavy metals in reclaimed water.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: A method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation. (a) Pollution exposure scale assessment This invention first involves the collection and pretreatment of reclaimed water samples. Based on the reclaimed water reuse pathways (landscape and recreational use, urban greening use, road dust suppression use, etc.), sampling points are set up in actual reclaimed water reuse areas: landscape and recreational use areas, urban greening use areas, road dust suppression use areas, etc., to collect representative reclaimed water samples. After pretreatment such as digestion and filtration, the concentration of heavy metal pollutants in the water samples is determined using heavy metal detection methods to obtain characteristic data of heavy metal pollution in the reclaimed water.

[0008] In this invention, heavy metal pollutants include, but are not limited to, chromium (Cr), arsenic (As), lead (Pb), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and manganese (Mn). Based on the detection concentrations and rates of different heavy metal pollutants, the heavy metal pollution levels and major pollutants in reclaimed water are analyzed, providing fundamental data for subsequent assessments at the scales of human health risk, ecological risk, and biological response.

[0009] (II) Assessment of Human Health Risk Scales A human exposure analysis model is established based on the reclaimed water reuse pathway. Combining the concentration of the heavy metal pollutants, the mode of human exposure, and the human exposure parameters, the human exposure level to the heavy metal pollutants is calculated (characterized by the average daily exposure dose). Based on the relationship between the exposure level of the pollutants and the toxicity parameters, the human health risk assessment results are obtained.

[0010] This invention establishes a human exposure analysis system based on different reuse pathways of reclaimed water. It combines different reuse scenarios such as landscape recreation, urban greening, and road dust reduction, and comprehensively considers the main human exposure methods such as oral ingestion and skin contact. It also combines human exposure parameters such as heavy metal pollutant concentration, exposure frequency, exposure time, exposure duration, human weight, and average lifespan to calculate the human exposure level to different heavy metal pollutants.

[0011] Furthermore, this invention conducts a human health risk scale assessment in four steps: hazard identification, dose-response relationship analysis, exposure assessment, and risk characterization.

[0012] The average daily dose (ADD) was calculated based on different exposure routes. Combined with the reference dose (RfD) and slope factor (SF) of heavy metal pollutants, the non-carcinogenic risk index (HQ) and cancer risk value (CR) of different heavy metal pollutants were calculated respectively.

[0013] By comparing the non-carcinogenic risk index (HQ) and carcinogenic risk value (CR) evaluation results of different heavy metal pollutants under different reuse pathways, the health risk contribution of each heavy metal pollutant is ranked, and the pollutants that contribute the most to health risks are identified, providing a basis for the safe reuse and risk management of reclaimed water.

[0014] (III) Ecological risk scale assessment This invention further establishes a method for assessing the ecological risk scale of heavy metals in reclaimed water, comprehensively analyzes the ecological and environmental risks that heavy metal pollutants may cause, establishes a heavy metal ecological risk assessment model based on the concentration of the heavy metal pollutants and the corresponding ecotoxicological response parameters, and obtains the ecological risk assessment results.

[0015] Specifically, based on the detected concentrations of various heavy metal pollutants in the reclaimed water and combined with different heavy metal toxicity response parameters, the Hakanson potential ecological risk index method was used to calculate the potential ecological risk factor (Ei) and the comprehensive potential ecological risk index (RI) for each heavy metal.

[0016] The ecological risk level of heavy metal pollutants in reclaimed water is evaluated based on the potential ecological risk factor (Ei) and the comprehensive potential ecological risk index (RI). The ecological risk levels of different heavy metal pollutants are obtained, and the main pollutants contributing to ecological risk are identified, providing a technical basis for the ecological safe utilization and pollution control of reclaimed water.

[0017] (iv) Evaluation of biological effect response scale This invention further establishes a biological effect response scale evaluation method based on the cytotoxic response of typical heavy metal pollutants. Using typical risk-contributing pollutants screened out by health risk assessment and / or ecological risk assessment as research objects, a corresponding heavy metal pollutant exposure biological model is established. The toxic response results of heavy metal pollutants are obtained by detecting biological effect response indicators. The toxic effects induced by heavy metal pollutants are analyzed at the cellular level, providing biological effect support for the health risk assessment of heavy metals in reclaimed water.

[0018] In some optional examples, the present invention selects lead (Pb), a representative heavy metal pollutant in the human health risk scale assessment results, as a typical evaluation object, establishes a normal liver cell model of AML12 mice exposed to Pb, and evaluates the biotoxic effects induced by Pb by detecting cell function damage, cytotoxicity and oxidative stress-related indicators.

[0019] The evaluation of biological effect response scales includes, but is not limited to, the following indicators: (1) Cell viability, used to evaluate the effect of Pb exposure on the proliferation and survival status of AML12 cells; (2) Reactive oxygen species (ROS) levels are used to evaluate the degree of Pb-induced cellular oxidative stress; (3) Antioxidant enzyme activities, including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), are used to evaluate the effects of Pb exposure on the cellular antioxidant defense system. (4) Lipid peroxidation level, with malondialdehyde (MDA) content as the evaluation index, is used to analyze the degree of Pb-induced lipid peroxidation damage to cell membranes. (5) Cell membrane damage indicators, using the release level of lactate dehydrogenase (LDH) to evaluate changes in cell membrane integrity; (6) Cell membrane ion transport function indicators, using Na⁺ / K⁺-ATPase activity to evaluate the effect of Pb exposure on cell membrane ion transport and energy metabolism.

[0020] (v) Based on the data correlation between the pollution exposure scale assessment results, the human health risk scale assessment results, the ecological risk scale assessment results, and the biological effect response scale assessment results, conduct a comprehensive analysis of the environmental health risks of heavy metal pollutants in reclaimed water, determine the main risk-contributing pollutants and their risk levels, and improve the completeness and reliability of the environmental health risk assessment of heavy metals in reclaimed water.

[0021] The beneficial effects of this invention are: 1. This invention establishes a multi-scale evaluation system for heavy metal risk assessment in reclaimed water. By integrating heavy metal pollution characteristic analysis, exposure analysis of multiple reuse pathways, human health risk scale evaluation, ecological risk scale evaluation, and biological effect response scale evaluation, it expands from traditional pollutant concentration evaluation to comprehensive environmental health risk evaluation, and can more comprehensively reflect the potential risks of heavy metal pollutants in the process of reclaimed water reuse.

[0022] 2. This invention detects multiple heavy metal pollutants such as Cr, As, Pb, Ni, Cu, Zn, Cd, and Mn in reclaimed water and conducts health risk assessments by combining the toxicity parameters of different pollutants. It can simultaneously evaluate the carcinogenic and non-carcinogenic risks of multiple heavy metal pollutants, identify the main pollutants contributing to health risks, and avoid the problem of incomplete risk information caused by traditional single-pollutant assessments.

[0023] 3. This invention combines different reclaimed water reuse pathways such as landscape recreation, urban greening, and road dust suppression, and comprehensively considers the differences in human exposure methods and exposure parameters under different reuse scenarios. It analyzes the health risks of heavy metal pollutants under different reuse pathways, and can identify the main risk-contributing pollutants under different reuse pathways, providing a technical basis for the safe reuse of reclaimed water, pollution prevention and control, and risk management.

[0024] 4. Based on the human health risk scale assessment, this invention further introduces the ecological risk scale assessment. By calculating the potential ecological hazard coefficient (Ei) and the comprehensive potential ecological risk index (RI) of heavy metals, the potential impact of residual heavy metals in reclaimed water on human health and the ecological environment can be evaluated simultaneously, realizing a comprehensive analysis of environmental and health risks and improving the completeness and scientific nature of the risk assessment results.

[0025] 5. The evaluation method of this invention can directly utilize existing heavy metal monitoring data in reclaimed water and combine it with human exposure parameters, toxicity parameters, and risk assessment models for analysis. It does not require changes to the existing water quality testing process and monitoring system. It has the advantages of simple operation, convenient data acquisition, wide applicability, and high value for promotion and application, and can effectively improve the engineering application feasibility of the health risk assessment method for heavy metals in reclaimed water.

[0026] 6. This invention further introduces a biological effect response scale assessment of typical heavy metal pollutants. Taking lead (Pb), a typical risk-contributing pollutant screened by human health risk scale assessment, as the research object, a Pb-exposed AML12 cell model is established. By detecting biological effect indicators such as cell viability, reactive oxygen species (ROS), antioxidant enzyme activity (CAT, SOD, GSH-Px), lipid peroxidation level (MDA), cell membrane damage index (LDH), and Na⁺ / K⁺-ATPase activity, biological effect support is provided for health risk assessment results at the cellular level. This enables the correlation analysis between environmental exposure risk and biotoxic response, improving the accuracy and reliability of heavy metal environmental health risk assessment in reclaimed water.

[0027] 7. This invention constructs a comprehensive evaluation system that combines pollution exposure scale, human health risk scale, ecological risk scale, and biological effect response scale, realizing the integration of pollutant detection, human exposure analysis, risk identification, and biotoxicity evaluation. It provides a scientific, systematic, and widely applicable evaluation method for the safe reuse of reclaimed water, environmental health risk early warning, and pollution control. Attached Figure Description

[0028] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings; Figure 1 This is a data graph showing the heavy metal content at each sampling point in an embodiment of the present invention; Figure 2 This is a data graph showing the maximum concentration of residual heavy metals detected in the effluent of the water purification plant in this embodiment of the invention. Figure 3 This is a data graph showing the health risk values ​​of residual heavy metals in the effluent of a water purification plant under the landscape and recreation reuse pathway in an embodiment of the present invention; Figure 4 This is a data graph showing the health risk values ​​of residual heavy metals in the effluent of a water purification plant under the urban greening reuse pathway in an embodiment of the present invention; Figure 5 This is a data graph showing the health risk values ​​of residual heavy metals in the effluent of a water purification plant under the road dust suppression and reuse pathway in an embodiment of the present invention; Figure 6 This is a data graph showing the ecological risk values ​​of residual heavy metals in the effluent of a water purification plant in an embodiment of the present invention; Figure 7 This is a graph showing the effect of different concentrations of Pb on the viability of AML12 cells in the embodiments of the present invention; Figure 8 This is a graph showing the effect of different concentrations of Pb on intracellular oxidative stress indicators in AML12 cells in this embodiment of the invention. Figure 9 This figure shows the effect of different concentrations of Pb on the cell membrane integrity index of AML12 in this embodiment of the invention. Detailed Implementation

[0029] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein. Example

[0030] This embodiment provides a method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation, including: (a) Pollution exposure scale assessment This embodiment uses the effluent from a water purification plant in Qingdao and its replenishing river as the research object to conduct a pollution exposure analysis of heavy metal pollutants in reclaimed water. Sampling points were set up according to the reclaimed water reuse pathways and the distribution of receiving water bodies. Reclaimed water samples were collected in different months, and after pretreatment, the concentrations of eight heavy metal pollutants, including Cr, As, Pb, Ni, Cu, Zn, Cd, and Mn, were determined using inductively coupled plasma mass spectrometry (ICP-MS). Figure 1 This yielded characteristic data on heavy metal pollution in reclaimed water.

[0031] Table 1 shows the exposure modes and parameters of reclaimed water under different reuse pathways, such as landscaping and recreation, urban greening, and road dust suppression. Based on the human exposure modes of different reuse pathways, the exposure frequency, exposure time, and exposure amount for occupational workers and the general public were determined, providing basic parameters for subsequent human health risk assessment.

[0032] Table 1. Pollutant Exposure Routes and Exposure Levels Table 1 Exposure route and exposure amount of pollutants

[0033] Based on the detection results from each sampling point, a statistical analysis of the heavy metal pollutant concentrations was performed. The results showed that, except for Cu and Zn, the detection rate of all other heavy metals reached 100%, and the average concentrations of the eight heavy metals followed a pattern as follows: Zn>Pb>Mn>Ni>Cr>As>Cu>Cd.

[0034] There are certain spatial differences in heavy metal concentrations at different sampling points. Overall, the concentrations are higher upstream than downstream, and gradually decrease from the discharge outlet of the water purification plant. This indicates that the discharge of reclaimed water and the dilution effect of rivers have a certain impact on the spatial distribution of heavy metals.

[0035] Further analysis of the maximum detectable concentrations of various heavy metals in the effluent from the water purification plant was conducted, and the results are shown below. Figure 2 The maximum detectable concentrations of Cr, As, Pb, Ni, Cu, Zn, Cd, and Mn were 3.57, 9.69, 4.31, 12.73, 1.58, 0.33, 0.15, and 9.96 ng / L, respectively. Following the worst-case scenario principle in risk assessment, the maximum detectable concentrations of each pollutant were used as the basis for subsequent human health risk scale assessments and ecological risk scale assessments.

[0036] In summary, the pollution exposure scale has completed the detection of heavy metal pollutants in reclaimed water, the identification of pollution characteristics, and the screening of key pollutants, providing basic data support for subsequent human health risk scale assessment, ecological risk scale assessment, and biological effect response scale assessment.

[0037] (II) Assessment of Human Health Risk Scales Based on the completed pollution exposure analysis, this embodiment evaluates the human health risks of heavy metal pollutants in reclaimed water under different reuse pathways according to the human health risk assessment model recommended by the U.S. Environmental Protection Agency (EPA). According to the human exposure analysis model established in the technical solution, combined with heavy metal detection concentrations, human exposure parameters, reference dose (RfD), and carcinogenicity slope factor (SF), the non-carcinogenic risk index (HQ) and carcinogenic risk value (CR) of different heavy metal pollutants are calculated, and the health risk levels of each pollutant under different reuse pathways are compared.

[0038] 1. Health Risk Assessment of Reuse Pathways for Landscape and Recreation The maximum detectable concentrations of various heavy metal pollutants at the effluent outlet of the water purification plant were used as evaluation concentrations to calculate the human health risks under the landscaping and recreational reuse pathway. The evaluation results are shown in Table 2 and [Table data missing]. Figure 3 .

[0039] Table 2 Health Risk Values ​​of Residual Heavy Metals in Water Purification Plant Effluent under Landscape and Recreation Reuse Pathways Table.2 Health risk value of residual heavy metals in effluent ofwater purification plant under the way of landscape entertainment reuse.

[0040] The results showed that, under the urban green space reuse pathway, the health risks for occupational workers and the general public followed the same pattern, exhibiting the following characteristics: Cr>As>Cd>Ni>Cu>Pb>Mn>Zn.

[0041] The health risk values ​​for different population groups are all within acceptable ranges. The risk value for occupational personnel is slightly higher than that for the general public, but overall it is lower than the acceptable risk limit, indicating that the human health risk from heavy metal pollutants under this recycling route is low.

[0042] 2. Health Risk Assessment of Urban Green Space Reuse Pathways Further evaluation of the health risks to occupational workers and the public when reclaimed water is used for urban greening is presented in Table 3. Figure 4 .

[0043] Table 3 Health risk values ​​of residual heavy metals in water purification plant effluent under urban greening reuse pathways. Table 3 Health risk value of residual heavy metals in effluent ofwater purification plant under the way of urban greening reuse.

[0044] The results showed that, under the urban green space reuse pathway, the health risks for occupational workers and the general public followed the same pattern, exhibiting the following characteristics: Cr>As>Cd>Ni>Cu>Pb>Mn>Zn.

[0045] The health risk values ​​for different population groups are all within acceptable ranges. The risk value for occupational personnel is slightly higher than that for the general public, but overall it is lower than the acceptable risk limit, indicating that the human health risk from heavy metal pollutants under this recycling route is low.

[0046] 3. Health risk assessment of road dust suppression reuse methods Using the same evaluation method, the health risks to occupational workers and the public under the road dust suppression reuse pathway were evaluated. The results are shown in Table 4 and [Table data missing]. Figure 5 .

[0047] Table 4 Health Risk Values ​​of Residual Heavy Metals in Effluent from Water Purification Plants under Road Dust Retention Pathways Table 4 Health risk value of residual heavy metals in effluent ofwater purification plant under the way of road dust removal reuse.

[0048] The evaluation results show that, under the road dust suppression reuse pathway, the health risks of various heavy metals still follow the same pattern: Cr>As>Cd>Ni>Cu>Pb>Mn>Zn.

[0049] The overall health risks for occupational workers are higher than those for the general public, but the risk values ​​for all heavy metals are below acceptable risk levels, indicating that the use of recycled water for road dust suppression will not pose a significant health risk to humans.

[0050] 4. Comprehensive analysis of human health risks The evaluation results of the three reuse pathways—landscape recreation, urban greening, and road dust suppression—show that the health risks of heavy metal pollutants follow a generally consistent pattern across these pathways. Cr, As, and Cd are the main contributors to health risk, while Pb, Ni, Cu, Zn, and Mn contribute relatively less. The overall health risk for occupational workers is higher than that for the general public under different reuse pathways, but the health risk values ​​for each heavy metal are all below the internationally recommended acceptable risk levels, indicating that residual heavy metals in the reclaimed water of the study area do not pose a significant threat to human health. The results of the human health risk scale assessment can further provide a basis for subsequent ecological risk scale assessments and biological effect response scale analyses of typical pollutants.

[0051] (III) Ecological risk scale assessment After completing the human health risk scale assessment, this embodiment further evaluates the ecological risk of residual heavy metals in the effluent of the water purification plant. Following the worst-case scenario principle, the maximum measured concentrations of Cr, As, Pb, Ni, Cu, Zn, Cd, and Mn at the effluent outlet of the water purification plant are used as the evaluation concentrations. Combined with the toxicity response coefficients of each heavy metal, the Hakanson potential ecological risk index method is used to calculate the potential ecological hazard coefficient (Ei) and the comprehensive potential ecological risk index (RI) for each heavy metal.

[0052] The ecological risk level of heavy metals is classified according to the potential ecological hazard coefficient and the comprehensive potential ecological risk index. The specific evaluation criteria are shown in Table 5.

[0053] Table 5 Classification of Ecological Risk Levels Table 5 Classification of ecological risk degree

[0054] According to Table 5, when Ei ≤ 40, a single heavy metal is at a low ecological risk level; when RI ≤ 150, the combined ecological risk of multiple heavy metals is at a low risk level. Using this classification standard as the basis for judgment, the single-factor ecological risk and overall combined ecological risk of each heavy metal are evaluated.

[0055] The ecological risk results calculated based on the maximum detectable concentrations of each heavy metal and their toxicity response coefficients are shown in Table 6 and... Figure 6 .

[0056] Table 6 Ecological risk values ​​of residual heavy metals in the effluent from water purification plants Table 6 Ecological risk value of residual heavy metals in effluent ofwater purification plant.

[0057] From Table 6 and Figure 6 It can be seen that the potential ecological hazard coefficients of each heavy metal are at a low level, and the order of ecological risk of each single factor is as follows: Cd>As>Ni>Pb>Cu>Cr>Mn>Zn.

[0058] Among the eight heavy metals, Cd had the highest potential ecological risk contribution, with a potential ecological risk coefficient of 5.37 × 10⁻². As and Ni were next, with potential ecological risk coefficients of 1.04 × 10⁻² and 2.47 × 10⁻³, respectively. Pb, Cu, Cr, Mn, and Zn had relatively low ecological risk contributions. Although the risk contributions of different heavy metals varied, the Ei values ​​of all heavy metals were well below 40, indicating a low ecological risk level.

[0059] Further summing the potential ecological hazard coefficients of the eight heavy metals yielded a comprehensive potential ecological risk index (RI) of 6.79 × 10⁻², which is far lower than the low ecological risk level of 150, indicating that the comprehensive ecological risk caused by multiple heavy metals in the effluent from the water purification plant is relatively low.

[0060] The combined results of single-factor and comprehensive ecological risk assessments show that although Cd, As, and Ni are the main pollutants contributing to ecological risk, all eight heavy metals detected in this embodiment are at a low ecological risk level, indicating a relatively small overall ecological risk. These assessment results can be combined with human health risk assessments to identify the main risk-contributing factors of heavy metals in reclaimed water from both human health and ecological environment perspectives, providing a basis for subsequent assessments of typical heavy metal biological effects.

[0061] (iv) Evaluation of biological effect response scale To further verify the biological effects of the results of human health risk scale assessment and ecological risk scale assessment, this embodiment uses lead (Pb), a typical risk-contributing pollutant screened by the human health risk scale assessment, as a representative pollutant. An AML12 mouse normal hepatocyte exposure model was established to evaluate the Pb-induced toxic effects at the cellular level. After treating AML12 cells with different concentrations of Pb for 24 hours, cell viability, oxidative stress indicators, and cell membrane damage-related indicators were detected to construct a heavy metal pollutant biological effect response evaluation system.

[0062] 1. Effects of Pb on AML12 cell viability The changes in AML12 cell viability after exposure to different concentrations of Pb were detected using the CCK-8 assay. The evaluation results are shown below. Figure 7 .

[0063] Depend on Figure 7 (Compared to the blank control group, "**" indicates) p <0.01, "***" indicates p As shown by the value <0.001, the viability of AML12 cells gradually decreased with increasing Pb exposure concentration. When the Pb concentration was low, the change in cell viability was small; when the Pb concentration was further increased, the cell viability decreased significantly and showed a certain concentration dependence, indicating that Pb exposure can inhibit the proliferation of AML12 cells and reduce cell survival.

[0064] 2. Pb-induced oxidative stress response Further analysis was conducted on the intracellular antioxidant system and lipid peroxidation levels of AML12 cells after Pb exposure. The evaluation results are shown below. Figure 8 (Compared to the blank control group, "*" indicates) p <0.05, "**" indicates p <0.01, “***” indicates p <0.001).

[0065] Depend on Figure 8It was found that with increasing Pb exposure concentration, the activities of CAT, SOD, and GSH-Px generally decreased, while the MDA content gradually increased. These results indicate that Pb exposure weakens cellular antioxidant defense capabilities and promotes lipid peroxidation, suggesting that Pb can induce oxidative stress damage in AML12 cells.

[0066] 3. Effects of Pb on cell membrane integrity LDH and Na⁺ / K⁺-ATPase activities were used to evaluate cell membrane damage after Pb exposure. The evaluation results are shown in […]. Figure 9 (Compared to the blank control group, "*" indicates) p <0.05, "**" indicates p <0.01, “***” indicates p <0.001).

[0067] Depend on Figure 9 It was found that with increasing Pb exposure concentration, both LDH and Na⁺ / K⁺-ATPase activities changed significantly, indicating that Pb exposure damaged the cell membrane integrity of AML12 cells and affected cell membrane ion transport function. The degree of cell membrane damage gradually increased with increasing Pb concentration, further demonstrating that Pb has a significant cytotoxic effect.

[0068] 4. Comprehensive Analysis of Biological Effect Response The comprehensive evaluation results of cell viability, oxidative stress, and cell membrane integrity indicate that Pb exposure can lead to decreased AML12 cell viability, induce oxidative stress, and cause cell membrane function damage. These biological response results corroborate the human health risk assessment and ecological risk assessment results, reflecting the toxic effects of typical heavy metal pollutants at the cellular level and providing a biological basis for the comprehensive assessment of the environmental health risks of heavy metals in reclaimed water.

[0069] (V) Comprehensive Evaluation This embodiment takes the effluent from a water purification plant in Qingdao and its replenishing river as the research object, and constructs a four-scale comprehensive evaluation system of "pollution exposure—human health risk—ecological risk—biological effect response" to systematically evaluate the environmental health risks of residual heavy metals in reclaimed water. First, the contents of eight heavy metals, namely Cr, As, Pb, Ni, Cu, Zn, Cd, and Mn, were determined by ICP-MS to obtain the heavy metal pollution levels and spatial distribution characteristics at different sampling points, providing basic data for subsequent risk assessment. Subsequently, based on the human health risk assessment model of the U.S. Environmental Protection Agency (EPA), human health risk assessments were carried out on typical reuse pathways such as landscape recreation, urban greening, and road dust suppression, identifying the main risk-contributing pollutants under different reuse pathways and clarifying the health risk levels of different exposed populations.

[0070] Based on this, the Hakanson potential ecological risk index method was used to assess the ecological risk of heavy metals, calculating the potential ecological hazard coefficient (Ei) and comprehensive potential ecological risk index (RI) for each heavy metal, thus achieving a quantitative analysis of the ecological risk of heavy metals. The evaluation results show that the heavy metals detected in this embodiment are generally at a low ecological risk level. Both evaluation methods identified As and Cd as the main risk-contributing pollutants, reflecting the potential hazards of heavy metals in reclaimed water from different evaluation perspectives.

[0071] Furthermore, using Pb, a typical risk-contributing pollutant screened in the human health risk scale assessment, as a representative, an exposure model of normal hepatocytes in AML12 mice was established. By detecting cell viability, antioxidant enzyme activity, lipid peroxidation levels, and cell membrane damage-related indicators, the biotoxic effects of heavy metals were verified, realizing the correlation analysis between environmental risk assessment results and biological effects. Cellular experimental results can serve as an important supplement to the human health risk scale assessment, providing biological evidence for the assessment results and improving the scientific rigor and credibility of the risk assessment results.

[0072] In summary, the multi-scale evaluation method proposed in this invention organically combines pollutant concentration detection, human health risk assessment, ecological risk assessment, and cellular biological effect assessment. It not only identifies the main risk-contributing factors of heavy metals in reclaimed water but also comprehensively evaluates the environmental health risks of heavy metals from both environmental exposure and biological response perspectives. This method has a complete evaluation process and a wide range of applications, including reclaimed water reuse safety assessment, environmental risk monitoring, and pollution control. It verifies that the multi-scale evaluation method proposed in this invention can achieve a comprehensive assessment of the environmental health risks of heavy metals in reclaimed water, demonstrating good engineering application value and promising prospects for widespread application.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation, characterized in that: include (I) Pollution exposure scale assessment Collect reclaimed water samples, pretreat the reclaimed water samples, and detect the concentration of one or more heavy metal pollutants to obtain heavy metal pollution characteristic data in the reclaimed water. (II) Assessment of Human Health Risk Scales A human exposure analysis model is established based on the reclaimed water reuse pathway. Combining the concentration of the heavy metal pollutants, the human exposure mode, and the human exposure parameters, the human exposure level to the heavy metal pollutants is calculated. Based on the relationship between the exposure level of the pollutants and the toxicity parameters, the human health risk assessment results are obtained. (III) Ecological risk scale assessment Based on the concentration of the heavy metal pollutants and the corresponding ecotoxicity response parameters, a heavy metal ecological risk assessment model is established to obtain the ecological risk assessment results. (IV) Evaluation of biological effect response scale Based on the results of human health risk assessment and / or ecological risk assessment, typical risk-contributing pollutants are screened, corresponding heavy metal pollutant exposure biological models are established, and heavy metal pollutant toxicity response results are obtained by detecting biological effect response indicators. (V) Based on the data correlation between the pollution exposure scale assessment results, the human health risk scale assessment results, the ecological risk scale assessment results, and the biological effect response scale assessment results, a comprehensive analysis of the environmental health risks of heavy metal pollutants in reclaimed water is conducted to determine the main risk-contributing pollutants and their risk levels.

2. The method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation according to claim 1, characterized in that: The reclaimed water reuse pathways include at least one of landscape and recreation reuse, urban greening reuse, and road dust suppression reuse. The heavy metal pollutants include at least one of chromium, arsenic, lead, nickel, copper, zinc, cadmium, and manganese.

3. The method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation according to claim 1, characterized in that: In content (I), Sampling points are set up according to the actual reuse area of ​​reclaimed water. The collected reclaimed water samples are digested, filtered or otherwise pretreated, and the concentration data of heavy metal pollutants are obtained by heavy metal detection methods. Based on the detection concentration and detection rate of different heavy metal pollutants, the heavy metal pollution level and main pollutants in reclaimed water were analyzed.

4. The method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation according to claim 1, characterized in that: In content (II), Human exposure can occur through at least one of oral ingestion or skin contact. The human exposure parameters include at least one of the following: pollutant exposure frequency, exposure time, exposure duration in years, human body weight, and average lifespan.

5. The method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation according to claim 4, characterized in that: In content (II), The human body's exposure level to the aforementioned heavy metal pollutants is characterized by the average daily exposure dose. The results of the human health risk assessment are characterized by at least one of the non-carcinogenic risk index and carcinogenic risk value. The non-carcinogenic risk index and carcinogenic risk value are calculated based on the average daily exposure dose to humans, the reference dose of heavy metal pollutants, and the carcinogenic slope factor.

6. The method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation according to claim 1, characterized in that: In content (III), the ecological risk scale assessment includes, Based on the detected concentrations of heavy metal pollutants and their corresponding toxicity response parameters, the potential ecological risk index method is used to calculate the potential ecological hazard coefficient of a single heavy metal pollutant and the comprehensive potential ecological risk index of multiple heavy metal pollutants, so as to evaluate the ecological risk level of heavy metal pollutants in reclaimed water. The ecological risk levels of heavy metal pollutants in the reclaimed water obtained from the evaluation include the ecological risk levels of different heavy metal pollutants, as well as the identification of heavy metal pollutants that contribute to the main ecological risks.

7. The method for assessing the health risks of heavy metals in reclaimed water based on multi-scale evaluation according to claim 1, characterized in that: In section (IV), the evaluation of biological effect response scales includes The biological model of heavy metal pollutant exposure evaluates the biotoxic effects induced by heavy metal pollutants by detecting at least one of the following: cytotoxicity indicators, oxidative stress indicators, and cell function damage indicators.

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