Rapid method for comprehensive toxicity determination of sewage

Abstract

A method for rapid determination of comprehensive toxicity of sewage is provided. The method includes the following steps: (S1) measuring zebrafish embryo toxicity indexes from water samples in the full process of a sewage treatment plant, including traditional toxicity indexes and behavioral toxicity indexes, and performing data preprocessing; (S2) using the traditional toxicity indexes as target variables and the behavioral toxicity indexes as features to establish a comprehensive sewage toxicity prediction model based on different target variables; (S3) inputting the zebrafish embryo behavioral toxicity index data from the test water sample into the prediction model as input data and selecting a corresponding prediction model according to the prediction results of the target variables to obtain the comprehensive toxicity of the test sewage sample. The present invention can obtain a standardized comprehensive toxicity index for actual sewage samples, while maintaining the advantages of speed, simple operation, and low cost, making it suitable for quickly measuring the comprehensive toxicity of large quantities of actual sewage samples.

Description

[Technical Field]

[0001] The present invention relates to the field of water quality monitoring, and more particularly to a method for rapid determination of the comprehensive toxicity of sewage. [Background technology]

[0002] Human activities have led to the spread of many pollutants into the environment, posing potential risks to human health and the environment. Traditional chemical methods are often used to measure specific pollutants in sewage, but because sewage often exists in the form of complex mixtures, chemical analysis cannot identify many components, increasing uncertainty in water quality assessment. Compared with chemical analysis, biological analysis can comprehensively measure the actual toxicity of all pollutants, i.e., the comprehensive toxicity of sewage. Zebrafish embryos are widely used in bioanalytical methods due to their fast reproductive cycle and transparent embryos. The comprehensive toxicity index obtained by traditional experimental methods is LC 10 or LC 50 This method (units: percentage of the water sample concentration) is standardized and widely recognized. However, this method requires the setting up of multiple concentration gradients and the running of multiple parallel experiments, which increases the number of embryos used and the experimental procedure time. To address this issue, Chinese Patent Application No. 202010577907.X discloses a method for assessing the developmental neurotoxicity of wastewater. This method involves exposing transgenic zebrafish embryos to concentrated or diluted test wastewater up to 24 hpf, removing the exposed embryos, observing them under a fluorescent inverted microscope, and capturing images for analysis. This method has the advantages of being simple, fast, and efficient. However, because the water samples measured using this method require filtration and concentration, the results may not reflect the actual conditions of the wastewater. Furthermore, this method only provides an indicator of neurotoxicity, not the comprehensive toxicity of the wastewater. Summary of the Invention [Problem to be solved by the invention]

[0003] Objective of the invention: The objective of the present invention is to provide a method for rapidly measuring the comprehensive toxicity of sewage, which not only can obtain a standardized comprehensive toxicity index for actual sewage samples, but also maintains the advantages of speed, simple operation and low cost, making it suitable for rapidly measuring the comprehensive toxicity of large amounts of actual sewage samples. [Means for solving the problem]

[0004] Technical Solution: The method for rapid comprehensive toxicity determination of sewage according to the present invention includes the following steps:

[0005] Step (S1) measures zebrafish embryo toxicity indicators of sewage samples in the full process of several sewage treatment plants, including traditional toxicity indicators and behavioral toxicity indicators, and performs data preprocessing.

[0006] Step (S2) takes traditional toxicity indicators as target variables and behavioral toxicity indicators as features to establish a comprehensive wastewater toxicity prediction model based on different target variables.

[0007] Step (S3): The zebrafish embryo behavioral toxicity index data of the test sewage sample is input into the prediction model as input data, and the corresponding prediction model is selected according to the prediction result of the target variable to obtain the comprehensive toxicity of the test sewage sample.

[0008] Preferably, the traditional toxicity index is the median lethal dose (LC 50 and 10% lethal dose LC 10 This includes the mortality rate of zebrafish embryos over a specific time period, and is obtained by observing the mortality rate of zebrafish embryos over a specific time period.

[0009] Preferably, in step (S2), the sewage comprehensive toxicity prediction model based on different target variables includes:

[0010] Depending on the target variable, LC 50 Select sewage samples with a median lethal dose (LC) of <100. 50We obtain prediction model 1 by training it with LC 50 Select sewage samples with a concentration of ≥100 and measure the 10% lethal dose (LC 10 Prediction model 2 is obtained by training with the target variable.

[0011] Preferably, in step (S3), selecting a corresponding prediction model according to the prediction result of the target variable to obtain the comprehensive toxicity of the test sewage sample includes:

[0012] The embryo behavioral toxicity index data from the measurement sewage samples was input into the prediction model as input data, and the output value of prediction model 1 was LC 50 If <100, the median lethal dose (LC) 50 is the comprehensive toxicity of the sewage sample being measured.

[0013] The output value of prediction model 1 is LC 50 If the value is ≧100, the embryo behavioral toxicity index data from the measurement sewage sample is input to prediction model 2 as input data, and the output value of prediction model 2 is LC 10 , that is, the comprehensive toxicity of the test sewage sample is obtained.

[0014] Preferably, the behavioral toxicity indexes include the activity of zebrafish embryos in a dark environment within a specific time, the activity of zebrafish embryos in a light environment within a specific time, the total distance traveled by zebrafish embryos in a dark environment within a specific time, the total distance traveled by zebrafish embryos in a light environment within a specific time, the burst distance of zebrafish embryos within a specific time, the range of zebrafish embryos within a specific time, and the freezing distance of zebrafish embryos within a specific time, measured by the zebrafish behavior detector.

[0015] Preferably, the Lasso model is utilized to establish a comprehensive sewage toxicity prediction model.

[0016] Preferably, in establishing a comprehensive sewage toxicity prediction model, the coefficient of determination R 2The performance of the comprehensive wastewater toxicity prediction model is evaluated based on the coefficient of determination R 2 As a calculation method, TIFF0007822645000002.tif1751However, TIFF0007822645000003.tif55 is the coefficient of determination, TIFF0007822645000004.tif55 is the value of the i-th traditional toxicity index in the test set, TIFF0007822645000005.tif65 is the average value of traditional toxicity indices in the test set, TIFF0007822645000006.tif65 is the predicted value output by the prediction model, and n is the number of traditional toxicity index values.

[0017] Preferably, the data pre-processing includes data cleaning, data standardization, and feature selection.

[0018] Preferably, data standardization utilizes the Z-Score method or the Max-Min method.

[0019] Preferably, the feature selection method utilizes the Pearson correlation coefficient measure. [Effects of the Invention]

[0020] Beneficial effects: Compared with conventional techniques, the present invention has the following significant advantages: 1. The present invention can quickly and easily realize the toxicity measurement of a large amount of sewage samples, and the number of embryos used is significantly reduced compared with conventional experiments; 2. The corresponding prediction model is selected according to the prediction result of the target variable, so the accuracy of the model in practical use is further improved; 3. The model determination coefficient R established by the present invention 2 >0.85, so it has high accuracy. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following further describes embodiments of the present invention with reference to the accompanying drawings.

[0023] As shown in FIG. 1, the method for rapid determination of comprehensive toxicity of sewage according to the present invention mainly includes a step of establishing a comprehensive toxicity model of sewage (1) and a step of determining comprehensive toxicity of sewage (2).

[0024] Among these, the stage (1) of establishing a comprehensive sewage toxicity model mainly includes the following steps:

[0025] (1.1) Data collection: Measurement of zebrafish embryo toxicity indicators in sewage samples from several sewage treatment plants throughout the entire process. The zebrafish embryo toxicity indicators include traditional toxicity indicators and behavioral toxicity indicators.

[0026] The traditional toxicity index is the median lethal dose (LC 50 and 10% lethal dose LC 10 This is achieved by observing the mortality rate of zebrafish embryos within a specific time period.

[0027] Behavioral toxicity indices, including the activity of zebrafish embryos in a dark environment within a specific time period (activity-dark), the activity of zebrafish embryos in a light environment within a specific time period (activity-light), the total distance traveled by zebrafish embryos in a dark environment within a specific time period (total distance-dark), the total distance traveled by zebrafish embryos in a light environment within a specific time period (total distance-light), the burst distance of zebrafish embryos in dark and light environments within a specific time period, the range of zebrafish embryos in dark and light environments within a specific time period, and the freezing distance of zebrafish embryos in dark and light environments within a specific time period, are measured by the zebrafish behavior detector.

[0028] (1.2) Data preprocessing includes data cleaning, data standardization, and feature selection.

[0029] The data standardization includes, but is not limited to, the Z-Score method and the Max-Min method. In this embodiment, the Z-Score method is used. TIFF0007822645000007.tif1951

[0030] however, TIFF0007822645000008.tif55 is the standard score, TIFF0007822645000009.tif66 is the value of a certain index in the behavioral toxicity index, TIFF0007822645000010.tif65 is the average value of the index data, TIFF0007822645000011.tif55 is the standard deviation of the index data.

[0031] The feature selection method uses the Pearson correlation coefficient measurement method, and the correlation coefficient r 2 If it is >0.8, remove one of the indices and make the correlation coefficient between each two features r 2 Set it to <0.8.

[0032] The processed data is divided into a training set and a test set.

[0033] (1.3) Establishing the model A comprehensive sewage toxicity prediction model is established based on the Lasso model, taking traditional toxicity indicators as target variables and behavioral toxicity indicators as features.

[0034] (1.4) Model training and testing The training set data is used to train a predictive model, and the test set data is used to calculate the coefficient of determination, R 2 The performance of the predictive model is evaluated based on this.

[0035] Of these, the coefficient of determination R 2 As a calculation method, TIFF0007822645000012.tif1651

[0036] however, TIFF0007822645000013.tif55 is the coefficient of determination, TIFF0007822645000014.tif55 is the value of the i-th traditional toxicity index in the test set, TIFF0007822645000015.tif65 is the average value of traditional toxicity indices in the test set, TIFF0007822645000016.tif65 is the i-th predicted value output based on the features in the test set, and n is the number of traditional toxicity index values.

[0037] Specifically, depending on the target variable, LC 50 Select a sewage sample with a concentration of <100 (i.e., the water sample concentration is 100%) and measure the LC 50 We obtained prediction model 1 by training with LC 50 Select ≥100 sewage samples and analyze them by LC 10 Prediction model 2 was obtained by training with the target variable.

[0038] The phase (2) of establishing a comprehensive wastewater toxicity model mainly includes the following:

[0039] (2.1) Measurement of behavioral toxicity index in zebrafish embryos using test water samples: Using zebrafish embryos, the behavioral toxicity index of test sewage samples is measured, and data preprocessing is performed.

[0040] (2.2) The preprocessed behavioral toxicity index data is input to prediction model 1 as input data, and the output value of prediction model 1, LC 50 If <100, the LC 50 The value represents the overall toxicity of the water sample.

[0041] The output value of prediction model 1 is LC 50 If ≧100, the embryo behavioral toxicity index data of the measurement sewage sample is input to prediction model 2 as input data, and the output value LC 10, i.e., the comprehensive toxicity of the sewage sample was obtained.

[0042] The method of the present invention will be further described below using embodiments.

[0043] The sewage samples used to establish the sewage comprehensive toxicity prediction model were collected from multiple process sections of 40 sewage treatment plants, totaling 300 sewage samples. The test sewage samples were actual influent and actual effluent from a municipal sewage treatment plant. The rapid method for determining the comprehensive toxicity of sewage according to the present invention includes the following steps:

[0044] (1) LC based on behavioral data from zebrafish embryos 50 and L.C. 10 Establish a predictive model for

[0045] (1.1) Data collection: Zebrafish embryo toxicity indicators were measured for 300 sewage samples, including traditional and behavioral toxicity indicators. Traditional toxicity indicators included LC, which was measured by observing embryo mortality within a specific time period. 50 and L.C. 10 In this embodiment, LC 50 <100 sewage samples were 130, LC 50 There were 170 sewage samples with a density of ≥100. Behavioral toxicity indicators, including embryo activity in 5 min of dark and 5 min of light, total distance traveled in 5 min of dark, total distance traveled in 5 min of light, burst distance, range, and freezing distance in 5 min of dark and light, were measured by the zebrafish behavior detector.

[0046] (1.2) Data preprocessing: Data cleaning, data standardization, and feature selection are performed on the collected data. Data standardization uses the Z-Score method, and feature selection uses the Pearson correlation coefficient measurement method to obtain the final correlation coefficient r between each pair of features. 2 The range is 0.496-0.770.

[0047] (1.3) Model training: The dataset was divided into a 70% training set and a 30% test set. The traditional toxicity index was used as the target variable and the behavioral toxicity index was used as the feature to train the Lasso model. 50 <100 water sample is 130, LC 50 ≥ 100 water samples are 170, so to obtain the prediction model 1, LC 50 130 water samples were analyzed using the target variable LC 10 was used as the target variable to train 170 water samples.

[0048] (1.4) Testing the model: Based on the trained model, we use the test set data to measure the coefficient of determination, R 2 The performance of the model is evaluated based on the following. Of these, prediction model 1:R 2 = 0.874, and prediction model 2: R 2 =0.893.

[0049] (2) Utilize established models to measure the comprehensive toxicity of wastewater.

[0050] (a) The measurement sewage sample is actual influent from a municipal sewage treatment plant. (2.1a) Measurement of behavioral toxicity indexes: Zebrafish embryos were used to measure the behavioral toxicity indexes of the sewage samples used for the experiment. Ten parallel groups were set up for each water sample, and the obtained behavioral toxicity index data are shown in Table 1.

[0051] [Table 1]

[0052] (2.2a) Model selection: Enter the average value of the behavioral toxicity index obtained as input data into prediction model 1, and then select the influent LC 50 =65. LC 50 <100, so LC 50 = 65 is the overall toxicity of the water sample.

[0053] (b) The test sewage sample is an actual discharge from a municipal sewage treatment plant. (2.1b) Measurement of behavioral toxicity indexes: Zebrafish embryos were used to measure the behavioral toxicity indexes of the sewage samples used for the experiment. Ten parallel groups were set up for each water sample, and the obtained behavioral toxicity index data are shown in Table 2.

[0054] [Table 2]

[0055] (2.2b) Model selection: The average values ​​of the behavioral toxicity index obtained were input into prediction model 1 as input data to calculate the LC of the effluent. 50 The result was LC = 136. 50 >100 indicates that the toxicity of the test water sample is low, and the LC 50 This means that it is not appropriate to use LC as a toxicity index. Therefore, the behavioral toxicity index parameters of the effluent water are input into prediction model 2 to obtain the comprehensive toxicity value of the water sample, LC 10 =43 was obtained.

Claims

1. Step (S1) measures zebrafish embryo toxicity indicators of sewage samples in the full process of a sewage treatment plant, including traditional toxicity indicators and behavioral toxicity indicators, and performs data preprocessing; Step (S2), taking the traditional toxicity index as the target variable and the behavioral toxicity index as the feature, to establish a comprehensive sewage toxicity prediction model based on different target variables; Step (S3): inputting the behavioral toxicity index data of zebrafish embryos in the test sewage sample into a prediction model as input data, and selecting a corresponding prediction model according to the prediction result of the target variable to obtain the comprehensive toxicity of the test sewage sample; This includes the steps: The traditional toxicity indexes include the median lethal dose (LC 50 ) and the 10% lethal dose (LC 10 ), which are obtained by observing the mortality rate of zebrafish embryos within a specific time period; The method for rapid comprehensive toxicity measurement of sewage, characterized in that the behavioral toxicity indicators include the activity of zebrafish embryos in a dark environment within a specific time period, the activity of zebrafish embryos in a bright environment within a specific time period, the total distance traveled by zebrafish embryos in a dark environment within a specific time period, the total distance traveled by zebrafish embryos in a bright environment within a specific time period, the explosion distance of zebrafish embryos within a specific time period, the travel distance of zebrafish embryos within a specific time period, and the freezing distance of zebrafish embryos within a specific time period, which are measured by a zebrafish behavior detector.

2. In the step (S2), the sewage comprehensive toxicity prediction model based on different target variables includes: 50 Select <100 sewage samples and measure the median lethal dose (LC 50 Prediction model 1 obtained by training with LC as the target variable 50 Select sewage samples with a density of ≥ 100 and measure the 10% lethal dose (LC 10 2. The method for rapid comprehensive toxicity determination of sewage as claimed in claim 1, further comprising a prediction model 2 obtained by training the above as a target variable.

3. In the step (S3), the corresponding prediction model is selected according to the prediction result of the target variable to obtain the comprehensive toxicity of the test sewage sample, The behavioral toxicity index data of the zebrafish embryos in the measurement sewage sample is input as input data to the prediction model 1, and the output value of the prediction model 1 is LC 50 If <100, the median lethal dose (LC 50 This is the overall toxicity of sewage, The output value of the prediction model 1 is LC 50 If ≧100, the 10% lethal dose LC 10 is the comprehensive toxicity of the sewage sample used for measurement, The method for rapid comprehensive toxicity determination of sewage as claimed in claim 2.

4. The method for rapid determination of comprehensive toxicity of sewage as described in claim 1, characterized in that the Lasso model is used to establish the comprehensive toxicity prediction model of sewage.

5. In establishing the comprehensive wastewater toxicity prediction model, the coefficient of determination R 2 The performance of the comprehensive wastewater toxicity prediction model is evaluated based on the coefficient of determination R 2 As a calculation method, however, is the coefficient of determination, is the value of the i-th traditional toxicity index in the test set, is the average value of traditional toxicity indices in the test set, 2. The method for rapid comprehensive toxicity determination of sewage as claimed in claim 1, wherein n is the predicted value output by the prediction model, and n is the number of traditional toxicity index values.

6. The method for rapid determination of comprehensive toxicity of sewage as described in claim 1, characterized in that the data pre-processing includes data cleaning, data standardization and feature selection.

7. The method for rapid determination of comprehensive toxicity of sewage as claimed in claim 6, characterized in that the data normalization is performed by using Z-Score method or Max-Min method.

8. The method for rapid determination of comprehensive toxicity of sewage as claimed in claim 6, wherein the feature selection method is based on Pearson correlation coefficient measurement.

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