A method and system for detecting heavy metal chromium pollution in water body

Abstract

The present application relates to the technical field of pollution detection, in particular to a water body heavy metal chromium pollution detection method and system, the method comprising the following steps: obtaining the concentration of water body dissolved organic matter, hydrogen ion concentration, oxidation-reduction potential, temperature and initial hexavalent chromium concentration and normalizing, determining the reduction reaction rate constant according to the temperature and oxidation-reduction potential, predicting the reduction rate of hexavalent chromium, the theoretical reduction amount and the theoretical residual concentration, collecting the online electrochemical concentration and the unmanned aerial vehicle hyperspectral inversion concentration and performing difference verification, respectively correcting the electrochemical concentration and the hyperspectral concentration when there is data contradiction, and fusing the two types of correction results to judge the pollution state. In the present application, by establishing a hexavalent chromium natural evolution reference and combining multi-source observation consistency verification, the electrochemical underestimation caused by organic matter passivation and the hyperspectral overestimation caused by spectral background are identified, compensation correction and background stripping are completed, and the accuracy and reliability of chromium pollution detection in complex water bodies are improved.

Description

Technical Field

[0001] This invention relates to the field of pollution detection technology, and in particular to a method and system for detecting heavy metal chromium pollution in water. Background Technology

[0002] The field of pollution detection technology mainly involves technical activities for identifying and measuring the types, contents, forms, and distribution of pollutants in environmental media. Its core aspects include sample collection point layout, sampling container cleaning and preservation, sample filtration or digestion and other pretreatment, selection of target pollutant reaction reagents, preparation of standard solutions, setting of blank and parallel samples, calibration of detection instruments, reading of detection signals, concentration conversion basis, and judgment basis related to water quality limits or emission limits. It typically covers objects such as water bodies, soil, air, solid waste and emission sources, and establishes sampling, preservation, measurement and recording processes around inorganic pollutants, organic pollutants, nutrients, suspended solids, microbial indicators and toxicity indicators.

[0003] Traditional methods for detecting heavy metal chromium pollution in water refer to methods for determining the content of total chromium, hexavalent chromium, and related chromium speciation in rivers, lakes, groundwater, industrial wastewater, or domestic sewage. The technical aspects addressed include sampling and preservation of chromium in water samples, maintenance of valence states, impurity separation, colorimetric reactions, instrument readings, and concentration calculations. Traditional methods typically involve collecting water samples at selected cross-sections and depths, storing them in acid-washed polyethylene bottles, adding nitric acid for total chromium sample preservation, and controlling the pH of hexavalent chromium samples while protecting them from light. The samples are then filtered through a membrane. Suspended particles are removed by filtration. The total chromium sample is then wet-digested using nitric acid, perchloric acid, or hydrogen peroxide. Diphenylcarbazide is then used to react with hexavalent chromium to form a purple-red complex, and the absorbance is read at a set wavelength on a spectrophotometer. Alternatively, instruments such as flame atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, or inductively coupled plasma mass spectrometry are used to read the absorption intensity, emission intensity, or ion count based on the chromium standard solution calibration curve. The concentration data required for chromium pollution detection in the water sample are recorded in conjunction with blank samples, standard samples, parallel samples, and spiked samples.

[0004] Traditional detection of heavy metal chromium in water relies on a long process involving on-site sampling and preservation, filtration and digestion, colorimetric reaction, instrument calibration and reading, and concentration conversion. The valence state is easily affected by the pH of the water sample, light, suspended particles, and coexisting impurities. Contact readings only reflect the local state at the sampling point, making it difficult to reflect changes in the wide distribution area in a timely manner. In complex water bodies, natural active components such as organic matter can change the form of chromium and interfere with the spectral response, resulting in underestimation or overestimation of the chromium. When monitoring data are contradictory, there is a lack of unified verification criteria, and the judgment of the true pollution state is delayed and unreliable. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and to propose a method and system for detecting heavy metal chromium pollution in water.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for detecting heavy metal chromium pollution in water, comprising the following steps: S1: Obtain the concentration of dissolved organic matter, hydrogen ion concentration, redox potential, water temperature and initial hexavalent chromium concentration in the water body during the current time period, and normalize the concentration of dissolved organic matter, hydrogen ion concentration and initial hexavalent chromium concentration in the water body to generate normalized values ​​of organic matter concentration, hydrogen ion concentration and initial hexavalent chromium concentration in the water body respectively. S2: Determine the water body reduction reaction rate constant based on the water body temperature and redox potential; determine the hexavalent chromium reduction rate based on the water body reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration; determine the theoretical hexavalent chromium reduction amount based on the hexavalent chromium reduction rate and the preset time interval; and evaluate and obtain the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration and the theoretical hexavalent chromium reduction amount. S3: After the preset time interval, the concentration of the first hexavalent chromium measured by the online electrochemical sensor at the same monitoring location is collected, the reflectance of the characteristic band in the hyperspectral image data of the water body collected by the UAV is extracted, and the reflectance of the characteristic band is substituted into the pre-trained concentration inversion model to obtain the concentration of the second hexavalent chromium. According to the concentration difference between the first hexavalent chromium concentration and the second hexavalent chromium concentration, when the concentration difference is greater than the preset difference threshold, a data contradiction marker signal is generated. S4: Based on the data contradiction marker signal, when the first hexavalent chromium concentration is less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold, it is determined that the online electrochemical sensor is subject to organic matter passivation interference. The sensor measurement attenuation compensation amount is calculated based on the dissolved organic matter concentration in the water and the theoretical hexavalent chromium reduction amount. The first hexavalent chromium concentration is summed with the measurement attenuation compensation amount to obtain the electrochemical correction concentration. When the first hexavalent chromium concentration is not less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, it is determined that the electrochemical sensor is not significantly interfered with, and the first hexavalent chromium concentration is directly used as the electrochemical correction concentration. S5: Based on the data contradiction marker signal, when the concentration of the second hexavalent chromium is greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold, background interference source removal is performed using the hyperspectral image data of the water body and the concentration of dissolved organic matter in the water body to generate a hyperspectral correction concentration; when the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water body being greater than the preset organic matter concentration threshold are not met, it is determined that the hyperspectral data is not significantly affected by background interference, and the second hexavalent chromium concentration is directly used as the hyperspectral correction concentration; the average concentration reference value is calculated using the electrochemical correction concentration and the hyperspectral correction concentration, and the pollution status is judged based on the average concentration reference value to obtain the detection result of heavy metal chromium pollution in the water body.

[0007] The present invention is improved in that the step of obtaining the normalized value of the initial hexavalent chromium concentration in the water body is specifically as follows: S111: Collect the concentration of dissolved organic matter in the water, the concentration of hydrogen ions in the water, the redox potential of the water, the temperature of the water, and the initial concentration of hexavalent chromium in the water during the current time period; S112: Extract the maximum and minimum dissolved organic matter concentrations, maximum and minimum hydrogen ion concentrations, and maximum and minimum initial hexavalent chromium concentrations of the current water body within a preset historical period to obtain historical extreme value parameters; S113: Call the historical extreme value parameters, substitute the concentration of dissolved organic matter in the water, the concentration of hydrogen ions in the water, and the initial concentration of hexavalent chromium in the water into the range normalization function, and calculate the ratio of the difference to the range by combining the corresponding maximum and minimum values, to generate the normalized values ​​of organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration mapped to the [0,1] interval.

[0008] The present invention is improved in that the step of obtaining the theoretical remaining hexavalent chromium concentration is specifically as follows: S211: Extract the water reduction reaction rate constant based on the water temperature and water redox potential. Then, based on the water reduction reaction rate constant, the normalized initial hexavalent chromium concentration, the normalized organic matter concentration, and the normalized hydrogen ion concentration, use the following formula: ; Calculate the reduction rate of hexavalent chromium; in, This represents the reduction rate of the hexavalent chromium. This represents the rate constant of the reduction reaction in the water body. This represents the normalized value of the initial hexavalent chromium concentration in the water body. This represents the pre-defined first reaction order. This represents the normalized value of the organic matter concentration. This represents the pre-defined second reaction order. This represents the normalized value of the hydrogen ion concentration. This represents the pre-defined third reaction order; S212: Call a preset time interval, calculate the theoretical amount of hexavalent chromium reduction based on the hexavalent chromium reduction rate and the preset time interval, and calculate the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration in the water and the theoretical amount of hexavalent chromium reduction.

[0009] The present invention is improved in that the formula for calculating the theoretical residual hexavalent chromium concentration is as follows: ; in, Represents the theoretical concentration of remaining hexavalent chromium. This represents the initial concentration of hexavalent chromium in the water body. This represents the preset time interval.

[0010] The present invention is improved in that the step of obtaining the data contradiction marker signal is specifically as follows: S311: Collect the concentration of hexavalent chromium measured by the online electrochemical sensor at the same monitoring location after the preset time interval, and the water body hyperspectral image data collected by the UAV to obtain the water body multi-source signal detection parameters; S312: Extract the hyperspectral characteristic band reflectance from the multi-source signal detection parameters of the water body, substitute it into the preset concentration inversion model to obtain the second hexavalent chromium concentration, calculate the absolute concentration deviation between the first hexavalent chromium concentration and the second hexavalent chromium concentration, and obtain the concentration difference value. S313: Obtain a preset difference threshold, compare the concentration difference value with the preset difference threshold, determine the contradictory state parameter when the concentration difference value is greater than the preset difference threshold, and generate a data contradiction marker signal.

[0011] The present invention is improved in that the difference threshold is set in the following way: Multiple sets of hexavalent chromium concentration control samples were collected from historical synchronous environmental monitoring data using online electrochemical sensors and hyperspectral equipment in water bodies that meet pollution management requirements. The absolute deviation values ​​between each set of control samples were calculated. Statistical analysis was performed on the multiple sets of absolute deviation values ​​to generate a probability distribution interval for equipment measurement deviation. The upper confidence limit boundary value in the probability distribution interval was extracted, and the upper confidence limit boundary value was weighted and summed with the calibration error tolerance of the online electrochemical sensor to obtain the difference threshold.

[0012] The present invention is improved in that the step of obtaining the electrochemical correction concentration is specifically as follows: S411: Obtain the first hexavalent chromium concentration and the theoretical remaining hexavalent chromium concentration when the data contradiction marker signal is generated; call the preset organic matter concentration threshold; when the first hexavalent chromium concentration is less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, extract the corresponding first hexavalent chromium concentration and dissolved organic matter concentration in the water to obtain the electrochemical compensation trigger parameter; when the first hexavalent chromium concentration is not less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, generate the parameter to maintain the original value; S412: Call the electrochemical compensation trigger parameter, construct the sensor measurement attenuation compensation amount using the concentration of dissolved organic matter in the water and the theoretical reduction amount of hexavalent chromium, sum the first hexavalent chromium concentration and the sensor measurement attenuation compensation amount to generate the electrochemical correction concentration; for the parameter to maintain the original value, directly assign the first hexavalent chromium concentration as the electrochemical correction concentration.

[0013] The present invention is improved in that the method for setting the organic matter concentration threshold is as follows: The distribution data of hexavalent chromium reduction rate at different dissolved organic matter concentrations in the current historical monitoring records of the water body are collected. A reaction kinetic mapping curve between dissolved organic matter concentration and reduction rate is constructed. The mapping curve is analyzed to extract the inflection point where the reduction rate increases. The dissolved organic matter concentration value corresponding to the inflection point is extracted as the interference critical reference value. The interference critical reference value is smoothed and corrected by combining the average natural background organic matter content of the target water body under normal conditions to generate an organic matter concentration threshold.

[0014] The present invention is improved in that the steps for obtaining the detection results of heavy metal chromium pollution in the water are specifically as follows: S511: Based on the data contradiction marker signal, the concentration of the second hexavalent chromium and the theoretical remaining hexavalent chromium concentration are numerically compared. When the concentration of the second hexavalent chromium is greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, the hyperspectral image data of the water body is mapped to a mixed signal observation value, and the concentration of dissolved organic matter in the water body is mapped to a background interference source component, thereby obtaining a hyperspectral unmixing parameter set containing the mixed signal observation value and the background interference source component; when the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, a background interference-free parameter is generated. S512: For the hyperspectral unmixing parameter set, the independent target signal component between the observed mixed signal value and the background interference source component is calculated using the independent component analysis algorithm, and the target substance concentration is converted to obtain the hyperspectral corrected concentration; for the background interference-free parameter, the second hexavalent chromium concentration is directly assigned and output as the hyperspectral corrected concentration. S513: Calculate the average concentration reference value based on the electrochemical correction concentration and the hyperspectral correction concentration, map the average concentration reference value to the preset pollution division interval, determine the pollution status, and generate the water heavy metal chromium pollution detection result.

[0015] A system for detecting chromium pollution in water, the system being used to implement the aforementioned method for detecting chromium pollution in water, the system comprising: The multi-dimensional element sensing module acquires the concentration of dissolved organic matter, hydrogen ion concentration, redox potential, water temperature, and initial hexavalent chromium concentration in the water body during the current time period. It then normalizes the concentrations of dissolved organic matter, hydrogen ion, and initial hexavalent chromium to generate normalized values ​​for organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration, respectively. The kinetic evolution prediction module determines the water body reduction reaction rate constant based on the water temperature and redox potential, determines the hexavalent chromium reduction rate based on the water body reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration, determines the theoretical hexavalent chromium reduction amount based on the hexavalent chromium reduction rate and the preset time interval, and evaluates and obtains the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration and the theoretical hexavalent chromium reduction amount. The observation consistency verification module collects the concentration of the first hexavalent chromium measured by the online electrochemical sensor at the same monitoring location after the preset time interval, extracts the characteristic band reflectance from the water hyperspectral image data collected by the UAV, and substitutes the characteristic band reflectance into the pre-trained concentration inversion model to invert the concentration of the second hexavalent chromium. Based on the concentration difference between the first hexavalent chromium concentration and the second hexavalent chromium concentration, when the concentration difference is greater than the preset difference threshold, a data contradiction marker signal is generated. The mechanism deviation compensation module, based on the data contradiction marker signal, determines that the online electrochemical sensor is subject to organic matter passivation interference when the first hexavalent chromium concentration is less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold. It then calculates the sensor measurement attenuation compensation amount based on the dissolved organic matter concentration in the water and the theoretical hexavalent chromium reduction amount, and sums the first hexavalent chromium concentration with the measurement attenuation compensation amount to obtain the electrochemical correction concentration. If the conditions of the first hexavalent chromium concentration being less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, it determines that the electrochemical sensor is not significantly interfered with, and directly uses the first hexavalent chromium concentration as the electrochemical correction concentration. The image decoupling and fusion decision module, based on the data contradiction marker signal, performs background interference source removal using the water hyperspectral image data and the water dissolved organic matter concentration after a preset time interval when the second hexavalent chromium concentration is greater than the theoretical remaining hexavalent chromium concentration and the water dissolved organic matter concentration obtained after a preset time interval is greater than a preset organic matter concentration threshold, generating a hyperspectral corrected concentration. When the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the water dissolved organic matter concentration obtained after a preset time interval not being met, it is determined that the hyperspectral data is not significantly affected by background interference, and the second hexavalent chromium concentration is directly used as the hyperspectral corrected concentration. The average concentration reference value is calculated using the electrochemical corrected concentration and the hyperspectral corrected concentration, and the pollution status is judged based on the average concentration reference value to obtain the detection result of heavy metal chromium pollution in the water.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, a natural reduction prediction logic is established based on the concentration of organic matter, hydrogen ion concentration, redox potential, temperature, and initial hexavalent chromium concentration in the water body. A theoretical reference for evaluating the evolution of hexavalent chromium over time is used. The results of online electrochemical measurement and UAV hyperspectral inversion are used for discrepancy verification, so that data contradictions can be identified in a timely manner. When the electrochemical reading is low and the organic matter level is high, attenuation compensation is introduced. When the hyperspectral inversion is high and there is an organic matter background, background stripping is performed to correct contact false negatives and spectroscopic false positives. The two types of corrected concentrations are combined to form the basis for pollution judgment, thereby improving the accuracy and reliability of chromium pollution detection in complex water bodies. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a system module diagram of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Please see Figure 1 This invention provides a technical solution: a method for detecting heavy metal chromium pollution in water, comprising the following steps: S1: Obtain the concentration of dissolved organic matter, hydrogen ion concentration, redox potential, water temperature and initial hexavalent chromium concentration in the water body during the current time period. Normalize the concentration of dissolved organic matter, hydrogen ion concentration and initial hexavalent chromium concentration in the water body to generate normalized values ​​of organic matter concentration, hydrogen ion concentration and initial hexavalent chromium concentration in the water body respectively. S2: Determine the water reduction reaction rate constant based on water temperature and redox potential; determine the hexavalent chromium reduction rate based on the water reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration; determine the theoretical hexavalent chromium reduction amount based on the hexavalent chromium reduction rate and the preset time interval; and evaluate and obtain the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration and the theoretical hexavalent chromium reduction amount. S3: After a preset time interval, the concentration of hexavalent chromium measured by the online electrochemical sensor at the same monitoring location is collected. The reflectance of the characteristic band in the hyperspectral image data of the water body collected by the UAV is extracted, and the reflectance of the characteristic band is substituted into the pre-trained concentration inversion model to obtain the concentration of hexavalent chromium. Based on the concentration difference between the concentration of hexavalent chromium and the concentration of hexavalent chromium, when the concentration difference is greater than the preset difference threshold, a data contradiction marker signal is generated. S4: Based on the data contradiction marker signal, when the concentration of hexavalent chromium is less than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, it is determined that the online electrochemical sensor is affected by organic matter passivation interference. The sensor measurement attenuation compensation amount is calculated based on the concentration of dissolved organic matter in the water and the theoretical reduction amount of hexavalent chromium. The concentration of hexavalent chromium is added to the measurement attenuation compensation amount to obtain the electrochemical correction concentration. If the conditions of the concentration of hexavalent chromium being less than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, it is determined that the electrochemical sensor is not significantly affected, and the concentration of hexavalent chromium is directly used as the electrochemical correction concentration. S5: Based on the data contradiction marker signal, when the concentration of hexavalent chromium (H2) is greater than the theoretical remaining H2 concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, background interference source removal is performed using the water body hyperspectral image data and the water body dissolved organic matter concentration to generate a hyperspectral corrected concentration; when the conditions of the concentration of H2 being greater than the theoretical remaining H2 concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, it is determined that the hyperspectral data is not significantly affected by background interference, and the concentration of H2 is directly used as the hyperspectral corrected concentration; the average concentration reference value is calculated using the electrochemical corrected concentration and the hyperspectral corrected concentration, and the pollution status is judged based on the average concentration reference value to obtain the detection result of heavy metal chromium pollution in the water body.

[0020] The specific steps for obtaining the normalized value of the initial hexavalent chromium concentration in water are as follows: S111: Collect the concentration of dissolved organic matter in the water, the concentration of hydrogen ions in the water, the redox potential of the water, the temperature of the water, and the initial concentration of hexavalent chromium in the water during the current time period; Real-time monitoring data streams are received by a multi-parameter water quality sensor array deployed on an underwater fixed support within the target monitoring area, and this data stream is directly imported into the MATLAB software workspace. The collected data specifically includes: dissolved organic matter concentration (representing the total mass of dissolved organic carbon compounds in the water, reflecting the background reducing agent content); hydrogen ion concentration (representing the acid-base balance of the water, directly affecting the potential tendency of redox reactions); redox potential (indicating the tendency of the water to gain or lose electrons macroscopically); water temperature (a fundamental parameter of the water's thermodynamic state); and initial hexavalent chromium concentration (representing the level of heavy metal chromium ions at the time of measurement before further reactions occur). The input monitoring data stream is presented as a continuous floating-point time series, and the file is stored in a structured data table format. In MATLAB software, internal data preprocessing functions are called to directly remove null data points caused by sensor communication failures. A moving average filter function is used to smooth the continuous sequence to eliminate high-frequency random noise caused by physical disturbances in the water flow. A built-in standardization function is used to uniformly adjust all physical parameters to the standard normal distribution range. Through these processes, the following values ​​are obtained for a specific water body at the current time period: dissolved organic matter concentration 25.0 mg / L, hydrogen ion concentration 10⁻⁶⁵ mol / L, redox potential 300.0 mV, temperature 25.0℃, and initial hexavalent chromium concentration 0.5 mg / L.

[0021] S112: Extract the maximum and minimum dissolved organic matter concentrations, maximum and minimum hydrogen ion concentrations, and maximum and minimum initial hexavalent chromium concentrations of the current water body within a preset historical period to obtain historical extreme value parameters; A connection was established with an environmental monitoring relational database in the MATLAB software environment to retrieve a 30-day continuously stored multidimensional water quality feature dataset. The 30-day preset historical period was determined by retrieving the measured water level and flow velocity curves from hydrological stations in the target water area over the past five years. Through time series autocorrelation function calculations, it was found that a complete cycle of alternating extreme values ​​of various hydrological physical characteristics constitutes a 30-day period, which was thus used as a reference window for the normal fluctuation limit. The sets of dissolved organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration in the water body stored within this time span were extracted. The software's sorting function was used to perform ascending sorting of the values ​​in each one-dimensional array set, extracting the minimum value at the beginning of the array and the maximum value at the end. The maximum soluble organic matter concentration was 40.0 mg / L, the minimum soluble organic matter concentration was 10.0 mg / L, the maximum hydrogen ion concentration was 10⁻⁵ mol / L, the minimum hydrogen ion concentration was 10⁻⁸ mol / L, the maximum initial hexavalent chromium concentration was 1.0 mg / L, and the minimum initial hexavalent chromium concentration was 0.1 mg / L. These were used to obtain the historical extreme values.

[0022] S113: Call the historical extreme value parameters, substitute the concentration of dissolved organic matter, the concentration of hydrogen ions, and the initial concentration of hexavalent chromium in the water into the range normalization function, and calculate the ratio of the difference to the range by combining the corresponding maximum and minimum values, and generate the normalized values ​​of organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration mapped to the [0,1] interval. In the MATLAB workspace, retrieve the acquired historical extreme value parameters, and substitute the aforementioned concentration data and their corresponding historical maximum and minimum values ​​into the normalization formula for calculation. Using the formula: ; Substituting the dissolved organic matter concentrations of 25.0 mg / L, 10.0 mg / L (minimum), and 40.0 mg / L (maximum), the normalized value of the organic matter concentration was calculated to be 0.5. Using the formula: ; Substituting the relevant values ​​for the hydrogen ion concentration in the water, a normalized value of 0.5 for the hydrogen ion concentration is calculated. Using the formula: ; Substituting the initial hexavalent chromium concentration of 0.5 mg / L, the minimum initial hexavalent chromium concentration of 0.1 mg / L, and the maximum initial hexavalent chromium concentration of 1.0 mg / L into the equation, the normalized value of the initial hexavalent chromium concentration in the water body was calculated to be 0.44.

[0023] The specific steps for obtaining the theoretical residual hexavalent chromium concentration are as follows: S211: The rate constant of the water reduction reaction is extracted based on water temperature and water redox potential. Based on the water reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration, the following formula is used: ; Calculate the reduction rate of hexavalent chromium; in, Represents the reduction rate of hexavalent chromium. Represents the rate constant of the reduction reaction in water. This represents the normalized value of the initial hexavalent chromium concentration in the water body. This represents the pre-defined first reaction order. Represents the normalized value of organic matter concentration. This represents the pre-defined second reaction order. This represents the normalized value of hydrogen ion concentration. This represents the pre-defined third reaction order; The water temperature (25.0℃) and redox potential (300.0mV) were used. A two-dimensional lookup table of thermodynamic reaction constants, pre-prepared through laboratory multiple temperature and potential gradient titration experiments, was imported into MATLAB. A two-dimensional interpolation algorithm was used to retrieve matching constant values, and the water reduction reaction rate constant was extracted to be 0.1. Dissolved organic matter in the water acts as electron donors under specific pH and redox potential conditions, reducing highly oxidizing hexavalent chromium ions to less toxic trivalent chromium ions. The obtained normalized parameters were substituted into the kinetic equation. The formula was then used: ; The complete process of setting the first reaction order *a*, the second reaction order *b*, and the third reaction order *c* in the formula is as follows: Import 5000 sets of measured historical samples from the past three years, containing initial hexavalent chromium, organic matter, hydrogen ions, and corresponding reduction rates, into MATLAB software. Use the nonlinear least squares toolbox to fit the multivariate power function equation, and determine the exponential weights of each variable that minimize the sum of squared residuals. Based on this, set the first reaction order *a* to 1.0, the second reaction order *b* to 0.5, and the third reaction order *c* to 0.5. Assign the water reduction reaction rate constant *k* to 0.1, the normalized value of the initial hexavalent chromium concentration *V* to 0.44, the normalized value of the organic matter concentration *M* to 0.5, and the normalized value of the hydrogen ion concentration *H* to 0.5. Perform the product operation to calculate the hexavalent chromium reduction rate *R* as 0.022 mg / (L·h).

[0024] S212: Call the preset time interval, calculate the theoretical amount of hexavalent chromium reduction based on the hexavalent chromium reduction rate and the preset time interval, and calculate the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration in the water and the theoretical amount of hexavalent chromium reduction. The specific formula for calculating the theoretical residual hexavalent chromium concentration is as follows: ; in, Represents the theoretical concentration of remaining hexavalent chromium. This represents the initial concentration of hexavalent chromium in the water. Represents a preset time interval; Extract the value of the preset time interval. The complete process of setting this preset time interval is as follows: Add 0.5 mg / L hexavalent chromium and 20.0 mg / L organic matter to a constant temperature laboratory water bath to prepare the reaction stock solution. Record the concentration every 10 minutes using a high-precision potentiometric titrator, and plot the time-concentration decrease curve. Extract the time point when the derivative of the curve first approaches stability and the cumulative change in concentration just reaches the sensor detection limit of 0.01 mg / L. At this point, the preset time interval is set to 2.0 hours. Using the formula: ; The initial hexavalent chromium concentration (I) in the water was assigned a value of 0.5 mg / L, the hexavalent chromium reduction rate (R) was assigned a value of 0.022 mg / (L·h), and the preset time interval (T) was assigned a value of 2.0 hours. The formula was executed in MATLAB, and the theoretical total amount of hexavalent chromium consumed by the reduction reaction within this time span was subtracted to obtain the theoretical remaining hexavalent chromium concentration (L) of 0.456 mg / L.

[0025] The specific steps for obtaining the data contradiction marker signal are as follows: S311: Collect the concentration of hexavalent chromium measured by the online electrochemical sensor at the same monitoring location after a preset time interval, and the water body hyperspectral image data collected by the UAV to obtain the multi-source signal detection parameters of the water body; After a time interval, real-time electrolysis current signals are read from an online electrochemical sensor at the same geographic coordinate monitoring location. The online electrochemical sensor, operating on the principle that the intensity of the redox current under fixed voltage excitation is proportional to the target ion concentration, converts the measured current response value into the concentration of hexavalent chromium (0.4 mg / L) using an internal calibration curve. Simultaneously, hyperspectral image data of the water body, synchronously captured by a pushbroom hyperspectral camera mounted on a UAV along a predetermined flight path over the target water area, is imported into the MATLAB software environment. The hyperspectral image data is in a multi-band image storage format, and the data type is a three-dimensional floating-point tensor containing two-dimensional spatial pixels and one-dimensional continuous spectral bands. In MATLAB, radiometric calibration is performed by multiplying the hyperspectral image data matrix by calibration coefficients to convert the digital quantization values ​​into spectral radiance. The minimum value of the near-infrared band is used as the atmospheric background color to subtract all bands to eliminate additive noise interference from aerosol scattering. Invalid null pixels at the edges of the matrix, caused by water surface reflection and resulting in brightness saturation, are identified and removed. The multi-source signal detection parameters of the water body are then extracted and processed.

[0026] S312: Extract the hyperspectral characteristic band reflectance from the multi-source signal detection parameters of the water body, substitute it into the preset concentration inversion model to obtain the concentration of the second hexavalent chromium, calculate the absolute concentration deviation between the concentration of the first hexavalent chromium and the concentration of the second hexavalent chromium, and obtain the concentration difference value. In MATLAB, the multi-source signal detection parameters of the water body are sliced ​​along the spectral dimension, and the reflectance numerical sequence with the center wavelength at 570nm is extracted. The 570nm band is chosen as the characteristic wavelength because hexavalent chromium complex ions exhibit a strong spectral energy absorption valley at this location. The extracted characteristic band reflectance is then fed into a pre-set concentration inversion model. The pre-set parameters and training process of the inversion model are as follows: 10,000 sets of hyperspectral reflectance vectors collected during water quality inspections of the target water area over the past three years are used as the training set, along with the corresponding pairs of actual hexavalent chromium concentrations measured by manual sampling and testing. In MATLAB's deep learning toolbox, mean squared error is used as the loss function, and an adaptive moment estimation optimization algorithm is used to continuously update the network weights through backpropagation until the loss function converges to below 0.001. The input layer receives a one-dimensional tensor of the characteristic band reflectance. The first hidden layer is a one-dimensional convolutional layer containing 32 one-dimensional convolutional kernels of size 3. These kernels establish a sliding connection with the input tensor to create a local receptive field, extracting local spectral absorption features. A max-pooling layer then performs downsampling to preserve salient features. A modified linear unit activation function (MRU) is used for activation. The second hidden layer is a fully connected layer with 128 neurons, establishing a non-linear mapping relationship. The MRU is also used for activation. The output layer is a single neuron that uses a linear activation function to output the result. Taking the reflectance of the current feature band as input, it outputs a predicted value of 0.45 mg / L for the second hexavalent chromium concentration. Using the formula: ; Substituting the concentrations of hexavalent chromium (0.4) and hexavalent chromium (0.45) into the equations and calculating the absolute values ​​in MATLAB, the concentration difference was found to be 0.05 mg / L.

[0027] S313: Obtain a preset difference threshold, compare the concentration difference value with the preset difference threshold, determine the contradictory state parameter when the concentration difference value is greater than the preset difference threshold, and generate a data contradiction marker signal; The difference threshold is set as follows: Multiple sets of hexavalent chromium concentration control samples were collected from historical synchronous environmental monitoring data using online electrochemical sensors and hyperspectral equipment in water bodies that meet pollution management requirements. The absolute deviation values ​​between each set of control samples were calculated. Statistical analysis was performed on the multiple sets of absolute deviation values ​​to generate a probability distribution interval for the equipment measurement deviation. The upper confidence limit boundary value in the probability distribution interval was extracted. The upper confidence limit boundary value was then weighted and summed with the calibration error tolerance of the online electrochemical sensor to obtain the difference threshold. One hundred control samples of hexavalent chromium concentration were extracted from the database, measured simultaneously by online electrochemical sensors and hyperspectral equipment under the same water body conditions that meet pollution management requirements. In MATLAB, the absolute value of the difference between the measurements from the two devices in each control sample was calculated. A normal distribution probability density curve was fitted to these 100 absolute deviation values ​​using mean and standard deviation functions. The upper confidence limit boundary value corresponding to the cumulative probability reaching 95% was obtained by inverse operation of the cumulative distribution function. The sensor calibration error tolerance values ​​provided by the equipment manufacturers with their products were also extracted. The complete process for setting the preset difference threshold was as follows: combining the reliability scores of devices based on different principles, the statistically based upper confidence limit boundary value of hyperspectral measurement was assigned a weight of 0.6, and the error tolerance of direct electrochemical calibration was assigned a weight of 0.4. The weighted sum of the two values ​​yielded a preset difference threshold of 0.03 mg / L. The concentration difference value is compared with the preset difference threshold. In the current case, the concentration difference value of 0.05 is greater than the preset difference threshold of 0.03. The data from different detection devices have logical conflicts, and it is determined that there is a contradictory state parameter between the data of the devices, generating a data contradiction marker signal. If the concentration difference value is less than or equal to the preset difference threshold, the data is determined to be consistent, and the current anomaly diagnosis process is terminated.

[0028] The specific steps for obtaining the electrochemical correction concentration are as follows: S411: Obtain the concentration of the first hexavalent chromium and the theoretical remaining hexavalent chromium concentration when the data contradiction marker signal is generated. Call the preset organic matter concentration threshold. When the concentration of the first hexavalent chromium is less than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, extract the corresponding concentration of the first hexavalent chromium and the concentration of dissolved organic matter in the water to obtain the electrochemical compensation trigger parameter. When the conditions of the first hexavalent chromium concentration being less than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, generate the parameter to maintain the original value. The method for setting the organic matter concentration threshold is as follows: The distribution data of hexavalent chromium reduction rate under different dissolved organic matter concentrations in the current historical monitoring records of water bodies were collected. A reaction kinetic mapping curve between dissolved organic matter concentration and reduction rate was constructed. The mapping curve was analyzed to extract the inflection point where the reduction rate increases. The dissolved organic matter concentration value corresponding to the inflection point was extracted as the interference critical reference value. The interference critical reference value was smoothed and corrected by combining the average natural background organic matter content of the target water body under normal conditions to generate an organic matter concentration threshold. When a data discrepancy signal appears, the concentration of the first hexavalent chromium (0.4 mg / L) and the theoretical remaining hexavalent chromium concentration (0.456 mg / L) are retrieved. The complete process for setting the preset organic matter concentration threshold is as follows: Discrete sample points of hexavalent chromium reduction rate distributed at multiple different dissolved organic matter concentrations are retrieved from the historical monitoring database. In the MATLAB workspace, a smooth mapping curve with dissolved organic matter concentration as the independent variable and reduction rate as the dependent variable is generated using a cubic spline interpolation algorithm. The first derivative vector of the curve is obtained using the difference operator. The coordinates of the local extreme point where the value changes abruptly from flat to steep is located in the derivative vector. The dissolved organic matter concentration value corresponding to the horizontal axis of this point is extracted as the critical reference quantity for interference. At the same time, the average natural background organic matter content of the water body is obtained from the records of the pollution-free period. The average natural background organic matter content is added to the critical reference quantity for interference and then divided by 2 for smoothing correction, resulting in a preset organic matter concentration threshold of 20.0 mg / L. The real-time dissolved organic matter concentration value of the water body after the time interval is obtained as 25.0 mg / L. Comparing the parameters, the current concentration of hexavalent chromium (0.4) is less than the theoretical remaining concentration of hexavalent chromium (0.456), and the concentration of dissolved organic matter in the water (25.0) is greater than the preset organic matter concentration threshold of 20.0. This indicates that the surface of the electrochemical sensor probe is passivated due to the adsorption of high concentrations of organic matter. The concentration of hexavalent chromium and the concentration of dissolved organic matter in the water are extracted and packaged to obtain the electrochemical compensation trigger parameter. If the concentration of hexavalent chromium is greater than or equal to the theoretical remaining concentration of hexavalent chromium, or the concentration of dissolved organic matter in the water is less than or equal to the preset organic matter concentration threshold, it indicates that the probe is not significantly disturbed, and the parameter that maintains the original value is generated.

[0029] S412: Call the electrochemical compensation trigger parameter, construct the sensor measurement attenuation compensation amount using the concentration of dissolved organic matter in the water and the theoretical reduction amount of hexavalent chromium, sum the first hexavalent chromium concentration and the sensor measurement attenuation compensation amount to generate the electrochemical correction concentration; for the parameter that maintains the original value, the first hexavalent chromium concentration is directly assigned and output as the electrochemical correction concentration. To address the different scenarios described above, when generating the electrochemical compensation trigger parameters, the dissolved organic matter concentration in the water was set to 25.0 mg / L, and the theoretical hexavalent chromium reduction capacity to be 0.044 mg / L. The complete process for setting the pre-calibrated empirical attenuation coefficient involved preparing a gradient sample of organic matter interference solution with concentrations ranging from 5.0 mg / L to 50.0 mg / L in 5.0 mg / L steps in the laboratory. An electrochemical probe of the same model was immersed in this sample, and the percentage decrease in current under a stable excitation voltage was recorded. In MATLAB, the slope correlated with the increase in concentration and the decrease in current was calculated using a linear regression function. The average value of this slope was set as the empirical attenuation coefficient of 0.05. The formula used was: ; Substituting the data, the calculated sensor measurement attenuation compensation is 0.055 mg / L. Using the formula: ; Substituting the hexavalent chromium concentration of 0.4 and the attenuation compensation of 0.055 into the sum, the electrochemically corrected concentration is 0.455 mg / L. If the original parameter is maintained, the hexavalent chromium concentration is not adjusted and is directly assigned as the output electrochemically corrected concentration.

[0030] The specific steps for obtaining the detection results of heavy metal chromium pollution in water are as follows: S511: Based on the data contradiction marker signal, the concentration of the second hexavalent chromium is numerically compared with the theoretical remaining hexavalent chromium concentration. When the concentration of the second hexavalent chromium is greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold, the hyperspectral image data of the water body is mapped to the mixed signal observation value, and the concentration of dissolved organic matter in the water body is mapped to the background interference source component, thus obtaining a hyperspectral unmixing parameter set containing the mixed signal observation value and the background interference source component; when the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, background interference-free parameters are generated. The subsequent judgment is activated based on the data contradiction marker signal, extracting the concentration of hexavalent chromium (0.45 mg / L) and the theoretical remaining hexavalent chromium concentration (0.456 mg / L). The current concentration of hexavalent chromium (0.45 mg / L) is less than the theoretical remaining hexavalent chromium concentration (0.456 mg / L), indicating that the optical image is not affected by optical scattering pseudo-enhancement caused by suspended organic matter particles, and no significant background interference is generated, resulting in a background interference-free parameter. If the concentration of hexavalent chromium (0.45 mg / L) is greater than the theoretical remaining hexavalent chromium concentration, and the concentration of dissolved organic matter in the water is greater than a preset organic matter concentration threshold, the three-dimensional data matrix of the hyperspectral image will be flattened into a two-dimensional matrix in MATLAB according to the spatial dimension, serving as the mixed signal observation value. The scalar value of the dissolved organic matter concentration in the water will be copied and expanded into a matrix of the corresponding size, serving as the background interference source component. The two matrices will be merged to obtain the hyperspectral unmixing parameter set.

[0031] S512: For the hyperspectral unmixing parameter set, the independent target signal component between the observed mixed signal value and the background interference source component is calculated by the independent component analysis algorithm, and the target substance concentration is converted to obtain the hyperspectral corrected concentration; for the background interference-free parameter, the second hexavalent chromium concentration is directly assigned and output as the hyperspectral corrected concentration. For hyperspectral data processing, to generate parameters without background interference, the concentration of hexavalent chromium (0.45 mg / L) is retrieved and directly retained, then output as the hyperspectral corrected concentration. For hyperspectral unmixing parameter sets, a fast independent component analysis blind source separation algorithm is called in MATLAB. The mixed signal observation matrix is ​​extracted, and mean centering and eigenvalue decomposition whitening operations are performed. The background interference source component matrix is ​​added as a fixed prior space constraint to the negative entropy maximization iterative objective function. The weight vector is repeatedly updated until convergence to obtain the separation matrix. The separation matrix is ​​multiplied by the mixed signal observation values ​​to calculate the independent target signal components after removing background interference. The complete process of setting the spectral absorbance conversion coefficient is as follows: the absorbance of a series of hexavalent chromium standard solutions of known concentrations is measured using a spectrophotometer. A concentration-absorbance standard curve is plotted in MATLAB, and the reciprocal of the slope of the linear portion of the curve is extracted and set as the spectral absorbance conversion coefficient. The independent target signal components are multiplied by this coefficient to convert them into substance concentrations, resulting in the hyperspectral corrected concentration.

[0032] S513: Calculate the average concentration reference value based on the electrochemical correction concentration and the hyperspectral correction concentration, map the average concentration reference value to the preset pollution division interval, determine the pollution status, and generate the detection results of heavy metal chromium pollution in the water. The obtained electrochemically corrected concentration was 0.455 mg / L, and the hyperspectral corrected concentration was 0.45 mg / L. Using the formula: ; Arithmetic operations were performed in the MATLAB workspace to calculate the average concentration reference value as 0.4525 mg / L. The complete process of setting the preset pollution classification intervals was as follows: the national standard "Surface Water Environmental Quality Standard" (GB 3838—2002) was consulted, and the standard limit value of "chromium (hexavalent)" was used as the reference basis for determining the water pollution status. In this standard, the limit value of chromium (hexavalent) for Class I water bodies is 0.01 mg / L, the limit value for Class II, III and IV water bodies is 0.05 mg / L, and the limit value for Class V water bodies is 0.1 mg / L. In combination with the classification requirements of this scheme for the degree of heavy metal chromium pollution in water bodies, 0.1 mg / L was set as the reference boundary for determining the unpolluted state and the polluted state, and 0.5 mg / L was set as the starting boundary for the heavily polluted state. If the average concentration reference value is greater than or equal to 0.0 mg / L and less than or equal to 0.1 mg / L, the water body is judged to be in a state of no pollution; if the average concentration reference value is greater than 0.1 mg / L and less than or equal to 0.5 mg / L, it is judged to be in a state of slight pollution; if the average concentration reference value is greater than 0.5 mg / L, it is judged to be in a state of heavy pollution. In the current example, the average concentration reference value is 0.4525 mg / L, which is within the range of 0.1 mg / L to 0.5 mg / L. The state is determined, and the water body heavy metal chromium pollution detection results containing the conclusion of slight pollution are generated and output.

[0033] Please see Figure 2 A system for detecting chromium pollution in water, the system being used to implement the aforementioned method for detecting chromium pollution in water, the system comprising: The multi-dimensional element sensing module obtains the concentration of dissolved organic matter, hydrogen ion concentration, redox potential, water temperature, and initial hexavalent chromium concentration in the water body during the current time period. It then normalizes the concentrations of dissolved organic matter, hydrogen ion, and initial hexavalent chromium in the water body to generate normalized values ​​for organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration, respectively. The kinetic evolution prediction module determines the water reduction reaction rate constant based on water temperature and redox potential, determines the hexavalent chromium reduction rate based on the water reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration, determines the theoretical hexavalent chromium reduction amount based on the hexavalent chromium reduction rate and the preset time interval, and evaluates and obtains the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration and the theoretical hexavalent chromium reduction amount. The observation consistency verification module collects the concentration of hexavalent chromium measured by the online electrochemical sensor at the same monitoring location after a preset time interval, extracts the characteristic band reflectance from the water hyperspectral image data collected by the UAV, and substitutes the characteristic band reflectance into the pre-trained concentration inversion model to obtain the concentration of hexavalent chromium. Based on the concentration difference between the concentration of hexavalent chromium and the concentration of hexavalent chromium, when the concentration difference is greater than the preset difference threshold, a data contradiction marker signal is generated. The mechanism deviation compensation module, based on the data contradiction marker signal, determines that the online electrochemical sensor is subject to organic matter passivation interference when the concentration of hexavalent chromium is less than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold. It then calculates the sensor measurement attenuation compensation amount based on the concentration of dissolved organic matter in the water and the theoretical reduction amount of hexavalent chromium, and sums the concentration of hexavalent chromium with the measurement attenuation compensation amount to obtain the electrochemical correction concentration. If the conditions of "the concentration of hexavalent chromium being less than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold" are not met, the module determines that the electrochemical sensor is not significantly interfered with, and directly uses the concentration of hexavalent chromium as the electrochemical correction concentration. The spectral decoupling and fusion decision module, based on the data contradiction marker signal, performs background interference source removal using the water hyperspectral image data and the water dissolved organic matter concentration after a preset time interval when the concentration of hexavalent chromium (HCI) is greater than the theoretical remaining HCI concentration and the concentration of dissolved organic matter in the water after a preset time interval is greater than a preset organic matter concentration threshold, generating a hyperspectral corrected concentration. If the conditions of the concentration of HCI being greater than the theoretical remaining HCI concentration and the concentration of dissolved organic matter in the water after a preset time interval not being met, it is determined that the hyperspectral data is not significantly affected by background interference, and the concentration of HCI is directly used as the hyperspectral corrected concentration. The average concentration reference value is calculated using the electrochemical corrected concentration and the hyperspectral corrected concentration, and the pollution status is judged based on the average concentration reference value to obtain the detection result of heavy metal chromium pollution in the water.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for detecting heavy metal chromium pollution in water, characterized in that, Includes the following steps: S1: Obtain the concentration of dissolved organic matter, hydrogen ion concentration, redox potential, water temperature and initial hexavalent chromium concentration in the water body during the current time period, and normalize the concentration of dissolved organic matter, hydrogen ion concentration and initial hexavalent chromium concentration in the water body to generate normalized values ​​of organic matter concentration, hydrogen ion concentration and initial hexavalent chromium concentration in the water body respectively. S2: Determine the water body reduction reaction rate constant based on the water body temperature and redox potential; determine the hexavalent chromium reduction rate based on the water body reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration; determine the theoretical hexavalent chromium reduction amount based on the hexavalent chromium reduction rate and the preset time interval; and evaluate and obtain the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration and the theoretical hexavalent chromium reduction amount. S3: After the preset time interval, the concentration of the first hexavalent chromium measured by the online electrochemical sensor at the same monitoring location is collected, the reflectance of the characteristic band in the hyperspectral image data of the water body collected by the UAV is extracted, and the reflectance of the characteristic band is substituted into the pre-trained concentration inversion model to obtain the concentration of the second hexavalent chromium. According to the concentration difference between the first hexavalent chromium concentration and the second hexavalent chromium concentration, when the concentration difference is greater than the preset difference threshold, a data contradiction marker signal is generated. S4: Based on the data contradiction marker signal, when the first hexavalent chromium concentration is less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold, it is determined that the online electrochemical sensor is subject to organic matter passivation interference. The sensor measurement attenuation compensation amount is calculated based on the dissolved organic matter concentration in the water and the theoretical hexavalent chromium reduction amount. The first hexavalent chromium concentration is summed with the measurement attenuation compensation amount to obtain the electrochemical correction concentration. When the first hexavalent chromium concentration is not less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, it is determined that the electrochemical sensor is not significantly interfered with, and the first hexavalent chromium concentration is directly used as the electrochemical correction concentration. S5: Based on the data contradiction marker signal, when the concentration of the second hexavalent chromium is greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold, background interference source removal is performed using the hyperspectral image data of the water body and the concentration of dissolved organic matter in the water body to generate a hyperspectral correction concentration; when the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water body being greater than the preset organic matter concentration threshold are not met, it is determined that the hyperspectral data is not significantly affected by background interference, and the second hexavalent chromium concentration is directly used as the hyperspectral correction concentration; the average concentration reference value is calculated using the electrochemical correction concentration and the hyperspectral correction concentration, and the pollution status is judged based on the average concentration reference value to obtain the detection result of heavy metal chromium pollution in the water body.

2. The method for detecting heavy metal chromium pollution in water according to claim 1, characterized in that, The specific steps for obtaining the normalized value of the initial hexavalent chromium concentration in the water body are as follows: S111: Collect the concentration of dissolved organic matter in the water, the concentration of hydrogen ions in the water, the redox potential of the water, the temperature of the water, and the initial concentration of hexavalent chromium in the water during the current time period; S112: Extract the maximum and minimum dissolved organic matter concentrations, maximum and minimum hydrogen ion concentrations, and maximum and minimum initial hexavalent chromium concentrations of the current water body within a preset historical period to obtain historical extreme value parameters; S113: Call the historical extreme value parameters, substitute the concentration of dissolved organic matter in the water, the concentration of hydrogen ions in the water, and the initial concentration of hexavalent chromium in the water into the range normalization function, and calculate the ratio of the difference to the range by combining the corresponding maximum and minimum values, to generate the normalized values ​​of organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration mapped to the [0,1] interval.

3. The method for detecting heavy metal chromium pollution in water according to claim 1, characterized in that, The specific steps for obtaining the theoretical remaining hexavalent chromium concentration are as follows: S211: Extract the water reduction reaction rate constant based on the water temperature and water redox potential. Then, based on the water reduction reaction rate constant, the normalized initial hexavalent chromium concentration, the normalized organic matter concentration, and the normalized hydrogen ion concentration, use the following formula: ； Calculate the reduction rate of hexavalent chromium; in, This represents the reduction rate of the hexavalent chromium. This represents the rate constant of the reduction reaction in the water body. This represents the normalized value of the initial hexavalent chromium concentration in the water body. This represents the pre-defined first reaction order. This represents the normalized value of the organic matter concentration. This represents the pre-defined second reaction order. This represents the normalized value of the hydrogen ion concentration. This represents the pre-defined third reaction order; S212: Call a preset time interval, calculate the theoretical amount of hexavalent chromium reduction based on the hexavalent chromium reduction rate and the preset time interval, and calculate the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration in the water and the theoretical amount of hexavalent chromium reduction.

4. The method for detecting heavy metal chromium pollution in water according to claim 3, characterized in that, The specific formula for calculating the theoretical residual hexavalent chromium concentration is as follows: ； in, Represents the theoretical concentration of remaining hexavalent chromium. This represents the initial concentration of hexavalent chromium in the water body. This represents the preset time interval.

5. The method for detecting heavy metal chromium pollution in water according to claim 1, characterized in that, The specific steps for obtaining the data contradiction marker signal are as follows: S311: Collect the concentration of hexavalent chromium measured by the online electrochemical sensor at the same monitoring location after the preset time interval, and the water body hyperspectral image data collected by the UAV to obtain the water body multi-source signal detection parameters; S312: Extract the hyperspectral characteristic band reflectance from the multi-source signal detection parameters of the water body, substitute it into the preset concentration inversion model to obtain the second hexavalent chromium concentration, calculate the absolute concentration deviation between the first hexavalent chromium concentration and the second hexavalent chromium concentration, and obtain the concentration difference value. S313: Obtain a preset difference threshold, compare the concentration difference value with the preset difference threshold, determine the contradictory state parameter when the concentration difference value is greater than the preset difference threshold, and generate a data contradiction marker signal.

6. The method for detecting heavy metal chromium pollution in water according to claim 5, characterized in that, The difference threshold is set as follows: Multiple sets of hexavalent chromium concentration control samples were collected from historical synchronous environmental monitoring data using online electrochemical sensors and hyperspectral equipment in water bodies that meet pollution management requirements. The absolute deviation values ​​between each set of control samples were calculated. Statistical analysis was performed on the multiple sets of absolute deviation values ​​to generate a probability distribution interval for equipment measurement deviation. The upper confidence limit boundary value in the probability distribution interval was extracted, and the upper confidence limit boundary value was weighted and summed with the calibration error tolerance of the online electrochemical sensor to obtain the difference threshold.

7. The method for detecting heavy metal chromium pollution in water according to claim 1, characterized in that, The specific steps for obtaining the electrochemical correction concentration are as follows: S411: Obtain the first hexavalent chromium concentration and the theoretical remaining hexavalent chromium concentration when the data contradiction marker signal is generated; call the preset organic matter concentration threshold; when the first hexavalent chromium concentration is less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, extract the corresponding first hexavalent chromium concentration and dissolved organic matter concentration in the water to obtain the electrochemical compensation trigger parameter; when the first hexavalent chromium concentration is not less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, generate the parameter to maintain the original value; S412: Call the electrochemical compensation trigger parameter, construct the sensor measurement attenuation compensation amount using the concentration of dissolved organic matter in the water and the theoretical reduction amount of hexavalent chromium, sum the first hexavalent chromium concentration and the sensor measurement attenuation compensation amount to generate the electrochemical correction concentration; for the parameter to maintain the original value, directly assign the first hexavalent chromium concentration as the electrochemical correction concentration.

8. The method for detecting heavy metal chromium pollution in water according to claim 7, characterized in that, The method for setting the organic matter concentration threshold is as follows: The distribution data of hexavalent chromium reduction rate at different dissolved organic matter concentrations in the current historical monitoring records of the water body are collected. A reaction kinetic mapping curve between dissolved organic matter concentration and reduction rate is constructed. The mapping curve is analyzed to extract the inflection point where the reduction rate increases. The dissolved organic matter concentration value corresponding to the inflection point is extracted as the interference critical reference value. The interference critical reference value is smoothed and corrected by combining the average natural background organic matter content of the target water body under normal conditions to generate an organic matter concentration threshold.

9. The method for detecting heavy metal chromium pollution in water according to claim 1, characterized in that, The specific steps for obtaining the detection results of heavy metal chromium pollution in the water are as follows: S511: Based on the data contradiction marker signal, the concentration of the second hexavalent chromium and the theoretical remaining hexavalent chromium concentration are numerically compared. When the concentration of the second hexavalent chromium is greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval is greater than the preset organic matter concentration threshold, the hyperspectral image data of the water body is mapped to a mixed signal observation value, and the concentration of dissolved organic matter in the water body is mapped to a background interference source component, thereby obtaining a hyperspectral unmixing parameter set containing the mixed signal observation value and the background interference source component; when the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the concentration of dissolved organic matter in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, a background interference-free parameter is generated. S512: For the hyperspectral unmixing parameter set, the independent target signal component between the observed mixed signal value and the background interference source component is calculated using the independent component analysis algorithm, and the target substance concentration is converted to obtain the hyperspectral corrected concentration; for the background interference-free parameter, the second hexavalent chromium concentration is directly assigned and output as the hyperspectral corrected concentration. S513: Calculate the average concentration reference value based on the electrochemical correction concentration and the hyperspectral correction concentration, map the average concentration reference value to the preset pollution division interval, determine the pollution status, and generate the water heavy metal chromium pollution detection result.

10. A system for detecting heavy metal chromium pollution in water, characterized in that, The system is used to implement the method for detecting heavy metal chromium pollution in water as described in any one of claims 1-9, the system comprising: The multi-dimensional element sensing module acquires the concentration of dissolved organic matter, hydrogen ion concentration, redox potential, water temperature, and initial hexavalent chromium concentration in the water body during the current time period. It then normalizes the concentrations of dissolved organic matter, hydrogen ion, and initial hexavalent chromium to generate normalized values ​​for organic matter concentration, hydrogen ion concentration, and initial hexavalent chromium concentration, respectively. The kinetic evolution prediction module determines the water body reduction reaction rate constant based on the water temperature and redox potential, determines the hexavalent chromium reduction rate based on the water body reduction reaction rate constant, the normalized value of the initial hexavalent chromium concentration, the normalized value of the organic matter concentration, and the normalized value of the hydrogen ion concentration, determines the theoretical hexavalent chromium reduction amount based on the hexavalent chromium reduction rate and the preset time interval, and evaluates and obtains the theoretical remaining hexavalent chromium concentration based on the initial hexavalent chromium concentration and the theoretical hexavalent chromium reduction amount. The observation consistency verification module collects the concentration of the first hexavalent chromium measured by the online electrochemical sensor at the same monitoring location after the preset time interval, extracts the characteristic band reflectance from the water hyperspectral image data collected by the UAV, and substitutes the characteristic band reflectance into the pre-trained concentration inversion model to invert the concentration of the second hexavalent chromium. Based on the concentration difference between the first hexavalent chromium concentration and the second hexavalent chromium concentration, when the concentration difference is greater than the preset difference threshold, a data contradiction marker signal is generated. The mechanism deviation compensation module, based on the data contradiction marker signal, determines that the online electrochemical sensor is subject to organic matter passivation interference when the first hexavalent chromium concentration is less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval is greater than a preset organic matter concentration threshold. It then calculates the sensor measurement attenuation compensation amount based on the dissolved organic matter concentration in the water and the theoretical hexavalent chromium reduction amount, and sums the first hexavalent chromium concentration with the measurement attenuation compensation amount to obtain the electrochemical correction concentration. If the conditions of the first hexavalent chromium concentration being less than the theoretical remaining hexavalent chromium concentration and the dissolved organic matter concentration in the water obtained after a preset time interval being greater than the preset organic matter concentration threshold are not met, it determines that the electrochemical sensor is not significantly interfered with, and directly uses the first hexavalent chromium concentration as the electrochemical correction concentration. The spectral decoupling and fusion decision module, based on the data contradiction marker signal, performs background interference source removal using the water hyperspectral image data and the water dissolved organic matter concentration after a preset time interval when the second hexavalent chromium concentration is greater than the theoretical remaining hexavalent chromium concentration and the water dissolved organic matter concentration obtained after a preset time interval is greater than a preset organic matter concentration threshold, generating a hyperspectral corrected concentration. If the conditions of the second hexavalent chromium concentration being greater than the theoretical remaining hexavalent chromium concentration and the water dissolved organic matter concentration after a preset time interval not being met, it is determined that the hyperspectral data is not significantly affected by background interference, and the second hexavalent chromium concentration is directly used as the hyperspectral corrected concentration. An average concentration reference value is calculated using the electrochemical corrected concentration and the hyperspectral corrected concentration, and the pollution status is determined based on the average concentration reference value to obtain the water heavy metal chromium pollution detection result.

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