Method for counting micro-plastics in water body

Abstract

The invention discloses a method for counting micro-plastics in a water body, and belongs to the technical field of micro-plastic counting, and the method comprises the following steps: 1, taking out a plurality of water samples from different positions of the water body to be detected, mixing the water samples, and randomly taking out quantitative water as a sample to be detected, 2, placing the obtained sample to be detected under an optical microscope for observation, step 3, identifying and marking the micro-plastics in the image according to the acquired image, counting the number of the micro-plastics in the sample according to the marking number, and determining the number of the micro-plastics in the sample according to the number of the micro-plastics in the sample according to the number of the micro-plastics in the sample. And 4, distinguishing the types of the micro-plastics in the sample, and respectively marking and counting the micro-plastics.

Description

Technical Field

[0001] The present invention relates to the technical field of microplastic counting, and more specifically, to a method for counting microplastics in water bodies. Background Art

[0002] Microplastics refer to plastic fragments with a diameter of less than 5 mm, also known as "microplastics". They are usually formed by physical or chemical decomposition of larger plastic products, which can pollute the environment, harm organisms, and undermine the stability of the ecosystem.

[0003] There are many types of microplastics, such as polyethylene, polypropylene, polyvinyl chloride and other materials, all of which will have an impact on the environment. There are a large number of microplastics in water bodies. Microplastics continue to spread with water sources, affecting the ecological environment in various places. In different water environments, due to different human production activities around them, different types of microplastic materials in the water are also different. It is difficult to determine the material proportion of microplastics, and it is difficult to make a reasonable treatment method for microplastics in water bodies. Therefore, it is necessary to provide a method for counting microplastics in water bodies to facilitate the calculation of the proportion of different types of microplastics in water bodies. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method for counting microplastics in water.

[0005] The present invention adopts the following technical solution: A method for counting microplastics in water, comprising the following steps: Step 1: Take multiple water samples from different locations of the water body to be tested, mix the water samples and randomly take out a certain amount of water as the sample to be tested; Step 2: Place the sample to be tested under an optical microscope for observation, install an image acquisition module at the observation port of the optical microscope, and the image acquisition module acquires an image of the magnified water body through the optical microscope; Step 3: Identify and mark the microplastics in the image based on the collected image, and count the number of microplastics in the sample based on the number of marks; Step 4: Differentiate, label and count the types of microplastics in the sample.

[0006] Furthermore, in step three, an appropriate amount of color-developing aid (such as a dye solution or an acid-base solution, etc.) is added to the sample whose image has been collected according to the sample quantity. After the color-developing aid is mixed with the sample, it will adhere to the surface of the microplastic or react with the microplastic to change the color of the microplastic particles.

[0007] Furthermore, the samples with added color-developing aids were observed under an optical microscope to analyze the types of microplastics contained in the water, and different types of microplastics were marked.

[0008] Furthermore, the calculation module is used to count the number of various types of microplastics and calculate the proportion of each type of microplastics in the water body to determine the degree of water pollution, which is specifically evaluated through the following formula: ; Among them, Q is the assessment value of the degree of water pollution, X is the fixed assessment value of the first type of microplastic (red) on water pollution, R in the formula is the amount of the first type of microplastic in the water, Y is the fixed assessment value of the second type of microplastic (green) on water pollution, G in the formula is the amount of the second type of microplastic in the water, Z is the fixed assessment value of the third type of microplastic (blue) on water pollution, Z in the formula is the amount of the third type of microplastic in the water, (X·R+Y·G+Z·B) max This is the group with the largest value during the detection process, (X·R+Y·G+Z·B) min is the group with the smallest value in the detection process, n is the number of detections, where It can represent a variety of situations, such as the fourth type of plastic, the fifth type of microplastic, etc.

[0009] Furthermore, microplastics are divided into large and small categories according to their size. Microplastics with a diameter greater than 2 mm and less than 5 mm are defined as large-sized microplastics, and microplastics between 100 nanometers and 2 mm are defined as small-sized microplastics.

[0010] Furthermore, the calculation module is used to calculate the respective numbers of large and small sized microplastics, and then the numbers of microplastics of the latter two sizes are compared to determine their respective proportions in the total amount of microplastics.

[0011] Furthermore, the calculation module will define the comparison results of the number of microplastics of the last two sizes and transmit them to the evaluation module, which will evaluate the comparison results. When the larger microplastic particles account for a large proportion, it is recommended to use the form of filtering first and then adding chemicals for treatment. When the smaller microplastic particles account for a large proportion, it is directly recommended to use the form of adding chemicals for treatment.

[0012] Furthermore, the evaluation module reasonably recommends corresponding treatment agents according to the types of microplastics and the proportions of various microplastics calculated by the calculation module, and evaluates the required amount of corresponding agents based on the amount of microplastics.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) This method can identify the content of microplastics in water bodies during water testing through an image acquisition module and an optical microscope in conjunction with a computing module, and can change the color of microplastics of different materials by adding dye solutions or acidic or alkaline solutions to the samples, thereby facilitating the subsequent development of appropriate treatment methods for polluted water bodies and the selection of different additives to remove microplastics from water bodies.

[0014] (2) This method can calculate the size of microplastics in water bodies and make reasonable solutions for microplastics of different sizes, which is convenient for subsequent treatment of water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 , a method for counting microplastics in water, comprising the following steps: Step 1: Take multiple water samples from different locations of the water body to be tested, mix the water samples and randomly take out a certain amount of water as the sample to be tested; Step 2: Place the sample to be tested under an optical microscope for observation, install an image acquisition module at the observation port of the optical microscope, and the image acquisition module acquires an image of the magnified water body through the optical microscope; Step 3: Identify and mark the microplastics in the image based on the collected image, count the number of microplastics in the sample based on the number of marks, dye the microplastics after counting, and observe and collect images again; Step 4: Distinguish, mark and count the types of microplastics in the sample, train the evaluation module, and use the evaluation module to evaluate the pollution level of the water body.

[0018] Among them, in step 1, it is necessary to evenly mix the samples collected at various locations to ensure that water sources at multiple locations in the same water body participate in the detection, and use a dropper to take out some water drops for detection; In step 2, an image acquisition module is used in conjunction with an optical microscope to acquire an image of the magnified sample to be tested, and the acquired image is processed, the obtained image is compared with the existing image, and the position and number of microplastics in the obtained image are marked. For example, the following code and steps can be used to identify and process the image: Convert the resulting image to grayscale and flatten it: gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) gray_image_flat = gray_image.reshape(-1, 1); Use K-means clustering to segment the image and find the cluster that is closest to the reference image: kmeans = KMeans(n_clusters=3, random_state=0) kmeans.fit(gray_image_flat) labels = kmeans.labels_.reshape(gray_image.shape) cluster_centers = kmeans.cluster_centers_ reference_image = np.mean(gray_image_flat, axis=0) closest_cluster = np.argmin(np.linalg.norm(cluster_centers - np.mean(reference_images), axis=1)) Then set the cluster closest to the reference image to microplastics and label it: microplastic_mask = labels == closest_cluster microplastics = np.zeros_like(image) microplastics[microplastic_mask] = image[microplastic_mask] contours, hierarchy = cv2.findContours(microplastic_mask.astype(np.uint8), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE) cv2.drawContours(microplastics, contours, -1, (0, 255, 0), 2) Finally, the marking and counting results are displayed: cv2.imshow('Original Image', image) cv2.imshow('Microplastics', microplastics) cv2.waitKey(0) cv2.waitKey(0)cv2.destroyAllWindows().

[0019] Among them, after the preliminary detection, according to the sample quantity, an appropriate amount of color development agent (such as dye solution or acid-base solution, etc.) is added to the sample whose image has been collected. After the color development agent is mixed with the sample, it will adhere to the surface of the microplastic or react with the microplastic to change the color of the microplastic particles; The sample with the color-developing agent added is observed under an optical microscope to analyze the types of microplastics contained in the water and mark different types of microplastics. This is achieved through the following code: Define the color range: lower_red = np.array([0, 50, 50]) upper_red = np.array([10, 255, 255]) lower_green = np.array([40, 50, 50]) upper_green = np.array([80, 255, 255]) lower_blue = np.array([100, 50, 50]) upper_blue = np.array([140, 255, 255]) Create the mask: mask_red = cv2.inRange(hsv, lower_red, upper_red) mask_green = cv2.inRange(hsv, lower_green, upper_green) mask_blue = cv2.inRange(hsv, lower_blue, upper_blue) Count colors: red_count = np.count_nonzero(mask_red) green_count = np.count_nonzero(mask_green) blue_count = np.count_nonzero(mask_blue) Marker Color: image[mask_red != 0] = [0, 0, 255] image[mask_green != 0] = [0, 255, 0] image[mask_blue != 0] = [255, 0, 0] Display results: cv2.imshow("marking result", image) cv2.waitKey(0) cv2.destroyAllWindows() Returns the color count: "red": red_count, "green": green_count, "blue": blue_count} Among them, red, green, and blue can be replaced with other colors to facilitate the recording of microplastics showing different colors. Similarly, the relevant parts of red, green, and blue can be deleted to reduce the screening range, which can be used to count one or more microplastics.

[0020] Among them, the calculation module is used to count the number of various types of microplastics, and calculate the proportion of various types of microplastics in the water body to determine the degree of pollution of the water body. The specific evaluation is carried out through the following formula: ; Among them, Q is the assessment value of the degree of water pollution, X is the fixed assessment value of the first type of microplastic (red) on water pollution, R in the formula is the amount of the first type of microplastic in the water, Y is the fixed assessment value of the second type of microplastic (green) on water pollution, G in the formula is the amount of the second type of microplastic in the water, Z is the fixed assessment value of the third type of microplastic (blue) on water pollution, Z in the formula is the amount of the third type of microplastic in the water, (X·R+Y·G+Z·B) max This is the group with the largest value during the detection process, (X·R+Y·G+Z·B) min is the group with the smallest value in the detection process, n is the number of detections, where It can represent multiple situations such as the fourth type of plastic and the fifth type of microplastic. When there are the fourth type of microplastic and the fifth type of microplastic, their fixed assessment of water pollution can be brought into the above formula for calculation.

[0021] Among them, the decision tree model can be trained to classify microplastics into large and small categories according to their sizes, and the ratio of large and small microplastics can be calculated. The size of microplastics can be calculated specifically through the following code: Finding contours: cnts, hierarchy = cv2.findContours(opening, cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE) microplastics_diameters = [] for cnt in cnts: Calculate the area of ​​the contour and infer the diameter from the area: area = cv2.contourArea(cnt) diameter = np.sqrt(4 * area / np.pi) microplastics_diameters.append(diameter) return microplastics_diameters; Among them, after calculation, the calculation module defines microplastics with a diameter greater than 2 mm as large-sized microplastics, and microplastics between 100 nanometers and 2 mm as small-sized microplastics. The number of large-sized microplastics is compared with the number of small-sized microplastics, and the water body is evaluated according to the ratio, and a reasonable treatment method is adopted. If there are more large-sized microplastics, filtration can be used for treatment. Otherwise, the microplastics can be adsorbed by adding adsorbents, or treated by aeration or the addition of chemicals.

[0022] The evaluation module reasonably recommends corresponding treatment agents according to the types of microplastics and the proportions of various microplastics calculated by the calculation module, and evaluates the required amount of corresponding agents according to the amount of microplastics. Specifically, the linear regression model is trained and the amount of treatment agent required is calculated by the calculation module. The calculation is performed specifically by the following formula: ; Among them, K is the required amount of treatment agent, H is the amount of agent required for each unit of microplastics, J is the corresponding unit amount of microplastics, and L is the allowable error value of the treatment agent dosage. By supplementing the corresponding error treatment agent dosage, it can be ensured that the agent can fully react physically and chemically with the microplastics when the water flows.

[0023] The above is only a preferred specific implementation of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved conception within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for counting microplastics in water, comprising the following steps: Step 1: Take multiple water samples from different locations of the water body to be tested, mix the water samples and randomly take out a certain amount of water as the sample to be tested; Step 2: Place the sample to be tested under an optical microscope for observation, install an image acquisition module at the observation port of the optical microscope, and the image acquisition module acquires an image of the magnified water body through the optical microscope; Step 3: Identify and mark the microplastics in the image based on the collected image, count the number of microplastics in the sample based on the number of marks, dye the microplastics after counting, and observe and collect images again; Step 4: Distinguish, mark and count the types of microplastics in the sample, train the evaluation module, and use the evaluation module to evaluate the pollution level of the water body.

2. A method for counting microplastics in water according to claim 1, characterized in that: In step three, an appropriate amount of color-developing aid is added to the sample whose image has been collected according to the sample quantity. After the color-developing aid is mixed with the sample, it will adhere to the surface of the microplastics or react with the microplastics to change the color of the microplastic particles.

3. A method for counting microplastics in water according to claim 2, characterized in that: The samples with added color-developing aids are observed under an optical microscope to analyze the types of microplastics contained in the water and mark different types of microplastics.

4. A method for counting microplastics in water according to claim 3, characterized in that: The calculation module is used to count the number of various types of microplastics and calculate the proportion of each type of microplastic in the water body to determine the degree of water pollution. The specific evaluation is carried out through the following formula: ； Among them, Q is the assessment value of the degree of water pollution, X is the fixed assessment value of the first type of microplastic (red) on water pollution, R in the formula is the amount of the first type of microplastic in the water, Y is the fixed assessment value of the second type of microplastic (green) on water pollution, G in the formula is the amount of the second type of microplastic in the water, Z is the fixed assessment value of the third type of microplastic (blue) on water pollution, Z in the formula is the amount of the third type of microplastic in the water, (X·R+Y·G+Z·B) max The group with the largest value during the test, (X·R+Y·G+Z·B) min It is the group with the smallest value in the detection process, and n is the number of detections.

5. A method for counting microplastics in water according to claim 4, characterized in that: Microplastics are divided into two categories according to their size: large and small. Microplastics with a diameter greater than 2 mm and less than 5 mm are defined as large microplastics, and microplastics between 100 nanometers and 2 mm are defined as small microplastics.

6. A method for counting microplastics in water according to claim 5, characterized in that: The calculation module is used to calculate the number of large and small sized microplastics, and then the number of microplastics of the latter two sizes is compared to determine their respective proportions in the total amount of microplastics.

7. A method for counting microplastics in water according to claim 6, characterized in that: The calculation module will define the comparison results of the number of microplastics of the last two sizes and transmit them to the evaluation module, which will evaluate the comparison results. When the larger microplastic particles account for a large proportion, it is recommended to use the method of filtering first and then adding chemicals for treatment. When the smaller microplastic particles account for a large proportion, it is directly recommended to use the method of adding chemicals for treatment.

8. A method for counting microplastics in water according to claim 7, characterized in that: The evaluation module reasonably recommends corresponding treatment agents according to the types of microplastics and the proportion of various microplastics calculated by the calculation module, and evaluates the required amount of corresponding agents based on the amount of microplastics.

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