Mulching film source microplastic-arsenic combined pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device and method thereof

Abstract

The invention relates to the technical field of soil pollutant detection, in particular to a mulching film source microplastic-arsenic combined pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device and a method thereof.The mulching film source microplastic-arsenic combined pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device comprises a soil filling mechanism, a sampling box and a plurality of experiment cups placed in the sampling box; the soil filling mechanism comprises a mixing tank and a compaction part arranged on the left side of the mixing tank. According to the mulch film source microplastic-arsenic combined pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device and method, the soil filling mechanism integrates the functions of mixing, quantitative subpackaging and compaction, and the mixing tank realizes efficient and uniform mixing of pollutants and soil in a closed space; the soil is accurately and quantitatively conveyed to each experiment cup through a reverse rotation mode, and uniform pressure is applied to the soil along with a compaction part behind the soil, so that the problems of non-uniform soil mixing, inconsistent filling volume and different compaction degrees caused by traditional manual operation are fundamentally solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil pollutant detection, in particular to a mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device and method thereof. BACKGROUND

[0002] The mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in-vivo enrichment dynamic experiment simulates the farmland environment to study the toxicity effect and enrichment rule of microplastic and arsenic composite pollution on earthworms, which reveals the migration and amplification risk of microplastic as a heavy metal carrier in the soil ecosystem, and provides a scientific basis for agricultural film pollution prevention and control and soil health assessment.

[0003] The patent with application number CN202310960921.1 discloses an earthworm ecological toxicology test exposure container, which solves the problems of inconvenient operation, confusion, non-reusable, time-consuming and inefficient, and inability to simulate or meet the test requirements in the prior art. The earthworm ecological toxicology test exposure container comprises a bottle body, a top cover connected to the top of the bottle body through screw threads, a plurality of holes formed in the top cover, and a spiral groove formed on the outer side of the upper part of the bottle body for cooperating with the top cover.

[0004] However, the soil filling process of the existing monitoring equipment relies on manual operation, which leads to uneven mixing of pollutants and soil, significant differences in filling density and compaction degree between different exposure containers, and inconsistency in experimental starting conditions. In addition, there is a lack of integrated in-situ leachate collection mechanism, which requires moving or opening the exposure container for sampling. This not only makes the operation complicated and prone to soil disturbance, but also makes it impossible to achieve continuous and undisturbed dynamic monitoring of the same sample at multiple time points, thereby limiting the possibility of obtaining high-quality and high-time-resolution environmental exposure data.

[0005] In view of this, we propose a mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device and method thereof. SUMMARY

[0006] The present application aims to provide a mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device and method thereof, which integrates the mixing, quantitative dispensing, and compaction functions of the soil filling mechanism to realize non-destructive continuous sampling of the experimental cups and sampling boxes, thereby solving the problems raised in the background technology.

[0007] To achieve the above-mentioned purpose, on the one hand, the present application provides the following technical solutions: The mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in-vivo enrichment dynamic monitoring device comprises a soil filling mechanism, a sampling box, and a plurality of experimental cups placed inside the sampling box. The soil filling mechanism comprises a mixing tank and a compaction part arranged on the left side of the mixing tank, the mixing tank comprises a tank body, a second motor arranged on the top of the tank body, and an agitator rod and an auger driven by the second motor, and the compaction part comprises an electric push rod and a pressing plate driven by the electric push rod. The second motor drives the agitator rod to rotate forward, so that the soil is mixed with the water solution of microplastics and arsenic in the tank body, and when the agitator rod is reversed, the auger is driven to divide the soil into experimental cups, and the electric push rod controls the pressing plate to move downward to compact the soil. The sampling box comprises a box body, a plurality of pull-out plates sliding in the box body, a plurality of sampling discs arranged on the top surface of the pull-out plates, and a pressing part arranged above the pull-out plates. The experimental cup comprises a cup body, a cross pipe arranged on the bottom of the cup body, and a piston sliding in the horizontal pipe of the cross pipe, and the piston is internally provided with a through hole with the same size as the vertical pipe of the cross pipe. The pressing part is arranged to drive the piston to retract, so that the soil leachate at the bottom of the cup body is collected into the sampling disc below.

[0008] In the technical scheme of the present application, the soil filling mechanism further comprises a support frame, a first motor fixedly connected to the left baffle of the support frame by a bolt, a lead screw coaxially connected to the output shaft of the first motor, a sliding plate slidingly connected to the internal frame of the support frame, and a positioning rod slidingly connected to the baffle on the outer wall of the support frame.

[0009] In the technical scheme of the present application, the other end of the lead screw is rotationally connected to the inner side wall of the right baffle, the sliding plate is threadedly connected to the lead screw, and the positioning rod has a T-shaped transverse cross section and a hemispherical protrusion integrally formed on the bottom surface of the end portion.

[0010] In the technical scheme of the present application, the tank body is clamped and fixed inside the sliding plate, the second motor is fixedly connected to the top surface of the tank body by a screw, the central shaft of the agitator rod is coaxially connected to the output shaft of the second motor, and the auger is welded and fixed to the outer wall of the central shaft of the agitator rod and located inside the circular pipe at the bottom of the tank body.

[0011] The above arrangement completes the mixing of pollutants and soil through the mixing tank, avoiding the problems of uneven mixing and inconsistent filling volume caused by traditional manual operation.

[0012] In the technical scheme of the present application, the electric push rod is fixedly connected to the top surface of the sliding plate by a screw, a telescopic rod is clamped and fixed between the end portion of the electric push rod and the pressing plate, a first spring is sleeved outside the telescopic rod, and the elastic force provided by the first spring pushes the pressing plate to move downward.

[0013] The first spring is contracted under the limitation of the telescopic rod, preventing the pressing plate from directly contacting the soil rigidly, and ensuring the consistency of the soil compaction degree inside the experimental cup.

[0014] In the technical scheme of the present application, a plurality of chutes communicating with the outer wall are formed in the inner bottom surface of the box, a plurality of regularly distributed circular holes are formed in the left and right outer walls of the box, a plurality of regularly distributed positioning holes matching the size of the protruding blocks are formed in the bottom plates at the left and right ends of the box, and a plurality of upper and lower through placing grooves are formed in the top surface of the box.

[0015] In the technical scheme of the present application, the placing frame is clamped in the interior of the placing groove, the observation windows are clamped and fixed on the front and rear sides of the box, and the pull-out plate is slidingly connected in the interior of the chute.

[0016] The above arrangement realizes the positioning of the sampling box position without the need for an additional driving source by forming a plurality of positioning holes in the two sides of the box bottom plate.

[0017] In the technical scheme of the present application, the pressing part comprises a sliding rod slidingly connected in the interior of the circular hole, a plurality of clamped and fixed protruding plates on the outer wall of the sliding rod, a clamped and fixed circular plate on the outer wall of the sliding rod, and a second spring welded and fixed on the outer wall of the circular plate, and the other end of the second spring is welded and fixed on the inner wall of the box.

[0018] This arrangement can complete the sampling work of the filtrate at the bottom of a plurality of experimental cups through the protruding plates by extruding the sliding rod, thereby improving the sampling efficiency.

[0019] In the technical scheme of the present application, the inner wall of the cup body is clamped and fixed with a filter screen near the bottom position, the vertical pipe top end of the cross pipe is clamped and fixed outside the opening in the bottom surface of the cup body, the piston is slidingly connected in the interior of the horizontal pipe of the cross pipe, and a third spring is adhesively fixed between the end of the piston and the inner wall of the horizontal pipe of the cross pipe.

[0020] This arrangement can collect the soil percolate without blockage without moving the experimental cup, thereby dynamically monitoring the bioavailable concentration of pollutants in the soil.

[0021] On the other hand, the present application also provides a mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring method using the above-mentioned mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device, which comprises the following steps: S1. According to the experimental design, the quantitative soil, the mulch source plastic ground into microplastics of the target particle size, and the aqueous solution of arsenic compound are added into the mixing tank, the second motor is started to drive the stirring rod to operate for a specified time to ensure that the pollutants are fully and uniformly mixed with the soil, and the healthy adult earthworms are domesticated in clean soil for one day to empty their intestines; S2. The pretreated earthworms are manually placed in the cup bodies of a plurality of experimental cups, and then the sampling box is moved to the position directly below the mixing tank, and the protruding block at the end of the positioning rod is ensured to be located in the frontmost positioning hole. S3, control the first motor to drive the screw rod to rotate, drive the sliding plate to move horizontally in the support frame, move the tank body bottom end discharge port to the leftmost experimental cup, after the first motor stops, control the second motor to rotate reversely, drive the auger to rotate, then send the quantitative soil into the cup body, then, the first motor starts again, moves the tank body to the right experimental cup, and repeats the soil filling work, at this time, control the electric push rod to drive the telescopic rod to move downward, and compact the soil in the leftmost experimental cup through the pressing plate, and repeat the operation until all the experimental cups are filled with soil; S4, then, add a proper amount of deionized water to each experimental cup to a standard humidity, after a short cultivation of 6 hours, make the slide rod of the extrusion pressing part contract inward, drive the piston to contract through the convex plate, make the through hole correspond to the vertical pipe of the cross pipe, and collect the soil leachate at the bottom of the cup body into the sampling tray below, the sample represents the initial time point of each experimental cup; S5, then, put the sampling box into the artificial climate box, set constant temperature and humidity and light period, formally start the exposure experiment, mark as the 1st day, take out the sampling box from the climate box at the preset sampling time point, and repeat the soil leachate sampling operation, and send the sampling tray to the laboratory, and analyze the concentration of bioavailable arsenic and the content of soluble substances in the soil leachate by using instruments; S6, and at the preset key time point, destructively sample the experimental cups of the whole repeated group, carefully take out all the soil and earthworms in the experimental cups, place the earthworms in a clean culture dish, after the earthworms are emptied, wash the earthworms, perform digestion treatment, and detect the total arsenic content and the number of microplastic particles in the earthworms by using instruments; S7, finally, correlate the chemical analysis data of the leachate at different time points with the pollutant enrichment amount in the earthworms at the corresponding time points, draw the time and leachate pollutant concentration curve and the time and earthworm body enrichment amount curve, and utilize the obtained time series data to establish a biological enrichment kinetics model, calculate enrichment factor, absorption rate constant and discharge rate constant parameters, and comprehensively evaluate the ecological risk of the complex pollution.

[0022] Compared with the prior art, the beneficial effects of the present application are: 1.The device and method for simulating and monitoring the dynamic enrichment of earthworms exposed to mulch-derived microplastics-arsenic composite pollution, which comprises a soil filling mechanism that integrates mixing, quantitative dispensing, and compaction functions; the mixing tank realizes efficient and uniform mixing of pollutants and soil in a closed space, and precisely and quantitatively delivers the soil to each experimental cup through a reverse mode; the compaction unit applies uniform pressure to the soil, fundamentally solving the problems of uneven soil mixing, inconsistent filling volume, and different compaction levels caused by traditional manual operation, ensuring that the initial conditions of each exposure experimental cup are highly consistent, and improving the accuracy, repeatability, and comparability of experimental data.

[0023] 2.The device and method for simulating and monitoring the dynamic enrichment of earthworms exposed to mulch-derived microplastics-arsenic composite pollution, which comprises an experimental cup and a sampling box structure that realizes non-destructive continuous sampling, allowing the operator to collect the soil leachate at the bottom of the cup into the sampling tray below through external pressing operation without moving the experimental cup, facilitating and quickly sampling the leachate of the same replicate group at multiple time points during the entire exposure experiment, and dynamically monitoring the concentration changes of bioavailable pollutants in the soil. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present application; Figure 2 It is a structural schematic diagram of the soil filling mechanism in the present application; Figure 3 It is a structural cross-sectional schematic diagram of the mixing tank in the present application; Figure 4 It is a structural schematic diagram of the compaction unit in the present application; Figure 5 It is a structural schematic diagram of the positioning rod in the present application; Figure 6 It is a structural cross-sectional schematic diagram of the sampling box in the present application; Figure 7 It is a structural cross-sectional schematic diagram of the box body in the present application; Figure 8 It is a partial structural schematic diagram of the sampling box in the present application; Figure 9 It is a structural schematic diagram of the pressing unit in the present application; Figure 10 It is a structural cross-sectional schematic diagram of the experimental cup in the present application; Figure 11 It is a partial structural cross-sectional schematic diagram of the experimental cup in the present application; REFERENCE SIGNS: 100, soil filling mechanism; 110, support frame; 120, first motor; 130, screw rod; 140, sliding plate; 150, mixing tank; 151, tank body; 152, second motor; 153, stirring rod; 154, auger; 160, compaction part; 161, electric push rod; 162, telescopic rod; 163, pressing plate; 164, first spring; 170, positioning rod; 171, protruding block; 200, sampling box; 210, box body; 211, chute; 212, round hole; 213, positioning hole; 214, placement groove; 220, placement frame; 230, observation window; 240, pull-out plate; 250, sampling disc; 260, pressing part; 261, sliding rod; 262, protruding plate; 263, round plate; 264, second spring; 300, experimental cup; 310, cup body; 320, filter screen; 330, cross pipe; 340, piston; 341, through hole; 350, third spring. DETAILED DESCRIPTION

[0025] The technical solutions in the present application will be described clearly and completely below in conjunction with the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0026] Please refer to Figures 1-5 The technical solutions provided by the embodiments are as follows: The earthworm exposure simulation and in-vivo enrichment dynamic monitoring device for mulch source microplastic-arsenic composite pollution comprises a soil filling mechanism 100, a sampling box 200, and a plurality of experimental cups 300 placed inside the sampling box 200. The soil filling mechanism 100 comprises a mixing tank 150 and a compaction part 160 arranged on the left side of the mixing tank 150. The mixing tank 150 comprises a tank body 151, a second motor 152 arranged on the top of the tank body 151, and a stirring rod 153 and an auger 154 driven by the second motor 152. The second motor 152 drives the stirring rod 153 to rotate forward, so that the soil is mixed with the aqueous solution of microplastics and arsenic compounds in the tank body 151. When the stirring rod 153 rotates reversely, the auger 154 is driven to divide the soil evenly into the experimental cups 300.

[0027] Specifically, the soil filling mechanism 100 further comprises a support frame 110, a first motor 120 fixedly connected to the left baffle of the support frame 110 by means of bolts, a screw rod 130 coaxially connected to the output shaft of the first motor 120, a sliding plate 140 slidingly connected to the internal frame of the support frame 110, and a positioning rod 170 slidingly connected to the baffle on the outer wall of the support frame 110.

[0028] Further, the other end of the screw rod 130 is rotationally connected to the inner side wall of the right baffle, the sliding plate 140 is threadedly connected with the screw rod 130, and the positioning rod 170 is T-shaped in transverse section and integrally formed with a hemispherical protrusion 171 at the bottom of the end.

[0029] Further, the tank body 151 is clamped and fixed in the interior of the sliding plate 140, the second motor 152 is fixedly connected to the top surface of the tank body 151 by screws, the stirring rod 153 is coaxially connected with the output shaft of the second motor 152 at the center axis, and the auger 154 is welded and fixed to the outer wall of the center axis of the stirring rod 153 and is located in the circular pipe at the bottom of the tank body 151.

[0030] Further, the first motor 120 is controlled to drive the screw rod 130 to rotate and drive the sliding plate 140 to move horizontally in the support frame 110, and after the bottom end discharge port of the tank body 151 is moved above the experimental cup 300 located at the leftmost side, the first motor 120 is stopped, and the second motor 152 is controlled to rotate reversely to drive the auger 154 to rotate, and then a certain amount of soil is fed into the interior of the cup body 310, and then the first motor 120 is started again to move the tank body 151 above the experimental cup 300 at the right side, and the previous soil filling work is repeated. This setting completes the mixing of the pollutants and the soil through the mixing tank 150, and avoids the problems of uneven mixing and inconsistent filling volume caused by traditional manual operation.

[0031] Please refer to Figure 4 In the embodiment, the compaction part 160 includes an electric push rod 161 and a pressing plate 163 driven by the electric push rod 161, the electric push rod 161 controls the pressing plate 163 to move downward to compact the soil.

[0032] Specifically, the electric push rod 161 is fixedly connected to the top surface of the sliding plate 140 by screws, the end of the electric push rod 161 is clamped and fixed with the telescopic rod 162, the telescopic rod 162 is sleeved with the first spring 164 at the outer side, and the elastic force provided by the first spring 164 pushes the pressing plate 163 to move downward.

[0033] Further, the electric push rod 161 is controlled to drive the telescopic rod 162 to move downward, and the soil in the experimental cup 300 at the leftmost side is compacted by the pressing plate 163, and the subsequent repeated operation is performed until all the experimental cups 300 are filled with soil. This setting causes the first spring 164 to contract under the limitation of the telescopic rod 162, and prevents the pressing plate 163 from directly rigidly contacting the soil, thereby ensuring the consistency of the soil compaction degree in the experimental cup 300.

[0034] Please refer to Figures 1-8 In the embodiment, the sampling box 200 includes a box body 210, a plurality of pull-out plates 240 sliding in the interior of the box body 210, a plurality of sampling discs 250 placed on the top surface of the pull-out plate 240, and a pressing part 260 arranged above the pull-out plate 240.

[0035] Specifically, a plurality of chutes 211 are formed in the inner bottom surface of the box 210 and communicated with the outer wall, a plurality of regularly distributed circular holes 212 are formed in the left and right outer walls of the box 210, a plurality of regularly distributed positioning holes 213 are formed in the bottom plates at the left and right ends of the box 210 and matched with the sizes of the protrusions 171, and a plurality of upper and lower through placing grooves 214 are formed in the top surface of the box 210.

[0036] Further, the placing rack 220 is clamped in the interior of the placing groove 214, the observation window 230 is clamped and fixed on the front and rear sides of the box 210, and the pull-out plate 240 is slidingly connected in the interior of the chute 211.

[0037] Further, the chute 211 and the circular hole 212 in the box 210 improve the sliding interval of the pull-out plate 240 and the pressing part 260 respectively, the positioning hole 213 cooperates with the protrusion 171 at the end of the positioning rod 170 to ensure that the experimental cup 300 and the discharge port at the bottom of the mixing tank 150 are located on the same axis, the observation window 230 is used for conveniently observing the internal condition of the sampling box 200 by the operator, and the pull-out plate 240 is used for placing the sampling tray 250. This setting realizes the positioning of the position of the sampling box 200 without an additional driving source by forming a plurality of positioning holes 213 on the two sides of the bottom plate of the box 210.

[0038] Please refer to Figures 1-9 In the embodiment, the pressing part 260 includes a sliding rod 261 slidingly connected in the interior of the circular hole 212, a plurality of flanges 262 clamped and fixed on the outer wall of the sliding rod 261, a circular plate 263 clamped and fixed on the outer wall of the sliding rod 261, and a second spring 264 welded and fixed on the outer wall of the circular plate 263, and the other end of the second spring 264 is welded and fixed on the inner wall of the box 210.

[0039] Further, extruding the sliding rod 261 can drive a plurality of flanges 262 to displace synchronously, and after the finger is released, the elastic force of the second spring 264 pushes the circular plate 263, and the sliding rod 261 can be reset. This setting can complete the sampling work of the filtrate at the bottom of a plurality of experimental cups 300 through the flanges 262 by extruding the sliding rod 261, thereby improving the sampling efficiency.

[0040] Please refer to Figures 1-11 In the embodiment, the experimental cup 300 includes a cup body 310, a cross pipe 330 arranged at the bottom of the cup body 310, and a piston 340 sliding in the horizontal pipe of the cross pipe 330, the interior of the piston 340 is provided with a through hole 341 with the same size as the vertical pipe of the cross pipe 330, and extruding the pressing part 260 can drive the piston 340 to retract, so that the soil filtrate at the bottom of the cup body 310 is collected to the sampling tray 250 below.

[0041] Further, the inner wall of the cup body 310 is clamped and fixed with a filter screen 320 near the bottom position, the vertical pipe top end of the cross pipe 330 is clamped and fixed outside the opening of the bottom surface of the cup body 310, the piston 340 is slidingly connected inside the horizontal pipe of the cross pipe 330, and the third spring 350 is adhesively fixed between the end of the piston 340 and the inner wall of the horizontal pipe of the cross pipe 330.

[0042] Further, the cup body 310 is used to prevent earthworms and soil, and the filter screen 320 inside the cup body 310 divides the cup body 310 into layers, so that the leachate can pass through the filter screen 320 and be concentrated at the bottom surface of the cup body 310, and the soil does not block the cross pipe 330 during subsequent sampling, the convex plate 262 drives the piston 340 to retract, the through hole 341 corresponds to the vertical pipe of the cross pipe 330, and the soil leachate at the bottom of the cup body 310 is collected into the sampling tray 250 below, so that the soil leachate can be collected without blockage without moving the experimental cup 300, and the bioavailable concentration of pollutants in the soil can be dynamically monitored.

[0043] The application also provides a mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring method, which uses the mulch source microplastic-arsenic composite pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device, and includes the following steps: S1, according to the experimental design, the quantitative soil, the mulch source plastic ground into the microplastic of the target particle size and the water solution of the arsenic compound are added into the mixing tank 150, the second motor 152 is started, the stirring rod 153 is driven to operate for a specified time, it is ensured that the pollutants are fully and uniformly mixed with the soil, and the healthy adult earthworms are domesticated in clean soil for one day to empty their intestines; S2, the pretreated earthworms are manually placed in the cup body 310 of the experimental cup 300, the sampling box 200 is moved to the position directly below the mixing tank 150, and it is ensured that the convex block 171 at the end of the positioning rod 170 is located in the positioning hole 213 at the front end; S3, the first motor 120 is controlled to drive the lead screw 130 to rotate, the sliding plate 140 is driven to move horizontally inside the support frame 110, the bottom end discharge port of the tank body 151 is moved to the leftmost experimental cup 300, then the first motor 120 is stopped, the second motor 152 is controlled to rotate in reverse, the auger 154 is driven to rotate, a certain amount of soil is fed into the cup body 310, then the first motor 120 is started again, the tank body 151 is moved to the right experimental cup 300, and the soil filling work is repeated, at this time, the electric push rod 161 is controlled to drive the telescopic rod 162 to move downward, the soil in the leftmost experimental cup 300 is compacted by the pressing plate 163, and the subsequent operation is repeated until all the experimental cups 300 are filled with soil; S4, then, add an appropriate amount of deionized water to each experimental cup 300 to the standard humidity, after a short culture for 6 hours, extrusion press the slide rod 261 of the press part 260 to make it shrink inwardly, while the piston 340 is driven to shrink inwardly by the cam 262, the through hole 341 is corresponded with the vertical tube of the cross tube 330, and the soil leachate at the bottom of the cup body 310 is collected into the sampling tray 250 below, this sample represents the initial time point of each experimental cup 300; S5, then, put the sampling box 200 into the artificial climate box, set constant temperature and humidity and light cycle, officially start the exposure experiment, record as the first day, and at the preset sampling time point, take out the sampling box 200 from the climate box, and repeat the soil leachate sampling operation, and send the sampling tray 250 to the laboratory, and use instruments to analyze the concentration of bioavailable arsenic and the content of soluble substances in the sampling tray 250; S6, and at the preset key time point, destructively sample the experimental cups of the whole repetition group, carefully take out all the soil and earthworms in the experimental cup 300, place the earthworms in a clean culture dish, wash the earthworm body surface with deionized water after the earthworms empty their intestinal contents, and use instruments to detect the total arsenic content and microplastic particle number in the earthworm body after digestion treatment; S7, finally, correlate the chemical analysis data of the leachate at different time points with the pollutant enrichment amount in the earthworm body at the corresponding time points, draw the time and leachate pollutant concentration curve and the time and earthworm body enrichment amount curve, and use the obtained time series data to establish a biological enrichment kinetics model, calculate the enrichment factor, absorption rate constant and discharge rate constant parameters, and comprehensively evaluate the ecological risk of the complex pollution.

[0044] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. An apparatus for simulating and monitoring the in vivo enrichment dynamics of earthworms exposed to mulch-derived microplastics-arsenic combined pollution, characterized in that it comprises: It includes a soil filling mechanism, a sampling box, and several experimental cups placed inside the sampling box; The soil filling mechanism includes a mixing tank and a compaction section located on its left side. The mixing tank includes a tank body, a second motor located on its top, and a stirring rod and an auger driven by the motor. The compaction section includes an electric push rod and a pressure plate driven by the electric push rod. The second motor drives the stirring rod to rotate forward, mixing the soil with an aqueous solution of microplastics and arsenic compounds in the tank body. When the stirring rod rotates in reverse, it drives the auger to evenly distribute the soil into the experimental cup. The electric push rod controls the pressure plate to move downward, compacting the soil. The sampling box includes a box body, several pull-out plates that slide inside it, several sampling trays placed on the top surface of the pull-out plates, and a pressing part set above the pull-out plates. The experimental cup includes a cup body, a cross tube set at the bottom of the cup body, and a piston that slides inside the horizontal tube of the cross tube. The piston has a through hole with the same size as the vertical tube of the cross tube. Squeezing and pressing the part can drive the piston to retract, collecting the soil leachate at the bottom of the cup body into the sampling plate below.

2. The apparatus for earthworm exposure simulation and in vivo accumulation dynamic monitoring of geofilm-derived microplastic-arsenic combined pollution according to claim 1, wherein: The soil filling mechanism also includes a support frame, a first motor fixedly connected to the left baffle of the support frame by bolts, a lead screw coaxially connected to the output shaft of the first motor, a sliding plate slidably connected to the inner frame of the support frame, and a positioning rod slidably connected to the outer wall baffle of the support frame.

3. The device for simulating earthworm exposure and monitoring in vivo enrichment dynamics caused by microplastic-arsenic composite pollution from plastic film source as described in claim 2, characterized in that: The other end of the lead screw is rotatably connected to the inner wall of the right baffle. The slide plate is threadedly connected to the lead screw. The positioning rod has a T-shaped transverse cross section and a hemispherical protrusion integrally formed on the bottom surface of its end.

4. The geocole microplastics-arsenic complex pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device according to claim 3, characterized in that: The tank body is snapped and fixed inside the slide plate. The second motor is fixedly connected to the top surface of the tank body by screws. The central shaft of the stirring rod is coaxially connected to the output shaft of the second motor. The auger is welded and fixed to the outer wall of the central shaft of the stirring rod, and its own position is located in the circular tube at the bottom of the tank body.

5. The geocole microplastics-arsenic complex pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device according to claim 4, characterized in that: The electric actuator is fixedly connected to the top surface of the slide plate by screws. A telescopic rod is snapped between the end of the electric actuator and the pressure plate. A first spring is sleeved on the outside of the telescopic rod. The elastic force provided by the first spring pushes the pressure plate to move downward.

6. The geocole microplastic-arsenic complex pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device according to claim 5, characterized in that: The bottom surface of the box has several sliding grooves that communicate with the outer wall. The outer walls on the left and right sides of the box have several regularly distributed round holes. The bottom plates at the left and right ends of the box have several regularly distributed positioning holes that match the size of the protrusions. The top surface of the box has several vertically connected placement grooves.

7. The geocole microplastic-arsenic complex pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device according to claim 6, characterized in that: The placement rack is snapped into the inside of the placement slot, and observation windows are snapped into and fixed on the front and rear sides of the box. The pull-out plate is slidably connected to the inside of the slide groove.

8. The geocole microplastic-arsenic complex pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device according to claim 7, characterized in that: The pressing part includes a slide rod slidably connected inside the circular hole, several protruding plates snapped and fixed to the outer wall of the slide rod, a circular plate snapped and fixed to the outer wall of the slide rod, and a second spring welded and fixed to the outer wall of the circular plate. The other end of the second spring is welded and fixed to the inner wall of the box.

9. The geocole microplastic-arsenic complex pollution earthworm exposure simulation and in vivo enrichment dynamic monitoring device according to claim 8, characterized in that: A filter screen is snapped and fixed to the inner wall of the cup near the bottom. The top end of the vertical tube of the cross tube is snapped and fixed to the outside of the opening on the bottom surface of the cup. The piston is slidably connected to the inside of the horizontal tube of the cross tube. A third spring is adhered and fixed between the end of the piston and the inner wall of the horizontal tube of the cross tube.

10. The method for earthworm exposure simulation and in vivo enrichment dynamic monitoring of mulch source microplastics-arsenic combined pollution, using the earthworm exposure simulation and in vivo enrichment dynamic monitoring device of mulch source microplastics-arsenic combined pollution according to claim 9, characterized in that, Includes the following steps: S1, according to the experimental design, the quantitative soil, mulch source plastic is ground into the target particle size of microplastics and arsenic solution, and the second motor is started to drive the stirring rod to operate for a specified time, so that the pollutants and the soil are fully and uniformly mixed, and the healthy adult earthworms are domesticated in the clean soil for one day to empty the intestinal tract; S2, the pretreated earthworms are manually placed in the cup body of a plurality of experimental cups, and then the sampling box is moved to the lower side of the mixing tank, and the protrusion at the end of the positioning rod is located in the frontmost positioning hole; S3, the first motor is controlled to drive the screw rod to rotate, the slide plate is driven to move horizontally in the support frame, the tank body is moved to the leftmost experimental cup, the first motor is stopped, and the second motor is controlled to rotate reversely to drive the auger to rotate, then a certain amount of soil is fed into the cup body, then the first motor is started again to move the tank body to the right experimental cup, and the soil filling operation is repeated, at this time, the electric push rod is controlled to drive the telescopic rod to move downward, and the soil in the leftmost experimental cup is compacted by the pressing plate, and the subsequent operation is repeated until all the experimental cups are filled with soil; S4, then, a certain amount of deionized water is added to each experimental cup to reach the standard humidity, after a short cultivation for 6 hours, the slide rod of the extrusion pressing part is retracted inward, the piston is retracted by the convex plate, the through hole is matched with the vertical pipe of the cross pipe, and the soil leachate at the bottom of the cup body is collected into the sampling disc below, and this sample represents the initial time point of each experimental cup; S5, then, the sampling box is placed in the artificial climate box, the constant temperature and humidity and light period are set, the exposure experiment is formally started, which is recorded as the first day, at the preset sampling time point, the sampling box is taken out of the climate box, and the soil leachate sampling operation is repeated, and the sampling disc is sent to the laboratory for instrument analysis of the concentration of bioavailable arsenic and the content of soluble substances; S6, at the preset key time point, destructive sampling is performed on the experimental cups of the whole repeated group, an experimental cup is selected, and all the soil and earthworms in the experimental cup are carefully taken out, the earthworms are placed in a clean culture dish, and after the intestinal contents are emptied, the earthworms are washed with deionized water, and after digestion treatment, the total arsenic content and the number of microplastic particles in the earthworms are detected by using the instrument; S7, finally, the chemical analysis data of the leachate at different time points are correlated with the pollutant enrichment amount in the earthworms at the corresponding time points, the time and leachate pollutant concentration curve and the time and enrichment amount curve of the earthworms are drawn, and the time series data obtained are used to establish a biological enrichment kinetics model, calculate the enrichment factor, absorption rate constant and discharge rate constant parameters, and comprehensively evaluate the ecological risk of the combined pollution.

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