Device and method for investigating enrichment conditions of heavy metals and micro-plastics in soil

Abstract

The invention discloses a soil heavy metal and micro-plastic enrichment condition investigation device and method.The device comprises a bottom plate and a plurality of soil collection mechanisms, the bottom plate is connected with a top plate through a guide rod, a pressing rod is movably inserted into the top plate, and one soil collection mechanism is detachably installed on an installation piece at the bottom of the pressing rod; wherein the soil collecting mechanism comprises a container I and a container II, and the container I and the container II are rotationally connected through a separating part; a sealing mechanism is arranged on the top plate, a liquid supply mechanism is arranged on the sealing mechanism, and an intercepting plate is movably inserted into the upper portion of the side wall of the first container. Soil samples of different sampling points are conveniently collected through a pressing rod and a plurality of soil collecting mechanisms, meanwhile, a sealing mechanism and a liquid supply mechanism are matched, flotation liquid is conveniently injected into the first container so that soil and micro-plastics in the first container can be separated, the applicability of the investigation device is improved, and the subsequent soil sample treatment cost is reduced; and the overall efficiency is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil pollution investigation, and in particular to a device and method for investigating the enrichment status of heavy metals and microplastics in soil. Background Art

[0002] At present, due to its efficient and intensive production methods, the intensity of land resource utilization in facility agriculture is increasing, which inevitably leads to a higher risk of land pollution. Among the many pollutants, heavy metals and microplastics are particularly concerning.

[0003] In order to effectively deal with the problem of heavy metal and microplastic pollution in facility agricultural soil, soil samples are usually collected at sampling points at the location to be investigated through an investigation device, and then the soil samples are manually brought back to the laboratory for processing and detection using corresponding equipment to obtain soil heavy metal and microplastic enrichment status data. However, the above-mentioned investigation device has certain limitations. It can only sample soil samples but cannot pre-treat soil samples. For example, when detecting microplastics through the device, it takes a lot of time to separate the microplastics in the soil sample from the soil, which is troublesome to use and affects the overall efficiency. To this end, we propose a soil heavy metal and microplastic enrichment status investigation device and method. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for investigating the enrichment status of heavy metals and microplastics in soil to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A soil heavy metal and microplastic enrichment status investigation device comprises a bottom plate and a plurality of soil collection mechanisms, wherein the bottom plate is connected to a top plate via a guide rod, a pressure rod is movably inserted into the top plate, and a soil collection mechanism is detachably mounted on a mounting piece at the bottom of the pressure rod;

[0007] Wherein, the soil collection mechanism comprises:

[0008] Container 1 and container 2 are hollow at both ends and used for collecting soil, and the two are rotatably connected via a separation part, and the separation part is used to control the inner cavities of container 1 and container 2 to be connected and closed to each other;

[0009] The top plate is provided with a closing mechanism for placing a soil collection mechanism and closing the end of the soil collection mechanism, the closing mechanism is provided with a liquid supply mechanism, the liquid supply mechanism is used to inject flotation liquid into container one to separate the soil and microplastics in container one, an interception plate is movably inserted into the upper part of the side wall of container one, and a through hole is opened on the interception plate for intercepting microplastics.

[0010] A further improvement is that the guide rods are divided into two groups, which are respectively arranged on both sides between the bottom plate and the top plate, and the two groups of guide rods are respectively movably inserted on both sides of the movable plate, and the movable plate is fixedly sleeved on the outside of the mounting member, and the outer wall of the guide rod is sleeved with an elastic member with one end connected to the movable plate and the other end connected to the top plate, and the outer wall of the movable plate is inserted with a fixing member, and the outer wall of the guide rod is provided with several groups of fixing grooves for inserting the fixing members.

[0011] A further improvement is that the separation part comprises a partition plate 1 and a partition plate 2, the partition plate 1 and the partition plate 2 are rotatably connected, and the partition plate 1 and the partition plate 2 are both provided with a plurality of groups of corresponding through holes for soil to pass through.

[0012] A further improvement is that the closing mechanism comprises:

[0013] A plurality of groups of bottom covers, which are used to be sleeved on the bottom end of the second container, wherein the plurality of groups of the bottom covers are detachably fixed on the top plate in a circular array, and the bottom covers are provided with fixing members for fixing the second container; and,

[0014] The pressure plate is movably sleeved on the outer wall of the pressure rod and is used to close the top of container one after container two is connected to the bottom cover. The top of the pressure plate is connected to the rotating member through a telescopic member. The rotating member is rotatably sleeved on the outer wall of the pressure rod and is located above the pressure plate.

[0015] A further improvement is that the outer wall of the pressure rod is also provided with a rotating part, which includes a driving gear fixedly sleeved on the outer wall of the pressure rod and located below the pressure plate, the outer wall of the container is sleeved with a driven gear for meshing with the driving gear, and the bottom of the pressure rod is rotatably connected to the top of the mounting piece.

[0016] A further improvement is that a hollow seat is provided at the top of the pressure rod, an operating handle is provided on the outer wall of the hollow seat, and the liquid supply mechanism includes a cavity opened in the hollow seat and used to store the flotation liquid and a micro-rotating device provided on the pressure plate;

[0017] In which, a micro pump is provided in the cavity, and the output end of the micro pump is connected to a diverter, and the diverter is connected to a plurality of groups of hollow rotating rods through a liquid outlet pipe and a rotating joint. The hollow rotating rods correspond to the bottom cover one by one, and the hollow rotating rods are rotatably inserted on the pressure plate, and the plurality of groups of hollow rotating rods are connected by a sprocket chain transmission group. A stirring sheet is provided on the outer wall of the hollow rotating rod and located below the pressure plate. A through hole for discharging flotation liquid is provided on the outer wall of the hollow rotating rod and located below the pressure plate. The output end of the micro rotating device is connected to one of the hollow rotating rods by a gear group.

[0018] A further improvement is that a drain port is provided at the bottom of the outer wall of a side of the container opposite to the intercepting plate, a sealing plate is provided in the drain port, a channel for accommodating the sealing plate is provided on the top inner wall of the drain port, a contact rod is provided on the top of the sealing plate, an elastic member for driving the contact rod to move upward is provided on the outer wall of the contact rod, the contact rod extends through the channel to a groove provided in a side wall of the container, the groove corresponds to the intercepting plate, a wedge block for contacting the intercepting plate is connected to the groove through an elastic guide rod, and the inclined surface of the wedge block is in sliding contact with the end of the contact rod away from the sealing plate, and when the wedge block is driven to move outward by the intercepting plate, the contact rod drives the sealing plate to open the drain port under the drive of the elastic member.

[0019] A method for investigating the enrichment status of heavy metals and microplastics in soil, using the above-mentioned investigation device, comprises the following steps:

[0020] S1: divide several sampling points in the survey area, place the survey device in the sampling point, install the soil collection mechanism at the mounting part, manually press the pressure rod to drive the soil collection mechanism into the soil at the sampling point, so that the soil enters the second container and the first container, and then control the pressure rod to drive the soil collection mechanism upward to leave the soil at the sampling point;

[0021] S2: First, the soil collection mechanism of the sampled soil is closed by the closing mechanism, and then the inner cavities of container 1 and container 2 are closed by rotating the separation member, and then an appropriate amount of flotation liquid is injected into container 1 through the liquid supply mechanism. After the soil and microplastics in container 1 are separated, the interception plate is manually pressed to enter container 1;

[0022] S3: Remove the soil collection mechanism on the sealing mechanism, and use external equipment to detect heavy metals in the soil in container 2 and the enrichment status of microplastics on the interception plate.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention facilitates the collection of soil samples at different sampling points through a pressure rod and a plurality of groups of soil collection mechanisms, and the collected soil can be classified and stored in container one and container two through a separation part, so as to facilitate the subsequent detection of heavy metal and microplastic enrichment conditions of the soil in container one and container two, respectively, thereby ensuring the accuracy of subsequent detection and improving the quality of investigation work. At the same time, in conjunction with a sealing mechanism and a liquid supply mechanism, it is convenient to inject flotation liquid into container one so that the soil and microplastics in container one are separated, thereby improving the applicability of the investigation device, reducing the cost of subsequent soil sample processing, and effectively improving the overall efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the investigation device of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of the soil collection mechanism of the present invention;

[0027] Figure 3 A top view of the pressing plate structure of the present invention;

[0028] Figure 4 For the present invention Figure 2 A magnified schematic diagram of structure A.

[0029] In the figure: 1. bottom plate; 2. top plate; 3. guide rod; 4. movable plate; 5. mounting part; 6. pressure rod; 7. hollow seat; 8. operating handle; 9. bottom cover; 10. container 1; 11. partition plate 1; 12. partition plate 2; 13. through port; 14. elastic guide rod; 15. driving gear; 16. intercepting plate; 17. pressure plate; 18. hollow rotating rod; 19. telescopic part; 20. micro pump; 21. liquid outlet pipe; 22. rotary joint; 23. sprocket chain transmission group; 24. gear group; 25. micro rotating device; 26. liquid discharge port; 27. sealing plate; 28. contact rod; 29. ​​wedge block. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] See also Figure 1-Figure 2 A soil heavy metal and microplastic enrichment status investigation device comprises a bottom plate 1 and a plurality of soil collection mechanisms, the bottom plate 1 is connected to a top plate 2 via a guide rod 3, a pressure rod 6 is movably inserted on the top plate 2, and one of the soil collection mechanisms is detachably mounted on a mounting member 5 at the bottom of the pressure rod 6;

[0032] Among them, soil collection agencies include:

[0033] The upper and lower ends of the container 10 and the container 2 are hollow and used for collecting soil. The two are rotatably connected by a separation part. The separation part is used to control the inner cavities of the container 10 and the container 2 to be connected and closed to each other. When collecting soil, the inner cavities of the container 10 and the container 2 are connected to each other through the separation part, so that the soil can enter the container 2 and then enter the container 10. Then, the inner cavities of the container 10 and the container 2 are closed to each other through the separation part, so that the soil in the container 10 will not enter the container 2. Preferably, the upper end of the outer wall of the container 10 can be provided with an external thread, and the bottom of the mounting member 5 is provided with a thread groove adapted to the external thread, so that the container 10 and the mounting member 5 are detachably connected. Of course, the two can also be installed by snap-fitting or the like. The bottom end of the container 2 can be provided with a plurality of toothed openings (not shown in the figure) so that the container 2 can be better inserted into the soil.

[0034] A closing mechanism for placing a soil collection mechanism and closing the end of the soil collection mechanism is provided on the top plate 2. The soil collection mechanism not installed at the mounting member 5 can be placed in the closing mechanism. The closing mechanism specifically closes the opposite ends of container 10 and container 2 so that the soil sampled inside will not leak out. A liquid supply mechanism is provided on the closing mechanism. The liquid supply mechanism is used to inject flotation liquid into container 10 to separate the soil and microplastics in container 10. Commonly used flotation liquids include saturated sodium chloride solutions, etc. After the flotation liquid enters container 10 and stands for a period of time, the soil particles will settle to the bottom, while the microplastics will float on the upper layer due to their low density. An interception plate 16 is movably inserted on the upper part of the side wall of container 10 in an L shape. A through hole for intercepting microplastics is provided on the interception plate 16, and its length is greater than the inner cavity length of container 10. After the soil particles and microplastics are layered, the interception plate 16 is pushed between the two. After the flotation liquid is discharged, the microplastics remain on the interception plate 16 under the action of their own gravity.

[0035] Preferably, the guide rods 3 of the present embodiment are divided into two groups, which are respectively arranged on both sides between the bottom plate 1 and the top plate 2. The two groups of guide rods 3 are respectively movably inserted on both sides of the movable plate 4 to ensure that the movable plate 4 can move up and down stably. The movable plate 4 is fixedly sleeved on the outside of the mounting member 5 and moves up and down with the mounting member 5. The outer wall of the guide rod 3 is sleeved with an elastic member with one end connected to the movable plate 4 and the other end connected to the top plate 2. The elastic member is, for example, a spring, which is used to assist the mounting member 5 to reset upward. A fixing member is inserted into the outer wall of the movable plate 4, which is, for example, a bolt. The outer wall of the guide rod 3 is provided with a plurality of groups of fixing grooves for inserting the fixing member, which is convenient for limiting the position of the mounting member 5.

[0036] Preferably, the separation portion of this embodiment includes a partition plate 11 and a partition plate 2 12, both of which are disc-shaped, and the partition plate 11 and the partition plate 2 12 are rotatably connected. Specifically, the top center of the partition plate 11 is rotatably connected to the partition plate 2 12 through a damping shaft and a bearing, and the partition plate 11 and the partition plate 2 12 are each provided with a plurality of groups of through openings 13 for soil to pass through and corresponding to each other. When the through openings 13 on the partition plate 11 and the partition plate 2 12 correspond to each other, as the container 2 enters the soil downward, the soil can first enter the container 2 and then enter the container 10 through the through openings 13. By rotating the container 10, the partition plate 2 12 is driven to rotate relative to the partition plate 11 and the container 2, so that the through openings 13 on the two are staggered. At this time, the soil in the container 10 cannot enter the container 2, and the entered soil is separated.

[0037] Preferably, the closing mechanism of this embodiment includes:

[0038] A plurality of bottom covers 9 are used to be sleeved on the bottom end of the second container to seal the second container so that the soil in the second container is not easy to leak out. It should be noted that when the second container is inserted into the soil, when the second container is separated from the soil, the soil is not easy to fall off from the bottom of the second container due to the friction of the container and the atmospheric pressure. The bottom cover 9 is further used to prevent the soil from falling off from the bottom of the second container. The plurality of bottom covers 9 are detachably fixed on the top plate 2 in an annular array, such as by bolts or buckles. A fixing part for fixing the second container is inserted on the bottom cover 9. The fixing part is, for example, a bolt. The plurality of bottom covers 9 are provided to facilitate carrying a plurality of soil collection mechanisms to collect soil from different sampling points respectively, and facilitate unified processing of soil collection mechanisms that sample soil from different sampling points; and,

[0039] The pressing plate 17 is movably sleeved on the outer wall of the pressing rod 6, and is used to close the top of the container 10 after the container 2 is connected to the bottom cover 9, so that the soil and flotation liquid in the container 10 are not easy to seep out. The top of the pressing plate 17 is connected to the rotating part through a telescopic part 19. The telescopic part 19 is, for example, an electric telescopic rod. The rotating part is rotatably sleeved on the outer wall of the pressing rod 6 and is located above the pressing plate 17. The rotating part is, for example, an annular block rotatably connected to the pressing rod 6 through a bearing, so that the pressing plate 17 is not easy to rotate. When in use, after the container 2 of the soil collection mechanism is connected to the bottom cover 9, the pressing plate 17 can be driven downward by opening the telescopic part 19. It should be noted that during normal sampling work, the telescopic part 19 drives the pressing plate 17 upward to the highest position, which does not affect the pressing rod 6 driving the mounting part 5 so that the soil collection mechanism at its bottom enters the soil at the sampling point.

[0040] See also Figure 3As a preferred embodiment, the outer wall of the pressure rod 6 of this embodiment is also provided with a rotating part, which includes a driving gear 15 fixedly sleeved on the outer wall of the pressure rod 6 and located below the pressure plate 17. The outer wall of the container 10 is sleeved with a driven gear for meshing with the driving gear 15. The bottom of the pressure rod 6 and the top of the mounting member 5 are rotatably connected through a bearing. When the pressure rod 6 is rotated to rotate the driving gear 15, the movable plate 4 can be fixed by a fixing member. After the container 2 is connected to the bottom cover 9, the driven gear on the corresponding container 10 is meshed with the driving gear 15. By rotating the pressure rod 6 to drive the driving gear 15, the driven gear meshed with it can be rotated synchronously in the same direction, thereby changing the through-ports 13 on the partition plate 11 and the partition plate 2 12. It should be noted that a movable port for the driving gear 15 to pass is opened on the top plate 2.

[0041] Preferably, a hollow seat 7 is provided at the top of the pressure rod 6 of the present embodiment, and an operating handle 8 is provided on the outer wall of the hollow seat 7 to facilitate manual sampling by the user. The liquid supply mechanism includes a cavity opened in the hollow seat 7 and used to store the flotation liquid, and a micro-rotating device 25 provided on the pressure plate 17. The micro-rotating device 25 is, for example, a micro-motor. The top of the hollow seat 7 has an inlet for adding the flotation liquid into the interior.

[0042] Among them, a micro pump 20 is provided in the cavity, and the output end of the micro pump 20 is connected to a diverter, and the diverter is connected to a plurality of groups of hollow rotating rods 18 through a liquid outlet pipe 21 and a rotating joint 22. The hollow rotating rods 18 correspond to the bottom cover 9 one by one, and the hollow rotating rods 18 are rotatably inserted on the pressure plate 17. A bearing is provided at the connection between the hollow rotating rods 18 and the pressure plate 17. The plurality of groups of hollow rotating rods 18 are connected by a sprocket chain transmission group 23. The sprocket chain transmission group 23 includes a sprocket sleeved on the outer wall of the hollow rotating rod 18 and a chain that connects the sprockets on the plurality of groups of hollow rotating rods 18. The hollow rotating rods 18 A stirring piece is provided on the outer wall and below the pressing plate 17. The vertical section of the stirring piece is triangular, which is convenient for entering the soil in the container 10. A through hole for discharging the flotation liquid is provided on the outer wall of the hollow rotating rod 18 and below the pressing plate 17. The output end of the micro-rotating device 25 is connected to one of the hollow rotating rods 18 through a gear set 24. The gear set 24 is two sets of meshing gears. The micro-rotating device 25 and the gear set 24 make one of the hollow rotating rods 18 rotate, and the hollow rotating rod 18 rotates synchronously with the rest of the hollow rotating rods 18 through the sprocket chain transmission group 23.

[0043] Preferably, a liquid discharge port 26 is provided at the bottom of the outer wall of the container 10 of the present embodiment on the side opposite to the interception plate 16, a sealing plate 27 is provided in the liquid discharge port 26, and a channel for accommodating the sealing plate 27 is provided on the top inner wall of the liquid discharge port 26 so that the sealing plate 27 can enter and open the liquid discharge port 26. Preferably, in actual situations, in order to discharge only the flotation liquid, a filter screen can be fixed on the outside of the sealing plate 27 in the liquid discharge port 26 so that the soil remains in the container 10; a contact rod 28 is provided on the top of the sealing plate 27, a ball is embedded in the top of the contact rod 28, an elastic member for driving it to move upward is provided on the outer wall of the contact rod 28, and the contact rod 28 extends to the container 10 through the channel. 0, an elastic member is in the groove provided on the side wall, the elastic member is, for example, a spring, one end of which is connected to the bottom inner wall of the groove, and the other end is connected to the top of the outer wall of the contact rod 28, the groove corresponds to the interception plate 16, and is used for the interception plate 16 to enter the groove, a wedge block 29 for contacting the interception plate 16 is connected in the groove through the elastic guide rod 14, and the inclined surface of the wedge block 29 is in sliding contact with one end of the contact rod 28 away from the sealing plate 27, the elastic guide rod 14 can be an elastic telescopic rod or a guide rod with a spring, the wedge block 29 is a right-angled trapezoid, when the wedge block 29 is driven to move outward by the interception plate 16, the contact rod 28 drives the sealing plate 27 to open the drain port 26 under the drive of the elastic member.

[0044] A method for investigating the enrichment status of heavy metals and microplastics in soil, using the above-mentioned investigation device, comprises the following steps:

[0045] S1: Divide a number of sampling points in the survey area, place the survey device in the sampling point, wherein the sampling point is a sample area of ​​1m2, and take samples at the center of the sample area. Install a soil collection mechanism at the mounting member 5, and install the extra soil collection mechanism on the bottom cover 9 for standby use. Manually press the pressure rod 6 to drive the soil collection mechanism into the soil at the sampling point, so that the soil enters the second container and the first container 10, and then manually control the pressure rod 6 to drive the soil collection mechanism upward to leave the soil at the sampling point;

[0046] S2: First, the soil collection mechanism for sampling soil is closed by the closing mechanism, and then the remaining soil collection mechanisms on the bottom cover 9 are taken out to sample at other sampling points. After all the soil collection mechanisms have sampled the soil and are installed on the bottom cover 9, the inner cavities of container 10 and container 2 are then closed to each other by rotating the separation member, that is, the pressure rod 6 is rotated to make the driving gear 15 drive the driven gear, and then a proper amount of flotation liquid is injected into container 10 through the liquid supply mechanism. After the soil and microplastics in container 10 are separated, the interception plate 16 is manually pressed to enter the container 10, and the interception plate 16 presses the wedge block 29 to squeeze the elastic guide rod 14, and then the contact rod 28 drives the sealing plate 27 upward into the channel under the action of the elastic member, thereby discharging the flotation liquid in container 10;

[0047] S3: Remove the soil collection mechanism on the sealing mechanism, and use external equipment to detect heavy metals in the soil in the container 2 and to detect the enrichment status of microplastics on the interception plate 16;

[0048] Among them, the determination of heavy metals in soil samples adopts nitric acid-hydrochloric acid wet digestion; the specific operation steps are as follows: accurately weigh 0.2g of the dry soil sample in container 2 and put it into a polytetrafluoroethylene digestion tube, add 10mL of aqua regia (the configuration ratio is 3:1 by volume of hydrochloric acid and nitric acid) to the digestion tube, and place the digestion tube in a digestion instrument preheated to 120°C, and digest for 6 hours until the yellow-brown gas is completely released. After observing that the gas disappears, gradually increase the temperature to 180°C and continue to digest until the sample solution is transparent and colorless. After the digestion solution is cooled, transfer it to a 50mL volumetric flask with a scale and dilute it to the mark with 1% nitric acid solution. Filter the above solution using a filter membrane with a pore size of 0.45μm. The filtered sample liquid can be directly used for the analysis and determination of heavy metal content. This method can effectively decompose the heavy metal elements in soil samples. Determination of heavy metals: The content of heavy metals (Cd, As, Pb, Ni, Zn, Mn, Cu and Cr) is determined using inductively coupled plasma mass spectrometry (ICP-MS);

[0049] For the microplastics on the interception plate 16, the separated microplastic particles can be directly observed and counted by using instruments such as a microscope or a scanning electron microscope (SEM). By counting the number of microplastics per unit mass or unit volume of soil, the enrichment degree of the microplastics can be preliminarily determined. The separated microplastics can also be weighed to obtain the total mass of the microplastics. By calculating the mass of microplastics per unit mass or unit volume of soil, the enrichment degree of the microplastics can be further quantified.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A soil heavy metal and microplastic enrichment status investigation device, characterized by: It comprises a bottom plate (1) and a plurality of groups of soil collecting mechanisms, wherein the bottom plate (1) is connected to a top plate (2) via a guide rod (3), a pressure rod (6) is movably inserted into the top plate (2), and one of the soil collecting mechanisms is detachably mounted on a mounting member (5) at the bottom of the pressure rod (6); Wherein, the soil collection mechanism comprises: Container 1 (10) and container 2, both of which are hollow at the upper and lower ends and are used to collect soil, are rotatably connected via a separation portion, and the separation portion is used to control the inner cavities of container 1 (10) and container 2 to be connected and closed to each other; The top plate (2) is provided with a closing mechanism for placing a soil collection mechanism and closing the end of the soil collection mechanism, the closing mechanism is provided with a liquid supply mechanism, the liquid supply mechanism is used to inject flotation liquid into the container one (10) so as to separate the soil and microplastics in the container one (10), and an interception plate (16) is movably inserted into the upper part of the side wall of the container one (10), and the interception plate (16) is provided with a through hole for intercepting microplastics.

2. The investigation device according to claim 1, characterized in that: The guide rods (3) are in two groups, which are respectively arranged on both sides between the bottom plate (1) and the top plate (2); the two groups of guide rods (3) are respectively movably inserted on both sides of the movable plate (4); the movable plate (4) is fixedly sleeved on the outside of the mounting member (5); the outer wall of the guide rod (3) is sleeved with an elastic member with one end connected to the movable plate (4) and the other end connected to the top plate (2); the outer wall of the movable plate (4) is inserted with a fixing member; and the outer wall of the guide rod (3) is provided with a plurality of fixing grooves for inserting the fixing members.

3. The investigation device according to claim 2, characterized in that: The separation part comprises a first partition plate (11) and a second partition plate (12), wherein the first partition plate (11) and the second partition plate (12) are rotatably connected, and each of the first partition plate (11) and the second partition plate (12) is provided with a plurality of mutually corresponding through openings (13) for soil to pass through.

4. The investigation device according to claim 3, characterized in that: The closing mechanism comprises: A plurality of groups of bottom covers (9) are used to be sleeved on the bottom end of the second container, and the plurality of groups of the bottom covers (9) are detachably fixedly arranged on the top plate (2) in a circular array, and a fixing piece for fixing the second container is inserted into the bottom covers (9); and, A pressure plate (17) is movably mounted on the outer wall of the pressure rod (6) and is used to close the top of the container one (10) after the container two is connected to the bottom cover (9). The top of the pressure plate (17) is connected to a rotating member through a telescopic member (19). The rotating member is rotatably mounted on the outer wall of the pressure rod (6) and is located above the pressure plate (17).

5. The investigation device according to claim 4, characterized in that: The outer wall of the pressure rod (6) is also provided with a rotating part, and the rotating part includes a driving gear (15) fixedly sleeved on the outer wall of the pressure rod (6) and located below the pressure plate (17); the outer wall of the container (10) is sleeved with a driven gear for meshing with the driving gear (15); the bottom of the pressure rod (6) and the top of the mounting member (5) are rotatably connected.

6. The investigation device according to claim 5, characterized in that: The top of the pressure rod (6) is provided with a hollow seat (7), the outer wall of the hollow seat (7) is provided with an operating handle (8), and the liquid supply mechanism comprises a cavity opened in the hollow seat (7) and used to store the flotation liquid, and a micro-rotating device (25) provided on the pressure plate (17); A micro pump (20) is arranged in the cavity, the output end of the micro pump (20) is connected to a flow divider, the flow divider is connected to a plurality of groups of hollow rotating rods (18) through a liquid outlet pipe (21) and a rotary joint (22), the hollow rotating rods (18) and the bottom cover (9) correspond one to one, and the hollow rotating rods (18) are rotatably inserted on the pressing plate (17), the plurality of groups of the hollow rotating rods (18) are connected by transmission through a sprocket chain transmission group (23), the outer wall of the hollow rotating rod (18) and located below the pressing plate (17) is provided with a stirring sheet, the outer wall of the hollow rotating rod (18) and located below the pressing plate (17) is provided with a through hole for discharging the flotation liquid, and the output end of the micro rotating device (25) is connected by transmission with one of the hollow rotating rods (18) through a gear group (24).

7. The investigation device according to claim 2, characterized in that: The container 1 (10) is provided with a liquid discharge port (26) at the bottom of the outer wall on the side opposite to the interception plate (16), a sealing plate (27) is provided in the liquid discharge port (26), a channel for accommodating the sealing plate (27) is provided on the top inner wall of the liquid discharge port (26), a contact rod (28) is provided on the top of the sealing plate (27), an elastic member for driving the contact rod (28) to move upward is provided on the outer wall of the contact rod (28), and the contact rod (28) extends through the channel to the container 1 (10). A groove is formed in the side wall, the groove corresponding to the interception plate (16), a wedge block (29) for contacting the interception plate (16) is connected in the groove via an elastic guide rod (14), and an inclined surface of the wedge block (29) is in sliding contact with an end of the contact rod (28) away from the sealing plate (27), and when the wedge block (29) is driven to move outward by the interception plate (16), the contact rod (28) drives the sealing plate (27) to open the discharge port (26) under the drive of the elastic member.

8. A method for investigating the enrichment of heavy metals and microplastics in soil, using the investigation device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: A number of sampling points are divided in the survey area, the survey device is placed in the sampling point, a soil collection mechanism is installed at the mounting part (5), and the pressure rod (6) is manually pressed to drive the soil collection mechanism into the soil at the sampling point so that the soil enters the second container and the first container (10), and then the pressure rod (6) is controlled to drive the soil collection mechanism upward to leave the soil at the sampling point; S2: First, the soil collection mechanism for sampling soil is closed by a sealing mechanism, then the inner cavities of container 1 (10) and container 2 are sealed with each other by rotating the separation member, and then an appropriate amount of flotation liquid is injected into container 1 (10) by a liquid supply mechanism. After the soil and microplastics in container 1 (10) are separated by layers, the interception plate (16) is manually pressed to enter container 1 (10); S3: Remove the soil collection mechanism on the sealing mechanism, and use external equipment to detect the heavy metal content of the soil in the second container and the enrichment status of the microplastics on the interception plate (16).

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