A method for evaluating heavy metal pollution in marine sediments based on multi-metric index of benthic animals

Abstract

The present invention relates to the technical field of heavy metal pollution assessment, and in particular to a method for assessing heavy metal pollution in marine sediments based on the benthic multimetric index. The method is based on the integrity index (MMI) constructed with large benthic animals to evaluate and grade the heavy metal pollution level in marine sediments. The present invention finds that the MMI index composed of RaoQ, filter-feeding species biomass%, ecological group I (EGI) biomass%, number of ecological group I taxa, and ecological group III (EGIII) biomass% can effectively distinguish differences in heavy metal pollution levels in marine sediments; through the cooperation of the cyclic adjustment mechanism and the angle fine-tuning component, the angle of the probe can be adjusted while rotating for detection, with a low operating threshold and low cost, and can effectively evaluate heavy metal pollution in marine sediments.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy metal pollution assessment, and in particular to a method for assessing heavy metal pollution in marine sediments based on a benthic animal multi-metric index. Background Art

[0002] As an important stress factor in the ecological environment, heavy metals are difficult to be biodegraded, and long-term residual pollution causes continuous pollution to the ecological environment, and can easily produce bioaccumulative effects through the food chain. With the development and progress of human society, the heavy metal pollution problem brought about by sustainable development has become an unavoidable pollution problem and has attracted widespread attention. In order to limit heavy metal pollution, the European Union has promulgated a variety of laws to restrict the discharge of heavy metals and other harmful substances into rivers and seas. For example, the Water Framework Directive sets strict control standards for heavy metals such as lead, mercury, and cadmium.

[0003] Sediments are important areas of heavy metal enrichment in aquatic environments. 99% of heavy metal loads in aquatic environments are eventually precipitated in sediments. Due to the low solubility, hydrolysis, adsorption and co-precipitation of heavy metal ions, heavy metal ions can be repeatedly exchanged and accumulated between surface sediments and water bodies. Heavy metal pollution in sediments is a comprehensive response to the surrounding ecological environment. Therefore, heavy metals in surface sediments can be used as a good indicator for evaluating regional pollution.

[0004] Compared with physical or chemical indicators, biological indicators have many advantages. Compared with single physical or chemical monitoring indicators, biological indicators can better reflect the comprehensive changes of physical, chemical, biological and other factors in the ecological environment. Compared with the high monitoring costs of heavy metal and other pollution indicators, biological indicators are cheap, which effectively reduces the operating costs of ecological environment quality monitoring. Multi-metric indexes (MMIs) are considered to be an important method to improve the sensitivity of biological indicator evaluation. The construction of multi-metric indexes fully considers the habitat type, while reducing the variability of biological indicators, and evaluates the ecological environment quality by evaluating multiple structural and functional indicators.

[0005] Large benthic animals refer to invertebrate groups that live at the bottom of water bodies for all or most of their life history. They are an important part of marine ecosystem communities and are widely distributed in sedimentary environments. Large benthic animals have a long life cycle, weak mobility, are easy to collect, and are sensitive to environmental changes. They are considered to be good biological indicators that reflect changes in the ecological environment. The AMBI and M-AMBI indices commonly used in China were invented by Spain. Some researchers have pointed out that the five ecological groups developed by this type of index are not fully adapted to non-Spanish areas, and countries need to actively invent biological evaluation indices suitable for their national conditions. However, the multi-metric index constructed based on benthic animals in China is generally used for freshwater ecosystem health assessment, and rarely involves marine ecosystems, which is not conducive to the development of a complete marine ecosystem health assessment. Moreover, the construction of multi-metric indexes is to screen the most suitable parameters, and it is necessary to consider the applicable parameter types and multiple parameter combinations. Due to the lack of relevant research, the parameters suitable for my country's sea areas are still unclear, and relevant work needs to be promoted urgently. The improvement of my country's marine ecosystem health assessment system is not perfect, and there is no reliable monitoring method for heavy metal pollution. The existing equipment is not simple and cannot effectively evaluate the heavy metal pollution in marine sediments. Summary of the invention

[0006] The present invention proposes a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index, comprising the following steps:

[0007] Step 1: Detect through benthic animal monitoring device, then collect, classify and identify the collected large benthic animal samples through stereoscope, count the number of large benthic animals collected, count the number of incomplete large benthic animals, weigh the biomass of large benthic animals, weigh mollusks and crustaceans with shells, and weigh hermit crabs without shells;

[0008] Step 2: Matching species’ ecological groups with functional trait information;

[0009] Step 3: Calculate the construction completeness index related indicators:

[0010]

[0011] Where S is the species richness, i is the i-th species, j is the i+1-th species, d ij is the difference between the i-th species and the j-th species, p i is the relative abundance among species; the actual calculation can be performed by the dbFD function of the "FD" installation package in R4.0.3;

[0012] The number of taxonomic units of ecological group I at the i-th point (Si) is the number of species in ecological group I at the collection point. The calculation formulas for the remaining indicators are as follows:

[0013]

[0014]

[0015]

[0016] Among them, W 滤食i is the biomass of filter-feeding species at the i-th point, weight 滤食i is the biomass of filter-feeding species at the ith site, W EGIi is the biomass of ecological group I at the ith point, weight EGI i is the biomass of ecological group I at the i-th point, W EGIIIi is the biomass of ecological group III at the ith site, weight EGIIIi is the biomass of ecological group III at the ith point, weight 总i is the total biomass at the ith point;

[0017] Step 4: Based on the parameters calculated in step (3), standardize the parameters:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023] The standardized index is used to calculate the MMI value:

[0024]

[0025] Step 5: Use MMI to classify the heavy metal pollution level of marine sediments. MMI ≤ 35.38 is Class III, 35.38 < MMI ≤ 70.76 is Class II, and 70.76 < MMI is Class I.

[0026] As a further solution of the present invention, the benthic animal monitoring device includes a base, a driving motor is provided on the top surface of the base, a driving gear is installed at the output end of the driving motor, and the driving gear is connected to the driven gear on the first transmission rod through a gear chain; one end of the first transmission rod is connected to the first transmission bearing on the base, and the other end is connected to the driving gear, and the driving gear is connected to the circulation adjustment mechanism.

[0027] As a further solution of the present invention, the circulation adjustment mechanism includes an externally rotating half gear meshing with the driving gear, and a rotating groove is provided on the externally rotating half gear, and the rotating groove is rotatably connected to a rotating bar on the top cover.

[0028] As a further solution of the present invention, a connecting rod is provided on the inner wall of the rotating bar, and the connecting rod passes through a circular hole provided on the outer rotating half gear and is connected to the half ring.

[0029] As a further solution of the present invention, a pad is provided on the semi-ring, guard plates are installed on both sides of the pad, a rotating shaft is provided on the guard plate, and a matching pulley is installed on the rotating shaft.

[0030] As a further solution of the present invention, a second rotating bearing is provided on the base, a second transmission rod is installed on the second rotating bearing, and a matching gear is provided at one end of the second transmission rod away from the second rotating bearing, and the matching gear meshes with the external rotating half gear.

[0031] As a further solution of the present invention, a vertical plate is installed on the base, a horizontal plate is provided on the side of the vertical plate, a first rotating rod is installed on the side of the horizontal plate away from the base, the first rotating rod is connected to the rotating groove provided on the bottom surface of the externally rotating half gear, a straight plate is provided on the side of the horizontal plate, a second rotating rod is provided on the side of the straight plate close to the vertical plate, and the second rotating rod is connected to the matching groove provided on the inner side surface of the externally rotating half gear.

[0032] As a further solution of the present invention, a supporting column is provided on the base, which is connected to the bottom surface of the top cover at one end away from the base. A control motor is provided on the top cover, which is connected to the angle fine-tuning component; a fixed block is installed on the bottom surface of the control motor, which is connected to the assembly.

[0033] As a further scheme of the present invention, the assembly includes a bottom box provided on the base, an auxiliary block is provided on the side of the bottom box, and a limit opening is provided on the side of the auxiliary block, the bottom box and the fixed block, which are limited by the limit block, and a pulling block is fixedly installed on the side of the limit block away from the limiting opening, and the pulling block and the auxiliary block are fixedly connected by a tension spring; a connecting block is provided on the side of the bottom box, and a round rod is provided on the connecting block, and one end of the round rod away from the bottom box is fixedly connected to the pulling plate, and the pulling plate and the connecting block are fixedly connected by a compression spring, and the round rod and the limit block, the bottom box and the fixed block are provided with a circular groove limiting setting on the side away from the tension spring.

[0034] As a further solution of the present invention, the angle fine-tuning assembly includes an active bevel gear connected to the output end of the control motor, the active bevel gear is meshingly connected with the driven bevel gear on the driving worm locking shaft, and both ends of the driving worm locking shaft are connected to the stabilizing block on the top cover; the driving worm locking shaft is provided with a first worm area and a second worm area, and the worm areas at both ends are opposite; the first worm area and the second worm area are meshingly connected with the turbine, the turbine is provided with a threaded shaft, the threaded shaft is connected to the threaded block, a placement plate is installed on the top of the threaded block, and a monitoring probe is provided on the top surface of the placement plate.

[0035] The beneficial effects of the present invention are:

[0036] 1. Compared with the single index method for judging sediment quality in "Marine Sediment Quality" (GB18668-2002) used in my country, the present invention selects the RI index popularly used internationally to judge the degree of heavy metal pollution in sediments. This index evaluates the comprehensive pollution risk of aquatic systems by the toxic reaction factor of a given substance, and can better reflect the actual pollution level of sediments under the condition of enrichment of multiple heavy metals;

[0037] 2. Compared with the expensive heavy metal detection costs and cumbersome monitoring steps, the method of the present invention greatly reduces the operating costs, reduces the use of chemical reagents, and reduces the pollution of the detection itself to the environment;

[0038] 3. The present invention selects five parameters to construct a multi-metric index, which fully considers the main change patterns of benthic animal communities under heavy metal pollution. The index is easy to calculate and suitable for promotion and use;

[0039] 4. The present invention is developed based on the domestic marine sediment environment. Its selected indicators and combinations are in line with my country's local environment. It develops and enriches the content and diversity of marine ecological environment biological indexes, deepens the basic theory of marine ecosystem health assessment, and provides valuable basic data for future marine ecosystem health assessment and management;

[0040] 5. The benthic animal monitoring device of the present invention can be matched with an underwater collection device to improve the collection efficiency. The benthic animal monitoring device starts the driving motor, which drives the driving gear to rotate. The gear chain and the driven gear cooperate to rotate the outer half gear. A connecting rod is provided on the inner wall of the rotating bar, which passes through a circular hole and is connected to the half ring, and then drives the half ring to rotate. The pulley on the half ring assists the top cover to rotate, so that the top cover rotates more stably. At the same time, the first rotating rod and the second rotating rod cooperate with the rotating groove and the matching groove, so that the device is simple and the top cover is safer when rotating.

[0041] 6. When the top cover rotates, it drives the monitoring probe to rotate. This device can be attached to the collection device for monitoring. At the same time, the drive motor and the control motor are waterproof. The angle of the monitoring probe on the top surface of the placement plate can be controlled by the angle fine-tuning component. When the top cover is rotating and the monitoring probe monitors benthic animals, the drive motor is turned off to stop the top cover from rotating. By starting the forward and reverse rotation of the control motor, the angle of the monitoring probe on the top cover can be controlled to ensure the efficiency and accuracy of the monitoring. When monitoring benthic animals, they are collected and analyzed by the collection device, which can effectively evaluate the heavy metal pollution in marine sediments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of a method for evaluating heavy metal pollution in marine sediments based on the benthic animal multi-metric index proposed by the present invention, in which the MMI index and the RI index are extremely significantly negatively correlated;

[0043] Figure 2 This is a result diagram of the classification of heavy metal pollution levels in marine sediments based on the MMI score of a method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index proposed by the present invention;

[0044] Figure 3 This is a schematic diagram of the overall structure of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0045] Figure 4 This is a schematic diagram of the local enlarged structure at point A of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0046] Figure 5 This is a schematic diagram of the upward-looking structure of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0047] Figure 6 This is a schematic diagram of the local enlarged structure of point B of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0048] Figure 7 This is a schematic diagram of the side structure of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0049] Figure 8 This is a schematic diagram of the partially enlarged structure at position C of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0050] Fig. 9A schematic diagram of the thread block decomposition structure of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0051] Fig.10 A schematic diagram of the assembly structure of a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index proposed by the present invention;

[0052] In the figure: 1, base; 2, driving motor; 3, driving gear; 4, gear chain; 5, driven gear; 6, outer half gear; 7, rotating groove; 8, top cover; 9, rotating bar; 10, connecting rod; 11, round hole; 12, half ring; 13, pad; 14, guard plate; 15, rotating shaft; 16, matching pulley; 17, first transmission rod; 18, first transmission bearing; 19, driving gear; 20, second rotating bearing; 21, second transmission rod; 22, matching gear; 23, vertical plate; 24, horizontal plate; 25, first rotating rod; 26, rotating groove; 27, straight plate; 2 8. Second rotating rod; 29. ​​Matching groove; 30. Support column; 31. Control motor; 32. Fixed block; 33. Bottom box; 34. Auxiliary block; 35. Limit block; 36. Limit opening; 37. Pull block; 38. Tension spring; 39. Connecting block; 40. Round rod; 41. Pull plate; 42. Compression spring; 43. Round groove; 44. Active bevel gear; 45. Drive worm locking shaft; 46. Driven bevel gear; 47. Stabilizing block; 48. First worm section; 49. Second worm section; 50. Turbine; 51. Threaded shaft; 52. Threaded block; 53. Placement plate; 54. Monitoring probe. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0054] The present embodiment provides a method for evaluating heavy metal pollution in marine sediments based on a benthic animal multi-metric index, comprising the following steps:

[0055] Step 1: Detect through benthic animal monitoring device, then collect, classify and identify the collected large benthic animal samples through stereoscope, count the number of large benthic animals collected, count the number of incomplete large benthic animals, weigh the biomass of large benthic animals, weigh mollusks and crustaceans with shells, and weigh hermit crabs without shells;

[0056] Step 2: Matching species’ ecological groups with functional trait information;

[0057] Step 3: Calculate the construction completeness index related indicators:

[0058]

[0059] Where S is the species richness, i is the i-th species, j is the i+1-th species, d ij is the difference between the i-th species and the j-th species, p i is the relative abundance among species; the actual calculation can be performed by the dbFD function of the "FD" installation package in R4.0.3;

[0060] The number of taxonomic units of ecological group I at the i-th point (Si) is the number of species in ecological group I at the collection point. The calculation formulas for the remaining indicators are as follows:

[0061]

[0062]

[0063]

[0064] Among them, W 滤食i is the biomass of filter-feeding species at the i-th point, weight 滤食i is the biomass of filter-feeding species at the ith site, W EGIi is the biomass of ecological group I at the ith point, weight EGI i is the biomass of ecological group I at the i-th point, W EGIIIi is the biomass of ecological group III at the ith site, weight EGIIIi is the biomass of ecological group III at the ith point, weight 总i is the total biomass at the ith point;

[0065] Step 4: Based on the parameters calculated in step (3), standardize the parameters:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] The standardized index is used to calculate the MMI value:

[0072]

[0073] Step 5: Use MMI to classify the heavy metal pollution level of marine sediments. MMI ≤ 35.38 is Class III, 35.38 < MMI ≤ 70.76 is Class II, and 70.76 < MMI is Class I.

[0074] The benthic animal monitoring device of this embodiment includes a base 1, a driving motor 2 is provided on the top surface of the base 1, a driving gear 3 is installed at the output end of the driving motor 2, and the driving gear 3 is connected to the driven gear 5 on the first transmission rod 17 through a gear chain 4; one end of the first transmission rod 17 is connected to the first transmission bearing 18 on the base 1, and the other end is connected to the driving gear 19, and the driving gear 19 is connected to the circulation adjustment mechanism.

[0075] The circulation adjustment mechanism of this embodiment includes an outer rotating half gear 6 meshing with the driving gear 19 , and a rotation groove 7 is provided on the outer rotating half gear 6 , and the rotation groove 7 is rotatably connected to a rotation bar 9 on the top cover 8 .

[0076] In this embodiment, a connecting rod 10 is provided on the inner wall of the rotating bar 9 , and the connecting rod 10 passes through a circular hole 11 provided on the outer rotating half gear 6 and is connected to the half ring 12 .

[0077] In this embodiment, a backing plate 13 is provided on the half ring 12 , and guard plates 14 are installed on both sides of the backing plate 13 . A rotating shaft 15 is provided on the guard plate 14 , and a matching pulley 16 is installed on the rotating shaft 15 .

[0078] In this embodiment, a second rotating bearing 20 is disposed on the base 1 , a second transmission rod 21 is mounted on the second rotating bearing 20 , and a matching gear 22 is disposed at one end of the second transmission rod 21 away from the second rotating bearing 20 , and the matching gear 22 meshes with the outer rotating half gear 6 .

[0079] A vertical plate 23 is installed on the base 1 of this embodiment, and a horizontal plate 24 is provided on the side of the vertical plate 23. A first rotating rod 25 is installed on the side of the horizontal plate 24 away from the base 1, and the first rotating rod 25 is connected to the rotating groove 26 provided on the bottom surface of the external rotating half gear 6. A straight plate 27 is provided on the side of the horizontal plate 24, and a second rotating rod 28 is provided on the side of the straight plate 27 close to the vertical plate 23. The second rotating rod 28 is connected to the matching groove 29 provided on the inner side of the external rotating half gear 6.

[0080] A supporting column 30 is provided on the base 1 of the present embodiment, and the supporting column 30 is connected to the bottom surface of the top cover 8 at one end away from the base 1. The top cover 8 is provided with a control motor 31, and the control motor 31 is connected to the angle fine-tuning component; a fixing block 32 is installed on the bottom surface of the control motor 31, and the fixing block 32 is connected to the assembly.

[0081] By starting the driving motor 2, the driving motor 2 drives the driving gear 3 to rotate, and through the cooperation of the gear chain 4 and the driven gear 5, the outward rotating half gear 6 is rotated. A connecting rod 10 is provided on the inner wall of the rotating bar 9, which passes through the circular hole 11 and is connected to the half ring 12, thereby driving the half ring 12 to rotate. The pulley 16 on the half ring 12 assists in the rotation of the top cover 8, so that the rotation of the top cover 8 is more stable. At the same time, through the cooperation of the first rotating rod 25 and the second rotating rod 28 with the rotating groove 26 and the matching groove 29, the device is simplified and the safety of the top cover 8 is improved when it is rotating.

[0082] The assembly of this embodiment includes a bottom box 33 provided on the base 1, an auxiliary block 34 is provided on the side of the bottom box 33, and a limiting opening 36 is provided on the side of the auxiliary block 34, the bottom box 33 and the fixed block 32, which are limited by the limiting block 35, and a pulling block 37 is fixedly installed on the side of the limiting block 35 away from the limiting opening 36, and the pulling block 37 is fixedly connected to the auxiliary block 34 by a tension spring 38; a connecting block 39 is provided on the side of the bottom box 33, and a round rod 40 is provided on the connecting block 39, and the end of the round rod 40 away from the bottom box 33 is fixedly connected to the pulling plate 41, and the pulling plate 41 and the connecting block 39 are fixedly connected by a compression spring 42, and the round rod 40 is limited by a round groove 43 provided on the side of the limiting block 35, the bottom box 33 and the fixed block 32 away from the tension spring 38.

[0083] The angle fine-tuning assembly of this embodiment includes a driving bevel gear 44 connected to the output end of the control motor 31, the driving bevel gear 44 is meshed with a driven bevel gear 46 on a driving worm locking shaft 45, and both ends of the driving worm locking shaft 45 are connected to a stabilizing block 47 on the top cover 8; the driving worm locking shaft 45 is provided with a first worm section 48 and a second worm section 49, and the worm sections at both ends are opposite; the first worm section 48 and the second worm section 49 are meshed with a turbine 50, the turbine 50 is provided with a threaded shaft 51, the threaded shaft 51 is connected to a threaded block 52, a placement plate 53 is installed at the top end of the threaded block 52, and a monitoring probe 54 is provided on the top surface of the placement plate 53;

[0084] When the top cover 8 rotates, it drives the monitoring probe 54 to rotate. The device can be attached to the collection device for monitoring. At the same time, the driving motor 2 and the control motor 31 have waterproof functions. The monitoring probe 54 on the top surface of the placement plate 53 can be controlled to adjust the angle through the angle fine-tuning component. When the top cover 8 is rotating and the monitoring probe 54 detects benthic animals, the driving motor 2 is turned off to stop the top cover 8 from rotating. By starting the forward and reverse rotation of the control motor 31, the monitoring probe 54 on the top cover 8 can be controlled to adjust the angle to ensure the efficiency and accuracy of the monitoring. When benthic animals are monitored, they are collected and analyzed through the collection device.

[0085] Example 1

[0086] (1) Collect samples of macrobenthic animals at designated sampling points in the Bohai Sea;

[0087] From 2020 to 2021, four seasons of field collection were carried out in the Bohai Sea, involving a total of 42 collection points, covering the main sea areas of the Bohai Sea. The Bohai Sea is one of the most seriously polluted coastal waters by heavy metals in the country. According to the "2021 China Ecological Environment Bulletin", the degree of seawater pollution in the Bohai Sea decreases with increasing distance from the shore. The multi-metric index constructed based on the data from this sea area can cover a wider range of heavy metal pollution and is more universal and generalizable.

[0088] After collecting sediment samples with a mud sampler, they were sieved and washed with a 40-mesh sieve. The sieved macrobenthic animal samples and the remaining residues were fixed with 75% alcohol and brought back to the laboratory for morphological identification. Sediment samples were also collected, bagged and stored at -20°C for heavy metal analysis in the laboratory. After identification, the samples were counted and weighed, the residues were counted by head, the wet weight of macrobenthic animals was weighed, the mollusks and crustaceans were weighed with shells, and the hermit crabs were weighed without shells. The number and wet weight were converted into abundance (ind / m) according to the collection area. 2 ) and biomass (g / m 2 ), and then matched the species’ ecological groups with functional trait information;

[0089] (2) Input the abundance and biomass data and calculate the completeness index related indicators according to the following formula

[0090]

[0091] Where S is the species richness, i is the i-th species, j is the i+1-th species, d ij is the difference between the i-th species and the j-th species, p i is the relative abundance among species; the actual calculation can be performed by the dbFD function of the "FD" installation package in R4.0.3;

[0092] The number of taxonomic units of ecological group I at the i-th point (Si) is the number of species in ecological group I at the collection point. The calculation formulas for the remaining indicators are as follows:

[0093]

[0094]

[0095]

[0096] Among them, W 滤食i is the biomass of filter-feeding species at the i-th point, weight 滤食i is the biomass of filter-feeding species at the ith site, W EGIiis the biomass of ecological group I at the ith point, weight EGI i is the biomass of ecological group I at the i-th point, W EGIIIi is the biomass of ecological group III at the ith site, weight EGIIIi is the biomass of ecological group III at the ith point, weight 总i is the total biomass at the ith point.

[0097] (3) Based on the parameters calculated in step (2), standardize the respective parameters:

[0098]

[0099]

[0100]

[0101]

[0102]

[0103] The standardized index is used to calculate the MMI value:

[0104]

[0105] (4) The MMI is used to classify the heavy metal pollution levels in marine sediments: MMI ≤ 35.38 is Class III, 35.38 < MMI ≤ 70.76 is Class II, and 70.76 < MMI is Class I.

[0106] Example 2

[0107] (1) The sediment samples collected at each point were air-dried in the laboratory, ground in a mortar, sieved through 100 mesh (0.149 nm) gauze, dried and stored for later use. When determining the heavy metal content, 0.1 g of sample was placed in a crucible, and nitric acid and perchloric acid were added for nitrolysis. After the acid was removed on a hot plate, 1 ml of hydrochloric acid was added and the sample was transferred to a 10 ml quantitative bottle to make up the volume. To ensure the accuracy of the data, all reagents used were ultra-pure.

[0108] (2) After the volume was fixed, the samples were used to monitor heavy metals. Cd, Pb, Cr, Cu and Ni were determined by atomic absorption spectrometry, Zn was determined by flame absorption spectrometry, and As and Hg were determined by fluorescence absorption. During the experiment, each batch of samples was subjected to full blank and parallel sample determination. After deducting the blank value, the experimental data of each element was reported as the average of the parallel sample determination values.

[0109] (3) Substitute the monitored data into the following formula to calculate the RI value:

[0110]

[0111]

[0112]

[0113] Among them C i and are the metal concentrations monitored in sediment samples and the geochemical background values ​​of metals, respectively; Value and B n The values ​​are the same; is a single pollution factor; It is a potential ecological risk factor; It is the "toxic reaction" factor of a specific substance, for example: Cu = Pb = Ni = 5, Zn = 1, Cd = 30, Cr = 2, As = 10, Hg = 40;

[0114] The RI index refers to the following criteria to judge the comprehensive pollution risk:

[0115] Low ecological risk: RI<150; moderate ecological risk: 150≤RI<300; high ecological risk: 300≤RI<600; extremely high ecological risk: RI≥600.

[0116] (4) Analysis of the relationship between MMI and RI index

[0117] Based on the MMI index and RI index calculated from the data of 42 points in Bohai Sea, the correlation between the two is analyzed; Figure 1 The relationship between the benthic animal MMI index constructed based on the Bohai Sea sites and the RI index based on 8 types of sediment heavy metal pollution information; Figure 1 It can be seen that the MMI index and the RI index are extremely significantly negatively correlated (after calibration R 2 =0.2295, p<0.001); Figure 2 The results show that the RI index shows an upward trend among the three levels of MMI classification, and there is a significant difference between the RI index of level I and level III (p<0.05), which proves that the MMI index of the present invention can effectively distinguish the heavy metal pollution levels in different sedimentary environments and is a reliable and accurate heavy metal pollution evaluation method.

[0118] The above description is only a preferred specific implementation manner of the present invention, but 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 scheme and inventive concept of the present invention 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 evaluating heavy metal pollution in marine sediments based on a multi-metric index of benthic animals, characterized in that: It includes the following steps: Step 1: Detect through a benthic animal monitoring device, then collect samples. Classify and identify the collected macro-benthic animal samples through a stereomicroscope, count the number of collected macro-benthic animals. Incomplete macro-benthic animals are counted by head, weigh the biomass of macro-benthic animals, weigh mollusks and crustaceans with shells, and weigh hermit crabs without shells; Step 2: Match the ecological group and functional trait information of the species; Step 3: Calculate the indicators related to constructing the integrity index: Where S is the species richness, i is the i-th species, j is the i+1-th species, d ij is the difference between the i-th species and the j-th species, p i is the relative abundance among species; the actual calculation is performed by the dbFD function of the "FD" installation package in R4.0.3; The number of taxonomic units Sn of ecological group I at the nth sampling point, that is, the number of species of ecological group I at the sampling point. The calculation formulas for the remaining indicators are as follows: Among them, W 滤食n is the biomass of filter-feeding species at the nth point, weight 滤食n is the biomass of filter-feeding species at the nth point, W EGIn is the biomass of ecological group I at the nth point, % weight EGI n is the biomass of ecological group I at the nth point, W EGIIIn is the biomass of ecological group III at the nth point, weight EGIIIn is the biomass of ecological group III at the nth point, weight 总n is the total biomass at the nth point; Step 4: Based on the parameters calculated in Step 3, standardize each parameter: The standardized index is used to calculate the MMI value: Step 5: Use MMI to divide the heavy metal pollution level of marine sediments. When MMI ≤ 35.38, it is Class III; when 35.38 < MMI ≤ 70.76, it is Class II; when 70.76 < MMI, it is Class I.

2. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 1, characterized in that: The benthic animal monitoring device includes a base (1). A driving motor (2) is provided on the top surface of the base (1). The output end of the driving motor (2) is equipped with a driving gear (3). The driving gear (3) is connected to a driven gear (5) on a first transmission rod (17) through a gear chain (4). One end of the first transmission rod (17) is connected to a first transmission bearing (18) on the base (1), and the other end is connected to a driving gear (19). The driving gear (19) is connected to a circulation adjustment mechanism.

3. The method for evaluating heavy metal pollution in marine sediments based on the benthic multi-metric index according to claim 2 is characterized in that: The circulation adjustment mechanism includes an outer rotating semi-gear (6) meshing with the driving gear (19). A rotating groove (7) is provided on the outer rotating semi-gear (6). The rotating groove (7) is rotatably connected to a rotating bar (9) on the top cover (8).

4. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 3 is characterized in that: A connecting rod (10) is provided on the inner wall of the rotating bar (9). The connecting rod (10) passes through a circular hole (11) provided on the outer rotating semi-gear (6) and is connected to a semi-ring (12).

5. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 4 is characterized in that: A cushion plate (13) is provided on the semi-ring (12). Protective plates (14) are installed on both sides of the cushion plate (13). A rotating shaft (15) is provided on the protective plate (14), and a mating pulley (16) is installed on the rotating shaft (15).

6. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 2 is characterized in that: A second rotating bearing (20) is provided on the base (1). A second transmission rod (21) is installed on the second rotating bearing (20). A mating gear (22) is provided at the end of the second transmission rod (21) away from the second rotating bearing (20). The mating gear (22) meshes with the outer rotating semi-gear (6).

7. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 2 is characterized in that: A vertical plate (23) is installed on the base (1). A horizontal plate (24) is provided on the side of the vertical plate (23). A first rotating rod (25) is installed on the side of the horizontal plate (24) away from the base (1). The first rotating rod (25) is connected to a rotating groove (26) provided on the bottom surface of the outer rotating semi-gear (6). A straight plate (27) is provided on the side of the horizontal plate (24). A second rotating rod (28) is provided on the side of the straight plate (27) close to the vertical plate (23). The second rotating rod (28) is connected to a mating groove (29) provided on the inner side surface of the outer rotating semi-gear (6).

8. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 2 is characterized in that: The base (1) is provided with a support column (30), the support column (30) is connected to the bottom surface of a top cover (8) at one end away from the base (1), the top cover (8) is provided with a control motor (31), the control motor (31) is connected to the angle fine adjustment component; the bottom surface of the control motor (31) is installed with a fixing block (32), and the fixing block (32) is connected to the assembly.

9. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 8, characterized in that: The assembly comprises a bottom box (33) provided on a base (1); an auxiliary block (34) is provided on a side of the bottom box (33); a limiting opening (36) which is limited by a limiting block (35) is provided on the sides of the auxiliary block (34), the bottom box (33) and the fixed block (32); a pulling block (37) is fixedly installed on a side of the limiting block (35) away from the limiting opening (36); the pulling block (37) is fixedly connected to the auxiliary block (34) via a tension spring (38); A connecting block (39) is provided on the side of the bottom box (33), and a round rod (40) is provided on the connecting block (39). One end of the round rod (40) away from the bottom box (33) is fixedly connected to a pull plate (41), and the pull plate (41) and the connecting block (39) are fixedly connected via a compression spring (42). The round rod (40) is limited by a round groove (43) provided on one side of the limiting block (35), the bottom box (33) and the fixed block (32) away from the tension spring (38).

10. The method for evaluating heavy metal pollution in marine sediments based on benthic animal multi-metric index according to claim 8, characterized in that: The angle fine-tuning assembly comprises an active bevel gear (44) connected to the output end of the control motor (31), the active bevel gear (44) is meshedly connected with a driven bevel gear (46) on a driving worm locking shaft (45), and both ends of the driving worm locking shaft (45) are connected with a stabilizing block (47) on a top cover (8); the driving worm locking shaft (45) is provided with a first worm section (48) and a second worm section (49), and the worm sections at both ends are opposite; the first worm section (48) and the second worm section (49) are meshedly connected with a turbine (50), the turbine (50) is provided with a threaded shaft (51), the threaded shaft (51) is connected with a threaded block (52), a placement plate (53) is installed at the top end of the threaded block (52), and a monitoring probe (54) is provided on the top surface of the placement plate (53).

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