JP2007285707A - Simplified test method for elution amount and content of toxic substance in soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simplified test method for the elution amount and the content of a toxic substance in a soil, capable of estimating easily a concentration corresponding to an official test method, in a sufficiently short time as compared with the official test method for a large number of specimens, without having to use organic solvents, and being usable for confirmation of the presence of contamination, search of a high concentration of contaminated point, or the like. <P>SOLUTION: The elution amount and the content of the toxic substances in the soil by the official test method are estimated, based on the analysis values of an elution amount testing specimen solution, obtained by collecting a relatively small amount of soil sample, by adding water of five times or more thereof thereto, to be shaken for about several minutes or shorter of a prescribed time, and by carrying out, thereafter, filtration with a plurality of layers of paper filters or the like, layered with a paper filter having 1 μm or larger pore size on a paper filter having 0.45 μm of pore size, and based on an analytical value for a content testing specimen solution obtained, by adding an acidic aqueous solution or a weak alkaline aqueous solution (in the case of Cr<SB>6+</SB>) of five times or more to the soil sample to be shaken in the same manner, and by carrying out thereafter filtration with a plurality of layers of similar paper filters. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a simple and rapid test method for the elution amount and content of harmful substances such as heavy metals contained in soil, and more specifically, for an elution test and content test prepared simply and quickly. It relates to a simple test method for estimating the elution amount and content of harmful substances in soil from the value obtained by analyzing the test solution by an official method, and further to a simple test kit for harmful substances in soil used in such a method and an analyzer with a calculation program. Is.

Hazardous substances such as Pb (lead), Cd (cadmium), Cr ⁶⁺ (hexavalent chromium), As (arsenic), F (fluorine), and B (boron) present in soil are contaminated with groundwater by elution from the soil. In addition, since there is a risk of causing health damage by direct ingestion, standards for the scope of application, test method and analysis method are set by the Soil Contamination Countermeasures Law.
However, in the test and analysis methods specified in the Soil Contamination Countermeasures Law, for example, the Environment Agency Notification No. 46 and the Ministry of the Environment Notification No. 19 (hereinafter referred to as “official test analysis methods”), the drying of samples In the pretreatment for preparing a test solution (preparation of test solution), it takes 3 days or more for drying and 1 day or more for the pretreatment operation. Further, when filtering with a 0.45 μm filter paper, if a large filter paper is used or if it is not centrifuged in advance, rapid filtration is often difficult due to clogging. Furthermore, in the analysis, there is a problem that it is necessary to use advanced techniques and to use expensive analytical instruments.

  On the other hand, as an opportunity for soil contamination investigations, prefectural governors, etc., may have a health hazard when abolishing factories that handle specified hazardous substances specified in the Soil Contamination Countermeasures Law or local government regulations. If approved, in addition to making large-scale land changes, or when there is a suspicion of contamination at a business site that is currently in operation, or when it is necessary to grasp the presence or absence of contamination related to periodic surveys, residential land sales, etc. There are also many measurement opportunities outside the range.

In addition, it is necessary to grasp the pollution status in accordance with the official law within the scope specified by the laws and regulations, but for the purpose of investigating outside the legal framework and supplementing the scope specified by the law, Therefore, the official test analysis method that requires technology and funding for analysis is not necessarily appropriate.
For example, at a construction site where there is a possibility of contamination, determination as quickly as possible is required. In addition, a simple and inexpensive measurement method is desired in the self-investigation in the factory premises and the residential land trading in operation.

Furthermore, even when conducting a pollution survey within the scope of the law, in order to conduct the survey efficiently, it is easy and quick to grasp the outline of the actual pollution situation at the site and determine the implementation point of the official test analysis method. Test methods are desired.
Therefore, many analysis pretreatment (test) methods and analysis methods have been proposed so far.

  As a method for accelerating the elution process in soil tests, an acid extraction elution accelerating metal measurement method has been proposed. This method is a simple rapid analysis method in which elution operation usually performed with pure water is performed with hydrochloric acid solution and heavy metals in the soil are extracted and analyzed in a short time, and can be used as a method to complement the official method. (See Non-Patent Document 1).

On the other hand, as a “determination method of soil contaminated area”, a method is disclosed in which a soil sample is processed by a decomposition apparatus using microwaves or ultrasonic waves, and the contained heavy metals are accelerated and eluted and analyzed by an ICP mass spectrometer. (See Patent Document 1).
In addition, as a “heavy metal extraction method and heavy metal elution measurement method”, water is mixed to a sample containing heavy metals such as contaminated soil and waste at a high concentration so that the liquid-solid ratio is 1 or less, and then centrifugal filtration is performed. And the measuring method of the heavy metal elution amount which analyzes the heavy metal density | concentration in a filtrate is known (refer patent document 2).

Furthermore, nitric acid, hydrofluoric acid and hydrogen peroxide water were added to the weighed soil sample, sealed, decomposed by pressure acid decomposition using microwaves, and distilled water was added thereto to adjust the weight. There is disclosed a method for measuring soil-containing heavy metals by analyzing the concentration of heavy metals with a simultaneous analyzer and determining the amount of harmful heavy metals in a soil sample based on the measured value of the sample (see Patent Document 3).
In addition, as a “soil-containing metal elution method”, distilled water or dilute hydrochloric acid or the like was added to a weighed soil sample, and ultrasonic waves of 30 to 40 KHz were irradiated to float and disperse in a range of 5 to 15 cm 2 per 1 g of the dried sample. A method is disclosed in which a heavy metal is eluted from a soil sample and a sample solution obtained by filtering the heavy metal is analyzed with a multi-element simultaneous analyzer to determine the amount of harmful heavy metal in the soil (see Patent Document 4).

  Furthermore, as a new analysis method for metals in soil and the like, Patent Document 5 describes a method for analyzing the amount of elution of heavy metals contained in soil and an analysis apparatus, and a sample used therefor. A procedure for adding a chelating agent at a predetermined ratio to the test solution, and adsorbing the measurement target substance in the test solution to this chelating agent, a procedure for filtering the test solution and collecting the chelating agent adsorbing the measurement target substance, A procedure is described in which the concentration of the target substance adsorbed on the collected chelating agent is quantified by an X-ray fluorescence analyzer, and this result is converted into the elution amount of the target substance in the test solution.

  In addition, as for a test analysis method for metals and the like in soil, Patent Document 6 describes as “Soil analysis method and fluorescent X-ray soil analysis device used therefor”, after crushing and stirring the soil, a part thereof is pressed. Disk-shaped pellet sample, and using an energy dispersive X-ray fluorescence spectrometer, the detection data is accumulated while moving the incident X-ray irradiation spot to a different disk-shaped area, and statistical processing is added. A method for measuring the content of heavy metals and the like, which is analyzed in this manner, is disclosed.

Patent Document 7 relating to a soil contamination test method discloses that the separation of a liquid to be extracted from a mixture of soil and an extract is promoted by adding a flocculant. In Patent Document 8 concerning the test method, an organic solvent is added to undried soil, shaken for 1 minute, allowed to stand for 30 minutes, centrifuged, and then filtered under reduced pressure using a 0.45 μm membrane filter. A method for analyzing a liquid with an ICP emission analyzer or the like is disclosed.
Environmental impact assessment technology study group in the atmosphere, water, and environmental impact field of the Ministry of the Environment “Environmental impact assessment technology in the air, water, and environmental impact field (III) <Procedure for Environmental Conservation Measures / Evaluation / Post-Investigation>” JP 2002-214199 A JP 2001-293454 A JP 2004-198324 A JP 2004-245579 A JP 2004-294329 A Japanese Patent Laying-Open No. 2005-049205 Japanese Patent Laid-Open No. 09-072898 JP 2005-331409 A

However, in the methods described in Non-Patent Document 1, Patent Document 1, Patent Document 2, Patent Document 3 and Patent Document 4, it is possible to relatively grasp the content of metals and the like in the soil, Since no correlation with the official method is obtained, it is difficult to make some judgment from the result, and the practical range is considerably limited.
The method described in Patent Document 5 is considered to be effective for components that can be selectively adsorbed by a chelating agent, but is applied to soil containing various metals other than the target substance. It is difficult to apply to a wide range of target substances.

  Furthermore, although the method described in Patent Document 6 is simple and can be screened for many metal species, in principle, it is more than an official method test in which only a part of metals and the like existing in soil are eluted. Concentrations may be several times higher and can only be used for relative comparisons and for determining that there is clearly no contamination.

Further, the method described in Patent Document 7 is only a part of the test method that has been accelerated, and when viewed from the whole test method, it can be said that the method is far from being simplified and quicker. Absent.
And although the method of patent document 8 is comparatively quick, since the data in the point which uses an organic solvent and the soil prepared by simulation are mainly, the practical measurement precision is unclear. However, there are problems in that the standing time for the purpose of diffusion elution and solid-liquid separation is long, the test size is large and the waste liquid is increased, and it takes time to conduct a multi-site field survey.

  The present invention has been made by paying attention to the above-mentioned problems in conventional methods for analyzing and measuring harmful substances in soil, and the object of the present invention is the official determination of a large number of specimens without using an organic solvent. Concentration equivalent to the official test method can be estimated easily in a sufficiently short time compared to the test method, and as a soil contamination survey screening, such as primary confirmation of the presence of contamination and search for high-concentration contamination points The object is to provide a simple test method for the amount and content of toxic substances in soil that can be used.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a considerable amount of harmful substances are eluted in a solvent such as water or an acid aqueous solution even in a sufficiently short time compared to the official test method. By knowing the elution behavior of each harmful substance, even if the test size is reduced and the preparation time of the test solution is shortened, the measured value by the official test method can be estimated, and the above objective can be achieved. The headline and the present invention have been completed.

  That is, the present invention is based on the above knowledge, and in the simple method for testing the amount of toxic substances in soil of the present invention, soil having a mass of less than 50 g is sampled and at least five times the mass of soil sampled therein. In addition, water was shaken for less than 360 minutes, filtered, and the official dissolution rate test concentration was estimated from the analytical value of the obtained dissolution rate test solution. In the method for testing the simple content of harmful substances, a soil with a mass of less than 6 g is collected, and an acid aqueous solution having a pH of 2 or lower or an alkaline aqueous solution having a pH of 10 or higher is added to the soil at least five times, and the time is less than 120 minutes After shaking, it is filtered, and the official content test concentration is estimated from the analysis value of the obtained test liquid for content test.

  At this time, in the filtration operation in the simple dissolution amount test method and the simple content test method, it is desirable to filter with a multilayer filter paper in which a filter paper with a pore diameter of 1 μm or more is stacked on a filter paper with a pore diameter of 0.45 μm.

And the simple test kit for harmful substances in soil of the present invention is preferably used in the above-described simple test method for harmful substances in soil, and at least a container with a lid for shaking a soil sample with a solvent, A filter paper having a pore diameter of 0.45 μm overlaid with a filter paper having a pore diameter of 1 μm or more, a multi-layer filter paper for filtering the supernatant liquid in the lidded container, and a test solution for storing the filtrate from the multi-layer filter paper It is characterized by having a container.
Furthermore, the analyzer of the present invention is characterized by comprising an arithmetic processing program for estimating the official test concentration from the analysis value of the dissolution test solution or content test solution obtained in the above method.

According to the present invention, a relatively small amount of soil of less than 50 g is added with a mass of water five times or more and shaken for an arbitrary time of less than 360 minutes, or a relatively small amount of soil of less than 6 g Add an acid aqueous solution (pH 2 or less) having a mass of 5 times or more (however, in the case of Cr ⁶⁺ , an alkaline aqueous solution of pH 10 or more), shake for an arbitrary time of less than 120 minutes, and filter. Therefore, it is possible to easily prepare test solutions for the amount and content of toxic substances in soil in a relatively short period of time. Since the amount is estimated, the concentration of harmful substances in the soil corresponding to the official test method can be easily grasped with considerable accuracy in a shorter time than the official test method.
Moreover, in the filtration operation, it was possible to test more quickly and easily by performing filtration with a multilayer filter paper in which a filter paper having a pore diameter of 1 μm or more is superimposed on a filter paper having a pore diameter of 0.45 μm.

  Hereinafter, the present invention will be described in more detail together with embodiments thereof. In the present specification, “%” represents mass percentage unless otherwise specified.

In the simple dissolution amount test method for harmful substances in soil of the present invention, in order to prepare a test solution, first, a soil sample to be investigated is weighed, a mass of less than 50 g is collected, and this is five times as much. Water having the above mass is added and shaken for an arbitrary time of less than 360 minutes to elute the substance in the soil into the solvent (in this case, water).
At this time, if the amount of the soil sample collected is too small, the measurement accuracy will deteriorate, and if it is too large, the amount of water will increase as will be described later, leading to an increase in the size and weight of the shaking container. Since it is difficult to perform a shaking operation by manual operation, it is desirable that the amount be about 3 to 10 g.

  About water as a solvent which elutes the substance in soil, deionized water or distilled water is usually used, but it is not particularly limited as long as it does not contain anything that affects the analysis value of the component to be detected.

If the amount of water added is too much for the collected soil sample, the detection sensitivity will decrease, and if it is too small, substances in the soil will not be sufficiently eluted, and solid-liquid separation (filtration) will be difficult. Therefore, the mass is preferably 8 to 15 times that of the collected soil sample.
In addition, since the unit of the elution amount is expressed in mg / L and the official test analysis method has a liquid-solid ratio 10 times that of the collected soil, it is necessary to convert to such a liquid-solid ratio. Therefore, also in the simple test method of the present invention, it is more desirable to add 10 times as much water as the collected soil sample, and the conversion labor can be saved.

As for the shaking time of water containing the soil sample, that is, the elution time of the substance in the soil, if it is too short, the substance in the soil will not be sufficiently eluted in the solvent, but if it is too long, there will be no merit as a simple method. As a simple method, considering the preparation of the test solution at the site, there is a limit in continuing the manual shaking operation.
From such a viewpoint, the shaking time can be within 30 minutes, for example, about 1 minute. It should be noted that the present invention does not exclude mechanical shaking using power, and the possibility of improving detection accuracy by adopting mechanical shaking according to the situation and further extending the elution time. is there.

  The suspension of the soil sample and water thus obtained is filtered, thereby obtaining a test solution for the elution amount test. For filtration, it is desirable to use a multilayer filter paper in which a filter paper having a pore diameter of 1 μm or more is stacked on a filter paper having a pore diameter of 0.45 μm.

At this time, after the suspension after shaking for a predetermined time is allowed to stand for several minutes, the supernatant collected using, for example, a syringe can be filtered by passing through the multilayer filter paper, as described above. By using such a multilayer filter paper, relatively coarse particles in the soil are captured by the filter paper having a coarse pore diameter on the upper layer side, so that the filtration operation can be greatly speeded up and downsized.
In addition, about the multilayer filter paper, what shape | molded the several filter paper from which a hole diameter differs is marketed, The thing which corresponds to the said hole diameter from such a commercial item can also be selected and used.

On the other hand, in the method for preparing a test solution for the content test of harmful substances in soil of the present invention, first, a soil sample to be investigated is weighed, and a mass of less than 6 g is collected, and a mass more than 5 times its mass is collected. The above-mentioned solvent, that is, an acid aqueous solution having a pH of 2 or lower, or an alkaline solution having a pH of 10 or higher (in the case of Cr ⁶⁺ ) is shaken for an arbitrary time of less than 120 minutes, and the substances in the soil are eluted into the aqueous acid solution.
At this time, if the amount of the collected soil sample is too small, the measurement accuracy deteriorates. If the amount is too large, the amount of the solvent increases as described later, leading to an increase in the size of the shaking container and an increase in weight. Since the shaking operation by manual operation becomes difficult and the amount of waste liquid increases, it is preferably about 1 to 3 g.

As the acid aqueous solution as a solvent for eluting the substances in the soil, those having a pH of 2 or less are used from the viewpoint of the cation exchange capacity and extraction ability of the soil itself, and specifically, about 0.5 or 1 mol / L. An aqueous solution of hydrochloric acid can be used. Instead of hydrochloric acid, other acids such as sulfuric acid and nitric acid can be used.
Since the cation exchange capacity of a general soil is about several tens to 400 meq / kg, more acid is required to maintain the acidity after mixing the soil and the solvent. That is, in order to neutralize 1 g of 400 meq / kg of soil, 33 mL of 12 meq / L (pH 1.9) acid is required from Xmeq / L × 33 mL / g. As described above, since the cation exchange capacity of most soils is 400 meq / kg or less, it is considered that the acidity can be maintained if the pH is 2 or less.

  As for the amount of the acid aqueous solution added, the detection sensitivity decreases if it is too much relative to the collected soil sample, and if it is too small, the substance in the soil may not be sufficiently eluted. It is desirable that the mass be about 20 to 40 times, more preferably about 33 times that of the above.

In the method for preparing a test solution for content test of harmful substances in soil of the present invention, an acid aqueous solution is used as a solvent for eluting substances such as Pb, Cd, As, etc., but Cr ⁶⁺ (hexavalent) is used. As for chromium, it is necessary to use a weakly alkaline aqueous solution having a pH of 10 or more, but it is desirable to use a solution having a pH of about 10.
The reagent used is not particularly limited as long as it is an aqueous solution exhibiting weak alkalinity as described above, but as specified in the official test analysis method, 0.005 mol of anhydrous sodium carbonate and 0.01 mol of carbonic acid are used. It is desirable to use a solution obtained by dissolving sodium hydride in 1 L of pure water.

  By setting the shaking time of the acid aqueous solution containing the soil sample to less than 120 minutes, it can be speeded up more than the official test method, but within 30 minutes as in the case of the above-described elution test solution. Desirably, it can be set to about 1 minute. Moreover, you may employ | adopt mechanical vibration by motive power according to a condition.

  The suspension of the soil sample thus obtained is similarly filtered using a multilayer filter paper in which one or more filter papers having coarse pores with a pore diameter of 1 μm or more are stacked on a filter paper with a pore diameter of 0.45 μm. Desirably, by using such a multilayer filter paper, a test solution for elution amount test can be obtained quickly, and the filtration operation can be speeded up. At this time, a commercially available molded product composed of a plurality of filter papers as described above can also be used.

  As described above, in the present invention, it is possible to significantly reduce the time required for preparing the test solution by reducing the sampling amount of the soil and the amount of the solvent, or shortening the shaking time, and by manual work. Since shaking is also possible, it is possible to prepare test solutions for elution and content tests at the site of soil sampling, making it possible to speed up and simplify the preparation of test solutions, and to investigate soil contamination as a whole. Leads to faster and easier operation.

  In the simple dissolution amount test method and the simple content test method for harmful substances in soil of the present invention, the official dissolution rate test from the analysis values of the dissolution test solution and the content test solution obtained by the above preparation methods, respectively. The concentration can be estimated.

  That is, when the present inventors calculated | required the relationship between the shaking time in the simple test method which made test size small as mentioned above, and the elution density | concentration to the solvent of the harmful substance in soil, it shows in Table 1 and Table 2. Thus, if the shaking time, that is, the elution time is matched with the official test method (elution amount test: 360 minutes, content test: 120 minutes), even if the test size is reduced, the elution concentration by the official test method is almost the same. It was confirmed that they matched.

  In addition, when the elution concentration is expressed as an elution rate with an elution concentration of 1 at the shaking time (elution time) specified in the official test method, regardless of the type of soil and the content of harmful substances, some It was found that the dissolution behavior of each substance was expressed by one exponential function with time as a variable.

By using this knowledge, the elution rate corresponding to the shaking time is obtained based on the elution rate curve of each toxic substance (it becomes a straight line if the time is displayed in logarithm), and the obtained analytical value is used as the elution rate. By dividing by the rate, the elution concentration corresponding to the official test method can be estimated.
In this case, although it is assumed that the parameters of the function are slightly different depending on the types of soil and contaminated metals, it is possible to make a determination on the safe side by using the minimum elution rate in the actual contaminated soil.

On the other hand, the official test analysis method stipulates that 50 g or more (elution amount test) and 6 g or more (content test) of air-dried soil are collected, but at least 3 days are required to air-dry the collected soil. In short, the preparation of the test solution at the site where the sample is collected becomes impossible, and the rapidity as a simple method is significantly impaired.
Tables 3 and 4 show the elution test (Table 3) and the content test (Table 4) using wet soil as collected at the site and air-dried soil obtained by subjecting it to air-drying treatment for 4 days. Each of the results is shown, and the results of investigating the influence of the dry state of the soil on the elution concentration in the solvent are shown. In addition, the elution density | concentration in a table | surface is converted into the elution density | concentration per 50g of dry soil (elution amount test) and 6g (content amount test) based on each moisture content.

As is clear from each table, when air-dried soil is used, or when wet soil is used as it is collected at the site, the concentration of elution is about the amount of elution and the amount of content when converted to mass. It can be regarded as almost the same.
Therefore, in the present invention, it is not always necessary to perform the air drying treatment over several days. When collecting a soil sample for preparing a test solution, if the sample for measuring the water content is sampled at the same time, Even if the elution amount and the test solution for the content test are prepared on the spot using the wet soil collected in step 3, as long as the measurement value correction based on the moisture content of the sample sampled at the same time is finally performed, It can be used for analysis of contained substances without any problems. In addition, although the accuracy is somewhat lowered, it is possible to determine the moisture content of the soil by visual inspection or the like and perform the test.

  Needless to say, the test solution can be prepared using air-dried soil or a soil sample dried by an appropriate drying apparatus brought to the site as long as the situation permits.

Thus, the simple dissolution amount test method and the simple content test method for harmful substances in soil of the present invention are simple methods, and it is possible to grasp the dissolution amount and content level of harmful substances very quickly and easily. It can be used for screening soil contamination surveys. In other words, by combining with official test methods as appropriate, it is confirmed that there is no obvious contamination, search for high concentration points, narrow down the points that need to be investigated by official methods, grasp of clear contaminated areas, rough contamination It can be widely applied to grasp the level.
For the analysis of harmful substances in soil, for example, an absorptiometric method, an ion electrode method, an ICP emission analysis method, an ion chromatographic method, or the like can be applied depending on the type of these harmful substances.

The simple test kit for toxic substances in soil of the present invention comprises a container with a lid for shaking a soil sample together with a solvent, a filter paper with a pore diameter of 0.45 μm and a filter paper with a pore diameter of 1 μm or more, A multi-layer filter paper for filtering the supernatant liquid, and a test container for storing the filtrate from the multi-layer filter paper. For example, if these are stored in a portable container such as a bag, the soil can be promptly It is possible to prepare a test solution for the amount of toxic substance elution and content test.
In addition, the test kit includes a syringe for collecting the supernatant of the suspension of the soil and solvent after shaking, a filter paper holder connected to the syringe, water for the elution amount test, , An acid (or alkali) aqueous solution prepared to a predetermined concentration for the content test, and a waste liquid container for storing a solvent waste liquid which has been prepared and the test liquid is no longer needed, and is used to neutralize such a waste liquid. A neutralizing agent such as an alkali (or acid) can be incorporated.

  And in the analytical apparatus for harmful substances in soil of the present invention, an arithmetic processing program for estimating the official test concentration from the analytical value obtained by the apparatus, for example, for each component obtained as described above It is desirable to have a calculation program based on the relationship between the obtained shaking time and dissolution rate, so that the value converted from the analytical value obtained by the simplified method of the present invention into the analytical value by the official test method is obtained. It can be obtained very easily.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(1) Preliminary test (Understanding the relationship between dissolution time and dissolution rate of each component)
(1) -1 As elution amount test Among various contaminated soils such as black soil and Kanto loam soil, sample 5g of sample B air-dried soil, put it in a 100mL polyethylene container, and add 50mL of deionized water to it. Water was added, and each time was shaken for 1 minute to 360 minutes using a tabletop shaker.

  After leaving each container for a predetermined shaking time for 5 minutes, about 20 mL of the supernatant of each container was collected with a syringe, and this was placed on a filter paper having a diameter of 47 mm and a hole diameter of 0.45 μm. Elution amount test solutions with different shaking times were obtained by filtering using a multilayer filter paper on which 7 μm filter paper was stacked and a filter paper holder.

The obtained test solution was appropriately diluted and analyzed with a hydride generation ICP emission spectrometer, and the elution concentration of As with respect to the shaking time was measured.
As a result, it was confirmed that the elution concentration when the shaking time was 360 minutes was 6.9 mg / L, which was almost equal to the value obtained by the official test analysis method.

Moreover, as a result of converting the elution concentration for each time into an elution rate with the above elution concentration of 6.9 mg / L at 360 minutes being “1” and plotting it with respect to the time axis, the elution curve shown in FIG. 1 was obtained. .
Then, when these two axes are logarithmically displayed, as shown in FIG. 2, a good linear relationship is obtained, and it has been found that the elution rate y of As is expressed by the following equation.
y = 0.455x ^0.136 (where x is the shaking time (minutes))

(1) -2 Cd elution amount test By using the air-dried soil of sample A among various contaminated soils and using the ICP emission analysis apparatus for the analysis of Cd, the same operation as described above was repeated, so that FIG. A Cd elution line as shown in FIG.
As shown in the figure, in the case of Cd, the elution rate is fast, and there is no difference in the elution concentration even after a shaking time of about 1 minute or after 360 minutes, and it almost matches the value by the official test method. It was confirmed that the analysis value obtained by the simplified method with a reduced test size can be used as it is. However, when a value close to the reference value is analyzed when determining the presence or absence of contamination, it is possible to obtain an estimated value on the safe side by using the minimum elution rate in the actual contaminated soil.

(1) -3 Elution amount test of B As shown in FIG. 4, an elution line of B is obtained by repeating the same operation except that the air-dried soil of sample F is used among various contaminated soils. It was.
As a result, when the shaking time is 360 minutes, the elution concentration of B is 20.2 mg / L, which is almost equal to the value obtained by the official test analysis method, and the elution rate y of B can be expressed by the following equation. found.
y = 0.524x ^0.108 (where x is the shaking time (minutes))

(1) -4 Cr ⁶⁺ elution amount test Among the various contaminated soils, while using the air-dried soil of sample D and using an absorptiometer for the analysis, the same operation as described above was repeated to obtain FIG. As shown, an elution line of Cr ⁶⁺ was obtained.
As a result, when the shaking time is 360 minutes, the elution concentration of Cr ⁶⁺ is 13.4 mg / L, which is almost equal to the value obtained by the official test analysis method, and the elution rate y of Cr ⁶⁺ is expressed by the following equation. It has been found.
y = 0.647x ^0.076 (where x is the shaking time (minutes))

(1) -5 F elution amount test By using the air-dried soil of sample E among various contaminated soils and repeating the same operation as above except that an ion chromatograph was used as an analyzer, FIG. An elution line of F as shown was obtained.
As a result, it was confirmed that the elution concentration of F when the shaking time was 360 minutes was 134 mg / L, almost equal to the value obtained by the official test analysis method, and the elution rate y of F was expressed by the following equation. It was.
y = 0.677x ^0.069 (where x is the shaking time (minutes))

(1) -6 Content test of As Among various contaminated soils, 1.5 g of sample G air-dried soil was sampled and placed in a 100 mL polyethylene container, and 50 mL of 1 mol / L hydrochloric acid aqueous solution was added thereto. Each shake was performed for 1 minute to 120 minutes using a tabletop shaker.
In this way, by repeating the same operation except that the upper limit of the collected amount of the soil sample, the solvent, and the shaking time was changed, content test solutions with different shaking times were obtained.

The obtained test solution was appropriately diluted and analyzed with a hydride generation ICP emission spectrometer, and the elution concentration of As with respect to the shaking time was measured.
As a result, when the shaking time was 120 minutes, the elution concentration was 0.06 mg / L, which was confirmed to be substantially equal to the value obtained by the official test analysis method.

Moreover, the elution concentration for each hour was converted into an elution rate with the elution concentration of 0.06 mg / L at 120 minutes as “1” and plotted against both axes of the logarithmic display. As a result, the elution line shown in FIG. As a result, it was found that the dissolution rate y of As in the content test is expressed by the following equation.
y = 0.789x ^0.051 (where x is the shaking time (minutes))

(1) -7 Cd content test By using the air-dried soil of sample A among various contaminated soils and using an ICP emission analyzer for analysis, the same operation as described above is repeated, and the results are shown in FIG. Cd elution line was obtained.
As shown in the figure, in the case of Cd, the elution rate is fast, and there is no difference in the elution concentration even after a shaking time of about 1 minute or after 120 minutes, and it almost agrees with the value according to the official test analysis method. It was confirmed that the analysis value obtained by the simplified method with a reduced test size can be used as it is.

(1) -8 Pb Content Test A Pb elution line as shown in FIG. 9 is obtained by repeating the same operation as above except that the air-dried soil of Sample I is used among various contaminated soils. It was.
As a result, when the shaking time was 120 minutes, the elution concentration of Pb was 0.25 mg / L, which was confirmed to be almost equal to the value obtained by the official test analysis method, and the dissolution rate of As in the content test. It was found that y is represented by the following equation.
y = 0.670x ^0.084 (where x is the shaking time (minutes))

(1) -9 B Content Test As shown in FIG. 10, an elution line of B was obtained by repeating the same operation as above except that the air-dried soil of Sample F was used among various contaminated soils. It was.
As a result, when the shaking time is 120 minutes, the elution concentration of B is 122 mg / L, which is almost equal to the value obtained by the official test method, and the elution rate y of B in the content test is expressed by the following equation. There was found.
y = 0.776x ^0.059 (where x is the shaking time (minutes))

(1) -10 Cr ⁶⁺ content test Using air-dried soil of sample D among various contaminated soils, 0.005 mol of anhydrous sodium carbonate and 0.01 mol of sodium hydrogen carbonate as solvents were used in 1 L of pure water. As shown in FIG. 11, elution of Cr ⁶⁺ was performed by repeating the same operation as described above except that a weak alkaline aqueous solution (pH = 10.06) dissolved in 1 was used and an absorptiometer was used for the analysis. A straight line was obtained.
As a result, the elution concentration of Cr6 + when the shaking time shaking was 120 minutes 8.7 mg / L, and the with approximately equal to the value by official testing method, dissolution rate y of Cr ⁶⁺ in the content tested by the following equation Turned out to be represented.
y = 0.593x ^0.116 (where x is the shaking time (minutes))

(1) -11 F content test Among the various contaminated soils, the air dry soil of sample E was used, a 1 mol / L hydrochloric acid aqueous solution was used as a solvent, and an ion chromatograph was used as an F analyzer. Except for the above, by repeating the same operation as described above, an F elution line as shown in FIG. 12 was obtained.
As shown in the figure, as in the case of Cd, the elution rate into the acid aqueous solution is fast, and there is no difference in the elution concentration even after a shaking time of about 1 minute or after 120 minutes, and a simple method in which the test size is reduced. It was confirmed that the analysis value by can be used as it is.

(2) Simplified test for harmful substances in soil according to the present invention (2) -1 Simple dissolution test Each of the soil samples B, G, L, M, and N in wet state is dry weight from various contaminated soils. Into a 100 mL polyethylene container, add 50 mL of deionized water, shake manually for 1 minute, let stand for 5 minutes, and add the supernatant in the container to the syringe. About 20 mL was collected by filtration, and this was filtered using a multilayer filter paper in which a filter paper with a pore size of 2.7 μm was superimposed on a filter paper with a pore size of 0.45 μm and a filter paper holder. Prepared.

The obtained test solution for dissolution test is appropriately diluted. As for hydride generation ICP emission analyzer for As, ICP emission analyzer for Pb, Cd and B, Absorptiometer for Cr ⁶⁺ , Ion chromatograph for F Each was analyzed by a graph, and the elution concentration of each component in the solvent (water) was measured.
And in the elution formula of each component calculated | required by the said preliminary test, as a result of calculating | requiring the elution amount y equivalent to x = 1 and dividing the obtained elution concentration by each elution rate y, as shown in Table 5, The result was almost consistent with the elution concentration obtained by the official test analysis method.

(2) -2 Simple content test From various contaminated soils, each of the soil samples B, L, M, N, and O in a wet state was collected to a dry weight of 1.5 g. Put in a polyethylene container, and for Cr ⁶⁺ , add 50 mL of weak alkaline aqueous solution in which 0.005 mol of anhydrous sodium carbonate and 0.01 mol of sodium hydrogen carbonate are dissolved in 1 L of pure water. Add 50 mL of 1 mol / L hydrochloric acid aqueous solution, shake manually for 1 minute, let stand for 5 minutes, and then collect about 20 mL of the supernatant in the container with a syringe in the same manner. A content test solution was prepared by filtering using a filter paper holder and a multilayer filter paper in which a filter paper having a pore size of 2.7 μm was superimposed on a filter paper having a pore size of 0.45 μm.

The obtained test solution for content test was appropriately diluted, each component was analyzed using the same analyzer as described above, and the elution concentration of each component in the solvent (aqueous hydrochloric acid solution or alkaline aqueous solution) was measured.
Similarly, the elution amount y is obtained from the elution formula of each component obtained by the preliminary test, and the obtained elution concentration is divided by the respective elution rate y. As shown in Table 6, official test analysis The result was almost consistent with the elution concentration obtained by the method.

  In addition, about a content test result, although it converts and displays originally from the said elution density | concentration to content (mg) per 1 kg of dry soil, the elution density | concentration was shown as data before conversion in this Example. .

In this embodiment, the analysis examples of Pb, Cd, As, B, Cr ⁶⁺ and F have been described as representative examples of harmful substances in the soil. However, the amount of Pb eluted and Se, which is a harmful substance other than these, are described. The elution amount and content of Hg, cyan can also be tested by the same operation.
Furthermore, for each formula used for estimation, it is considered that estimation with higher accuracy is possible by changing the coefficient of the formula based on further accumulated data.

It is a graph which shows the influence of the shaking time which acts on the elution rate in the water in the elution amount test. It is the graph which displayed both axes | shafts of FIG. 1 logarithmically. It is a logarithmic graph which shows the influence of the shaking time on the dissolution rate of Cd in water in the dissolution amount test. It is a logarithmic graph which shows the influence of the shaking time on the dissolution rate of B in water in the dissolution amount test. It is a logarithmic graph which shows the influence of the shaking time on the elution rate in the water of Cr6 + in the elution amount test. It is a logarithmic graph which shows the influence of the shaking time on the dissolution rate of F in water in the dissolution amount test. It is a logarithmic graph which shows the influence of the shaking time which acts on the elution rate in the acid aqueous solution of As in a content test. It is a logarithmic graph which shows the influence of the shaking time on the elution rate in the acid aqueous solution of Cd in a content test. It is a logarithmic graph which shows the influence of the shaking time on the elution rate in the acid aqueous solution of Pb in a content test. It is a logarithmic graph which shows the influence of the shaking time on the elution rate in the acid aqueous solution of B in a content test. It is a logarithmic graph which shows the influence of the shaking time which acts on the elution rate in the alkaline aqueous solution of Cr6 + in a content test. It is a logarithmic graph which shows the influence of the shaking time which acts on the elution rate in the acid aqueous solution of F in a content test.

Claims (9)

  Collect soil with a mass of less than 50 g, add water more than 5 times the mass of the collected soil, shake for less than 360 minutes, filter to obtain a test solution, and A simple elution test method for toxic substances in soil characterized by estimating the official elution test concentration from the analysis value.   2. The method for simply testing the amount of toxic substances in soil according to claim 1, wherein a multi-layer filter paper in which a filter paper having a pore diameter of 1 μm or more is superimposed on a filter paper having a pore diameter of 0.45 μm is used in the filtration operation.   Collect soil with a mass of less than 6 g, add an aqueous acid solution with a pH of 2 or less or an alkaline aqueous solution with a pH of 10 or more to the soil mass of 5 times or more, shake for a period of less than 120 minutes, filter and test A simple content test method for harmful substances in soil, characterized in that the official content test concentration is estimated from the analysis value of the obtained test solution.   4. The method for testing a simple content of harmful substances in soil according to claim 3, wherein a multilayer filter paper in which a filter paper having a pore diameter of 1 μm or more is stacked on a filter paper having a pore diameter of 0.45 μm is used in the filtration operation. A container with a lid for shaking a soil sample with a solvent;
A filter paper having a pore diameter of 0.45 μm overlaid with a filter paper having a pore diameter of 1 μm or more, and a multilayer filter paper for filtering the supernatant liquid in the lidded container;
A simple test kit for toxic substances in soil, comprising a test container for storing filtrate from the multilayer filter paper.   The simple test kit for toxic substances in soil according to claim 5, comprising a syringe for taking out the supernatant in the lidded container, and a filter paper holder connectable to the syringe.   The simple test kit for harmful substances in soil according to claim 5 or 6, further comprising a solvent.   The waste liquid container for storing a used solvent, and a neutralizing agent for neutralizing the waste liquid in the container, the harmful in the soil according to any one of claims 5 to 7, Simple test kit for substances.   5. An apparatus for analyzing harmful substances in soil, comprising an arithmetic processing program for estimating an official test concentration from an analysis value of a test solution obtained by the method according to claim 1.

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