JP4696035B2 - Asbestos judgment method - Google Patents

Description

  The present invention relates to an asbestos determination method capable of easily determining asbestos. In particular, the invention is suitable for asbestos determination in asbestos / rock wool mixed building materials and the like. In the following description, “%” means “% by mass” unless otherwise specified.

  Asbestos is a naturally occurring fibrous silicate mineral with a crystalline structure, defined by the International Labor Organization as "an inorganic silicate belonging to the serpentine and amphibole group of minerals that form rocks". Yes. That is, the six types of minerals shown in FIG. 1, chrysotile, amosite, crocidolite, anthophyllite, tremolite, and actinolite are classified as asbestos. Of these, amphibole-based anthophyllite, tremolite, and actinolite are rarely produced, and are not used as industrial raw materials because they are contained as impurities in other asbestos. For this reason, in this specification, asbestos means chrysotile, amosite, and crocidolite.

  Asbestos is excellent in durability, heat resistance, and heat retention, and has been widely used as a material for building / construction materials, water mains materials, industrial materials, household products, and the like.

  However, because asbestos is carcinogenic to the respiratory system, manufacturing is banned in principle, and from the viewpoint of occupational health, in particular, asbestos removal work during the dismantling of buildings and wall repairs is a problem. It has become.

  On the other hand, rock wool (rock wool) has been widely used for asbestos as a substitute material for asbestos.

  At that time, in the case of old buildings, it is often unclear whether rock wool material or asbestos material was used for the inner and outer wall surfaces. For this reason, in fact, it is necessary to have a working (working) environment corresponding to the asbestos content despite the absence of asbestos. In other words, the workplace must be closed, and the worker must wear a more complete (strict: high standard) protective mask / protective clothing.

  Moreover, although the use of rock wool is common to asbestos as described above, when handled as waste, it is necessary to clearly distinguish it from asbestos corresponding to specially controlled industrial waste. Note that rock wool is an industrial waste corresponding to glass waste.

  And in order to determine the presence or absence of the use of asbestos material in the above wall surfaces etc., the following asbestos determination methods (asbestos screening method) are proposed by patent document 1 (refer Claim 1 etc.).

`` A test method for determining the presence or absence of asbestos in a sample through the iron color reaction. (1) Prepare a sample by crushing a part of the sample lump collected from the specimen (2) A pretreatment step in which an organic acid is added to the sample, pulverized and mixed, and then the acid component is washed away with purified water. (3) A non-oxidizing inorganic acid aqueous solution and a sample after the pretreatment step Step of preparing a determination solution that elutes asbestos iron by adding a color reagent that is a chelating agent, (4) When the pH of the determination solution is in the coloration stable region, the pH is below the coloration stable region Is characterized by comprising a step of determining the presence or absence of coloration (coloration) by adding a pH regulator to adjust the pH to the coloration stable region, respectively. "
However, the present inventors have found that in the above asbestos determination, an asbestos-free rock wool material may be erroneously determined as containing asbestos.

  When the above asbestos determination method is applied to a sample, if the sample contains rock wool, the rock wool also contains iron element, and therefore, the silicic acid component is dissolved using hydrofluoric acid or silicohydrofluoric acid. Since a small amount of iron element is eluted and the color reaction of iron is used, even if it does not contain asbestos, a pseudo-judgment of containing asbestos containing iron element (amosite type or crocidolite type: see FIG. 1) can be obtained.

Therefore, when rock wool is included, there has been a demand for the appearance of a simple asbestos determination method that does not give a false determination of asbestos content.
Japanese Patent No. 3341152

  In view of the above, an object of the present invention is to provide an asbestos determination method in which asbestos-containing pseudo-judgment does not occur even when rock wool is included in building materials and heat insulating materials.

  As a result of diligent development to solve the above-mentioned problems, the present inventors have come up with an asbestos determination method having the following configuration.

1) A sample in a pulverized state is allowed to stand still in contact with a pretreatment liquid, and after elution of magnesium and iron in rock wool (hereinafter referred to as “rock wool metal component”), before the eluate is removed. Processing steps,
2) A determination solution for preparing a determination solution by allowing the solid content after removal of the eluate to stand still in contact with the solution and elution of magnesium and iron in asbestos (hereinafter referred to as “asbestos metal component”). A preparation step, and 3) a color determination step of adding a color reaction reagent of magnesium or iron to the determination solution and determining the presence or absence of asbestos by coloration,
The pretreatment liquid used is an acidic aqueous solution having a higher solubility in the rock wool metal component than the solubility in the asbestos metal component, and the solubility in the asbestos metal component is the pretreatment as the solution. What consists of acidic aqueous solution high compared with a liquid is used.

  Expressed in another aspect of the present invention, the asbestos determination method has the following configuration.

1) A pretreatment step in which a sample in a pulverized state is allowed to stand still in contact with a pretreatment liquid, and after elution of the rock wool metal component, the elution liquid is removed.
2) A determination liquid preparation step in which the solid content (residue) after removal of the eluate is allowed to stand still in contact with the dissolution liquid, and a determination liquid is prepared through an elution operation of the asbestos metal component, and
3) a color determination step of adding an iron or magnesium color reaction reagent to the determination solution and determining the presence or absence of asbestos by coloration,
The pretreatment liquid is composed of an acidic aqueous solution based on phosphoric acid, and the dissolution liquid is composed of an acidic aqueous solution based on hydrochloric acid.

  The asbestos determination method with the above configuration uses the eluate after the elution operation of the asbestos metal component in the solid content (residue: pretreated sample) from which the eluate was removed through the elution operation of the rock wool metal component in the pretreatment process. In order to perform a color reaction for asbestos determination, even if rock wool metal components are mixed in the sample, the rock wool metal components (magnesium content and iron content) are eluted and removed by pretreatment. The later sample (residue) is hardly contained. On the other hand, asbestos metal components (magnesium content and iron content) are not so much eluted and removed by the pretreatment. In this state, a solution that can be easily eluted is allowed to act on the metal component in the asbestos metal component, and the eluate is used as a determination solution. Asbestos metal components (magnesium and iron) are eluted. Therefore, the asbestos pseudo determination does not occur in the color reaction.

  In the asbestos determination method according to the present invention, even if a rock wool metal component is included by adopting the method as described above, a pseudo determination that an asbestos metal component is present does not occur. Therefore, asbestos determination can be performed reliably, and it is not necessary to take excessive work environment measures such as closed workplaces or protective clothing in asbestos removal work or the like. That is, wall repair work and dismantling work at the construction / construction site can be performed appropriately.

  The present embodiment basically relates to an asbestos determination method for determining the presence or absence of an asbestos metal component in a sample through a color reaction of magnesium or iron. The following 1) pretreatment step, 2) It consists of a determination liquid preparation step and 3) a coloration determination step (see FIGS. 2 and 3).

  (1) Pretreatment step: This is a step of removing the eluate after the pulverized sample is allowed to stand still in contact with the pretreatment liquid and the rock wool metal component is eluted.

  Here, as the pretreatment liquid, an acidic aqueous solution whose solubility in the rock wool metal component is higher than the solubility in the asbestos metal component, for example, a phosphoric acid-based acidic aqueous solution is used. More specifically, an acidic aqueous solution of 6 to 14% (preferably 8 to 12%) phosphoric acid is used. Here, phosphoric acid means normal phosphoric acid.

  It is desirable to add other inorganic acids, water-soluble carboxylic acids, and further lower aliphatic alcohols as additives to the acidic aqueous solution.

The purpose of adding other inorganic acids is to easily dissolve calcium and silicon coexisting in rock wool. As specific compounds, hydrofluoric acid, hydrochloric acid, nitric acid and the like can be suitably used. And it is preferable to combine hydrochloric acid and hydrofluoric acid. The amount of addition should be 0.5-4% (further 1.5-3%) hydrochloric acid, 0.1-1% hydrofluoric acid (further 0.2-0.8%) . desirable.

  The purpose of adding the water-soluble carboxylic acid is to dissolve a minute amount of color-disturbing components such as copper, and specific compounds include citric acid, acetic acid, tartaric acid and the like. The addition amount of the water-soluble carboxylic acid is preferably 0.5 to 4% (more preferably 1.5 to 3%).

  The purpose of adding the lower aliphatic alcohol is to ensure hydrophilicity to the sample, and specific compounds include ethyl alcohol and isopropyl alcohol. The amount of the lower aliphatic alcohol added is 0.5 to 4% (preferably 1.5 to 3%).

  The basis of these acid selections and acid addition amounts is based on the preliminary test results shown in FIGS.

  In addition, as a judgment sample, the rock wool specified in JIS A 9521 was used, and each asbestos was a reference material supplied by the Japan Working Environment Measurement Association.

  And the pretreatment liquid for each preliminary test was prepared as follows.

Phosphoric acid, hydrochloric acid, citric acid, mixed acid stock solution A (20% citric acid / hydrochloric acid 20% aqueous solution), mixed acid stock solution B (20% citric acid / hydrochloric acid 20% / hydrofluoric acid 5% aqueous solution), mixed acid stock solution C (Phosphoric acid 10% / citric acid 10% / hydrochloric acid 10% / hydrofluoric acid 2.5% aqueous solution) were prepared by diluting them so that their stock solutions had respective concentrations shown in FIGS. Furthermore, each pretreatment liquid was added so that ethyl alcohol might be 2%.

  Then, each pretreatment liquid was subjected to a preliminary test according to the procedure shown in FIG. The “ICP emission spectroscopic analysis” in FIG. 10 and the like is an emission spectroscopic analysis using ICP (inductively coupled plasma) as a light source, and is an analysis method capable of highly accurate analysis of a liquid sample. is there. As the analyzer, “VISTA-MPX type” manufactured by Seiko Instruments Inc. was used.

  The sample used for the test was about 100 mg for rock wool and about 50 mg for asbestos. The Mg content and Fe content of rock wool and asbestos vary to some extent, but the values (average values) determined as the total amount in the filtrate and the residue are as shown in Table 1, respectively.

各試料の残渣（濾滓）中の金属成分（Ｆｅ及びＭｇ）の含有量を示す図４〜９から、下記のことが分かる。なお、図４〜９において、（Ａ）はロックウール、（Ｂ）はアモサイト、（Ｃ）はクロシドライト、（Ｄ）はクリソタイルの予備試験の結果をそれぞれ示す。

The following can be seen from FIGS. 4 to 9 showing the contents of the metal components (Fe and Mg) in the residue (filter cake) of each sample. 4 to 9, (A) shows rock wool, (B) shows amosite, (C) shows crocidolite, and (D) shows the results of preliminary tests of chrysotile.

    1) Although the rock wool metal component is soluble in any acid, the tendency was noticeable in acids containing hydrofluoric acid (mixed acid B / C) and high-concentration phosphoric acid (about 8% or more). .

    2) The asbestos metal component in amosite is relatively strong in any acid, and although there is not much difference in dissolution tendency due to the difference in acid, it is soluble in a solution containing hydrofluoric acid at a high concentration (mixed acid B). I found out that The reason why more iron remains in the residue than magnesium is derived from the composition ratio of both elements contained in the amosite (see Table 1).

    3) The asbestos metal component in crocidolite showed the same tendency as amosite.

    4) Asbestos metal component in chrysotile tends to be eroded by acid compared to amosite and crocidolite. Some resistance was observed when the concentration of acids other than phosphoric acid and phosphoric acid was low.

  From the above, in order to elute and remove the rock wool metal component in the pretreatment step, a mixed acid containing phosphoric acid and preferably containing hydrofluoric acid is desirable. It was conceived that it would be desirable to use a product having a lower aliphatic alcohol added thereto.

Specifically, phosphoric acid: 6-14% (further 8-12%) , hydrochloric acid: 0.5-4% (further 1.5-3%), water-soluble carboxylic acid: 0.5-4 % (Further 1.5-3%), hydrofluoric acid: 0.1-1% (further 0.2-0.8%), lower aliphatic alcohol: 0.5-4% (further 1.5-3%).

  And in order to confirm that the said range is appropriate, about the pretreatment liquid of the composition shown in Table 2, the evaluation test is performed on the rock wool and chrysotile according to the procedure shown in FIG. It was performed as 10.20.40.60 minutes. Samples were rock wool: about 500 mg and chrysotile: about 200 mg for each test.

それらの結果を、図１１（Ａ）、（Ｂ）に示す。

The results are shown in FIGS. 11 (A) and (B).

  From the beginning, rock wool has much less residual amounts of both Fe and Mg than asbestos. Further, asbestos (chrysotile) tends to decrease in residual amount as the standing time becomes longer (Mg is more remarkable). Therefore, it can be seen that the standing time is required to be at least 30 minutes in both cases of the amount of 0.1 mg / 100 mg or less, the Fe color reaction, and the Mg color reaction.

  (2) Determination liquid preparation step: The solid content after removal of the eluate is allowed to stand still in contact with the dissolution liquid, and after elution of the asbestos metal component, a pH adjuster is appropriately added to the elution liquid to determine the determination liquid. Is a step of preparing

To use those solubility Asbestos metal component as solution having a higher acidic aqueous solution than the pretreatment liquid. For example, a hydrochloric acid-based acidic aqueous solution is used. More specifically, an acidic aqueous solution of 4 to 10% (preferably 6 to 8%) hydrochloric acid is used.

  It is desirable to mix hydrofluoric acid into the acidic aqueous solution because the solubility in asbestos components (Fe and Mg) increases. At that time, the addition amount of hydrofluoric acid is 2 to 6 parts (more 3 to 5 parts) with respect to 10 parts of hydrochloric acid.

  The basis for these acid selections and addition amounts is based on the preliminary test results shown in FIG. Preliminary tests were performed according to the procedure shown in FIG. 13 for the dissolving power of the dissolving solution shown in Table 3, targeting the residue after the treatment performed with the pretreatment solution having the composition (Example) shown in Table 2 above. Each sample was rock wool and asbestos used in the pretreatment liquid. The former was 100 mg, and the latter was 50 mg. For the pretreatment, a pretreatment liquid having the composition shown in Table 1 was used. The evaluation of dissolution was based on Mg and Fe.

それらの試験結果を示す図１２（Ａ）・（Ｂ）・（Ｃ）から、溶解液としては、表２の最下段に示すもの（塩酸：７％、フッ化水素酸：３％）が最適であることが分かる。フッ化水素酸含有量の増加とともにアスベスト金属成分の溶解量の増加が見られた。ロックウール残渣はフッ化水素酸濃度に関わりなく、ほとんどＦｅ、Ｍｇが溶出しなかった。これは、前処理工程によって、ロックウール金属成分のほとんどが溶出除去されたためと考えられる。

From the test results shown in FIGS. 12A, 12B, and 12C, the solution shown in the bottom row of Table 2 (hydrochloric acid: 7%, hydrofluoric acid: 3%) is optimal. It turns out that it is. As the hydrofluoric acid content increased, the amount of asbestos metal component dissolved increased. Regardless of the hydrofluoric acid concentration, almost no Fe or Mg eluted from the rock wool residue. This is presumably because most of the rock wool metal components were eluted and removed by the pretreatment process.

  (3) Coloration determination step: Addition of iron (Fe) or magnesium (Mg) color reaction reagent (sometimes simply referred to as “coloring reagent”) to the determination solution, and presence or absence of asbestos by coloration It is the process of determining.

  The reagent used in the color reaction step is preferably Mg as a reagent that can determine all asbestos, but in the case of amosite (tea asbestos) and crocidolite (white asbestos), it can also be determined with a color reagent of Fe. is there.

The Mg coloring reagent is not particularly limited as long as it is a chelating agent (coloring reagent) that reacts with Mg and is colored. Xylidine blue, titanium yellow, oxine, Eriochrome black T, phthalein complexone, methyl Examples include thymol blue. Among these, xylidyl blue I or xylidine blue II represented by the following structural formula is particularly desirable because it has the highest sensitivity as a spectrophotometric reagent for Mg. Xylidine blue II is obtained by taking SO ₃ Na from the structural formula of xylidine blue I, and is superior to xylidine blue I because it has about 7% higher sensitivity and a shorter reaction time. In this example, xylidine blue I was used.

その際、呈色に好適なｐＨに調節することが望ましく、ｐＨ調節液としては、塩基性緩衝液、例えば、塩化アンモニウム・アンモニア混液や酢酸アンモニウム・アンモニア混液等を使用することが望ましい。

At that time, it is desirable to adjust to a pH suitable for coloration, and it is desirable to use a basic buffer such as an ammonium chloride / ammonia mixed solution or an ammonium acetate / ammonia mixed solution as the pH adjusting solution.

  The basis for the selection of xylidyl blue is the result of investigation of sensitivity, coloring interference substances, safety, etc. by literature survey.

  Each reagent was prepared by the method shown below, and the color test was judged by the procedure shown in FIG. Here, in FIG. 14 and FIG. 15, the order of adding the pH adjusting liquid is reversed from that of adding the coloring liquid (coloring liquid).

  The standard solution was prepared in addition to Mg. The reason why Fe was prepared is that it is assumed that it coexists during measurement of an actual sample, and it is considered that the coexistence of Fe affects the coloration.

  In the present invention, when an Fe metal component such as amosite or crocidolite is also included, an Fe color reagent can be used. As the Fe color reagent, those described in Patent Document 1, that is, 4,7-diphenyl-1,10-phenanthroline, 1,10-phenanthroline, 2,2′-bipyridyl, 2,4,6 -Tris- (2-pyridyl) -s-triazine can be used. Of these, a compound of the following structural formula called bathophenanthroline (4,7-diphenyl-1,10-phenanthroline) is particularly desirable.

＜Ｍｇ標準液＞
１０００ｍｇ／ＬのＭｇ標準液を、希釈して、２ｍＬ中に０μｇ、２μｇ、５μｇ、１０μｇ、２０μｇ、５０μｇ、１００μｇを含有する各Ｍｇ標準液を作成した。

<Mg standard solution>
1000 mg / L Mg standard solution was diluted to prepare each Mg standard solution containing 0 μg, 2 μg, 5 μg, 10 μg, 20 μg, 50 μg, and 100 μg in 2 mL.

<Fe standard solution>
The Fe standard solution of 1000 mg / L was diluted to prepare each Fe standard solution containing 0.5 μg, 1 μg, 2 μg, 5 μg, 10 μg, and 20 μg in 2 mL. To this standard solution, hydroxylamine hydrochloride as a reducing agent was added to 0.1%. This is because divalent (II) and trivalent (III) iron may coexist.

<Mg color reagent (coloring solution)>
It was prepared by dissolving 0.08 g of xylidyl blue in 1 L of ethyl alcohol.

<PH adjusting solution 1 (buffer solution)>
After dissolving 70 g of ammonium chloride in about 200 mL of pure water, 570 mL of aqueous ammonia was added and the volume was adjusted to 1 L with pure water.
<Fe color reagent (coloring solution)>
After dissolving 0.05 g of bathophenanthroline in 500 mL of ethyl alcohol, 10 mL of hydrochloric acid was added to make 1 L with pure water.

<PH adjusting solution 2 (buffer solution)>
500 g of ammonium acetate was dissolved in pure water to make a constant volume of 1 L.

<Result>
And the reaction of xylidyl blue to rock wool and asbestos that had been treated (pre-treatment and dissolution) showed red or tan in all samples with an asbestos content of 1% or more when magnesium was 2 μg or less. Colored and determined to contain asbestos.

  On the other hand, coloration of bathophenanthroline was not observed in the sample set to 5% or less of chrysotile.

  30 samples collected from existing facilities were subjected to an asbestos / rock wall simple determination test according to the inspection method shown in FIGS. The sample was about 50 mg.

  The sample was prepared as follows.

  Using a tool (punch and hammer, spatula, etc.), a sample lump of a predetermined size is collected from the object to be inspected (screening object). A part of the sample lump is taken out and finely (1-2 mm) crushed (broken) to obtain a sample (determination target). The reason for making it fine is to facilitate miniaturization in the acid cleaning step. Of course, protective glasses, protective masks, gloves and the like were used at the time of sampling.

  In order to evaluate the suitability of the determination results, morphological observation, element qualitative analysis, X-ray diffraction analysis, and the like were performed using an electron beam microanalyzer (EPMA).

  Morphological observation and element qualitative analysis by EPMA were performed on 16 samples presumed to contain mainly rock wool.

  On the other hand, qualitative / quantitative analysis using an X-ray diffractometer was carried out on 15 samples presumed to contain mainly asbestos (one overlapped with that presumed to contain rock wool).

  As shown in Table 4, the results of the evaluation test performed by the method shown in FIG. 2 using xylidyl blue showed suitability of the determination method in 28 samples out of 30 samples. The two samples considered incompatible were both meteorite-containing samples. The main component of the meteorite is magnesium silicate, and even if it contains asbestos, a misjudgment appears. The presence or absence of meteorite can be visually determined because it has a mica-like shine of meteorite.

  On the other hand, as shown in Table 4, the results of the evaluation test in which the method shown in FIG. 3 using pasophenanthroline was used showed suitability of the determination method in 26 of 30 samples. The 4 samples that became incompatible were 2 samples containing chrysotile of 5% or less in addition to 2 samples containing meteorite.

なお、アスベスト１％含有物溶解液に相当するマグネシウム及び鉄を含有する溶解液を調製し、呈色判定を行った結果を表４に示す。表４から本発明の判定法は、図２に示すキシリジンブルーを使用する判定法では全てのアスベストに対し、図３に示すバソフェナントロリンを使用する判定法では、クリソタイルを除くアスベストに対して適合することが分かる。

In addition, Table 4 shows the results of preparing a solution containing magnesium and iron corresponding to the 1% asbestos-containing material solution and performing color determination. From Table 4, the determination method of the present invention is suitable for all asbestos in the determination method using xylidine blue shown in FIG. 2, and suitable for asbestos excluding chrysotile in the determination method using bathophenanthroline shown in FIG. I understand that

なお、クリソタイルであっても、通常の１０％以上含まれる場合は、鉄含量が多くなるため、図３に示す判定法でも、赤色を呈して判定可能である。

In addition, even if it is chrysotile, when it contains 10% or more of normal, iron content will increase, Therefore The determination method shown in FIG.

It is a classification figure of asbestos. It is process drawing which shows an example of the asbestos determination method of this invention. It is process drawing which shows another example in the asbestos determination method of this invention. It is a graph which shows the result of the preliminary test at the time of making a pretreatment liquid into phosphoric acid aqueous solution. It is a graph figure similarly in the case of hydrochloric acid aqueous solution. It is a graph figure similarly in the case of citric acid aqueous solution. It is a graph figure in the case of mixed acid A (citric acid / hydrochloric acid mixed acid aqueous solution). It is a graph figure in the case of the mixed acid B (citric acid / hydrochloric acid / hydrofluoric acid mixed acid aqueous solution) similarly. It is the graph figure in the case of mixed acid C (phosphoric acid, citric acid, hydrochloric acid, hydrofluoric acid mixed acid aqueous solution) similarly. It is a flowchart which shows the procedure of the pretreatment liquid preliminary test of the various acids of an Example, and the acid of an Example. It is a graph which shows the result of the evaluation test (relationship between stationary time and dissolution property) of the pretreatment liquid of the example performed according to the procedure of FIG. It is a graph which shows the result of the preliminary test of the various solution with respect to the residue after a pre-processing with a pre-processing liquid. It is a flowchart which shows the procedure of the preliminary test of various solution. It is a flowchart which shows the procedure of the coloration preliminary test of magnesium. It is a flowchart which shows the procedure of the coloration preliminary test of iron.

Claims (8)

1) A pretreatment step of removing the eluate after allowing the pulverized sample to stand still in contact with the pretreatment liquid and elution operation of magnesium and iron in rock wool;
2) A determination liquid preparation step for preparing a determination liquid through elution operation of magnesium and iron in asbestos, in which the solid content after removal of the eluate is left in contact with the dissolution liquid; and 3) Magnesium or iron in the determination liquid A coloring determination step of determining the presence or absence of asbestos by coloration,
An asbestos determination method characterized by using an acid aqueous solution of 6 to 14% phosphoric acid as the pretreatment liquid and an acid aqueous solution of 4 to 10% hydrochloric acid as the solution. The asbestos determination method according to claim 1, wherein the pretreatment liquid further contains 0.5 to 4% hydrochloric acid and 0.1 to 1% hydrofluoric acid as additives. The pretreatment liquid further as an additive, asbestos determination according to claim 2, characterized in that containing 0.5 to 4% water soluble carboxylic acid and 0.5 to 4% lower aliphatic alcohol Law. The asbestos determination method according to claim 3, wherein the water-soluble carboxylic acid is citric acid, and the lower aliphatic alcohol is ethyl alcohol or isopropyl alcohol. 5. The asbestos determination according to claim 1, wherein the solution further contains 2 to 6 parts of hydrofluoric acid as an additive with respect to 10 parts of the hydrochloric acid. Law. The asbestos determination method according to claim 1 , wherein xylidyl blue is used as the magnesium coloring reaction reagent . 6. The asbestos determination method according to claim 1 , wherein bathophenanthroline is used as the iron (II) color reaction reagent . The asbestos determination method according to claim 1 , wherein the determination in the color determination step is performed by adjusting the pH suitable for coloration with a pH adjuster.

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