JP2007256025A - Method and apparatus for detecting dissolved oxygen in underground water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply and rapidly detecting dissolved oxygen at the origin position of underground water, and a dissolved oxygen detector. <P>SOLUTION: The hole inner section 9 partitioned by a pair of packers 6 and 7, at least one of which has an optical sensor 10 attached thereto, is formed at the depth 4 of the underground water 2 in a boring hole 3. After it is detected that the hole inner section 9 is replaced with the underground water 2 at the depth 4 by a detector 14, an emission reagent 17 emitting light upon the reaction with oxygen is charged in the hole inner section 9 by a charging device 13. The output of the optical sensor 10 is input to a detector 12 and the dissolved oxygen in the underground water 2 at the depth 4 is detected by the detector 12. Preferably, the emission reagent 17 comprises a mixture of luciferin, luciferase, magnesium ions and ATP or a solution prepared by dissolving the mixture in deoxidized water. For example, a feed-in means for feeding the emission reagent 17 in the section 9 from the ground by a non-oxygen gas can be added to the charging device 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for detecting dissolved oxygen in groundwater, and more particularly, to a method and apparatus for detecting dissolved oxygen in the groundwater in its original position.

  Groundwater is roughly classified into an oxidized state (oxidizing atmosphere) and a reduced state (reducing atmosphere) depending on the presence or absence of dissolved oxygen. Since the oxidation / reduction state of groundwater affects the dissolution rate of radioactive elements (fission products), for example, when constructing a geological disposal site for high-level radioactive waste, it is necessary to investigate dissolved oxygen and its changes in groundwater (See Chapter 3 of Non-Patent Document 1). In addition, the groundwater oxidation / reduction state has a great influence on the activity of underground microorganisms, so it is necessary to investigate the dissolved oxygen in the groundwater when considering the microbial resistance of underground structures and the microbial purification of ground contamination. . For example, in an oxidized state, steel corrosion due to aerobic microorganisms such as sulfur-oxidizing bacteria becomes a problem, and in an anaerobic state, steel corrosion due to anaerobic microorganisms such as sulfate-reducing bacteria becomes a problem. In addition, while aerobic conditions can be expected to aerobically decompose oil and other contaminants, in anaerobic conditions such decomposition may not be expected.

  Conventionally, when investigating the oxidation / reduction state of groundwater, it is common to collect groundwater at the required depth and analyze it through a borehole drilled in the ground / rock (hereinafter collectively referred to as “rock”). . However, in order to examine the long-term state of groundwater, it is necessary to grasp the dissolved oxygen at the site where the groundwater exists, and it is not necessary to mix it with the drilling water during drilling or other depths of groundwater. It is necessary to collect water in a state where it is not in contact with the atmosphere while maintaining the pressure (hereinafter sometimes referred to as a pressurized inactive state).

  As techniques for collecting groundwater in a non-pressurized and inert state, Patent Documents 1 and 2 form a water sampling section separated by a water-blocking packer in a borehole (boring hole) and continuously collect groundwater in the water sampling section. It was determined that the sampling section was completely replaced with groundwater at the depth of the section (hereinafter sometimes referred to as section groundwater), and the replacement was confirmed. A groundwater sampling apparatus that collects groundwater in a sampling section in a sampling capsule (container) at that time. Moreover, it replaces with the sampling water sampling to the ground, and patent document 3 discloses the deep-hole water sampling apparatus which analyzes the ground water of a water sampling area with a hole system, and confirms substitution to a section ground water.

  FIG. 7 shows an example of the water sampling device of Patent Document 3. The water sampling apparatus in the figure has double packers 30a and 30b forming a water sampling section, a sampler (sampler) 33 and a bore pump 34 attached thereto, and a water quality sensor 38 and a water pressure gauge are provided in the sampler 33. An in-hole system 40 including 39 and an internal packer 41 are provided. During sampling, the packers 30a and 30b are suspended together with the sampler 33 and the bore pump 34 in the borehole, and the packers 30a and 30b are expanded to form a sampling section and the internal packer 41 is expanded. If all the packers 30a, 30b, and 41 are effective, the water pressure in the sampler 33 is increased by the spring pressure in the water sampling section, and the effectiveness of the packer is confirmed by the water pressure gauge 39. Next, the internal packer 41 is contracted, and the accumulated water in the water sampling section is drained to the outside of the section via the water sampling rod 31, the check valve 43, the water passage 42, the sampler 33, and the drain port 45 by the pump 34. At this time, the water pressure, water quality (electrical conductivity (EC), water temperature, pH, etc.) and water volume are measured by the borehole system 40 in the sampler 33, and the measured values are measured via the observation cable 44 and the surface data observation device 35 and Transmit to the recording device 36.

  The water quality in the sampling section is unstable at the beginning of drainage, but tends to stabilize as the amount of drainage increases. When the measured value of the borehole system 40 reaches a certain value, it is confirmed that the inside of the sampler 33 is completely replaced with the section groundwater. Thereafter, the pump 34 is stopped, and the internal packer 41 is expanded to close the sampler 33, whereby the groundwater in the water sampling section is stored in the sampler 33 in a pressurized and inactive state. The sampler 33 storing the groundwater contracts the packers 30a and 30b and pulls them up to the surface. Compared to the method of sampling water sampling on the ground, the sampling water sampling head can be shortened with the equipment shown in Fig. 7, so there is no restriction on the water sampling depth due to the pumping capacity of the pump 34, and efficient sampling is possible even at large depths of about 1,000m. Water is possible.

Nuclear Fuel Cycle Development Organization, “Technical reliability of geological disposal of high-level radioactive waste in Japan (Second report on geological disposal research and development) report, Volume 1 Japan's geological environment” November 1999 JP-A-6-193101 Japanese Patent Laid-Open No. 9-025783 JP-A-6-294270 JP 2002-010800 A

  However, although the conventional water sampling apparatus shown in patent documents 1-3 enables water sampling in a pressure inactive state, it does not guarantee water quality measurement in a pressure inactive state. For example, in Patent Document 3, the groundwater sampled is transferred to a water sampling bottle while maintaining the original pressure state (paragraph 0018), but the groundwater may come into contact with the atmosphere during the transfer or measurement. In other words, the method for detecting dissolved oxygen and the like by collecting groundwater to the ground surface has a problem that it is difficult to maintain the pressure-inactive state during measurement even when the water is strictly sampled in the pressure-inactive state.

  In order to measure dissolved oxygen in the inactive state under pressure, for example, a method of detecting dissolved oxygen by in-situ logging by including a dissolved oxygen meter or redox potential meter in the borehole system 40 of FIG. It is done. However, the conventional dissolved oxygen meter or oxidation-reduction potentiometer measures dissolved oxygen as an amount of dissolved oxygen (mg / liter unit) or oxidation-reduction potential (mV unit) using an electrode, so electrode maintenance (cleaning) is essential. If the electrode maintenance is insufficient, the measurement accuracy is lowered. It may take several days to one week to switch to the section groundwater in the sampler 33 described above, and there is a problem that measurement accuracy is lowered if the electrode is kept immersed in the groundwater for several days. Moreover, even if the electrode can be maintained by some method, there is a problem that it takes time to perform calibration after the maintenance. Development of technology that can easily and quickly detect dissolved oxygen in groundwater in a pressure-inactive state is desired.

  Accordingly, an object of the present invention is to provide a method and an apparatus for detecting dissolved oxygen in the groundwater in situ easily and quickly.

The inventor paid attention to a luminescent reagent that emits light by reacting with oxygen. For example, in the presence of magnesium ions, adenosine triphosphate (A denosine T ri p hosphate, hereinafter, ATP hereinafter) luciferin emits light by reacting with and oxygen (O ₂₎ (Luciferin, substrate) - luciferase (Luciferase, enzymes ) Luminescent systems are known. A reagent using a luciferin / luciferase luminescence system (hereinafter sometimes referred to as a bioluminescence reagent) conventionally measures ATP in a sample or a cell on a laboratory scale in the fields of medical and food as in Patent Document 4. Widely used as a method. However, a method for detecting dissolved oxygen in water using a bioluminescent reagent has not been developed.

The inventor conducted an experiment using tap water and degassed tap water to confirm whether or not dissolved oxygen in water can be detected with a bioluminescent reagent. In this experiment, tapalite (A solution) in which A powder was dissolved and tap water (B solution) in which B powder was dissolved was prepared using the following A powder and B powder (made by Kikkoman Corporation). The luminescence intensity at the time of mixing the tap water A / B solution and the luminescence intensity of the A / B solution deaerated after mixing the tap water A / B solution were visually detected. Moreover, the temperature, electrical conductivity, and pH of each mixed solution were detected together. The experimental results are shown in Table 1. The experimental results in Table 1 show that strong luminescence is detected in tap water in which oxygen is dissolved, whereas only weak luminescence can be detected when degassed. The present inventor confirmed that the emission intensity can be divided into, for example, five levels according to the degree of degassing of tap water by further experiments, and the amount of dissolved oxygen in water can be detected based on the emission intensity. did it.
A powder: Luciferase (enzyme)
B powder: luciferin (substrate), ATP, magnesium sulfate heptahydrate, glycine buffer

  In addition, the present inventor conducted an experiment to confirm the relationship between the dissolved oxygen concentration in water and the luminescence intensity by using the above-mentioned phorite as a luminescent reagent. In this experiment, a solution in which A powder was dissolved in 150 ml of tap water (A solution) and a solution in which B powder was similarly dissolved (B solution) were prepared, and a stirrer 51 and a dissolved oxygen meter (DO) shown in FIG. Meter) Luminescent by adding and stirring solution A and solution B into Erlenmeyer flask 52 equipped with 50 and thermometer 53, and let stand for 1 hour and 55 minutes. Luminescence was sufficiently weakened (stabilized), and then mixed Nitrogen gas is blown into the solution to drive out dissolved oxygen in the solution, and the output of the dissolved oxygen meter 50 and the thermometer 53 is read at intervals of 5 to 10 minutes. The emission spectrum and emission intensity were measured with a photometer (RF-5000 manufactured by Shimadzu Corporation). The reason for leaving the light emission until it stabilizes is to avoid a decrease in accuracy due to the decay of the light emission over time during the light intensity measurement. The photometric accuracy of the spectrofluorometer is ± 0.004 Abs at 0.5 to 1.0 Abs. The experimental results are shown in Table 2 and FIG.

  Nos. 1 to 6 in Table 2 and FIG. 6 indicate that the emission intensity decreases as the amount of dissolved oxygen in water (in the mixed solution) decreases, between 2 hours and 2 hours and 10 minutes after emission (No in Table 2). (Between .2 and No.3), both of them show a significant decrease. Further, FIG. 6 shows that the emission maximum wavelength of the photerite is around 545 nm, and the emission intensity at the emission maximum wavelength corresponds to the amount of dissolved oxygen in water. In this experiment, the proportional relationship between the luminescence intensity and the amount of dissolved oxygen in water could not be confirmed, but there was a correlation between the luminescence intensity and the amount of dissolved oxygen in water, and the amount of dissolved oxygen in water was detected based on the luminescence intensity. I was able to confirm that I could do it. Note that No. 7 in Table 2 and FIG. 6 shows the measured values of the luminescence intensity and dissolved oxygen at a time point before the luminescence was sufficiently weakened (55 minutes after luminescence). The luminescent reagent can be directly introduced into the groundwater at the original position in the borehole, and the luminescence intensity can be detected using a photosensor belonging to the prior art. The present invention has been completed as a result of research and development based on this finding.

  Referring to the embodiment of FIG. 1, the method for detecting dissolved oxygen in groundwater according to the present invention includes a section 9 divided by a pair of packers 6 and 7 with an optical sensor 10 at a groundwater depth 4 (see FIG. 2) in a borehole 3. After the section 9 is replaced with the groundwater 2 at the depth 4, a luminescent reagent 17 that reacts with oxygen to emit light is introduced into the section 9, and the groundwater 2 at the depth 4 is output by the output of the optical sensor 10. It is formed by detecting dissolved oxygen.

  In addition, referring to the block diagram of FIG. 1, the dissolved oxygen detection device for groundwater according to the present invention includes a packer pair 6 that forms a section 9 that is blocked by groundwater depth 4 in the borehole 3 (see FIG. 2), 7, a light sensor 10 attached to at least one of the packer pairs 6 and 7, a detection device 14 for detecting that the section 9 is replaced with the groundwater 2 at the depth 4, and the section 9 emits light in response to oxygen A charging device 13 for charging the luminescent reagent 17 and a detection device 12 for detecting dissolved oxygen in the groundwater 2 at the depth 4 by the output of the optical sensor 10 are provided.

  Preferably, the luminescent reagent 17 is a mixture of luciferin, luciferase, magnesium ion and ATP, or a solution obtained by dissolving the mixture in deoxygenated water. For example, the charging device 13 can include a feeding means for feeding the luminescent reagent 17 from the ground to the section 9 by non-oxygen gas.

  The method and apparatus for detecting dissolved oxygen in groundwater according to the present invention forms a section partitioned by a pair of packers with optical sensors at the depth of groundwater in a borehole, and after the section is replaced with groundwater at the depth, oxygen and A luminescent reagent that emits light in response is introduced, and dissolved oxygen in the groundwater at the depth is detected based on the output of the photosensor.

(B) It is not necessary to collect groundwater to the ground surface, and dissolved oxygen at an arbitrary depth of groundwater in rock can be directly measured in situ.
(B) Since it does not require conventional troublesome electrode maintenance or calibration, dissolved oxygen in groundwater can be detected by an extremely simple operation.
(C) Since no electrodes are used, the maintenance work can be greatly reduced, and the possibility of a decrease in detection accuracy due to insufficient maintenance is small.
(D) Since the luminescence of the luminescent reagent is detected by an optical sensor, it is possible to quickly detect dissolved oxygen in groundwater.
(E) Used to construct a system that digitally determines the presence or absence of dissolved oxygen based on the presence or absence of an optical sensor output when a luminescent reagent is charged, provided that the groundwater temperature, salinity, pH, etc. are within the luminescence range. it can.
(F) Quantitative measurement of dissolved oxygen in the groundwater can be expected by combining the output of the optical sensor with the groundwater temperature, electrical conductivity, and / or pH.

  FIG. 1 shows an embodiment of the dissolved oxygen detector of the present invention suspended in a borehole 3. The dissolved oxygen detection device of the illustrated example includes a packer system 5 that forms an in-hole section 9 partitioned from other depths at a required groundwater depth 4 in the borehole 3, and an in-hole section 9 is a section groundwater (with a required depth of 4). A detection device 14 for detecting the replacement with the groundwater 2, and a charging device 13 for charging the luminescent reagent 17 into the in-hole section 9. Moreover, it has the optical sensor 10 attached to the packer system 5, and the detection apparatus 12 which detects the dissolved oxygen of the groundwater 2 of the hole area 9 by the output of the optical sensor 10.

  The illustrated packer system 5 includes a pair of upper packer 6 and lower packer 7, a packer control device 8 that controls expansion and contraction of the packer pairs 6, 7, a winch 19 that suspends the packer pairs 6, 7 from the ground, and It is comprised by the ground parts, such as the wire 18. An example of the packer pairs 6 and 7 is a water-impervious packer or a mechanical packer that expands or contracts by the pressure of liquid (water or the like) or gas (air or the like) injected / collected by the control device 8. However, in the present invention, an appropriate packer system 5 belonging to the prior art can be used according to the depth of groundwater 4 in the borehole section 9, and the configuration of the packer system 5 is not limited to the illustrated example.

  The illustrated detection device 14 includes an in-hole system 20 coupled to the packer system 5 and a ground data processing device 23. The borehole system 20 includes a water sampling unit 21, a borehole pump 22, and a logging unit 24. The logging unit 24 is provided with a thermometer 25, an electric conductivity meter 26, a pH meter 27, and the like. For example, as described above with reference to FIG. 7, the groundwater 2 in the borehole section 9 is continuously drained out of the section 9 via the water passage (not shown) and the water sampling unit 21 by the borehole pump 22. The water quality and drainage amount in the water sampling unit 21 are continuously measured by the logging unit 24. The measured value of the logging unit 24 is transmitted to the data processing device 23 via the signal cable 23a, and the data processing device 23 detects that the in-hole section 9 has been replaced with the section groundwater 2. An example of the data processing device 23 is a computer with a built-in program that records the amount of drainage continuously measured by the logging unit 24 and the measured value and detects that the measured value has reached a certain value according to the amount of drainage. is there. When investigating relatively shallow groundwater, instead of the borehole system 20, a means (not shown) for sampling water from the borehole section 9 to the ground data processing device 23 is provided as in Patent Documents 1 and 2. May be.

  An example of the luminescent reagent 17 to be charged by the charging device 13 is a mixture of luciferin, luciferase, magnesium ion and ATP. For example, the mixture of A powder and B powder described above can be used. As luciferin and luciferase, those derived from organisms (fireflies etc.) can be used. This luminescent reagent 17 consumes ATP during luminescence and attenuates luminescence, but acts on the product of the luminescence reaction to regenerate ATP, and ATP regenerating enzyme such as pyruvate orthophosphate dikinase (PPDK) or phosphoenolpyruvate A reaction system is known (see, for example, Patent Document 4). In order to maintain light emission when the luminescent reagent 17 is charged for a long time, the reagent of the ATP regenerating enzyme reaction system may be mixed with the luminescent reagent 17 of the present invention.

  The charging device 13 in the illustrated example includes a charging control device 15 and a charging pipe 16. The input pipe 16 passes through the upper packer 6 and communicates the in-hole section 9 with the input control device 15 on the ground. For example, a deoxygenated water (degassed water, etc.) solution of a mixture of luciferin, luciferase, magnesium ions and ATP is stored in the input control device 15, and the input amount of the luminescent reagent (solution) 17 is controlled by the control device 15. An appropriate amount of the luminescent reagent 17 may be fed into the in-hole section 9 with non-oxygen gas by including a deoxygenating gas feeding means in the charging control device 15.

  The amount of the luminescent reagent 17 can be appropriately selected according to the capacity of the intra-pore section 9, etc. For example, the luminescent reagent 17 is dissolved in a small amount of oxygen-dissolved water that does not affect the water quality of the intra-pore section 9. In addition, it can be expected that the reduced state of the in-hole section 9 is detected by throwing the light into the in-hole section 9 and extinguishing the light emission after the injection. Further, instead of the method of introducing the luminescent reagent 17 from the ground into the in-hole section 9 as in the illustrated example, for example, an injection device (not shown) in which the luminescent reagent 17 is stored in the in-hole system 20, etc. A method of charging the luminescent reagent 17 into the in-hole section 9 by controlling the injection device of the in-hole system 20 by the input control device 15 is also conceivable.

  The optical sensor 10 in the illustrated example converts input light into, for example, an electrical signal and outputs it, and the detection device 12 receives the output of the optical sensor 10 via the signal cable 12a. An example of the optical sensor 10 is an image pickup device or a CCD (Charge Coupled Device) attached to a surface facing the in-hole section 9 of the upper packer 6. If necessary, the optical sensor 10 may be attached to the surface of the lower packer 7 facing the in-hole section 9. The optical sensor 10 can face the in-hole section 9 directly or through a glass plate or a transparent plastic plate.

  For example, if the luminescent reagent 17 is a bioluminescent reagent, it will dissolve if the groundwater 2 emits light when the luminescent reagent 17 is charged, provided that the temperature, salinity, pH, etc. of the groundwater 2 are within the luminescent range, as will be described later. A digital judgment system is established that there is oxygen and there is no dissolved oxygen if it does not emit light. An example of the detection device 12 is a computer with a built-in program that qualitatively detects the presence or absence of dissolved oxygen in the groundwater 2 based on the presence or absence of the output of the optical sensor 10.

  As described above, the dissolved oxygen amount in the groundwater 2 can be detected based on the luminescence intensity when the luminescent reagent 17 is introduced. For example, if a relational expression or graph between the luminescence intensity of the luminescence reagent 17 and dissolved oxygen is experimentally obtained and stored in the memory of the detection device 12, the luminescence intensity is calculated from the output of the optical sensor 10 by the built-in program of the detection device 12. Thus, the dissolved oxygen content of the groundwater 2 can be quantitatively detected. For example, when the luminescent reagent 17 is a bioluminescent reagent, the luminescence maximum wavelength of the bioluminescence reagent is about 540 to 560 nm, and the spectral intensity (luminescence intensity) of the maximal wavelength corresponds to the dissolved oxygen concentration. ing. Therefore, the amount of dissolved oxygen in the groundwater 2 can be detected from the output of the optical sensor 10 by using the optical sensor 10 that outputs a signal corresponding to the spectral intensity of wavelengths 540 to 560 nm. In this case, the optical sensor 10 can be a spectroscopic camera, and the detection device 12 can be a spectral analysis device (spectral fluorometer). Further, in order to avoid a decrease in detection accuracy due to the decay of emission intensity over time, the luminescent reagent 17 may be dissolved in oxygen-dissolved water to emit light, and after the emission is stabilized, it may be introduced into the in-hole section 9.

  Next, with reference to FIG.1 and FIG.2, the detection method by the dissolved oxygen detection apparatus of FIG. 1 is demonstrated. As shown in FIG. 2, the packer pairs 6 and 7 with the optical sensor 10 and the borehole system 20 are suspended at an arbitrary depth (groundwater depth) 4 where the groundwater 2 exists in the borehole 3 drilled in the bedrock 1. The pairs 6 and 7 are expanded to form an in-hole section 9. In order to protect the hole wall of the boring hole 3, the packer pair 6, 7 may be attached to the tip of a hole retaining member such as a casing pipe and inserted into the boring hole 3. After that, the water quality (electrical conductivity, water temperature, pH, etc.) and water volume are measured by the logging unit 24 while draining the accumulated water in the hole section 9 to the outside of the section 9 via the hole system 20, and the ground data processing device. 23 confirms that the borehole section 9 has been replaced with the section groundwater (groundwater of arbitrary depth 4) 2. After the replacement is confirmed, the luminescent reagent 17 is introduced into the in-hole section 9 by the input device 13, and the dissolved oxygen in the groundwater 2 in the in-hole section 9 is detected by the detection device 12 by the output of the optical sensor 10 facing the in-hole section 9. To detect.

  According to the present invention, it is not necessary to collect the groundwater 2 to the ground surface, and the dissolved oxygen in the groundwater 2 can be directly detected at the original position. Further, after confirming the replacement of the in-hole section 9 with the section groundwater 2, it is only necessary to put the luminescent reagent 17 into the in-hole section 9, and it is not necessary to perform conventional operations such as electrode maintenance and calibration. Therefore, the operation is extremely simple and there is little risk of a decrease in detection accuracy due to insufficient maintenance. In addition, since the light emission of the luminescent reagent 17 is detected by the optical sensor 10, the dissolved oxygen in the groundwater 2 can be quickly detected.

  Thus, provision of “a method and apparatus for detecting dissolved oxygen in situ in the groundwater simply and quickly”, which is an object of the present invention, can be achieved.

  When the luminescent reagent 17 is a bioluminescent reagent, the luminescence intensity when the luminescent reagent 17 is introduced into the groundwater 2 is not determined only by the dissolved oxygen in the groundwater 2, but other water quality conditions such as temperature and salinity in the groundwater 2. , PH, trace substances, etc. Therefore, in the present invention, when the presence or absence of dissolved oxygen is qualitatively detected based on the presence or absence of light emission from the groundwater 2, it is confirmed that the temperature, salt concentration, pH, etc. of the groundwater 2 are within the light emission range of the luminescent reagent 17. Is desirable. In addition, when the dissolved oxygen is quantitatively detected based on the luminescence intensity at the time of charging the luminescent reagent 17 in the groundwater 2, it is desirable to consider the influence on the luminescence intensity such as the temperature, salinity, and pH of the groundwater 2.

  The present inventor conducted an experiment for confirming the influence of the temperature in water, the salinity concentration, and the pH on the luminescence intensity of the bioluminescence reagent, using the fluorite composed of the A powder and the B powder as the luminescence reagent 17. First, in order to confirm the influence of the temperature of the groundwater 2, while adding ice to a solution obtained by dissolving the A and B powders of the bioluminescent reagent in tap water (22 ° C.) and measuring the temperature of the solution The change in emission intensity was observed. Further, the light-emitting solution was put in a transparent container and boiled at 80 ° C., and the change in light emission intensity was observed while measuring the temperature of the solution. The luminescence intensity of the solution was compared with the luminescence intensity level in five steps according to the degree of degassing of the tap water (see Table 1), and the level of the luminescence intensity was detected. The experimental results are shown in columns No. 3 to No. 5 in Table 3.

  As shown in Nos. 3 to 5 in Table 3, the luminescence intensity of the solution in which the bioluminescent reagent is dissolved gradually weakens when the temperature is lowered from 22 ° C., and becomes luminescence intensity of about level 1 at the temperature of 0 ° C. It was. Conversely, when the temperature rises to about 30 ° C, the light emission intensity gradually becomes weak orange from the surroundings of the container, reaches about level 1 at 45 ° C, which corresponds to a groundwater temperature of 1000 m at the underground depth, and completely emits light above 51 ° C. Became unobservable. From this experimental result, it was confirmed that the presence or absence of dissolved oxygen can be detected qualitatively by the presence or absence of luminescence if the temperature of the groundwater 2 is in the range of 0 to 50 ° C. In addition, if the temperature in water is within this range, the logarithmic unit can be obtained by experimentally obtaining a relational expression or graph of the luminescence intensity of the luminescent reagent 17 and the temperature and dissolved oxygen and storing it in the detection device 12. It is expected that the dissolved oxygen in the groundwater 2 can be detected quantitatively by the output of the 24 thermometers 25 and the output of the optical sensor 10.

Next, in order to confirm the influence of the salt concentration in water on the luminescence intensity of groundwater 2, bioluminescent reagents (A powder and B powder) are dissolved in sodium chloride (NaCl) solutions of different concentrations, and the electric conductivity of the solution The relationship with the emission intensity was observed. The reason for using the sodium chloride solution is to simulate the groundwater 2 in the bedrock affected by seawater (Na ⁺ concentration: 9,000 to 10,000 ppm, Cl ⁻ concentration: 18,000 to 20,000 ppm). The electrical conductivity can be used as a simple indicator of the salinity concentration. The experimental results when the sodium chloride concentration was 0.1 g / 10 ml (Na ⁺ concentration: 3,900 ppm, Cl ⁻ concentration: 6,100 ppm) and 0.5 g / 10 ml (Na ⁺ concentration: 19,500 ppm, Cl ⁻ concentration: 30,500 ppm) , No. 6 and 7 columns in Table 3 and FIG. FIG. 4 also shows the relationship between electric conductivity and light emission intensity in solutions Nos. 8 to 13 described later.

  From the graph of FIG. 4 and Table 3, if the groundwater 2 has a pH of about 6.88 to 9.92, the emission intensity gradually attenuates as the electrical conductivity increases, and the groundwater 2 has a salt concentration higher than seawater (Table 3). It can be seen that the light emission intensity of about level 1 can be observed even in column No. 7). From this experimental result, it was confirmed that the presence or absence of dissolved oxygen can be detected qualitatively by the presence or absence of luminescence even when seawater is mixed into the groundwater 2. Further, if the relational expression or graph of the luminescence intensity, electric conductivity, and dissolved oxygen of the luminescent reagent 17 is experimentally obtained and stored in the detection device 12, the output of the electric conductivity meter 26 of the logging unit 24 It can also be expected to detect the dissolved oxygen in the groundwater 2 quantitatively based on the output of the optical sensor 10.

  Furthermore, in order to confirm the effect of pH on the luminescence intensity of groundwater 2, bioluminescent reagents (A powder and B powder) are dissolved in pH buffer solution and natural mineral water (Kagoshima Tarumi hot spring water, Perrier, France) The relationship between pH and luminescence intensity was observed. The experimental results are shown in No. 8 to 12 columns of Table 3 and FIG. FIG. 3 also shows the relationship between the measured pH value and the luminescence intensity of the solutions No. 6 and No. 7 described above.

From the graph in Fig. 3 and Table 3, the luminescence intensity of groundwater 2 is neutral and strongest, and the luminescence intensity of level 2 can be observed even in alkaline groundwater 2 with a pH of about 10.02. Can not be observed. This experimental result is related to H ⁺ and OH ⁻ in the groundwater 2, and it is considered that the relationship between the oxidation-reduction potential and the emission intensity is implied. From the experimental results in Table 3 and FIG. 3, it was confirmed that the presence or absence of dissolved oxygen can be detected qualitatively by the presence or absence of luminescence if the groundwater 2 is neutral or alkaline at a pH of about 10.02 or lower. Further, if the relational expression or graph of the luminescence intensity of the luminescent reagent 17, pH and dissolved oxygen is experimentally determined and stored in the detection device 12, the output of the pH meter 27 of the logging unit 24 and the output of the optical sensor 10 are stored. Thus, it can be expected that the dissolved oxygen in the groundwater 2 is detected quantitatively.

  In column No. 13 of Table 3, 15 g of cement is stirred in 200 cc of distilled water and allowed to stand for 1 hour, and the bioluminescent reagent (A powder and B powder) is added to the supernatant solution (hereinafter referred to as cement extraction water). The experimental result which melt | dissolved and observed the emitted light intensity is shown. As shown in the same column, the cement-extracted water had a water temperature and electrical conductivity within the bioluminescence range, but had a pH of 12.17, and no luminescence could be observed. Therefore, for example, when the boring hole 3 is retained by cementing or bentonite pellets, care must be taken so that cement slurry and bentonite pellets eluted in the groundwater do not contaminate the in-hole section 9.

  FIG. 2 shows an embodiment of the present invention in which dissolved oxygen in groundwater 2 in the rock mass 1 is detected at a number of points (boring holes 3a to 3d). For example, groundwater 2 in sedimentary rocks and igneous rocks originating in precipitation is considered to have a gradual decrease in dissolved oxygen depending on the depth. The dissolved oxygen detection method of the present invention can easily and quickly detect dissolved oxygen in the groundwater 2 at a plurality of original positions (groundwater depths 4a to 4d) in the rock 1 as shown in FIG. Expected to be used for analysis of geological structure.

It is explanatory drawing of one Example of this invention. It is explanatory drawing of the other Example of this invention. It is an experimental result which shows the relationship between pH of groundwater and luminous intensity. It is an experimental result which shows the relationship between the electrical conductivity of groundwater and emitted light intensity. It is explanatory drawing of experiment which confirms the relationship between the dissolved oxygen concentration in water, and emitted light intensity. It is an experimental result which shows the relationship between the dissolved oxygen concentration in water, and emitted light intensity. It is explanatory drawing of an example of the conventional groundwater sampling apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bedrock 2 ... Groundwater 3 ... Boring hole 4 ... Groundwater depth 5 ... Packer system 6 ... Upper packer 7 ... Lower packer 8 ... Packer control device 9 ... (inside hole) Section 10 ... Optical sensor
12 ... Detection device 12a ... Signal cable
13… Inserting device 14… Detecting device
15 ... Input control device 16 ... Input pipe
17 ... Luminescent reagent 18 ... Wire
19 ... Winch 20 ... Hole system
21… Water sampling unit 22… Hole pump
23… Data processor 23a… Signal cable
24 ... Logging unit 25 ... Thermometer
26 ... Electric conductivity meter 27 ... pH meter
30a, 30b ... Packer 31 ... Water sampling rod
32… Gas cylinder 33… Sampler (sampler)
34 ... Pore pump 35 ... Data observation equipment
36 ... Recording equipment 37 ... Internal packer
38 ... Water quality sensor 39 ... Water pressure gauge
40… In-hole system 41… Internal packer
42 ... Water passage 43 ... Check valve
44 ... Observation cable 45 ... Drain port
50 ... dissolved oxygen meter (DO meter)
51 ... Stirrer 52 ... Erlenmeyer flask
53 ... Thermometer

Claims (10)

  A section partitioned by a pair of packers with a light sensor is formed at the groundwater depth in the borehole, and after the section is replaced with groundwater at the depth, a luminescent reagent that reacts with oxygen and emits light is introduced into the section. A method for detecting dissolved oxygen in groundwater by detecting dissolved oxygen in the groundwater at the above-described depth from the output of the sensor.   2. The detection method according to claim 1, wherein a thermometer, an electrical conductivity meter and / or a pH meter are attached to the packer, and the groundwater is determined by the output of the optical sensor and the output of the thermometer, the electrical conductivity meter and / or the pH meter. A method for detecting dissolved oxygen in groundwater by detecting dissolved oxygen in water.   The detection method according to claim 1 or 2, wherein the luminescent reagent is a mixture of luciferin, luciferase, magnesium ions and ATP, and dissolved oxygen is detected in groundwater.   The detection method according to claim 3, wherein the dissolved oxygen is detected as a solution of the mixture in which the luminescent reagent is dissolved in deoxygenated water.   The detection method in any one of Claim 1 to 4 WHEREIN: The dissolved oxygen detection method of the groundwater which sends the said luminescent reagent to the said area by non-oxygen gas from the ground.   A packer pair that forms a section blocked by the groundwater depth in the borehole, an optical sensor attached to at least one of the packer pair, a detection device that detects that the section is replaced with groundwater at the depth, and the section A groundwater dissolved oxygen detection device comprising: a charging device for charging a luminescent reagent that emits light by reacting with oxygen; and a detection device for detecting dissolved oxygen in the groundwater at the depth based on the output of the optical sensor.   The detection device according to claim 6, wherein a thermometer, an electric conductivity meter and / or a pH meter are attached to at least one of the packer pair, and the output of the photosensor and the thermometer, the electric conductivity meter and / or the pH meter are detected by the detection device. An apparatus for detecting dissolved oxygen in groundwater by detecting dissolved oxygen from the output of a pH meter.   8. The detection apparatus according to claim 6, wherein the luminescent reagent is a mixture of luciferin, luciferase, magnesium ions and ATP.   The detection device according to claim 8, wherein the dissolved oxygen detection device is a solution of the mixture in which the luminescent reagent is dissolved in deoxygenated water.   10. The dissolved oxygen detection device for groundwater according to claim 6, wherein the charging device includes a feeding means for feeding the luminescent reagent from the ground to the section by non-oxygen gas.

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