JP2007163162A - Method and apparatus for monitoring contamination with very small amount of toxicant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and rapidly judge the contamination of water to be tested due to a very small amount of a toxicant. <P>SOLUTION: When aquatic life is preliminarily bred in a water tank through which the water to be tested is passed and the presence of the contamination of the water to be tested by the toxicant is monitored on the basis of a change in the action potential of the aquatic life is sampled for a predetermined time at a predetermined sampling interval and the action potential of the aquatic life during the predetermined time is subjected to fast Forier transform before converted to a power spectrum. After the sum total of powers at every frequency up to low frequency in the frequencies of the vallelys on both sides of the peak of the power spectrum and the sum total of the powers at every frequency from low frequency to high frequency are calculated, the sum total ratio of both powers is calculated and, when this sum total ratio is more increased than before, contamination is judged to be present. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a trace poison contamination monitoring method and apparatus for monitoring the trace poison contamination of water by measuring the action potential of aquatic organisms in an aquarium.

As a toxic pollution monitoring technology that monitors toxic pollution of rivers, dams, groundwater, business wastewater, factory wastewater, etc., breeding aquatic organisms such as medaka in the monitoring section of the tank that introduces and drains test water such as rivers and dams There is a method of measuring the action potential of aquatic organisms with a pair of electrodes equipped in the monitoring unit and monitoring the presence or absence of poisonous contamination based on the change of the action potential (Patent Document 1). This toxic contamination monitoring method measures changes in myoelectric potential due to aquatic organism activity in an aquarium using a pair of electrodes, and integrates the absolute value of the myoelectric potential per unit time to obtain an activity amount. A method is used in which a moving average value with the amount of activity during a certain number of measurements is obtained and water quality abnormality is determined when the moving average value exceeds a control limit value.
JP-A-11-125628

  This toxic contamination monitoring method measures the myoelectric potential of aquatic organisms over a predetermined period of time, amplifies the myoelectric potential with an amplifier, and then filters out 0.2-2 Hz frequency components resulting from the muscle activity of aquatic organisms. The A / D converted by the A / D converter is used as the action potential, the absolute value of this action potential is integrated to determine the amount of activity, and the poisoning contamination depends on whether the moving average value exceeds the control limit value. Whether or not there is.

  However, since the conventional monitoring method is basically a determination method based on the amplitude measurement of the peak value of the action potential of aquatic organisms, it is very difficult to determine the presence or absence of toxic contamination. There is a drawback that it is easy to invite judgment. Further, the time axis data of myoelectric potential has a very complicated waveform, and the voltage value is used after A / D conversion. However, subsequent information processing is complicated, and in this respect, erroneous determination is likely to occur. There is a drawback.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a trace poison contamination monitoring method and apparatus that can easily and quickly determine the contamination of test water by trace poisons.

  In the first method of the present invention, aquatic organisms are bred in an aquarium through which the test water passes, and the presence or absence of contamination by the poison of the test water is monitored based on a change in action potential of the aquatic organisms. In the toxic substance monitoring method, the action potential of the aquatic organism is sampled at a predetermined sampling interval for a predetermined time, and the action potential at the predetermined time is fast Fourier transformed and then converted into a power spectrum, and both sides of the peaks of the power spectrum The sum of the power for each frequency up to the lower frequency and the sum of the power of each frequency from the lower frequency to the higher frequency are obtained, and the presence or absence of contamination is determined based on the sum of the two powers. Judgment. At that time, the ratio of the sum of the two electric powers may be obtained, and it may be determined that there is a possibility of contamination when the ratio of the sum is higher than before.

  In the second method of the present invention, aquatic organisms are bred in an aquarium through which the test water passes, and the presence or absence of contamination by the poison of the test water is monitored based on a change in action potential of the aquatic organisms. In the toxic substance monitoring method, the action potential of the aquatic organism is sampled for a predetermined time at a predetermined sampling interval, and the action potential at the predetermined time is fast Fourier transformed into a power spectrum, and a peak value of the power spectrum is obtained. When the peak value increases more than before, it is determined that there is a possibility of contamination.

  In the third method of the present invention, aquatic organisms are bred in a water tank through which the test water passes, and the presence or absence of contamination by the poison of the test water is monitored based on a change in action potential of the aquatic organisms. In the toxic substance monitoring method, the action potential of the aquatic organism is sampled for a predetermined time at a predetermined sampling interval, and the action potential at the predetermined time is converted into a power spectrum after fast Fourier transform, and the power spectrum is a peak value. Is determined, and when the peak frequency increases more than before, it is determined that there is a possibility of contamination.

  According to the fourth method of the present invention, the possibility of contamination is determined as a multi-stage risk level based on the ratio of the sum of the first method, the peak value of the second method, and the peak frequency of the third method. Judgment.

  The apparatus of the present invention is a poison monitoring apparatus that keeps aquatic organisms in a water tank through which test water passes, and monitors the presence or absence of contamination by the poison of the test water based on a change in action potential of the aquatic organisms. A sampling means for sampling the action potential of the aquatic organism for a predetermined time at a predetermined sampling interval; a conversion means for converting the action potential for the predetermined time into a power spectrum by fast Fourier transform; and a peak of the power spectrum. Power ratio calculating means for calculating a ratio of the sum of power for each frequency to the lower frequency and the sum of power for each frequency from the lower frequency to the higher frequency among the trough frequencies on both sides of the power spectrum, and the power spectrum A peak value calculating means for calculating a peak value of the power spectrum, a peak frequency calculating means for calculating a peak frequency at which the power spectrum becomes a peak value, The ratio of the serial sum, the peak value, in which the peak frequency and a determination means that there is a possibility of contamination when increased.

  According to the present invention, it is possible to easily and quickly determine whether or not the test water is contaminated with a trace amount of toxic substances, and prevent erroneous determination as in the prior art.

  Embodiments of the present invention will be described below in detail with reference to the drawings. The drawings illustrate one embodiment of the invention. As shown in FIG. 3 and FIG. 4, the tank 1 for monitoring the trace poison contamination has a rectangular interior with an inflow part 2, a rectification part 3, a feeding part 4, a distribution part 5, a first monitoring part 6, and a second monitoring part. 7, it is divided into the preliminary breeding part 8 and the drainage part 9, and the test water passes through the water tank 1 from the inflow part 2 to the drainage part 9 in the direction of the arrow.

  The inflow part 2, the rectification part 3, and the feeding part 4 are arranged in the lateral direction on the upstream side of the water tank 1, and an inflow pipe 10 through which the test water flows into the water tank 1 is provided in the inflow part 2. The test water that flows in from the pipe 10 flows from the inflow part 2 to the feeding part 4 through the rectification part 3. The feeding unit 4 is provided with a feeder 11.

  The distribution unit 5 is disposed on the upstream side, and the drainage unit 9 is disposed on the downstream side in the lateral direction. Between the distribution unit 5 and the drainage unit 9, the first monitoring unit 6 and the first monitoring unit 6 for breeding aquatic organisms, for example, medaka fish. 2 Monitoring unit 7 and preliminary breeding unit 8 are arranged in the horizontal direction. The test water from the feeding unit 4 is distributed by the distribution unit 5 to the first monitoring unit 6, the second monitoring unit 7, and the preliminary breeding unit 8, and passes through the monitoring units 6 and 7 and the preliminary breeding unit 8. After that, it is discharged to the outside through the drain pipe 11a of the drainage section 9. The drain pipes 11a are provided corresponding to the monitoring units 6 and 7 and the preliminary breeding unit 8, respectively.

  The monitoring units 6 and 7 and the preliminary breeding unit 8 are partitioned from each other by a partition wall 12, and are divided by partition plates 13 and 14 having stitches, holes and the like that pass bait and the like and do not pass medaka. It is divided into nine. In the monitoring units 6 and 7, for example, a large number (plural) of about 13 or 25 medaka are raised. A spare medaka is raised in the preliminary breeding unit 8.

  The monitoring units 6 and 7 have a pair of electrodes 13a and 14a facing each other at both ends in the flow direction of the test water, that is, upstream (inlet side) and downstream (outlet side). They are arranged in parallel. For each electrode 13a, 14a, a material suitable for observing the action potential of the medaka, for example, a metal plate coated with platinum oxide is used, and the partition plates 13, 14 are also used. The electrodes 13a and 14a may be provided separately from the partition plates 13 and 14. The pair of electrodes 13a and 14a are preferably arranged in parallel. Further, the electrodes 13a and 14a may be made of platinum oxide.

  The monitoring units 6 and 7 are provided with protrusions 15 such as a plurality of poles between the pair of electrodes 13a and 14a so that the medaka swims in the direction against the flow of the test water downstream. This is because when the direction of the body of the medaka is the same as the direction between the pair of electrodes 13a and 14a, the measurement efficiency of the myoelectric potential is the best.

  The monitoring units 6 and 7 are provided with a plurality of sets of electrodes so that the direction connecting the pair of electrodes is different, such as providing another pair of electrodes on both sides of the direction substantially orthogonal to the flow direction of the test water. They may be arranged in different directions. The water tank 1 is disposed on a metal ground plate 16 to prevent the influence of static electricity. One of the monitoring units 6 and 7 may be omitted.

  As shown in FIG. 1, in addition to the aquarium 1, the trace poison contamination monitoring apparatus includes sampling means 17 for sampling the action potentials of a predetermined number of medaka bred in the monitoring units 6 and 7 at a predetermined sampling interval for a certain period of time. , A conversion means 18 for converting an action potential for a predetermined time into a power spectrum (see FIG. 2) which is a power density distribution with respect to the frequency by fast Fourier transform and the like, and frequencies f1 (Hz) and f2 of valleys on both sides of the peak of the power spectrum. Of the frequency setting means 19 for setting (Hz) and the frequencies f1 (Hz) and f2 (Hz) of the valleys on both sides of the peaks of the power spectrum set by the frequency setting means 19, up to the lower frequency f1 (Hz) The sum of the power for each frequency in the frequency band and the power of each frequency in the frequency band from the low frequency f1 (Hz) to the high frequency f2 (Hz) Power ratio calculating means 20 for calculating the ratio with the sum, peak value calculating means 21 for calculating the peak value of the power spectrum, peak frequency calculating means 22 for calculating the peak frequency at which the power spectrum becomes the peak value, and action potential When the maximum value of the amplitude exceeds the reference value A0, the determination means 23 for determining that there is a possibility of contamination when the sum ratio, peak value, and peak frequency increase, and the determination result of the determination means 23 are output. An informing means 24 for informing is provided, and the presence or absence of contamination by a trace amount of toxic water in the test water is monitored based on a change in action potential of the medaka.

  In addition, the main parts except the water tank 1 etc. of a trace poison contamination monitoring apparatus are comprised by CPU, ROM, RAM, etc., or are comprised by the personal computer etc.

  The sampling means 17 is connected to the pair of electrodes 13a, 14a of the monitoring units 6, 7, and samples the action potential of the medaka between the electrodes 13a, 14a at a predetermined sampling interval Δt over a predetermined time T at every predetermined monitoring time. To record. The sampling means 17 has a function of amplifying the sampled action potential voltage signal.

  The conversion means 18 includes a fast Fourier transform unit 25 and a power spectrum conversion unit 26. The fast Fourier transform unit 25 converts an action potential at a predetermined time T into a frequency spectrum by a fast Fourier transform algorithm. The frequency spectrum value is squared and multiplied by ½ to convert the frequency spectrum into a power spectrum shown in FIG.

  The frequency setting means 19 can arbitrarily set the predetermined frequencies f1 (Hz) and f2 (Hz) corresponding to the valleys on both sides of the peak of the power spectrum in normal times. When looking at the power spectrum in normal times, there is a peak derived from muscle activity for posture control by medaka breathing movement and chest fin. Accordingly, the frequency setting means 19 sets the lower frequency of the valley frequencies f1 (Hz) and f2 (Hz) on both sides of the peak as f1 (Hz) and the higher frequency as f2 (Hz).

  In addition, when the action potential of a medaka in a normal condition is observed for a long time, the peak of the power spectrum changes daily, so it is necessary to newly set the frequencies f1 (Hz) and f2 (Hz) every time the power spectrum is obtained. However, if there is no significant change in the frequency based on the actual measurement result, the average value may be fixed.

  The power ratio calculation means 20 includes a total power calculation unit 27 and a power ratio calculation unit 28. The total power calculation unit 27 includes a total power P1 obtained by summing the power for each frequency in the frequency range from 0 (Hz) to the lower frequency f1 (Hz) among both frequencies f1 and f2 set by the frequency setting means 19. The total power P2 obtained by summing the power of each frequency in the frequency band from the low frequency f1 (Hz) to the high frequency f2 (Hz) is calculated. The power ratio calculation unit 28 calculates a power ratio (P2 / P1) that is a ratio of the total power P1 and P2 calculated by the total power calculation unit 27.

  The peak value calculation means 21 has a power spectrum in each frequency range from 0 (Hz) to a low frequency f1 (Hz) set by the frequency setting means 19 and from a low frequency f1 (Hz) to a high frequency f2 (Hz). Peak values D1 and D2 are calculated. Only the peak value D2 may be used. The peak frequency calculation means 22 has a peak power spectrum in each frequency band from 0 (Hz) to a low frequency f1 (Hz) set by the frequency setting means 19 and from a low frequency f1 (Hz) to a high frequency f2 (Hz). Are calculated (peak frequencies indicating peak values D1 and D2) F1 and F2. Only the peak frequency F2 may be used.

  The determination unit 23 includes an amplitude determination unit 29, a power ratio determination unit 30, a peak value determination unit 31, a peak frequency determination unit 32, and a comprehensive determination unit 33. The amplitude determination unit 29 compares the maximum value of the action potential amplitude sampled by the sampling means 17 with the reference value A0, and determines that there is a possibility of poisoning when the maximum value of the amplitude exceeds the reference value A0. In addition, when the maximum value suddenly increases with respect to the reference value A0, it is determined that "abnormal situation such as poisoning". Since the average amplitude of the action potential of medaka varies daily, it is desirable to record the maximum value of the action potential every predetermined time (for example, 1 hour) and set the maximum value as the reference value A0.

  The peak value determination unit 31 determines “possibility of poisoning” when the peak value calculated by the peak value calculation means 21 increases from the previous normal value. The peak frequency determination unit 32 determines that there is a possibility of poisoning when the peak frequency calculated by the peak frequency calculation unit is higher than the previous peak frequency (normal value). The comprehensive determination unit 33 comprehensively determines the determination results of the amplitude determination unit 29, the power ratio determination unit 30, the peak value determination unit 31, and the peak frequency determination unit 32, and determines the possibility of poison contamination as several levels of danger levels. It comes to judge.

  The notification means 24 is composed of a monitor or the like, and displays each determination result of the amplitude determination unit 29, the power ratio determination unit 30, the peak value determination unit 31, the peak frequency determination unit 32, and the comprehensive determination unit 33 of the determination unit 23 as an image or the like. It is like that. For example, the notification unit 24 uses the action potential amplitude reference value A0 and its determination result (voltage amplitude magnification at the time of abnormality), the normal value of the power ratio P2 / P1 and its determination result (abnormal power ratio P2 / P1). Value magnification), power spectrum peak value normal value and its determination result (abnormal peak value magnification), power spectrum peak frequency normal value and its determination result (abnormal peak frequency value magnification) Furthermore, a stepwise comprehensive judgment result or the like obtained by comprehensively judging them is displayed on the monitor. In addition to the visual notification means such as a monitor that visually notifies the determination result, the notification means 24 may be an auditory notification means that provides an audible notification.

  Next, a method for monitoring the test water will be described with reference to the flowchart of FIG. During monitoring, the sampling means 17 samples the action potential of the medaka between the electrodes 13a and 14a at a predetermined sampling interval Δt at a predetermined monitoring time over a predetermined time T (step S1). For example, sampling is performed at a fixed time T at 8192 points (T = 81.92 seconds) at a sampling interval of 0.01 seconds.

  When the sampling means 17 samples the action potential of the medaka, the amplitude determination unit 29 of the determination means 23 determines the presence or absence of poisonous contamination based on the amplitude of the action potential. As will be described later, the amplitude of the action potential of the medaka changes depending on the presence or absence of poisoning. Therefore, the amplitude determination unit 29 of the determination unit 23 obtains the maximum value A of the amplitude of the action potential of the sampled medaka and compares it with the reference value A0 (step S2), and if the maximum value A exceeds the reference value A0, “ It is determined that there is a possibility of poisoning "(step S3), and the notification means 24 notifies the fact.

  On the other hand, in parallel with this, the action potential of the sampled medaka is converted into a power spectrum through the fast Fourier transform unit 25 and the power spectrum conversion unit 26 of the conversion means 18 (step S4). First, the action potential of the medaka at a fixed time is converted by a fast Fourier transform unit 25 by a fast Fourier transform algorithm and converted into a frequency spectrum, and then the frequency spectrum is converted into a power spectrum by the power spectrum conversion unit 26 (frequency spectrum). Square the value and multiply by 1/2).

  Subsequently, the total power P1, P2 and the power ratio (P2 / P1) are calculated through the total power calculation unit 27 and the power ratio calculation unit 28 of the power ratio calculation means 20 (steps S5 and S6). That is, the total power calculator 27 calculates the total power P1 in the frequency range from 0 (Hz) to the low frequency f1 (Hz) and the total power in the frequency range from the low frequency f1 (Hz) to the high frequency f2 (Hz). P2 is calculated, and the power ratio calculation unit 28 calculates the power ratio P2 / P1 of the total power P1, P2.

  When the power ratio P2 / P1 is obtained, the power ratio determination unit 30 of the determination unit 23 determines the presence / absence of poisonous contamination based on the change in the power ratio P2 / P1 (step S7). That is, if there is poisonous contamination, the power ratio P2 / P1 increases as will be described later, so the power ratio determination unit 30 of the determination means 23 compares the current power ratio P2 / P1 with the previous one, If the current power ratio P2 / P1 is higher than before, it is determined that there is a possibility of poisoning (step S8), and the notification means 24 notifies it.

  The peak value calculation means 21 calculates the peak values D1 and D2 of the power spectrum in each frequency range from 0 (Hz) to the frequency f1 (Hz) and from the frequency f1 (Hz) to the frequency f2 (Hz) (step S9). ). When the peak values D1 and D2 are obtained, the peak value determination unit 31 of the determination unit 23 determines the presence / absence of poisonous contamination based on the change of the peak value D2 (step S10). If there is poisonous contamination, the peak value D2 increases as will be described later. Therefore, the peak value determination unit 31 of the determination means 23 compares the current peak value D2 with the previous peak value, and the current peak value D2 is If it has increased, it is determined that there is a possibility of poisoning (step S11), and the notification means 24 notifies it.

  Further, the peak frequency calculation means 22 calculates peak frequencies F1 and F2 at which the power spectrum peaks in each frequency range from 0 (Hz) to frequency f1 (Hz) and from frequency f1 (Hz) to frequency f2 (Hz). (Step S12). Then, when the peak frequency F2 is obtained, the peak frequency determination unit 32 of the determination unit 23 determines the presence / absence of poisonous contamination based on the change in the peak frequency F2 (step S13). If there is poisonous contamination, the peak frequency F2 increases as will be described later, so the peak frequency determination unit 32 of the determination means 23 compares the current peak frequency F2 with the previous peak frequency F2, and the current peak frequency F2 is If it has increased, it is determined that there is a possibility of poisoning (step S14), and the notification means 24 notifies it.

  The determination means 23 performs individual determination by the amplitude determination unit 29, the power ratio determination unit 30, the peak value determination unit 31, and the peak frequency determination unit 32, and combines the maximum amplitude value, power ratio, peak value, and peak frequency. Judgment is made to determine the “possibility of poisoning” as several levels of danger. And the determination means 24 notifies the determination result of the comprehensive determination.

  Note that the maximum value A of the amplitude of the action potential, the power ratio P2 / P1, the peak value D2, and the peak frequency F2 are sequentially stored by the storage means to create a database. And when each determination part of the determination means 23 compares with a present value, it utilizes as a comparison reference value before that.

  As described above, the present invention measures not only the voltage amplitude of the action potential generated from a predetermined number of medakas (for example, about 20 to 30) raised in the aquarium 1, but also the power spectrum of the action potential. The poison contamination is detected from the relationship between the physiological response of the medaka to the poison contamination, the action potential and the power spectrum.

  When a medaka is raised in the aquarium 1, an action potential derived from the muscle activity is generated from the medaka. That is, medaka swimming movements, opening and closing of jaws and lids during feeding and breathing are all due to the action of muscles, and these muscles are components of skeletal muscles and internal organs that move bones and heels. It is roughly divided into a built-in muscle and a myocardium constituting the heart wall. The action potential is a potential generated by the activity of the skeletal muscle.

  When the muscles are classified into voluntary muscles and involuntary muscles, skeletal muscles are voluntary muscles and visceral muscles are involuntary muscles. Although the myocardium is skeletal muscle morphologically, it is functionally considered to be an involuntary muscle that is controlled by the autonomous nervous system. According to this classification, the muscles of the chin and pallid are voluntary muscles, but they are involuntarily exercised with breathing at all times. This movement is also considered involuntary because the chest is moved to maintain the posture at all times.

  The relationship between the medaka physiological response to toxic contamination and the action potential and power spectrum is as follows.

    Relevance I: When the toxic concentration is sufficiently high, the action potential of medaka is abnormally high.

    Relevance II: When the concentration of toxic substances is not so high, the action potential of medaka does not change so much, but the opening and closing movements of the mouth and lids accompanying breathing become faster, and the peak frequency of the power spectrum corresponding to the opening and closing movements Becomes higher.

Relevance III: Voluntary movement (swimming movement) becomes inactive due to poisoning, and involuntary movement (movement of mouth and lids accompanying breathing, posture control by chest ribs) is the main.
<About Relevance I>
Relevance I is due to medaka's madness. Medaka takes madness when the concentration of poison is high, but no madism appears when the concentration is relatively low. For example, the action potential of medaka when the poison is KCN (potassium cyanide) is shown in FIG. (A) to (e) in FIG. 6 are cases where the KCN concentration is 1 ppm, 0.5 ppm, 0.1 ppm, 0.05 ppm, 2.0 ppm, and t = 0.5 min in the water tank 1 with a water flow. KCN is used. In any of (a) to (e), there is no significant change in the maximum value of the action potential. Note that the voltage amplitude fluctuates to ± 1.5 V in the vicinity of t = 0.5 min in (d), but this is noise from the outside. In (e) where the KCN concentration is 2 ppm, the voltage amplitude fluctuates to ± 5 V around t = 4 min. This is due to the big medaka's madness.

Therefore, when the poison concentration is high (for example, 2 ppm or more, etc.), the voltage amplitude is frequently increased due to such a frenzy action. Therefore, the maximum value of the voltage amplitude indicates “possibility of poison contamination”. , “Abnormal situation such as poisoning” can be determined. However, the action potential may increase when the medaka gathers near the electrodes 13a and 14a or suddenly starts swimming even in normal times. Also, at low concentrations of poisoning, no frenzy behavior is observed, and the action potential amplitude itself may change little.
<Relevance II and III>
A comparison of the action potentials when the medaka swims in the water tank 1 without water flow, the water tank 1 with water flow, and the water tank 1 with water flow into which KCN concentration is 1 ppm is as follows.

  FIG. 7 shows a voltage signal (amplified by about 50,000 times) generated from a medaka (13 animals) swimming in a water tank 1 having no water flow, and FIG. 8 shows its power spectrum. In FIG. 7, a periodic waveform of about 3.2 Hz is seen, which is an action potential due to the movement of the jaw and the lid and the movement of the thorax (involuntary movement) that maintains the posture during breathing. It can be seen from the power spectrum of FIG. 8 that power is concentrated at the fundamental frequency of 3.2 Hz and the harmonic component of 6.4 Hz.

  In quiet water with no water flow, the medaka moves very slowly, but the mouth and wings move regularly for breathing, and the chest fin also moves regularly for posture control. For this reason, there are 13 medaka fish in the aquarium 1, but the action potential has a waveform very similar to that of one. The peak value of the power spectrum is seen at a frequency of about 3 Hz, because the mouth, lid and chest are moving at a repetition rate of about 3 times per second.

  FIG. 9 shows a voltage signal generated from medaka (25 animals) swimming in the water tank 1 with water flow, and FIG. 10 shows its power spectrum (the black thick line is a power spectrum averaged for each frequency width of 0.1 Hz). In FIG. 9 and FIG. 10, the action potential due to medaka respiration and posture control (involuntary movement) mainly has a frequency component of about 4 Hz, and in addition, irregular action potential due to swimming movement (voluntary movement) It is superimposed.

  When the water current is intense, the medaka swims without being swept away by the water current, so the movement becomes intense. At this time, since 25 medakas are swimming against the water flow apart, the periodicity of the waveform of the action potential is considerably disturbed, and the power spectrum is also dispersed from 0 Hz to 10 Hz. However, when taking an average, a peak value is seen around 4 Hz. This is thought to be due to the rapid movements of breathing and thorax accompanying intense exercise.

  FIG. 11 shows a voltage signal when KCN (concentration of 1 ppm) is added to the aquarium 1 with a water flow where medaka (25 animals) swim, and FIG. 12 shows its power spectrum. When KCN is added to the running water of the water tank 1, the action potential of the medaka becomes regular as shown in FIGS. And the frequency of the action potential by respiration and posture control has risen to about 5.8 Hz, and the power density has also increased compared with before adding KCN.

  When KCN is introduced into the water tank 1 where the water flow is intense, the action potential waveform and power spectrum distribution of the medaka change as shown in FIGS. 5 and 6, and the action potential is cyclic again even though the water flow is intense. In the power spectrum, power is concentrated around 5.6 Hz. The shape of the power spectrum is very similar to the shape without water flow, and this phenomenon is the same even when the KCN concentration is 1 ppm or less.

  The present invention determines the presence / absence of poisonous contamination by utilizing the phenomenon of electric power concentration when there is poisonous contamination. That is, as shown in FIG. 10, the peak of the power spectrum is at 4 Hz in the normal state before the poison is charged, and there are valleys near 2.5 Hz and 7.5 Hz on both sides of the peak. On the other hand, when a poison is introduced, the peak of the power spectrum moves to around 6 Hz as shown in FIG. However, there are valleys in the vicinity of 2.5 Hz and 7.5 Hz in the same manner as before the poisoning. When the total power of 2.5 Hz or less is compared with the total power from 2.5 Hz to 7.5 Hz, the ratio of the total power changes abruptly before and after the poisoning. Therefore, toxic contamination can be determined from the change in the power ratio.

  Relevance II and III can also be seen from this measurement result. That is, comparing the voltage width of the action potential between FIG. 9 and FIG. 11, the voltage width of FIG. 9 is 3V, the voltage width of FIG. 11 is 3.5V, and the voltage amplitude when the KCN concentration is 1 ppm or less is toxic. There is no effect of contamination. However, comparing the power spectra of FIG. 10 and FIG. 12, the frequency corresponding to the opening / closing movement of the lid is about 4 Hz in FIG. 10 and about 5.8 Hz in FIG. 12, and a change is seen in the peak frequency.

  Examining how the effects of toxic substances appear in the power spectrum of action potentials using KCN aqueous solutions with different concentrations is as follows. There are five types of KCN concentrations: 2 ppm, 1 ppm, 0.5 ppm, 0.1 ppm, and 0.05 ppm. The water temperature is 27 ° C., and the water flow is a little stronger, but it is strong enough to prevent medaka from flowing. The number of medaka at each concentration is 25, and the size varies. The size of the water tank 1 is a width of 100 mm, a length of 245 mm, a water depth of 123 mm, a water volume of 3000 ml (well water), and a water flow of 1.5 l / min.

  The power and maximum power frequency for each action band of the medaka action potential are determined as follows. First, the action potential is sampled at 8192 points (81.92 seconds) at a sampling interval of 0.01 seconds. After obtaining a frequency spectrum from the time signal obtained by sampling by a fast Fourier transform algorithm, the frequency spectrum is converted into a power spectrum. Then, total powers P1 and P2 for each frequency band from 0.0 Hz to 2.5 Hz and 2.5 Hz to 7.5 Hz of the power spectrum are obtained, and their power ratio P2 / P1 is calculated. Further, peak frequencies F1 and F2 of the power spectrum for each frequency band from 0.0 Hz to 2.5 Hz and from 2.5 Hz to 7.5 Hz are obtained.

  FIG. 13 and FIG. 14 show the relationship between the total power P1, P2, the power ratio P2 / P1, the time change of the peak frequencies F1, F2 and the KCN concentration for each frequency band. FIG. 14 shows the power and frequency of the action potential of the medaka in the KCN aqueous solution for each frequency band, and FIG. 13 shows the power ratio of the action potential of the medaka in the KCN aqueous solution for each frequency band. In FIG. 13 and FIG. 14, the KCN input time is 0 minute, and the values obtained every about 82 seconds are plotted (because Fourier transformation is performed every observation time 81.92 seconds).

  When KCN is added, it can be seen that the power ratio P2 / P1 for each frequency band increases as shown in FIGS. In particular, when the KCN concentration is 0.5 ppm or more, the power ratio P2 / P1 is significantly increased. However, in the case of 2 ppm, the concentration is too high, and it seems that the activity of medaka decreases immediately. At a concentration of 0.5 ppm or less, an increase in the power ratio P2 / P1 is observed over time, but it is moderate. It can be seen that the maximum power frequency F2 for each frequency band of the action potential also increases immediately when KCN is added.

  The maximum power frequency and the peak value of the power spectrum for each frequency band of the action potential are as follows. That is, as described above, the maximum power frequency F2 for each action potential frequency band rises when KCN is added, but as can be seen from FIGS. 15 to 19, the power spectrum value itself at the maximum power frequency F2 is also KCN. Rises when is added.

  (A1) to (a4) in FIG. 15 show power spectra before and after introducing KCN having a concentration of 1 ppm. (A1) is a medaka power spectrum for 11 minutes before KCN is input (that is, in a normal state), but the 11 minutes are divided into 8 sections (the length of one section is 81.92 seconds). The power spectrum is obtained with and superimposed. (A2) shows the power spectrum for 11 minutes after the introduction of KCN, (a3) shows the power spectrum for 11 to 22 minutes after the introduction of KCN, and (a4) shows the power spectrum for 22 to 33 minutes after the introduction of KCN.

  At the time of 11 minutes before the introduction of KCN, the water in the aquarium 1 is agitated by a water pump, and 25 large and small medaka are swimming against the water flow. Therefore, the power spectrum has a peak at a substantially constant frequency, and the peak value is only slightly changed. This is because the frequency component of the voltage signal is averaged because the voltage data of a fairly long time of 81.92 seconds is Fourier transformed.

  When poison is introduced (KCN concentration = 1 ppm), the peak value of the power spectrum that was in the vicinity of 4 Hz has moved to around 5.8 Hz. This is because the peak value (broken line) suddenly changed from 4 Hz to 5.8 Hz before or after comparison with (a1) and (a2) in FIG. 15 or KCN concentration in FIG. 14 (b) = 1 ppm and t = 0. I know from that.

  Further, the peak value of the power spectrum increases from 0.025 to 0.075, which is a triple value. The peak frequency F2 at this time is considered to be the myoelectric potential frequency at which the opening and closing movements of the mouth and lid are accompanied by respiration. It can be said that it is appropriate that the frequency F2, which has been stable for 11 minutes before t = 0, suddenly changes after t = 0 (poisoning) is caused by an abnormal situation such as poisoning.

  (B1) to (b5) in FIG. 16 show power spectra before and after the introduction of KCN having a concentration of 0.5 ppm. (B1) is 11 minutes in the normal state, (b2) is about 11 minutes immediately after the KCN input, (b3) is about 11-22 minutes after the KCN input, and (b4) is about 22-33 minutes after the KCN input. , (B5) is a power spectrum for about 33 to 44 minutes after the introduction of KCN, and is overwritten in the same manner.

  In (b1), there is a peak at 4.8 Hz, but this peak moves to 5.2 Hz in (b2). The peak value of the power spectrum increases from 0.014 to 0.019 (on average). Further, in (b3), the peak frequency remains at 5.2 Hz, but the peak value increases to 0.02. In (b4), the peak frequency is 5.8 Hz and the peak value is 0.23, (b5) Then, the peak frequency changes to 5.0 Hz and the peak value changes to 0.024. From FIG. 14C, the power ratio P2 / P1 (thick broken line) between the total power P1 around the peak value on the low frequency side (near F1) and the total power P2 around the peak value at the frequency F2 is after t = 0. It can be seen that it has increased over time. Thus, the fact that the power ratio P2 / P1 changes in proportion to time indicates that the movement of the mouth and lid of the medaka gradually and rapidly became violent due to the influence of the poisonous substance.

  (C1) to (c5) in FIG. 17 show power spectra before and after introducing KCN having a concentration of 0.1 ppm. (C1) is 11 minutes in the normal state, (c2) is about 11 minutes immediately after the KCN input, (c3) is about 11-22 minutes after the KCN input, and (c4) is about 22-33 minutes after the KCN input. , (C5) is a power spectrum for about 33 to 44 minutes after the introduction of KCN, and is overwritten in the same manner.

  The peak of the power spectrum that appears around 5 Hz before and after the KCN is charged does not change much, but the peak value changes from 0.016 to 0.017, 0.022, 0.21, and 0.019. ing. As shown in (c1), the peak value at 5 Hz was about 0.016 at most even if observed for 11 minutes before KCN was added, but it was about 0.02 for about 30 minutes after KCN was added (normally (About 1.2 times the peak value).

  (D1) to (d5) in FIG. 18 show power spectra before and after introducing KCN having a concentration of 0.05 ppm (minimum concentration in this observation). (D1) is 11 minutes in the normal state, (d2) is about 11 minutes immediately after the KCN input, (d3) is about 11-22 minutes after the KCN input, and (d4) is about 22-33 minutes after the KCN input. , (D5) is a power spectrum for about 33 to 44 minutes after the introduction of KCN, and is overwritten in the same manner.

  There is no change in the power spectrum before and after the introduction of KCN. Although it seems that the power ratio P2 / P1 shown in FIG. 13 slightly increases after t = 0, it cannot be said to be a clear increase. Therefore, from this experiment, if the KCN concentration is 0.1 ppm or more, it is possible to determine the mixing of KCN from the change of the frequency F2 of the peak value of the power spectrum, the change of the peak value D2, and the change of the power ratio P2 / P1. It can be said.

  (E1) to (e5) in FIG. 14 show power spectra before and after the KCN having a concentration of 2 ppm (the highest concentration in this observation) is input. (E1) is 11 minutes in the normal state, (e2) is about 11 minutes immediately after the KCN input, (e3) is about 11-22 minutes after the KCN input, and (e4) is about 22-33 minutes after the KCN input. , (E5) is a power spectrum for about 33 to 44 minutes after the introduction of KCN, and is overwritten in the same manner.

  The frequency F2 of the peak value of the power spectrum fluctuates around 4.6 Hz before and after the introduction of KCN, but the peak value is 0.013 before the introduction of the toxic substance and 0.022 for 11 minutes immediately after the introduction of the poison. 1.7 times), from 11 minutes to 22 minutes after charging, 0.018 (1.38 times), and from 22 minutes to 33 minutes after charging, 0.022 (1.7 times). In this case, the KCN concentration was too high, and the medaka became crazy immediately after the introduction of KCN and weakened. (E2) is the power spectrum for 11 minutes immediately after the poison is added, but unlike FIGS. 15 to 18, the frequency distribution of the power spectrum has changed in a complicated manner in 11 minutes. Absent. This is because frequency components are also disturbed by extremely unnatural crazy behavior.

  FIG. 20 shows the peak value of the power spectrum at each time before and after the introduction of KCN and the frequency thereof for each KCN concentration. From FIG. 15 to FIG. 19 and FIG. 20, it can be seen that when KCN is added, the peak value of the power spectrum in the frequency band from 2.5 Hz to 7.5 Hz increases, and the frequency giving the peak value generally increases. The increase in the peak value of the power spectrum appears immediately after the introduction of KCN and increases 1.4 times between 11 minutes and 22 minutes after the introduction even in the case of a low concentration of 0.1 ppm.

  After sampling the action potential time data of the medaka in this way, the amplitude of the action potential is first compared with the reference value A0, and if it exceeds the reference value A0, it is determined that there is a “possibility of poisoning”. In some cases, the medaka may only act intensely due to the effects of things other than poisonous substances. Next, if the power ratio P2 / P1, peak value D2, and peak frequency F2 are compared with the previous one (normal value) from the power spectrum, and the power ratio P2 / P1, peak value D2, and peak frequency F2 are increased, It is determined that there is a risk of contamination.

  The monitor of the notification means 24 includes the action potential reference value A0, the voltage amplitude magnification at the time of abnormality, the normal value of the power ratio P2 / P1, the magnification of the value at the time of abnormality, the normal value of the peak value, and the value at the time of abnormality. The magnification, the normal value of the peak frequency, and the frequency change width at the time of abnormality are displayed. What is the value of these determination variables may be determined as “poisonous contamination” based on the normal data and referring to the statistical data of the determination variables. For example, when the magnification is displayed in color, it is blue when the magnification is low, but red when the magnification is high. What is necessary is just to set the level which sounds an alarm suitably according to the use of the target water to be tested and other conditions.

  As mentioned above, although the Example of this invention was explained in full detail, a various change is possible within the range which does not deviate from the meaning of this invention. For example, in the examples, medaka is illustrated as an aquatic organism, but fish, shellfish, moss, horns, etc. other than medaka may be used as long as action potential is generated by the physiological reaction. . Further, after obtaining the total power P1 and P2 for each frequency band of the power spectrum, it is desirable to determine the presence or absence of poisoning from the change in the power ratio P2 / P1, but adding both the total power P1 and P2, You may determine the presence or absence of poisoning from the change.

  The total power P1 and P2 are added and the added power value is compared with the normal power value. The added power value is higher than the normal power value depending on whether or not the added power value is substantially the same as the normal power value. When it is low, “Medaka's activity is too quiet and may be abnormal”, and when the added power is higher than normal, it is judged that “Medaka's activity is too active and may be abnormal” Is also possible.

  One rearing part of the aquarium 1 may be sufficient. In the water tank 1, in addition to the pair of electrodes 13a and 14a arranged in the flow direction of the test water, both sides of the direction intersecting the flow direction of the test water, for example, the left and right directions sandwiching the flow of the test water May be arranged so as to face each other, or to face each other in the vertical direction. In addition, when arrange | positioning the electrodes 13a and 14a on both upper and lower sides, it is desirable to arrange | position so that the upper electrodes 13a and 14a may be immersed in the water surface vicinity of test water. Moreover, you may arrange | position the electrodes 13a and 14a on the both sides of the diagonal direction of the water tank 1. FIG. The pair of electrodes 13a and 14a are desirably arranged substantially in parallel.

It is a block diagram of a trace poison contamination monitoring device. It is explanatory drawing of the power spectrum of action potential. It is a top view of a water tank. It is sectional drawing of a water tank. It is a flowchart of trace poison contamination monitoring. It is a wave form diagram of action potential when a toxic substance is thrown in. It is a wave form diagram of the action potential of the medaka in the water tank without a water flow. It is a power spectrum figure of the action potential of the medaka in the water tank without a water flow. It is a wave form diagram of the action potential of the medaka in the water tank with a water flow. It is a power spectrum figure of the action potential of the medaka in the water tank with a water flow. It is a wave form diagram of the action potential of a medaka when KCN is thrown into the water tank with a water flow. It is a power spectrum figure of the action potential of the medaka when KCN is thrown into the water tank with a water flow. It is a figure which shows the power ratio of the electric power according to the frequency band of the action potential of a medaka when KCN is thrown in. It is a figure which shows the electric power according to the frequency band of the action potential of a medaka when KCN is thrown in, and the maximum power frequency. It is a power spectrum figure in the case of KCN1ppm. It is a power spectrum figure in the case of KCN0.5ppm. It is a power spectrum figure in the case of KCN0.1ppm. It is a power spectrum figure in the case of KCN0.05ppm. It is a power spectrum figure in the case of KCN2ppm. It is a figure which shows the relationship between the peak value and peak frequency of the power spectrum before and behind KCN injection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water tank 6 1st monitoring part 7 2nd monitoring part 13a, 14a Electrode 17 Sampling means 18 Conversion means 19 Frequency setting means 20 Power ratio calculation means 21 Peak value calculation means 22 Peak frequency calculation means 23 Determination means 24 Notification means

Claims (6)

In a poison monitoring method for raising aquatic organisms in a water tank through which test water passes and monitoring the presence or absence of contamination by the poison of the test water based on a change in action potential of the aquatic organisms, a predetermined sampling interval is used. The action potential of the aquatic organism is sampled for a predetermined time, and the action potential at the predetermined time is subjected to fast Fourier transform and then converted to a power spectrum, and the lower one of the frequencies of the valleys on both sides of the peak of the power spectrum. A trace amount toxic substance characterized by obtaining a sum of power for each frequency up to a frequency and a sum of power of each frequency from a low frequency to a high frequency and determining the presence or absence of contamination based on the sum of both powers Contamination monitoring method. 2. The trace poison contamination monitoring method according to claim 1, wherein a ratio of the sum of the two electric powers is obtained, and it is determined that there is a possibility of contamination when the ratio of the sum is larger than before. In a poison monitoring method for raising aquatic organisms in a water tank through which test water passes and monitoring the presence or absence of contamination by the poison of the test water based on a change in action potential of the aquatic organisms, a predetermined sampling interval is used. The action potential of the aquatic organism is sampled for a predetermined time, and the action potential at the predetermined time is subjected to fast Fourier transform and then converted to a power spectrum to obtain a peak value of the power spectrum, and the peak value is more than before. A trace poison contamination monitoring method, characterized by determining that there is a possibility of contamination when increased. In a poison monitoring method for raising aquatic organisms in a water tank through which test water passes and monitoring the presence or absence of contamination by the poison of the test water based on a change in action potential of the aquatic organisms, a predetermined sampling interval is used. The action potential of the aquatic organism is sampled for a predetermined time, and the action potential at the predetermined time is subjected to fast Fourier transform and then converted into a power spectrum, and a peak frequency at which the power spectrum becomes a peak value is obtained, and the peak frequency A trace poison contamination monitoring method, characterized in that it is determined that there is a possibility of contamination when the amount of water increases from before. The possibility of contamination is determined as a multi-stage risk level based on the ratio of the sum total according to claim 1, the peak value according to claim 2, and the peak frequency according to claim 4. To monitor micro-toxic contamination. In a poison monitoring apparatus that keeps aquatic organisms in a water tank through which the test water passes and monitors the presence or absence of contamination by the poison of the test water based on a change in action potential of the aquatic organisms, a predetermined sampling interval Sampling means for sampling the action potential of the aquatic organism for a predetermined time; conversion means for converting the action potential of the predetermined time into a power spectrum by fast Fourier transform; and frequency of valleys on both sides of the peak of the power spectrum A power ratio calculation means for calculating a ratio between the sum of the power for each frequency up to the low frequency and the sum of the power of each frequency from the low frequency to the high frequency, and the peak value of the power spectrum is calculated A peak value calculating means, a peak frequency calculating means for calculating a peak frequency at which the power spectrum becomes a peak value, a ratio of the sum, Peak value, there is a possibility of contamination when the peak frequency is increased the determining means and trace toxic pollution monitoring apparatus characterized by comprising a.

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