JP3607284B2 - Method for detecting harmful water quality environment and water quality environment monitoring system - Google Patents

Description

Background of the Invention

The present invention relates to a method for detecting harmful water quality environments. More specifically, the present invention relates to a method for detecting a water quality environment harmful to shellfish belonging to bivalves using a non-contact sensor. The present invention also relates to a harmful water quality monitoring system.

Background Technology In the coastal waters of western Japan, water pollution and eutrophication have rapidly progressed along with industrial development after the war and population concentration in cities, and red tides have become frequent. As a result, a large amount of aquatic products such as cultured seafood drowned, causing serious damage to the fishery industry. The number of red tide occurrences increased rapidly with high economic growth and gradually decreased since 1978, but it still occurs every year (T. Honjo, Rev. Fish. Sci., 2,225-253 (1994); Y Fukuyo et al., Uchida Rokakuho (Tokyo), p407 (1990)).

In particular, since the new species of algae 1988, Heterocapsa circularisquama (T.Horiguchi, Phycol.Res. , 43,129-136 (1995)) is made to form a red tide, every year specifically to mortality shellfish such as oysters and clams It has caused many fishery damages (Yamamoto Chihiro and Tanaka Yoshiko, Fukuoka Water Research Institute, 16, 43-44 (1990); Matsuyama Yukihiko et al., Nippon Suisan Gakkaishi, 61, 35-41 (1995)). When red tide occurs, time and skill are required for water sampling and plankton species identification / counting work, so it is very difficult to take damage control measures immediately.

Since shellfish change the opening and closing movement of shells depending on the habitat state, detection of pollutants in seawater using this fact has been reported. For example, Kramer is investigating shell responses to pollutants in seawater (Baldwin, IGand Kramer, KJM, Biomonitoring of Coastal Waters and Estuaries, CRC Press, Boca Raton, FL, 1-28 (1994)). 1)), Gainey and Shamway are investigating the response of shellfish to noxious plankton Alexandrium (Gainey Jr.LE & SEShumway, J. shellfish Res, 7,623-628 (1988) ( non-Patent Document 2)). In addition, Fujii is investigating the effects of tides on the movement of shellfish shell muscle (T. Fujii, Bulletin of the Japanese Society of Scientific Fisheries, 43 (7), 901 (1977) (Non-patent Document 3)) .

Among them, Kramer attaches two small coils to both mussel shells as a transmitter and a receiver, respectively, and a signal is transmitted from the transmitter to the receiver by the shellfish shell, and the signal is sent from the receiver to the land. Therefore, an electrical engineering method for detecting abnormalities was used. In addition, Fujii detects the movement of the shell by attaching a U-shaped metal plate with a putty so as to straddle both shells of the shell, and detecting strain of the metal piece caused by the opening and closing movement of the shell with a strain gauge. did.
In addition to these, as a method for detecting pollutants in seawater using changes in shell opening and closing movement, a method for measuring myoelectric potential in bivalves has been reported (Japanese Patent No. 3383223 (Patent Document 1)). .

However, both the method using the coil by Kramer and the method by the strain gauge by Fujii require high technology and skill for attaching the sensor to the shell, and the durability is not always good. In addition, these methods sometimes put an excessive burden on the shells equipped with the sensors. For this reason, it may be difficult to measure continuously for a long time in the aquaculture area. Therefore, these methods may not always be suitable for on-site fishing grounds.
For this reason, there is still a demand for a method that can reduce the burden on the test organism and that can easily and stably measure the opening and closing movement of the shell.

  The documents listed in the above description are listed below.

Baldwin, I.G.and Kramer, K.J.M, Biomonitoring of Coastal Waters and Estuaries, CRC Press, Boca Raton, FL, 1-28 (1994) Gainey Jr.L.E. & S.E.Shumway, J. Shellfish Res, 7, 623-628 (1988) T. Fujii, Bulletin of the Japanese Society of Scientific Fisheries, 43 (7), 901 (1977) Japanese Patent No. 3383223

Summary of the Invention

  The present inventors have recently found that a change in the shell opening / closing motion of the pearl oyster can be detected extremely sensitively by mounting a non-contact sensor on the shell of the pearl oyster and measuring the shell opening / closing motion. It was found that by using the detailed data of the shell opening / closing movement obtained in this way, the water quality environment harmful to the clams belonging to bivalves can be detected sensitively. Also, by observing the waveform of the obtained data, it was possible to determine the type of harmful water quality environment. Furthermore, such detection and discrimination of the water quality environment could be performed using shellfish other than the pearl oyster, such as clams. The present invention is based on these findings.

  Accordingly, an object of the present invention is to provide a highly sensitive detection method for a harmful water quality environment, which can be easily and stably performed over a long period of time, and has a low burden on a test organism.

According to the present invention, a method for detecting a water quality environment harmful to a shell belonging to a bivalve is a bivalve in which a non-contact sensor capable of detecting a magnetic field is attached to one shell and a member for generating a magnetic field is attached to the other shell. A shell belonging to ( Bivalvia ) is brought into contact with the sample water, and the change in shell opening and closing movement of the shell is measured by the non-contact sensor.

  According to a preferred aspect of the present invention, the harmful water environment detection method observes a spike waveform of a change in the open shell distance in a graph representing the open shell distance with respect to time obtained by measurement by a non-contact sensor, It further includes determining whether or not the sample water is a harmful water quality environment from the waveform.

A water quality environment monitoring system according to the present invention is a water quality environment monitoring system for monitoring a water quality environment harmful to shellfish belonging to bivalves,
A shell of a shell formed by contact between the shell and sample water, in which a non-contact sensor capable of detecting a magnetic field is mounted on one of the shells belonging to the bivalve, and a member that generates a magnetic field is mounted on the other shell Sensing means for measuring changes in opening and closing movements;
Recording means for recording the voltage data output from the sensing means over time;
By comparing the open shell distance data of the shell calculated from the voltage data recorded in the recording means and the data in the database separately recorded in the recording means, the sample water is in a water quality environment harmful to the shellfish. An analysis means for determining whether or not there is;
Data transmission means for converting the output result of the analysis means into transmission data and transmitting the data;
Data receiving means for receiving data sent from the data transmitting means;
Display means for displaying the data received by the data receiving means for notifying the supervisor.

In the method according to the present invention, since a non-contact sensor is used, the sensor can be easily and quickly attached to the shellfish. For this reason, according to the method of this invention, if it is a shellfish which belongs to a bivalve, it can implement using most bivalve regardless of the form of the shellfish. Since the method according to the present invention places little burden on the test organism, it can be carried out stably for a long period of time. The present invention can be directly and easily installed in field fishing grounds such as inner bays, ponds, and lakes. Further, according to the method of the present invention, reproducible data can be easily measured.
According to the present invention, even when the harmful water quality environment has a slight impact on the shell, for example, when the concentration (or density) of the harmful water quality environment is relatively low, it is detected sharply. be able to. For this reason, abnormalities in the water quality environment can be detected from the early stage of occurrence. Therefore, according to the present invention, it is possible to detect the occurrence or approach of a harmful water quality environment at an early stage in aquaculture and fishery, and it is possible to respond to it more quickly.

Detailed description of the invention

As described above, the method for detecting a water quality environment harmful to shellfish belonging to the bivalve according to the present invention includes a non-contact sensor capable of detecting a magnetic field attached to one shell and the other shell. A shell belonging to a bivalve ( Bivalvia ) equipped with a member for generating a magnetic field is brought into contact with the sample water, and a change in shell opening / closing movement of the shell is measured by the non-contact sensor.

In the detection method according to the present invention, first, a shellfish belonging to a bivalve ( Bivalvia ) is brought into contact with sample water. The sample water can be collected from the sea area where the fishing ground environment is monitored or from the culture pond, but is not limited thereto, and may be, for example, sea, river, or lake water. The term “contact with the sample water” means that the shellfish and the sample water can be used in any manner as long as the shellfish belonging to the bivalve is in contact with the sample water to such an extent that the shell opening / closing movement can be changed by the presence of the sample water. And may contact. For example, a mode in which a shell belonging to a bivalve is immersed in a sea area or a water area or an aquaculture pond where monitoring is performed, and a mode in which the shellfish is fixed and immersed therein are also included in “contact with sample water”. The The fixation of the bivalve to a fishing ground or the like may be performed in an aquaculture basket hung on a shore floating offshore or in a container filled with seawater pumped to the land by a pump.

Here, as a shellfish which belongs to a bivalve, marine bivalve and freshwater bivalve are mentioned.
Marine bivalves include shellfish belonging to Lamellibranchia , for example, shellfish belonging to Pteridae such as pearl oyster, white butterfly, black butterfly, mabe, etc .; mussels such as mussels, green mussels, etc. family shellfish belong to (Mytilidae); Tairagi Haboukigai family, such as shellfish belong to (Pinnidae); scallops, Hiougigai, shellfish belongs to the Pectinidae family (Pectinidae) such as Pectinidae; Itabogaki family, such as oyster (Ostreidae) shellfish belongs to; clam, clams, mussels belonging to veneridae (Veneridae) such as Uchi purple; ark shell, shellfish belonging to ark clam (Arcidae) such as Sarubou the like.
The freshwater bivalves, include shellfish belonging to Shinben gill class (Eulamellibranchia), for example, Ikechougai, fin Ike butterfly Guy, mussels Department of shellfish belong to (Unionidae) such as mussels; such as Mashijimi, Corbicula japonica Shijimigai Shellfish belonging to the family ( Corbiculidae) .

  In the present invention, the clam belonging to the bivalve is preferably a clam belonging to the mussel family, a clam belonging to the clamaceae family, a shell belonging to the family lobster family, a clam belonging to the marsdalae family or a shell belonging to the mussel family, more preferably , Oyster oysters, oysters, oysters, clams, or mussels, more preferably pearl oysters or clams.

  In the present invention, the non-contact sensor capable of detecting a magnetic field includes any sensor that can measure the strength of the magnetic field without contacting the member that generates the magnetic field, for example, , Hall element sensors, and lead type sensors.

  The Hall element sensor is a sensor using a Hall element which is a magnetoelectric conversion element utilizing the Hall effect, and can measure the strength of a magnetic field. According to the Hall element sensor, the distance from a member that generates a magnetic field can be sequentially measured in a sharp and detailed manner. Hall element sensors can be classified according to the materials used, such as GaAs (gallium arsenide) hall sensors, InSb (indium / antimony) hall sensors, Ge (germanium) hall sensors, and InAs (indium arsenide) hall sensors. Is mentioned.

  The reed-type sensor is a sensor that uses a reed switch, and is a sensor that utilizes the on / off state of the reed switch that changes according to the approach of a member that generates a magnetic field. According to the lead sensor, only the result of either the on state or the off state can be obtained, so that data obtained by measurement can be simplified and the amount of data can be reduced. When using a lead type sensor in the present invention, for example, by arranging a plurality of lead type sensors for one bivalve so that the level of the shell opening and closing movement can be detected, more information on the shell opening and closing movement can be obtained. Details can be obtained.

  In the present invention, the non-contact sensor is preferably a Hall element sensor, and more preferably an InSb type Hall element sensor. In the present invention, the non-contact sensor is preferably small in size so that it can be easily attached to a shell belonging to the bivalve used and does not obstruct the shell opening / closing movement.

  Examples of the member that generates a magnetic field include permanent magnets and electromagnets. Preferable examples include a ferrite magnet having a suitable magnetic force and corrosion resistance, and a samarium cobalt magnet. Among these, the samarium cobalt magnet is small and has a strong magnetic force, and therefore is advantageous when using a small bivalve (for example, clams, blue mussels, swordfish). The member that generates the magnetic field is preferably a small member that can be easily attached to a shell belonging to the bivalve used and does not obstruct the shell opening and closing movement.

  The means for attaching a non-contact sensor and a member for generating a magnetic field to the shell of the shell to be used can be attached by any means as long as the sensor etc. can be fixed so as not to fall off due to contact with the sample water. Good. For example, the sensor and the member can be attached to the shell by bonding them onto the shell using dental cement or a conventional adhesive. In the present invention, it is preferable to fix the sensor to the shell using an adhesive from the viewpoint that the influence on the shell itself is slight and stable over a long period of time. More preferably, an epoxy resin is used as the adhesive, and an epoxy resin for underwater lining is more preferably used.

  In the present invention, the non-contact sensor and the member for generating a magnetic field are attached to each of the two shells of the shell belonging to the bivalve. The mounting position is usually on the outer surface of the shell of the shell, but preferably it is mounted near the front of the outer surface of the shell of each shell, that is, at the tip of the shell on the side where the bivalve opening is located. Is preferred. Further, the non-contact sensor and the member for generating a magnetic field are preferably mounted so as to be arranged on a straight line parallel to the shell opening / closing movement direction. That is, it is preferable that the sensor and the member are arranged at positions symmetrical with respect to the joint surface of the left and right shells of the two shells.

By the method according to the present invention, a harmful water quality environment, particularly a water quality environment harmful to a clam belonging to a bivalve can be detected. Examples of such a harmful water quality environment include a floating organism harmful to a shellfish. Hazardous water quality environment.
Here, “floating organisms harmful to shellfish” mean floating organisms that hinder the survival, reproduction, and growth of shellfish, many of which can cause red tides. “Floating organisms” include not only phytoplankton but also zooplankton.

The floating organisms that can be detected by the detection method according to the present invention include floating organisms belonging to dinophyceae and Rhaphidophyceae , particularly when using pearl oysters or clams as test subjects, and in particular, Heterocapsa circularisquama , Chattonella Antiqua , Gymnodinium mikimotoi , Gymnodinium catenatum , Cochlodinium polykrikoides , Alexandrium tamarense , Alexandrium catenells and Chattonella marina .

  It should be noted that the detection method according to the present invention can be used for monitoring the fishing ground environment not only for pearl oysters or clams, but also for scallops, snails, scallops, Japanese oysters, oysters, mussels, etc. Needless to say.

The floating organism harmful to the shellfish is preferably a floating organism belonging to Dinophyceae , more preferably Heterocapsa circularisquama .

“Hazardous water quality environment caused by floating organisms harmful to shellfish” means that the floating organisms are contained in a sample water at a predetermined concentration (or cell density) or more, for example, a concentration harmful to shellfish or more. Say. Concentration ranges that are harmful are known to those skilled in the art.
For example, when referring to Heterocapsa circularisquama, cell density, which appears colored seawater in Heterocapsa circularisquama is, 700 cells / ml (Yukihiko Matsuyama et al., "Heterocapsa circularisquama red tide of Hiroshima Bay", the South West Sea National Fisheries Research Institute report, 30,189-207 ( 1997)), and the cell density at which the pearl oysters are closed is reported to be 50 cells / ml (K. Nagai et al., Aquaculture, 144, 149-154 (1996)).

Therefore, in the present invention, “hazardous water quality environment caused by an increase in Heterocapsa circularisquama ” refers to a case where the Heterocapsa circularisquama cell density in the sample water is, for example, 10 cells / ml or more. The ability to detect a water quality environment with a cell density as described above is effective for predicting the occurrence of Heterocapsa circularisquama red tide.

  The harmful water environment that can be detected by the present invention includes (b) a harmful water environment caused by a decrease in dissolved oxygen concentration in water, ) Hazardous water environment caused by increased dissolved sulfide concentration in water, (d) Harmful water environment caused by increased suspended particle density in water, (e) Harm caused by increased concentration of toxic chemicals in water Water quality environment, and (f) harmful water quality environment caused by increased concentration of environmental pollutants in water.

  The “harmful water quality environment caused by the decrease in dissolved oxygen concentration in water” is usually known as an anoxic water mass, and hinders the survival, reproduction, and growth of shellfish. Such a water quality environment is known to occur due to, for example, oxidative decomposition of organic matter such as dead animals and plants deposited on the seabed and feces. In the present invention, such a water quality environment refers to a state where the dissolved oxygen concentration of the sample water is, for example, 0.5 mg / L or less. The dissolved oxygen concentration in water can be easily measured by a conventional electrode-type dissolved oxygen meter (for example, a multi-item water quality measuring device) or the winker method.

“Hazardous water quality environment caused by an increase in the concentration of dissolved sulfides in water” usually hinders the survival, reproduction and growth of shellfish, and may occur in combination with a decrease in dissolved oxygen concentration. It is known that such a water quality environment is caused by the generation of a large amount of hydrogen sulfide due to reduction of sulfate by the propagation of anaerobic bacteria (sulfate-reducing bacteria) accompanying the decrease in dissolved oxygen. It is known that the produced hydrogen sulfide is combined with iron present in a large amount on the seabed to become black iron sulfide and black to the sea surface, and the water quality environment is in a sewage state. Examples of the sulfide include hydrogen sulfide. In the present invention, such a water quality environment refers to a state where the total sulfide (S ²⁻ ) concentration dissolved in the sample water is, for example, 0.2 mg / L or more. The dissolved sulfide concentration in water can be easily measured by a conventional measurement method such as the methylene blue method.

  In inner bay waters, the aquaculture species may be damaged by high density floating mud (suspended particles). The “hazardous water quality environment caused by an increase in the density of suspended particles in water” as used herein refers to a water quality environment in which such floating mud is increased. Such a water quality environment can be caused by, for example, inflow of mud from land due to rainfall, inflow of sand mud by coastal civil engineering work, and raising of the bottom mud generated by seabed agitation due to the influence of seabed dredging and waves. Are known. Accordingly, examples of the suspended particles include sand, mud, viscosity, and seabed sediment. In the present invention, such a water quality environment refers to a state in which suspended particles having a diameter of, for example, about 10 to 100 μm are present in a sample water at a concentration of, for example, 5000 particles / L or more.

  “Hazardous water quality environment caused by increased concentration of toxic chemicals in water” refers to toxic substances that hinder the survival, reproduction, and growth of living species and aquaculture species inhabited by inflow from land or dumping A water quality environment in which the concentration of various chemical substances is increased. Such a harmful water quality environment may directly or indirectly impair human health. Examples of toxic chemicals include organophosphorus pesticides (eg, EPN, parathion, methyl parathion, methyl dimethone), cyanide compounds, heavy metals (eg, cadmium, chromium, mercury, copper) and compounds thereof. Among these, organophosphorus pesticides can be exemplified as preferred for the present invention. In the present invention, such a water quality environment refers to a state where, for example, an organophosphorus pesticide (eg, EPN) is present in a sample water at a concentration of 0.76 ppm or more. The EPN concentration can be measured by a conventional measurement method such as gas chromatography mass spectrometry.

  “Hazardous water quality environment caused by increased concentration of environmental pollutants in water” refers to environmental pollutants that hinder the survival, reproduction, and growth of living species and target species inhabited by domestic and industrial wastewater. The water quality environment in which the concentration of water is increased. Examples of such environmental pollutants include synthetic detergents such as surfactants (for example, anionic surfactants) and oily substances. In one embodiment of the present invention, such a water quality environment is a state in which, for example, a surfactant (for example, sodium linear alkylbenzene sulfonate (LAS)) is present in a sample water at a concentration of 3.7 ppm or more. Say. The surfactant concentration can be measured by a conventional measurement method such as the methylene blue method.

In the method according to the present invention, the change in the shell opening / closing movement is measured by a non-contact sensor.
For example, when the non-contact sensor is a Hall element sensor, a voltage change occurs in the sensor in accordance with a change in the distance between the sensor and the magnet caused by the shell opening / closing movement. By measuring this voltage change with a conventional measuring instrument, it is possible to detect a change in the shell movement. In this case, a certain relational expression may be established between the sensor output voltage value and the open shell distance, and the open / close state of the shell can be accurately monitored from this relational expression. Specific examples include relational expressions (1) and (2) shown in the examples described later.

  In the present invention, when a graph representing the open shell distance with respect to the measurement time is created based on the data obtained by the measurement by the non-contact sensor, the graph waveform obtained in the harmful water quality environment is the shellfish belonging to the bivalve. Compared with the graph waveform obtained in a substantially harmless water quality environment (normal water quality environment), it has distinctly different characteristics. For example, regarding the peak generated in the graph, that is, the spike frequency, spike time, and spike accumulation time regarding the spike waveform of the change in the open shell distance, it is obvious in normal water quality environment and harmful water quality environment. There is a difference.

  Therefore, for the target sample water, a graph representing the open shell distance with respect to the measurement time is obtained, and by comparing this graph with a graph obtained in a normal water quality environment in advance, the target water quality environment is determined. Whether or not it is a harmful water quality environment can be determined. When comparing the graphs, focusing on the spike frequency, spike time, and spike integration time in the graph, it is possible to make it easier and more reliable to determine whether the sample water is a harmful water quality environment. .

  Therefore, according to a preferred embodiment of the present invention, the detection method according to the present invention observes a spike waveform of a change in the open shell distance in a graph representing the open shell distance with respect to time obtained by measurement by a non-contact sensor, and It further includes determining whether or not the sample water is a harmful water quality environment from the waveform.

  According to a more preferred aspect of the present invention, the detection method according to the present invention is determined based on at least one index selected from the group consisting of spike frequency, spike time and spike integral value in the spike waveform. . At this time, it is more preferable to make a determination based on at least two or more indices.

Here, the spike frequency refers to the number of spikes generated in the graph waveform per predetermined time. For example, the number of spikes generated per predetermined time such as 10 minutes, 30 minutes, or 60 minutes is counted. And it can obtain | require by calculating the average value of the spike time each obtained in different elapsed time.
The spike time is an average time from the occurrence of one spike to the disappearance, and the spike waveform time having a sharper peak tends to be shorter.

  Spike integration time is a value obtained by summing spike times of spikes generated per predetermined time, and can be calculated by calculating this value at different elapsed times and calculating the average value of the obtained values. it can. For example, the spike integration time per predetermined time such as 30 minutes or 60 minutes can be calculated at different elapsed times and the average value thereof can be calculated.

  According to a further preferred aspect of the present invention, when comparing a graph obtained for a target sample water with a previously obtained graph, instead of paying attention to the spike frequency, spike time, and spike integration time in the graph. In addition to or in addition to this, the determination can be made by paying attention to at least one kind of index selected from the group consisting of presence / absence of the waveform in the spike waveform, amplitude of the wave, wavelength, period, and frequency. At this time, it is more preferable to make a determination based on at least two kinds of indicators.

Specific examples of the graph include graphs (FIGS. 3 to 7 and FIGS. 10, 12, and 13) shown in examples described later. 3 and 12 are graph waveforms obtained in a normal water quality environment, and FIGS. 4 to 7, 10 and 13 are graph waveforms obtained in a harmful water quality environment. When these graphs are compared by paying attention to spike frequency, spike time, and spike integration time, there is a clearly different tendency. Specifically, compared to the normal case of FIG. 3 or 12, in the case of FIGS. 4 to 7, 10 and 13, at least one of the spike frequency, spike time, and spike integration time is significantly increased. Yes.
Therefore, for the target sample water, a graph representing the open shell distance with respect to the measurement time is obtained, and by comparing this graph with the graph in the normal water quality environment of FIG. Whether or not it is a harmful water quality environment can be determined.

In the specific examples based on these figures, the tendency of the waveform within the operation time of 120 minutes is compared. However, when the method of the present invention is applied, it is normal to perform a longer operation. . By comparing the graphs obtained with a longer operating time, the tendency of the spike waveform in the graphs becomes clearer, so it is possible to more easily determine whether the sample water is in a harmful water quality environment.
In addition, these specific examples are examples in which pearl oysters or clams are used as shellfish, but it is obvious to those skilled in the art that the water quality environment can be determined by the same method even if shellfish belonging to other bivalves are used. Let ’s go.

According to a further preferred aspect of the present invention, the waveform of the spike of the open shell distance change is observed, and the sample water is a harmful water quality environment of any of the following types (a) to (g): You can determine whether:
(a) Hazardous water quality environment caused by increased Heterocapsa circularisquama ,
(b) Harmful water quality environment caused by a decrease in dissolved oxygen concentration in water,
(c) Hazardous water quality environment caused by increased dissolved sulfide concentration in water,
(d) a hazardous water quality environment caused by an increase in suspended particle density in water,
(e) a hazardous water quality environment caused by an increase in the concentration of toxic chemicals in the water;
(f) Hazardous water quality environment caused by increase of environmental pollutants in water, or
(g) Hazardous water quality environment due to causes other than the above (a) to (f).
That is, in this detection method, it is determined whether the sample water is a harmful water quality environment (a) to (g) or a water quality environment that is substantially harmless to shellfish belonging to bivalves. judge. Alternatively, the detection method includes determining whether the sample water is a combination of any two or more types of harmful water quality environments of (a) to (g). In cases where it is not possible to identify whether the water is a harmful water quality environment of any of the types (a) to (g), enumeration of possible types and determination of any of them are also included. To do.

  According to another more preferable aspect of the present invention, the waveform of the spike of the open shell distance change is observed, and from the waveform, the sample water is the water quality environment of (a) to (d) or (a It is possible to determine which type of water quality environment other than () to (d) is harmful.

Here, the water quality environment of (a) to (f) is as defined above, and the harmful water quality environment of (g) is a water quality environment harmful to shellfish belonging to bivalves, and (a) The water quality environment determined not to belong to any of the water quality environments in (f).
The water environment that is substantially harmless to bivalves is a normal water environment that is not a harmful water environment such as (a) to (g). An environment that is virtually unimpeded.

Specifically, for each shell used as a test shell, a normal spike waveform and standard spike waveforms (a) to (f) were obtained, and by comparing this with the actually measured waveform, To determine whether the sample water to be used is a harmful water environment, and if the sample water is a harmful water environment, the type of the harmful water environment is (a) to (g) Can do.
In addition, from the measured waveform, the water quality environment of the sample water is clearly not normal, but if it cannot be classified as any of the harmful water quality environments of (a) to (f), this water quality environment is the above (g ) Is judged to be a harmful water quality environment.

In each of the graphs showing the normal water quality environment and the harmful water quality environments of types (a) to (f), an arbitrary spike was selected, and data for a total of 10 minutes was extracted before and after the peak. ~ D and graphs such as A and B in FIG. 11 can be obtained. These graphs in FIGS. 8 and 11 represent typical model waveforms exhibited by each of the water quality environments.
Here, FIG. 8A is a characteristic model waveform observed when the sample water is a normal water quality environment, and FIG. 8B is a case where the sample water is the water quality environment of (b) or (d). FIG. 8C is a characteristic model waveform observed when the sample water is in the water quality environment of (c) or (d), and FIG. 8D is a characteristic model waveform observed in FIG. It is a characteristic model waveform observed when water is the water quality environment of (a). FIG. 11A is a characteristic model waveform observed when the sample water is the water quality environment of (e), and FIG. 11B is observed when the sample water is the water quality environment of (f). This is a characteristic model waveform.
By obtaining such a model waveform for each water quality environment in advance and comparing this with the actual measured waveform, the water quality environment of the sample water can be more easily determined.

  As a specific example, the case of an embodiment to be described later will be described as an example and further described below. Here, a case where pearl oysters are used as test shells is used as an example. When the pearl oyster is used in this way, whether the sample water is in a normal water quality environment or any harmful water quality environment of (a) to (g) can be determined as follows. .

First, in each case of a normal water quality environment and a harmful water quality environment (a) to (f), the open shell distance with respect to time is expressed by measurement with a non-contact sensor according to the method of the present invention in advance. Obtain the graphs (FIGS. 3-7 and 10).
Here, FIG. 3 shows a case of a normal water quality environment, FIG. 4 shows a case of a (a) type harmful water quality environment, and FIGS. 5A and 5B and FIG. 6 show a (b) type of harmful water quality. FIG. 5C and FIG. 5D show a case of a harmful water quality environment of the type (c), and FIG. 7 shows a case of a harmful water quality environment of the type (d). FIG. 10A shows a case of a (e) type harmful water quality environment, and FIG. 10B shows a case of a (f) type harmful water quality environment.

  Next, for the target sample water, a graph representing the open shell distance with respect to the measurement time is obtained, and this graph is compared with the graphs of FIGS. When it is determined that the obtained graph regarding the sample water has the same tendency as the graph of FIG. 3, it is determined that the sample water is in a normal water quality environment. Similarly, when it is determined that the obtained graph regarding the sample water has the same tendency as the graphs of FIGS. 4, 5A and B and FIGS. 6, 5C and D, FIGS. 7, 10A and B, The sample water is determined to be a harmful water quality environment of the types (a), (b), (c), (d), (e) and (f), respectively. When the graph shows other trends, it is determined that the water environment is of the type (g).

  When making these determinations, as described above, it is preferable to make the determination based on at least one index selected from the group consisting of spike frequency, spike time, and spike integration value in the spike waveform.

  Moreover, by comparing with graphs representing typical model waveforms of the respective water quality environments as shown in FIGS. 8A to 8D and FIGS. 11A and 11B, the type of the water quality environment can be more easily determined. More preferably, the type of the water quality environment of the sample water can be determined based on the following information regarding the graph of each model waveform in FIGS. 8A to 8D and FIGS. 11A and 11B. This makes it possible to make the determination easier and more reliable.

  FIG. 8A is a characteristic waveform typically observed when the sample water is in a normal water quality environment, with an average of usually 0-2, preferably 0-1 spikes per 10 minutes, The spike time (ST) of the spike is normally 12 to 200 seconds, and on average is about 81 ± 96 seconds.

  FIG. 8B is a harmful water quality environment in which the sample water is a harmful water quality environment caused by an increase in the concentration of dissolved sulfide in the water in (c), or a harmful water quality environment caused by an increase in suspended particle density in the water in (d). A characteristic waveform typically observed in the case, with an average of typically 1-5, preferably 2-4 spikes per 10 minutes, the spike time (ST) of that spike being typically 10-35. The second is an average of about 19 ± 6 seconds. For this reason, the spike waveform is relatively uniform.

  FIG. 8C shows a case where the sample water is a harmful water quality environment caused by a decrease in dissolved oxygen concentration in the water in (b) or a harmful water quality environment caused by an increase in suspended particle density in the water in (d). The characteristic waveform typically observed in Fig. 1 has an average of 1 to 3, preferably 1 to 2 spikes per 10 minutes, and the spike time (ST) of the spike is usually 200 seconds or more. Become.

FIG. 8D is a characteristic waveform typically observed when the sample water is a harmful water quality environment caused by the increase in Heterocapsa circularisquama in (a), and is typically 5 to 13 on average per 10 minutes, preferably Has 7 to 12 spikes, and the spike time (ST) of the spikes is usually 20 to 75 seconds, and on average is about 53 ± 30 seconds.

  FIG. 11A is a characteristic model waveform observed when the sample water is a harmful water quality environment caused by an increase in the concentration of toxic chemicals in the water of (e), and is typically 7 to 20 on average per 10 minutes. , Preferably 8 to 13, with an average of 10.9 ± 2.6 spikes, and the spike spike time (ST) averages about 595 ± 10 seconds.

FIG. 11B is a characteristic model waveform observed when the sample water is a harmful water quality environment caused by an increase in the concentration of environmental pollutants in the water of (f), and is typically 0 on average per 10 minutes. -16, preferably 3-7, with an average of 4.6 ± 2.2 spikes, and the spike spike time (ST) averages about 583 ± 44 seconds.
In FIGS. 11A and 11B, the feature of the spike is that a relatively uniform spike having a pointed tip (right triangle) appears regularly, and the spike shape is usually sharper in the former, and the spike frequency. There are also many.

  With respect to the target sample water, a graph representing the open shell distance with respect to time is obtained by measurement with a non-contact sensor according to the present invention, and the waveform for each 10 minutes of the graph and the models of FIGS. 8A to D and FIGS. When the waveform is compared and a tendency of the same waveform as any of the model waveforms is recognized on the graph, the target sample water corresponds to each of FIGS. 8A to 8D and FIGS. 11A and 11B ( It is determined that the water quality environment is any one of types a) to (f).

  In addition, when the waveform of the obtained graph is FIG. 8B or FIG. 8C, the water quality environment of the sample water is (c) or (d), respectively (b) or (d) It may not be easy to determine whether there is any. In such a case, the tendency of the obtained graph as a whole can be determined by comparison with FIGS. 4 to 7 and FIG. 10, and at that time, based on the spike frequency, spike time, spike integration time, etc. It can also be determined.

  According to a further preferred aspect of the present invention, the target sample water is obtained by measurement with a non-contact sensor according to the present invention to obtain a graph representing the open shell distance with respect to time. By classifying in this way, it is possible to determine which type of water quality environment the sample water belongs to.

Table 1 is a specific example of the case of an embodiment described later.
In addition, the data of Table 1 are based on the result measured in a predetermined environment using an pearl oyster as a test shellfish. Therefore, when determining the actual water quality environment, consider the type of shellfish to be used and the environment in which it is to be implemented, and further carry out detection with higher accuracy by collecting individual reference data in advance. Is possible.

  Here, first, a graph representing the open shell distance with respect to time is obtained for the target sample water by measurement with a non-contact sensor according to the present invention. Next, on the basis of the graph, the average of the spike frequency and the spike integration time is obtained for about 30 minutes and about 60 minutes. At this time, if the measurement time is long, it is desirable from the viewpoint of data stability that the spike frequency per 30 minutes and 60 minutes and the average value of the spike integration time are obtained over as long a period as possible.

  Then, by comparing the spike frequency and spike accumulation time data obtained for the target sample water with Table 1, it is possible to determine which type of water quality environment the sample water belongs to. .

  That is, by classifying the measurement results of the spike frequency per 30 minutes and the spike frequency per 60 minutes using the data in Table 1, whether the target sample water is a normal water quality environment, (b), (c) and (d) type water quality environment, (a) and (e) type water quality environment, or (f) type water quality environment Can be determined.

If it is determined by the above determination that the target sample water is the water quality environment of the types (b), (c) and (d), the spike integration time per 30 minutes and 60 minutes By classifying the measurement results with the spike accumulation time per hour using the data of Table 1, whether it is the water quality environment of the type (b) or the above (c) and (d) It can be judged whether it is a type of water quality environment.
Furthermore, when determining whether the sample water is a (c) type hazardous water quality environment or a (d) type hazardous water quality environment, a graph of spike accumulation time per 60 minutes is created against spike frequency per 60 minutes. The determination can also be made by looking at the tendency of the data plot in the graph (FIG. 9). That is, if the data can be plotted upward in this graph, the sample water can be determined to be a harmful water quality environment of the type (d), and if it cannot be plotted as such, the sample water is It can be judged that it is a hazardous water quality environment of type (c). In determining whether the sample water is the type (c) or the type (d), the former method and the latter method may be combined.

  Note that whether or not the plot of data in the graph is rising to the right can be determined by obtaining the correlation coefficient of each plot by the least square method and evaluating the variation of the plot.

  When it is determined by the above determination that the target sample water has the water quality environment of the types (a) and (e), the measurement result of the spike integration time per 60 minutes is shown in Table 1. By classifying using the data, it is possible to determine whether it is the water quality environment of the type (a) or the water quality environment of the type (e).

  Furthermore, in determining the water quality environment of the target sample water, as shown in Table 1, average spike time per spike, spike shape, spike cycle regularity, spike characteristics, and spike integration for spike frequency More accurate judgment can be made by using information such as a trend of a time graph in combination.

  The above is an example of using pearl oysters as shellfish, but even when other shellfish are used, the same classification method is applied to obtain the water quality environment of the sample water by obtaining data as an index in advance. It will be apparent to those skilled in the art that

Water quality monitoring system The water quality monitoring system according to the present invention, as described above, is a water quality monitoring system for monitoring a water quality environment harmful to shellfish belonging to bivalves,
A non-contact sensor (32) capable of detecting a magnetic field is attached to one shell of a clam belonging to a bivalve shell, and a member for generating a magnetic field is attached to the other shell. Sensing means (31) for measuring changes in the shell opening and closing movement of the shell;
Recording means (34) for recording the voltage data output from the sensing means over time;
By comparing the open shell distance data of the shell calculated from the voltage data recorded in the recording means and the data of the database separately recorded in the recording means, the sample water is in a water quality environment harmful to the shellfish. An analysis means (33) for determining whether or not there is;
Data transmitting means (35) for converting the output result of the analyzing means into transmission data and transmitting the data;
Data receiving means (41) for receiving data sent from the data transmitting means;
Display means (42) for displaying the data received by the data receiving means for notifying the monitor.

According to one preferred embodiment of the present invention, the water quality environment monitoring system comprises:
Charging means (36) formed by charging power to be supplied to the sensing means, recording means, analysis means, and transmission means;
It further includes electromotive means (37) for generating electric power for charging the charging means.

  In the water quality monitoring system, the sensing means is typically provided in the water of a sea, river, or lake that requires monitoring of the water quality environment. The sensing means and the recording means can be connected by, for example, a wired voltage transmission means such as a lead wire or a wireless signal transmission means.

  Examples of the recording means include a magnetic recording device such as a hard disk, an optical disk recording device, and the like, and voltage data output from the sensing means is recorded over time. When recording, if there are a plurality of sensing means, each data can be recorded separately. The recording means separately records a database for water quality environment determination used in the analyzing means. This database includes standard data of various water quality environments for determination.

  The analysis means compares the open shell distance data of the shell calculated from the voltage data recorded in the recording means with the data of the database separately recorded in the recording means, and the sample water is supplied to the shell. Determine whether the water environment is harmful. In calculating the open shell distance data of the shell from the voltage data recorded in the recording means, a conversion formula or a calibration curve prepared in advance can be used. In determining the water quality environment by comparing the open shell distance data of the shell and the data of the database, it can be performed according to the determination method in the detection method described above.

  The data transmission means converts the output result of the analysis means into transmission data and transmits the data. Here, the conversion to transmission data includes conversion to an Internet protocol format (for example, e-mail) and data compression.

The data receiving means receives data sent from the data transmitting means. There may be a plurality of data receiving means.
Examples of the data transmitting unit and the data receiving unit include an analog or digital wireless or wired transceiver, a mobile phone system, a wireless modem, a wireless LAN, and the like.

  The display means displays the data received by the data receiving means in order to inform the supervisor. The display means is not particularly limited as long as it is a means capable of appealing to the five senses of a person who is a monitor, and may be, for example, a visual or audible display means. Examples of the display means include a microcomputer, a graph recorder, a personal computer, a mobile phone, and a PDA, and preferably a personal computer, a mobile phone, or a PDA. There may be a plurality of display means.

  The charging means charges power supplied to the sensing means, recording means, analysis means, and transmission means. The charging means is charged periodically like a rechargeable battery. The charging means may charge the power sent from the electromotive means.

  The electromotive means generates electric power for charging the charging means, and examples thereof include a solar power generator.

  In the present invention, it is desirable that the sensing means, the analysis means, the recording means, the data transmission means, the charging means, and the electromotive means are typically configured so as to exist on the water or at the shore (30). Here, the surface of water means the surface of water such as the sea, lakes, and rivers or the vicinity thereof, and includes, for example, the surface of a ship or a float. Moreover, the waterside means a land portion close to the sea, lakes, rivers and the like. Among these, in order to avoid problems such as corrosion due to seawater, the analyzing means, the recording means, the data transmitting means, and the charging means are preferably covered with a waterproof case (39).

  In the present invention, it is desirable that the data receiving means and the display means are configured to exist in the office (40) on the ground.

According to another aspect of the present invention, a monitoring system for a water quality environment harmful to shellfish belonging to a bivalve according to the present invention,
A shell belonging to a bivalve ( Bivalvia ), equipped with a non-contact sensor capable of detecting a magnetic field in one shell and a member generating a magnetic field in the other shell,
Means for detecting a change in shell opening and closing movement of the shell caused by contact between the shell and the sample water by measuring an output voltage from the non-contact sensor;
Means for determining whether or not the sample water is a water quality environment harmful to the shell based on the detected change in the shell opening / closing motion.

  Here, examples of the “means for detecting a change in the shell opening / closing movement” include a voltage measuring device and a waveform recorder. Examples of the “means for determining whether the sample water is a water quality environment harmful to shellfish” include a microcomputer, a graph recorder, a personal computer, and the like.

  According to another preferred aspect of the present invention, the determining means observes a spike waveform of a change in the open shell distance in a graph representing the open shell distance with respect to time obtained by measurement by a non-contact sensor, and the waveform Determining whether the sample water is a harmful water quality environment.

  Monitoring the water quality environment such as the fishing ground environment is based on detecting the voltage change of the sensor caused by the shell opening and closing movement obtained from the bivalve placed in the fishing ground by the detecting means, and then judging by the judging method, and the result is sent to the transmitter. May be sent to the manned facility, but the sensor voltage change or data sent to the detection means is sent to the manned facility by the transmitter, and the signal received by the receiver is analyzed and determined there. Good. The analysis can be performed artificially through a monitor or can be performed by an analysis device. The analysis device may further be connected to an alarm device, which can automatically issue an alarm when a specific signal is input.

  The present invention will be described in detail by the following examples, but the present invention is not limited thereto.

Experiment A: (Experiment using pearl oysters)
In the experiment of attaching the sensor to the shell, a 2-year-old shell of Pinctada fucata from Ago Bay was used.
A Hall element sensor (HW-300A (manufactured by Asahi Kasei Corporation)) is used as a non-contact sensor, and the sensor is fixed to the outer surface of the outer shell of the left shell of the experimental shell with adhesive, and the same position on the opposite right shell. The small magnet was similarly fixed with an adhesive (FIG. 1).
Here, an epoxy resin (epoxy resin for underwater lining, Three Longji W-801 (paint type) (Three Bond Co., Ltd.)) was used as the adhesive. This adhesive had no adverse effect on the pearl oyster. In addition, this adhesive exhibited a strong adhesive force over a long period of time (for example, at least half a year) in seawater.

Measurement of the open shell distance by the sensor The voltage change that occurs in the sensor due to the change in the distance between the sensor and the magnet due to the open / close state of the shell is continuously recorded by the measuring instrument DC-104R (manufactured by Tokyo Sokki Kenkyujo) did. The following relational expression holds between the sensor output voltage value (V) and the open shell distance (L). It is possible to accurately monitor the open / close state by the following formula.
(1) When the open shell distance is less than 10 mm:
V = 4079.6e ^-0.1175L
(Correlation coefficient: R ² = 0.9964)
(2) When the open shell distance is 10 to 30 mm:
V = 2615.8e ^-0.0728L
(Correlation coefficient: R ² = 0.9947)

  The shell of the pearl oyster is composed of a pearl layer of the inner shell and a ridge column layer of the outer shell, and the ridge column layer extends to the tip of the shell body and is relatively elastic. The closed shell of the pearl oyster is normally closed at the tip of the shell (ridge column layer) (Fig. 2C), but it closes more strongly when abnormalities such as high-density red tide occur and closes at the tip of the inner shell pearl layer. May be closed (fully closed shell) (FIG. 2D). In this case, the elastic ridge column layer of the left shell and the right shell tip is in close contact, and the ridge column layer on the right shell side is slightly warped outward. For this reason, in the case of the pearl oyster, even in the closed shell state, the sensor output value changes according to the strength of the closed shell. It is desirable to consider these points when evaluating the measurement results.

Example 1: Measurement of shell opening and closing movement in a normal water quality environment Opening a pearl oyster fitted with a sensor to an indoor aquarium (500L) filled with seawater of normal water quality and an aquaculture basin in an inner bay, the shell opening and closing obtained from the sensor Data on exercise were recorded.
The result was as shown in FIG.
Here, the result obtained in the case of the indoor water tank is shown. One spike corresponds to one closing shell movement of the pearl oyster. In the figure, there are spikes that show a closed shell for a short time with a large open shell.
In addition, when the number of closed shells was measured by dropping a sensor-equipped shellfish in the sea area (2m layer) in the inner bay fishing ground, the number of closed shells was almost 3 times or less (93%) in 30 minutes and in 60 minutes. Less than 5 times (91%).

Waveform analysis:
The experiment was continuously performed for a long period (about 3 weeks), and the waveform of the graph was analyzed based on the obtained measurement data. In the analysis, the width of the spike was measured as a spike time (ST), and the spike frequency and each spike integration time were determined with 30 minutes and 60 minutes as one unit.
The results were as follows.

  Spike frequency in 30 minutes was within 6 times (about 90% is 3 times or less). Even if six or more spikes occurred in the process of continuous measurement, they rarely lasted for a long time. The spike frequency in 60 minutes was within 10 times (about 90% is 5 times or less). Even if 10 or more spikes occurred in the course of continuous measurement, they hardly lasted for a long time.

  Spike integration time at 30 minute intervals was 89% less than 300 seconds and 98% less than 420 seconds. In the process of continuous measurement, even if these values were exceeded, they did not last long and rarely exceeded 1200 seconds. The spike integration time at 60-minute intervals was 92% less than 600 seconds and 99% less than 1200 seconds. In the process of continuous measurement, even if it exceeded 1200 seconds or more, it did not last long and hardly exceeded 1800 seconds. Therefore, 95% of the spike accumulation time per 30 minutes and 60 minutes was within about 400 seconds or less and within 650 seconds.

  The above results are summarized in Table 1.

Example 2: Measurement of shell opening and closing movement in the harmful water quality environment caused by the increase of Heterocapsa circularisquama To reduce the damage caused by the red tide, it is necessary to avoid shells from the red tide area, and it is important to predict the occurrence of red tide Said. In order to predict the occurrence of red tide by Heterocapsa circularisquama, it is necessary to detect cells at a low density stage. Therefore, we examined the changes in the shell opening and closing movements of pearl oysters when exposed to water with a low cell density of around 50 cells / ml of Heterocapsa circularisquama .

2-1) Seawater with a cell density of Heterocapsa circularisquama of 60 cells / ml was filled in a 100 L circular water tank in an indoor laboratory . The shells equipped with sensors were exposed here, and changes in the shell opening and closing movements were measured.
The result was as shown in FIG. 4A.
As shown in the figure, a waveform with a remarkably short open shell time, which is different from the spikes seen in normal time, frequently appeared. The number of spikes in a short time has increased remarkably, and it is considered that intense shell opening / closing movement has occurred due to the presence of Heterocapsa circularisquama cells.

In the same manner as in Example 1, the experiment was continuously performed for a long time, and the waveform of the graph was analyzed based on the obtained measurement data. The results were as follows.
Spike frequencies were about 5-20 times per 30 minutes (on average more than 12) and about 10-40 times per 60 minutes.

2-2) Inner bay fishing ground experiment A relatively low cell density Heterocapsa which occurred in summer by hanging a sensor-equipped shellfish in the inner bay fishing ground, specifically in the inner bay (2m layer) of Ago Bay, Mie Prefecture. the change in the shell closing motion of the oyster in circularisquama red tide waters (43 cells / ml) were measured.
The results were as shown in FIGS. 4B and 4C.
As shown in the figure, spike waveforms with extremely short open shell time frequently appeared in the graph.

In the same manner as in Example 1, the experiment was continuously performed for a long time, and the waveform of the graph was analyzed based on the obtained measurement data. The results were as follows.
The spike frequency per 30 minutes and spike frequency per 60 minutes reached a maximum of 39 and 73, respectively. When the spike frequency was plotted against the spike accumulation time, the graph showed a trend of rising right.

  The above results are summarized in Table 1.

Example 3: Measurement of shell opening and closing movements in a harmful water quality environment (anoxic water mass) caused by a decrease in dissolved oxygen concentration in water and a harmful water quality environment caused by an increase in sulfide concentration in water There is also concern about the influence of sulfides as oxygen decreases. Therefore, in order to investigate the effects of anoxia and sulfide separately, indoor oysters equipped with sensors were exposed to seawater in anoxic conditions and seawater in which sulfides were dissolved and anoxic. Changes in shell opening and closing movements were measured.

3-1) Exposure to anoxic seawater By collecting normal water quality seawater and ventilating about 12 L of nitrogen gas per minute, the dissolved oxygen concentration is 0.5 mg / L or less. Anoxic seawater was prepared. An indoor 100 L circular aquarium was filled with this anoxic seawater. The shells equipped with sensors were exposed here, and changes in the shell opening and closing movements were measured.
The results were as shown in FIGS. 5A and 5B.
As shown in the figure, sharp spikes indicating a short closed shell appeared frequently, and the number of closed shells increased significantly. At this time, the spike time was short and the size was relatively uniform.

  In the same manner as in Example 1, the experiment was continuously performed for a long time, and the waveform of the graph was analyzed based on the obtained measurement data.

3-2) Exposure to seawater in which sulfides are dissolved and anoxic conditions Normal seawater quality was sampled, and after aeration of nitrogen to adjust the anoxic seawater, sodium hydrogen sulfide was dissolved. By adding the stock solution, the sulfide-dissolved oxygen ^- free seawater having a sulfide concentration of 0.87 ± 0.11 mg / L (S ²⁻ ) and a dissolved oxygen concentration of 0.5 mg / L or less is obtained. Prepared. This seawater was used to fill an indoor 100 L circular tank. The shells equipped with sensors were exposed here, and changes in the shell opening and closing movements were measured.
The results were as shown in FIGS. 5C and 5D.
As shown in the figure, there was a tendency for the spike time to be longer (spike width was wider) and for the closed shell to be longer.

In the same manner as in Example 1, the experiment was continuously performed for a long time, and the waveform of the graph was analyzed based on the obtained measurement data. The results were as follows.
The spike frequency per 30 minutes was about 4 to 12 times. Compared to the case of seawater in an anoxic state, the spikes were uneven and the closed shell time was long, so the spike integration time tended to be a significantly large value. The spike integration time per 60 minutes was in the range of more than 1600 seconds, specifically in the range of 2000 to 3600 seconds. Further, in the case of around 60 minutes, no constant relationship was observed between the spike frequency and the spike integration time (FIG. 9A).

3-3) Exposure to anoxic waters in the inner bay fishing ground An inner oxygen fishing area (dissolved ) in the inner bay fishing ground, specifically in the inner part of Ago Bay, Mie Prefecture, where a shell with a sensor is suspended. Changes in the shell opening and closing movements of the pearl oysters at oxygen concentrations of 0.5 mg / L or less were measured.
The results were as shown in FIGS. 6A and 6B.
As shown in the figure, in the measured waveform, not only a sharp spike indicating a short closed shell but also a wide spike and a closed shell state over a long time were confirmed.

In the same manner as in Example 1, the experiment was continuously performed for a long time, and the waveform of the graph was analyzed based on the obtained measurement data. The results were as follows.
In both cases of 30 minutes and 60 minutes, the increase in the spike integration time was significant compared to the increase in the spike frequency.
In the case of around 60 minutes, there was no constant relationship between the spike frequency and the spike accumulation time, which was consistent with the characteristics of the analysis pattern exposed to sulfide-containing hypoxia. Therefore, it was inferred that these trends were not only caused by poor oxygen but were simultaneously affected by sulfides.

  The above results are summarized in Table 1.

Example 4: Measurement of shell opening and closing movement in a harmful water environment caused by an increase in the density of suspended particles in water As a model fine particle suspension, carbon particles having a particle size of 20 μm (MCMB25G, available from Osaka Gas Chemical Co., Ltd.) are used. It was.
Seawater with normal water quality was collected, and the fine particle suspension was suspended in the seawater so that the particle density was about 8000 grains / ml, thereby preparing seawater with increased suspended particle density. Using this seawater, a 500 L circular water tank was filled, and a shell equipped with a sensor was exposed to measure the change in the shell opening and closing movement.
The results were as shown in FIGS. 7A to 7C.
As shown in the figure, many sharp spikes and relatively wide spikes appeared for a short time, and the spike widths were not uniform.

  Based on FIGS. 3 to 7, characteristic and typical spike waveforms obtained from the shell opening and closing movement of the pearl oyster were obtained (FIG. 8).

In the same manner as in Example 1, the experiment was continuously performed for a long time, and the waveform of the graph was analyzed based on the obtained measurement data. The results were as follows.
As compared with the case of around 60 minutes, the spike frequency increased as the range of the spike integration time of 1000 to 2000 seconds increased remarkably. When the spike frequency was plotted with respect to the spike integration time, a tendency of rising to the right was observed (FIG. 9B). Such a tendency was not observed in the case of seawater in a sulfide-dissolved anoxic state.

  The above results are summarized in Table 1.

Example 5: As a measure toxic chemicals shells closing movement in adverse water quality environment caused by increased concentrations of toxic chemicals in water, an organic phosphorus-based pesticides (EPN (EPN emulsion (Nissan Chemical Industries, Ltd.))) . Specifically, the components of this pesticide were EPN (ethyl paranitrophenylthionobenzenephosphonate) 45%, organic solvent / emulsifier 55% (xylene 40%, toluene 1.7%).
Seawater containing an EPN emulsion (EPN concentration of 1 ppm) was prepared and viewed in a 100 L circular water tank. A shell equipped with a sensor was exposed here, and changes in the shell opening and closing movement were measured.

  The result was as shown in FIG. 10A. As shown in the figure, a sharp increase in sharp spikes with a spike time of about 40 to 70 seconds was observed, and the shell body was opened and closed violently. The spike shape and spike spacing were relatively uniform.

  The above results are summarized in Table 1.

Example 6: As measured environmental pollutants shell closing movement in adverse water quality environment caused by increased concentration of pollutants in water, the surfactant, specifically, using synthetic detergent (commercially available dishwashing detergent) . The components of this synthetic detergent were 37% surfactant (sodium linear alkylbenzene sulfonate, polyoxyethylene alkyl ether, fatty acid alkanolamide).
Prepared seawater containing a detergent (surfactant concentration 3.7 ppm), viewed in a 100 L circular tank, exposed a shell with a sensor attached to it, and measured changes in the shell opening and closing movement did.

  The result was as shown in FIG. 10B. As shown in the figure, regular and uniform spikes with a spike time of 80 to 180 seconds remarkably increased, and the shell motion was regularly performed in an open shell state.

  The above results are summarized in Table 1.

  In the experiment, depending on the type of water quality environment, it was recognized that the analysis interval was made longer than that in the case of 30 minutes or 60 minutes, thereby enabling clearer identification. In addition, the longer the observation time, the higher the accuracy.

Experiment B: (Experiment using clams)
Attaching the sensor to the shellfish Attaching the sensor to the shellfish as in Experiment A, except that clams ( Ruditapes Philippinarum ) were used as test shellfish and samarium cobalt magnets (φ4 × 3mm) were used as small magnets did.

Example 7: Measurement of shell opening / closing movement in a normal water quality environment In the same manner as in Example 1, the shell opening / closing movement in a normal water quality environment was measured.
The result was as shown in FIG.
A sharp spike with a large amplitude and a slightly wider spike appeared, each showing a quick opening and closing movement and a slow shell movement.

Example 8: Measurement of shell opening and closing movement in harmful water quality environment caused by increase of Heterocapsa circularisquama A 100 L circular aquarium in a chamber was filled with seawater with a Heterocapsa circularisquama cell density of 10-50 cells / ml. The shells equipped with sensors were exposed here, and changes in the shell opening and closing movements were measured.
The results were as shown in FIGS. 13A and B.
A sharp increase in sharp spikes of 20 to 35 seconds was observed, and the shells were violently opened and closed.
The results are summarized in Table 2.

Example 9: Measurement of shell opening and closing movements in a hazardous water environment caused by an increase in the concentration of toxic chemicals in the water Seawater containing EPN emulsion (EPN concentration 1 ppm) was prepared and viewed in a 100 L circular tank, The shells equipped with sensors were exposed here, and changes in the shell opening and closing movements were measured.
The results were as shown in FIGS. 13C and D.
After a significant increase in sharp spikes of 15-60 seconds lasted for about 447-3045 seconds, long waveforms with spike times of about 463-9619 seconds were seen alternately. This indicated that small shell movements in an open shell state of about 447-3045 seconds and a closed shell state for a long time of about 463-9619 seconds occurred alternately.
The results are summarized in Table 2.

It is the figure which showed the shellfish which belongs to the bivalve with which the non-contact sensor and the member which generate | occur | produces a magnetic field were mounted | worn. It is the figure which showed the mode of the shell opening / closing movement of the pearl oyster with which the non-contact sensor and the member which generate | occur | produces a magnetic field were mounted | worn. In the figure, A and B show an open shell state, and C and D show a closed shell state. Among these, D shows a completely closed shell state. In D, * represents a shell opening in a completely closed shell state. It is a graph showing the open shell distance with respect to time in the normal water quality environment obtained according to the method by this invention (in the case of a pearl oyster). A and B in the figure are measurement examples in laboratory experiments. It is the graph showing the open shell distance with respect to time in the harmful | toxic water quality environment produced by the increase of (a) Heterocapsa circularisquama obtained according to the method by this invention (in the case of a pearl oyster). In the figure, A is a measurement example in a laboratory experiment, and B and C are measurement examples in an inner bay fishing ground. Obtained according to the method of the present invention, (b) a harmful water quality environment caused by a decrease in dissolved oxygen concentration in water, and (c) an open shell distance over time in a harmful water quality environment caused by an increase in dissolved sulfide concentration in water. It is a graph showing (for the pearl oyster). In the figure, A and B are measurement examples in laboratory experiments on the harmful water quality environment caused by the decrease in dissolved oxygen concentration in the water. In the figure, C and D are the harmful water quality environment caused by the increase in dissolved sulfide concentration in the water. It is an example of a measurement in an indoor experiment. It is the graph showing the open shell distance with respect to time in the harmful | toxic water quality environment produced by the fall of the dissolved oxygen concentration in water obtained according to the method by this invention (in the case of a pearl oyster). A and B in the figure are both measurement examples in the inner bay fishing ground. FIG. 6 is a graph showing the open shell distance against time in a noxious water quality environment caused by an increase in suspended particle density in water, obtained according to the method according to the present invention (in the case of the pearl oyster). In the figure, A to C are measurement examples in laboratory experiments. It is a typical model waveform which shows each water quality environment extracted from the graph showing the open shell distance with respect to time obtained according to the method by this invention. Shown per 10 minutes. Among these, FIG. 8A is a characteristic model waveform observed when the sample water is in a normal water quality environment, and FIG. 8B is a case where the sample water is in the water quality environment of (b) or (d). FIG. 8C is a characteristic model waveform observed, and FIG. 8C is a characteristic model waveform observed when the sample water is in the water quality environment of (c) or (d), and FIG. It is a characteristic model waveform observed when it is the water quality environment of (a). It is the graph which showed the spike integration time per 60 minutes with respect to the spike frequency per 60 minutes in the case of the harmful water quality environment produced by the increase in the suspended particle density in water. In the figure, A is a graph in (c) a harmful water quality environment caused by an increase in the concentration of dissolved sulfide in water, and B in the figure is (d) in a harmful water quality environment caused by an increase in the density of suspended particles in water. It is a graph. Obtained according to the method of the present invention, (e) a hazardous water quality environment caused by an increase in the concentration of toxic chemicals in water, and (f) an open shell against time in a hazardous water environment caused by an increase in environmental pollutants in water. It is a graph showing a distance (in the case of an pearl oyster). A in the figure is a measurement example in a laboratory experiment on the harmful water quality environment caused by an increase in the concentration of toxic chemical substances in water (organophosphorus pesticides mainly composed of EPN), and B in the figure is an environmental pollutant in the water ( It is an example of a measurement in a laboratory experiment on a harmful water quality environment caused by an increase in anionic surfactant). It is a typical model waveform which shows each water quality environment extracted from the graph showing the open shell distance with respect to time obtained according to the method by this invention. Shown per 10 minutes. 11A is a characteristic model waveform observed when the sample water is in the water quality environment of (e), and FIG. 11B is observed when the sample water is in the water quality environment of (f). This is a characteristic model waveform. It is a graph showing the open shell distance with respect to time in the normal water quality environment obtained according to the method by this invention (in the case of clams). A and B in the figure are measurement examples in laboratory experiments. Graph obtained by the method according to the present invention, showing the open shell distance with respect to time in (a) a harmful water quality environment caused by an increase in Heterocapsa circularisquama and (e) a harmful water quality environment caused by an increase in the concentration of toxic chemicals in water. (For clams). In the figure, A and B are measurement examples in laboratory experiments on the harmful water quality environment caused by the increase in Heterocapsa circularisquama . In the figure, C and D are the concentrations of toxic chemical substances (organophosphorus pesticides mainly composed of EPN) in water. It is the example of a measurement in the laboratory experiment about the harmful water quality environment which arose by increase. It is a block diagram which shows the structure of the water quality environment monitoring system by this invention.

Explanation of symbols

10 Shellfish belonging to bivalves 11 Non-contact sensor 12 Member for generating magnetic field 13 Open shell distance 14 Lead wire 15 Measuring device 20 Akoya oyster 21 Hall element sensor 22 Magnet 23 Open shell distance 30 On or near water 31 Sensing means 32 Non-contact sensor 33 Analyzing means 34 Recording means 35 Data transmitting means 36 Charging means 37 Electromotive means 38 Power supply 39 for each part Waterproof case 40 Office 41 Data receiving means 42 Display means

Claims (26)

Non-contact sensors on one shell which can detect a magnetic field is mounted, and a shellfish belonging to bivalves which member is mounted for generating a magnetic field in the other shell (Bivalvia), in contact with sample water, the shellfish A method for detecting a water quality environment harmful to a shell belonging to a bivalve, comprising measuring a change in a shell opening / closing motion by the non-contact sensor.   The detection method according to claim 1, wherein the water quality environment harmful to the shellfish belonging to the bivalve is a harmful water quality environment caused by floating organisms harmful to the shellfish. The detection method according to claim 2, wherein the floating organism harmful to the shellfish is Heterocapsa circularisquama .   The detection method according to claim 1, wherein the water quality environment harmful to shellfish belonging to the bivalve is a harmful water quality environment caused by a decrease in dissolved oxygen concentration in water.   The detection method according to claim 1, wherein the water quality environment harmful to the shellfish belonging to the bivalve is a harmful water quality environment caused by an increase in the concentration of dissolved sulfide in water.   The detection method according to claim 1, wherein the water quality environment harmful to the shellfish belonging to the bivalve is a harmful water quality environment caused by an increase in suspended particle density in water.   The detection method according to claim 1, wherein the water quality environment harmful to shellfish belonging to bivalves is a harmful water quality environment caused by an increase in the concentration of toxic chemical substances in water.   The detection method according to claim 1, wherein the water quality environment harmful to the clams belonging to the bivalve is a harmful water quality environment caused by an increase in the concentration of environmental pollutants in the water.   In the graph showing the open shell distance against time obtained by measurement with a non-contact sensor, observe the spike waveform of the change in open shell distance and determine whether the sample water is a harmful water quality environment from the waveform. The detection method according to any one of claims 1 to 8, further comprising: In a monitoring system for the water environment harmful to shellfish belonging to bivalves ( Bivalvia ), a non-contact sensor capable of detecting a magnetic field is attached to one shell of the shell, and a member that generates a magnetic field is attached to the other shell. In the graph showing the open shell distance with respect to time, calculated from the voltage data output from the sensing means for measuring the change in shell shell opening and closing movement caused by the contact between the shellfish and the sample water,
The method according to any one of claims 1 to 8, further comprising observing a waveform of a spike of an open shell distance change and determining whether or not the sample water is a harmful water quality environment from the waveform. Detection method. The detection method according to claim 9 or 10, further comprising determining whether the sample water is a harmful water quality environment of the following types (a) to (g):
(a) Hazardous water quality environment caused by increased Heterocapsa circularisquama ,
(b) Harmful water quality environment caused by a decrease in dissolved oxygen concentration in water,
(c) Hazardous water quality environment caused by increased dissolved sulfide concentration in water,
(d) a hazardous water quality environment caused by an increase in suspended particle density in water,
(e) a hazardous water quality environment caused by an increase in the concentration of toxic chemicals in the water;
(f) Hazardous water environment caused by increased concentration of environmental pollutants in water, or
(g) Hazardous water quality environment due to causes other than the above (a) to (f).   The detection method according to any one of claims 9 to 11, wherein determination is made based on at least one index selected from the group consisting of spike frequency, spike time, and spike integration value in a spike waveform.   12. The determination according to claim 9, wherein the determination is made based on at least one index selected from the group consisting of presence / absence of a waveform in a spike waveform, wave amplitude, wavelength, period, and frequency. Detection method.   The detection method according to any one of claims 1 to 13, wherein the non-contact sensor is a Hall element sensor.   The detection method as described in any one of Claims 1-14 whose shellfish which belongs to a bivalve is an pearl oyster or a clam.   The detection method according to claim 1, wherein the magnetic field generating member is a magnet.   The detection method according to any one of claims 1 to 16, wherein the sample water is water of a sea, a river, or a lake.   The detection method according to any one of claims 1 to 17, wherein a non-contact sensor and a member that generates a magnetic field are each mounted on a shell near a distal portion where an opening is formed on an outer surface of the shell of the shell. A water quality monitoring system for monitoring the water quality environment harmful to shellfish belonging to bivalves ( Bivalvia ),
A shell of a shell formed by contact between the shell and sample water, in which a non-contact sensor capable of detecting a magnetic field is mounted on one of the shells belonging to the bivalve, and a member that generates a magnetic field is mounted on the other shell Sensing means for measuring changes in opening and closing movements;
Recording means for recording the voltage data output from the sensing means over time;
By comparing the open shell distance data of the shell calculated from the voltage data recorded in the recording means and the data in the database separately recorded in the recording means, the sample water is in a water quality environment harmful to the shellfish. An analysis means for determining whether or not there is;
Data transmission means for converting the output result of the analysis means into transmission data and transmitting the data;
Data receiving means for receiving data sent from the data transmitting means;
A water quality environment monitoring system comprising display means for displaying the data received by the data receiving means for notifying a monitor. Charging means formed by charging power supplied to sensing means, recording means, analysis means, and transmission means;
The water quality environment monitoring system according to claim 19, further comprising electromotive means for generating electric power for charging the charging means.   The water quality environment monitoring system according to claim 19 or 20, wherein the sensing means is provided in water of a sea, a river, or a lake that requires monitoring of the water quality environment.   The comparison of data in the analysis means is performed based on at least one index selected from the group consisting of spike frequency, spike time and spike integration value in spike waveforms. Water quality environmental monitoring system described in 1.   The water quality environment monitoring system according to any one of claims 19 to 22, wherein the non-contact sensor is a Hall element sensor.   The water quality environment monitoring system according to any one of claims 19 to 23, wherein the clam belonging to the bivalve is a pearl oyster or a clam. The water quality environment monitoring system according to any one of claims 19 to 24, wherein the water quality environment harmful to shellfish belonging to bivalves is selected from the following (a) to (g):
(a) Hazardous water quality environment caused by increased Heterocapsa circularisquama ,
(b) Harmful water quality environment caused by a decrease in dissolved oxygen concentration in water,
(c) Hazardous water quality environment caused by increased dissolved sulfide concentration in water,
(d) a hazardous water quality environment caused by an increase in suspended particle density in water,
(e) a hazardous water quality environment caused by an increase in the concentration of toxic chemicals in the water;
(f) Hazardous water environment caused by increased concentration of environmental pollutants in water, or
(g) Hazardous water quality environment due to causes other than the above (a) to (f).   The water quality environment monitoring system according to any one of claims 19 to 25, wherein the display means is a personal computer, a mobile phone, or a PDA.

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