Online Water Environmental Pollution Assessment Based On Zebrafish Metabolism And Behavior Response Technology

The increase of pollutant content in water environment destroy the water ecosystem and threatens the survival of aquatic organisms.At present,75 percent of China’s lakes are polluted,seriously affecting the drinking water and agricultural water necessary for the survival of living things.Heavy metal is an important pollutant of water environment pollution.The living environment of human beings is seriously threatened.More and more attention has been paid to the studies on metabolism and behavior of aquatic organisms.Metabolism and behavior are the most basic physiological indicators of organisms and are the external manifestations of the external environment and the internal environment.In this paper,two kinds of pollutants,such as cadmium chloride and thallium nitrate,which are widely applied in water pollution are selected as the representative of heavy metals.The metabolic and behavioral response signals of zebrafish were collected by online metabolic monitoring system of aquatic organisms and online behavior monitoring system of aquatic organisms.The relationship between metabolic toxicity and behavioral toxicity of zebrafish and the relationship between metabolism and behavior were analyzed by Excel software,SPSS 22 and Matlab software.With the development of technology,online biomonitoring technology has been widely applied.The on-line metabolic technology is to determine the content of dissolved oxygen at the in and out of the respiratory chamber.And then through the calculation of the formula to obtain the metabolic rate of aquatic organisms.The system adopts the principle of intermittent flow measurement,which not only has the advantages of open real-time measurement,but also overcomes the shortcoming of poor closed precision and continuous time measurement.At the same time,multiple parameters are collected to ensure the stability of dissolved oxygen in different environments.Online behavior monitoring system is based on the principle of low-voltage electrical signals to collect aquatic organisms’behavioral intensity.The online acquisition system ensures the accuracy of data acquisition and real-time and long-term measurements.1.Cadmium chloride inhibits the metabolism of zebrafish.The inhibition rate of oxygen consumption（OC）is lower when exposed to 0.1 TU,and increased in higher exposure concentration.The toxic effects of the tested organisms were related to the concentration of cadmium chloride,and there was a dose-response relationship between them.The OC value of the photo-period was significantly higher than dark-period.When the light and dark phases alternated,the zebrafish OC changed significantly.A similar phenomenon was also observed in respiratory activity by OC analysis.Zebrafish metabolism has a circadian rhythm.2.Cadmium chloride inhibited the behavior response of zebrafish.The average values of zebrafish’s behavioral strength（BS）was the highest in low concentration exposure,and decreased gradually with the increase of concentration.There is a dose-effect relationship between the BS of zebrafish and the exposure of pollutants.Under high concentration exposure,the value of BS is relatively close to that of the bs-time series in the initial stage.After comprehensive analysis of BS under high concentration exposure,it was found that the slope of 1TU and 2TU was relatively close,indicating that the toxicity mechanism of high concentration of cadmium chloride on behavior was relatively close.Changes in BS and BA in zebrafish are also related to circadian rhythms.3.The OC and BS of zebrafish were analyzed using online monitoring system at different concentrations of cadmium chloride exposure.The results showed that CdCl₂significantly inhibited the zebrafish OC and BS.There is a dose-response relationship between the intensity of zebrafish exposure and exposure to contaminants.The RA and BA curves of zebrafish exposed to cadmium chloride show a similar curve after16 h.The changes of both are closely related with the light conditions and have circadian rhythms.Correlation analysis between OC and BS showed that the correlation between the two parameters was highly significant（r=0.93 and p<0.01）.Therefore,the water quality could be monitored by both the metabolic and behavioral indicators of zebrafish.4.The surface water concentration of thallium nitrate exposure experiments not only realized the monitoring of low-concentration pollutants,but also realized the study on the chronic toxicity of heavy metals.TlNO₃ inhibited the standard metabolic rate of zebrafish,and the change of OC was affected by the photoperiod.In the control and experimental groups,the OC value in the light phase was significantly higher than in the dark phase.The periodicity in the control group was 24 hours.The periodic time was affected due to the toxic effect of TlNO₃.Under the exposure of TlNO3,the value of OC autocorrelation analysis fluctuated greatly,leading to the disorder of zebrafish metabolism in rhythmic advance.The study found that zebrafish’s respiration is related to its sensitivity to pollutants and their activity.5.The long-term toxicity of thallium nitrate in surface water concentration on zebrafish behavior was studied.The behavior intensity of the experimental group was higher than that of the control group,indicating that TlNO₃ at the surface water concentration promoted the behavior.The toxicity effect of TlNO₃ is stronger,from the initial experiment,nitrate thallium began to play a role of toxicity,and after 72 h,nitrate thallium toxicity of zebrafish to strengthen gradually,the toxic effects of96-120h is strongest,the BS value maximum.The behavior intensity of zebrafish is affected by light and has obvious circadian rhythm.When TlNO₃ was exposed,the BS autocorrelation analysis fluctuated greatly,and the circadian rhythm was disordered after 96h.In conclusion,the use of zebrafish metabolic changes to assess the water environment is feasible,but there are limitations.By analyzing the metabolic and behavioral response indicators of zebrafish under the exposure of pollutants,it is possible to more fully utilize the changes in aquatic bio-physiological indicators,monitor and evaluate the water environment,and realize early warning of the water environment.