Study On Dynamic Simulation Of Typical Antibiotics' Environmental Behavior And Risk Assessment Based On ? Fugacity Model

Antibiotics are widely used in the prevention and treatment of diseases in humans and livestock.However,in recent years,the problem of antibiotic abuse and pollution has become increasingly serious,especially in developing countries such as China and Vietnam.At present,the environmental behavior and ecological risk assessment of antibiotics in environmental media have been highly valued by the academic community,and it is one of the hot scientific issues in the field of antibiotic pollution and control research at home and abroad.Applying mathematical models to study the distribution and fate of chemicals in environmental ecosystems is one of the hot spots in environmental simulation technology.Environmental mathematical models are an effective tool for evaluating the behavior of chemicals in a multi-media environment.When antibiotics enter the environment,they will spread,migrate,and transform between various environmental media,affecting the environment and human health in different ways and ways.Therefore,it is necessary to study the distribution and fate of antibiotics in the environment.Currently,the Fugacity Model proposed by Professor Donald Mackay of the University of Toronto Environmental Research Center is one of the most widely used environmental multi-media models.In the I,II,III and IV Fugacity Models,the IV Fugacity Model can study the dynamic environmental behavior of organic pollutants,characterize the pollution level of pollutants in the multi-medium environment,and the migration and transformation.The quantitative results are highly regarded.The Huai River Basin is China's main grain producing area,with a large population,developed livestock and poultry breeding industry,and the production,use and discharge of antibiotics.The environmental pollution of antibiotics is more serious.In this thesis,the Huai River Basin is a typical sub-basin study area,with four major isomers of tetracycline antibiotics(TCs),such as oxytetracycline(OTC),tetracycline(TC),chlortetracycline(CTC),and doxycycline(DXC).For the research object,the dynamic simulation of antibiotic environmental media in the Huai River Basin was carried out by constructing a class IV multi-media fugacity model suitable for the characteristics of the Huai River Basin.At the same time,according to the simulation results using the IV Fugacity Model,the ecological risk entropy method was used to evaluate the ecological risk of tetracycline antibiotics in different environmental phases of the study area,and the corresponding human health ecological risk in the study area was predicted.Finally,the prevention and control measures and control recommendations for antibiotic pollution in the basin were proposed.Based on the IV-degree Fugacity Model,this thesis simulates the environmental fate of TCs in the Huai River Basin from 2002 to 2020.The TCs concentration predicted by the model agrees well with the measured values,and most of the residuals are less than 1 log unit.The simulation results show that the concentration of TCs in the multi-media environment has been slowly increasing from 2002 to 2020.After 2015,the concentration of TCs in soil and sediments tends to be gradually stable,and the content and changes in the air phase.The average concentration is low in the water environment,and the DXC residue content is the highest.It is predicted that the DXC concentration in the water environment phase of the study area will reach 35 ng/L by 2020.In the study area,TCs enter the multi-media environment system mainly in the form of sewage irrigation and wastewater discharge,and the water phase advection is the main output mode;the migration and transformation trend of TCs between media is obvious,especially in sediments and water bodies.There is also a similar trend between soil and water.The risk entropy method was introduced to evaluate the ecological risk of TCs in different environmental phases of the Huai River Basin,and the results showed that the remaining TCs in the water phase had the highest ecological risk level,among which OTC and DXC belonged to high risk level,TC And CTC is a medium risk,and the risk level in the sediment phase is the lowest.Generally speaking,the risk level of TCs in the Huai River Basin is relatively high,especially the DXC content remaining in the environment,which should be paid attention to by relevant departments,and propose antibiotic pollution prevention.Control measures and policies;the content of residual TCs in the study area does not pose a direct risk to human health,but its potential comprehensive risks and long-term risks are worthy of attention.The relevant results of this study can not only promote the theoretical understanding of the migration and transformation behaviors and final fate of the typical antibiotics entering the environment in the Huai River Basin,but also engage in environmental pollution assessment,environmental quality assessment,and ecological health risks for the basin environmental management departments.The assessment provides theoretical guidance and a basis for work.