Study On Leaching And Migration Of Tetracycline Antibiotics In Soil

Tetracyclines(Tetracyclines,TCs),the most produced and most widely used type of antibiotics in China,were exposed to various environmental media due to unreasonable use in daily life.Soil was the ultimate destination of this type of antibiotics,and its high detection rate and various behaviors in the soil(adsorption-desorption,degradation,migration and transformation)posed a serious threat to the ecological environment.In this paper,chlortetracycline(Chlortetracycline,CTC)and doxycycline(Doxycycline,DC),which were frequently used and had a high detection rate,were selected as the research pollution objects,and the soils in different sections around North University of China were used as the test soils,the analytical methods of the two antibiotics were optimized by solid phase extraction combined with liquid chromatography,based on this,the soil column leaching method was used to study the leaching behavior of CTC and DC in different sections of soil and different influencing factors,the influence of(initial concentration,p H,leaching solution)on the leaching behavior of CTC and DC in the soil column,and analyzing the leaching migration ability of several types of TCs and other widely used antibiotics.The final research results are as follows:(1)The high-performance liquid chromatography-ultraviolet(HPLC-UV)detection method was optimized,and the extraction solution,ultrasonic time,and eluent in the pretreatment process were selected and compared.Under this method,the TCs standard solution had a good linear relationship in the concentration range of 0?100mg/L,R²was above 0.999,and the recovery rate of the blank soil sample was 80.3%?90.15%,and the relative standard deviation(RSD)was less than 3%.This method was not only suitable for the detection of TCs,but also for most substances that were not easily separated,which could achieve efficient and rapid detection..(2)Soil leaching experiments showed that the leaching and migration behavior of TCs in soil was related to p H,initial concentration of pollutants,and leaching solution.The leaching of TCs in different sections of soil increased with the increased of p H value;the smaller the p H value,the residue of TCs in the soil could be enhanced,and the downward migration ability could be weakened;the leaching of TCs was positively correlated with the initial concentration of pollutants,The greater the pollution concentration,the more obvious the downward migration ability;The 0.01mo L/LCa Cl₂leaching solution had a certain hindrance to the downward migration of TCs,which was mainly related to the certain reaction between Ca²⁺and TCs.At the same time,this result also showed that TCs or other antibiotics were prone to leaching and migration in the environment with higher pollution concentration and higher p H.(3)The leaching migration of widely used TCs and other antibiotics was analyzed by GUS value.The results showed that the GUS values of tetracycline antibiotics(TCs)were all greater than 2.8,which belonged to the category of high leaching migration,while the other antibiotics were in the category of high leaching migration.Over 78%of medium to high leaching migration levels.The groundwater pollution index GUS and lg K_ocof tetracycline antibiotics(TCs)showed a good negative correlation,the correlation formula was:GUS=-0.9172lg K_oc+6.4170,R²=0.9453;the correlation formula of other types of antibiotics was:GUS=-2.2145g K_oc+8.579,R²=0.9710.A simple and convenient method for evaluating the leaching migration of antibiotics and other organic pollutants was provided by the GUS value.