The Effects Of Fluoride On The Bioaccumulation Characteristics Of Florfenicol And Ofloxacin In Crucian Carp (Carassius Auratus)

In recent years,fluorinated antibiotics have occupied a large proportion in medical antibiotics due to their safety and efficiency.There have great differences between the fluorinated antibiotics and the nonfluorinated antibiotics in many aspects,such as structure and environmental behavior.Therefore,it has great practical significance to study the changes of antibiotics after fluoride substitution.To investigate the effects of fluorine,environmental concentration,and temperature on the bioaccumulation of florfenicol?FLO?,thiamphenicol?TAP?,ofloxacin?OFX?,and pipemidic acid?PPA?,crucian carp were exposed to different concentrations of the chemicals and different temperatures for 21 days.The results indicated that:?1?FLO,TAP,OFX,and PPA accumulated in crucian carp tissues.The concentration in all tissues increased and then decreased during the 21-day period.The highest levels of FLO,TAP,OFX,and PPA in liver tissues were 335.3 ng g^-1,184.9 ng g^-1,177.6 ng g^-1,and 57.7 ng g^-1.The highest levels of antibiotics in muscle tissues were 59.5 ng g^-1,48.3 ng g^-1,46.9 ng g^-1,and 25.7 ng g^-1.The highest levels of antibiotics in gill tissues were 50.7 ng g^-1,35.8 ng g^-1,34.9 ng g^-1,and 22.5ng g^-1?The highest levels of antibiotics in bile tissues were 293.3 ng mL^-1,179.7 ng mL^-1,176.5 ng mL^-1,and 57.6 ng mL^-1.The bioaccumulation of antibiotics in the four tissues had the following order:liver>bile>muscle>gill.?2?The environmental concentration did not affect the maximum bioaccumulation concentrations and accumulation rates of antibiotics?p>0.05?,but it affected the bioaccumulation factors?BCF?,the log BCF values decreased with the increased of the environmental concentration.Similarly,temperature did not affect the maximum bioaccumulation concentrations and the log BCF values of target antibiotics?p>0.05?,but it affected the accumulation rate,which was accelerated with the increased of temperature.The changes of environmental concentration and water temperature did not affect the tissue-specific distribution of antibiotics,and the liver was the most important bioaccumulation tissue storage area for antibiotics.?3?The effects of fluoride substitution on fluorinated antibiotics are mainly reflected in three aspects:firstly,fluorine changed the lipophilicity of FLO and OFX,which made it easier for FLO and OFX to accumulate in fatty tissues such as the liver;the introduction of fluorine at specific sites reduced the metabolic sites and enhanced the metabolic stability of FLO and OFX;secondly,fluorine reduced the ability of the target antibiotic to bind to the plasma protein,which increased the transportable free concentration in the organism.Fluoride substitution affected the bioconcentration behavior of antibiotics in crucian carp,FLO and OFX were easier to accumulate than TAP and PPA.The research on the structure and properties of fluorinated antibiotics and various environmental behaviors can enrich the cognition of the properties of fluorinated antibiotics,and provide theoretical and scientific basis for the treatment of environmental pollution caused by fluorinated antibiotics in the future.