1 Absorption kinetics of Climbazole
As shown in Figure 1, the concentration of Climbazole in the fish reaches the maximum at the 72th hour of the absorption period (i.e. the 3rd day); the concentration of Climbazole in the fish body remains the same at the end of the 72h~168h exposure period of the absorption period (i.e. the 7th day). Stablize. The stable concentrations of campanolain in gills and liver, bile and plasma were 2.91 and 33.7ng/g, 4.84 and 2.58ng/mL, respectively. According to the curve nonlinear fitting results, the absorption kinetics of Campanola in fish gills, liver, bile and plasma all conform to the pseudo-first-order kinetic equation, and the correlation coefficients r2 of the equation fitting results are 0.75, 0.83, 0.90 and 0.96. Comparison shows that: Climbazole has the highest ku in the liver, an order of magnitude higher than the ku in the gills, 2 times and 5 times higher than the bile and plasma, respectively, indicating that compared with other parts, the liver of tilapia is more likely to absorb clambazole. Previous studies have pointed out that the concentration and absorption rate of hydroxyazepam, methocarbamol, and tetrabromobisphenol A in the fish liver are also higher than those in the brain, bile, gills, and muscles in the water body, which may be due to the liver as a detoxification organ. , more easily absorb exogenous pollutants.
2 Clearance kinetics of Climbazole
As shown in Figure 1, at the 72th hour of the washout period (i.e. the 3rd day), the concentration of Campanuin in the fish reached the lowest value; at the end of the experiment at 72h~168h of the washout period (i.e. the 7th day), the concentration of Campanile in the fish body remained Stable. The stable concentrations of Campanola in gills, liver, bile, and plasma are 0.10ng/g (<MQLs), 1.28ng/g, 0.26ng/mL (<MQLs) and 0.05ng/mL (<MQLs), respectively. After the 3-day clearance period, the residual amount of Climbazole in tilapia was relatively low. According to the nonlinear fitting results of the curve, the clearance kinetics of Climbazole in the gills, liver, bile and plasma of the fish all conformed to the pseudo-first-order kinetics equation, and the correlation coefficients r2 of the equation fitting results are 0.97, 0.98, 0.77 and 0.98, respectively. The kinetic equations of the clearance of Campanola in tilapia are shown in Table 3. Through the equation parameters, the kinetic constants ke of the clearance of Campanola in the gills, liver, bile and plasma of Tilapia are 0.033, 0.029, 0.082 and 0.060 respectively. h-1; according to the ke value, the half-life t1/2 of Campanola in tilapia gills, liver, bile and plasma can be calculated to be 21.1, 23.9, 8.51 and 11.6h respectively. t1/2 is the smallest, and t1/2 in gills and liver is 2-fold and 3-fold higher than that in bile, respectively. Compared with other parts, the metabolism rate of campanolain in bile is faster, indicating that enterohepatic circulation in bile is an important metabolic pathway for fish to excrete Climbazole.
3 Fish body enrichment rules of Climbazole
According to the method recommended by OECD, the kinetic bioconcentration factor logBCFK of tilapia gills, liver, bile and plasma was calculated to be 0.32, 1.45, 0.54 and 0.36 respectively; During the 7d absorption kinetics experiment, the average concentration of Campanola in exposed water was 0.92ng/mL. The steady-state bioconcentration factor logBCFss of tilapia gills, liver, bile and plasma were calculated to be 0.50, 1.56, 0.72 and 0.45, respectively. The kinetic bioconcentration factor logBCFK and the steady-state bioconcentration factor logBCFss of campanola in fish gills, liver, bile and plasma are relatively close. It shows that during the 7d absorption kinetics experiment, Campanile has reached the equilibrium of absorption/clearance kinetics in fish. The comparison shows that the bioaccumulation level of Campanuin in the liver is higher, and the bioaccumulation level in gills and plasma is lower. According to the previous investigation results, the average logBAF value of logBAF of campanola in the liver of wild tilapia in the Yangtze River and Pearl River basins was 2.42. In comparison, the bioaccumulation level of clambachia in tilapia under laboratory exposure conditions was lower than that in tilapia under field exposure. , wild fish take in passively through predation on lower aquatic animals and plants, and actively absorb these two ways through gill respiration, and at the same time, take in campanol from food and surface water. Due to the continuous excretion of campanol into the receiving environment, it persists in the environment and is continuously ingested by wild fish, while the organisms have a limited removal rate of pollutants, resulting in the continuous accumulation of campanol in the fish, which eventually leads to field investigations. The logBAF is higher than the logBCFss of Climbazole in fish exposed to a single water body in the laboratory.
