1 Absorption kinetics of Climbazole
As shown in Figure 1, the concentration of Climbazole in the fish reached the maximum at the 72nd hour of the absorption period (ie, the 3rd day); the concentration of Climbazole in the fish remained at the end of the exposure at the 72nd to 168th hours of the absorption period (ie, the 7th day). Stablize. The stable concentrations of Climbazole in gill and liver, bile and plasma were 2.91 and 33.7 ng/g, 4.84 and 2.58 ng/mL, respectively. According to the curve nonlinear fitting results, the absorption kinetics of Climbazole in fish gills, liver, bile and plasma are in line with pseudo-first-order kinetic equations, 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, which is an order of magnitude higher than that in the gills, and 2 times and 5 times higher than that of bile and plasma, respectively, indicating that compared with other parts, the liver of tilapia is easier to absorb Gumbosu. Previous studies have pointed out that the concentration and absorption rate of hydroxydiazepine, methocarbamol, and tetrabromobisphenol A in the fish liver are also higher than those in the brain, bile, gills, muscles, etc., which may be due to the liver as a detoxification organ. , it is easier to absorb exogenous pollutants.
2 Clearance kinetics of Climbazole
As shown in Figure 1, the concentration of Climbazole in the fish reached the lowest value on the 72nd (ie, the 3rd day) of the clearance period; the concentration of Climbazole in the fish was maintained at the end of the experiment (ie, the 7th day) from the 72nd to the 168th hour of the clearance period (ie, the 7th day). Stable. The stable concentrations of Climbazole in gill, liver, bile and plasma were 0.10ng/g (<MQLs), 1.28ng/g, 0.26ng/mL (<MQLs) and 0.05ng/mL (<MQLs), respectively, indicating After the 3-day clearance period, the residual amount of Climbazole in tilapia was relatively low. According to the nonlinear curve fitting results, the clearance kinetics of Climbazole in fish gills, liver, bile and plasma were all in line with pseudo-first-order kinetics equation, the correlation coefficients r2 of the equation fitting results are 0.97, 0.98, 0.77 and 0.98, respectively. The kinetic equations of Climbazole in tilapia are shown in Table 3. The kinetic constants ke of Climbazole in tilapia gills, liver, bile and plasma can be obtained from the equation parameters, which are 0.033, 0.029, 0.082 and 0.060, respectively. h-1; according to the ke value, the half-lives of Climbazole in tilapia gills, liver, bile and plasma can be calculated as t1/2 of 21.1, 23.9, 8.51 and 11.6h, respectively. By comparison, it can be known that: Climbazole in tilapia bile t1/2 was the smallest, with t1/2 in gill and liver being 2-fold and 3-fold higher than that in bile, respectively. Compared with other parts, the metabolic rate of Climbazole in bile was faster, indicating that the enterohepatic circulation of bile was an important metabolic pathway for the excretion of Climbazole from fish.
3 The fish enrichment rule of Climbazole
According to the method recommended by OECD, the log BCFK values of Climbazole in tilapia gills, liver, bile and plasma were calculated to be 0.32, 1.45, 0.54 and 0.36, respectively; The average concentration of Climbazole in exposed water was 0.92ng/mL during the 7-day absorption kinetics experiment. Thus, the logarithmic bioconcentration coefficients logBCFss of Kambaosu in 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 Climbazole in fish gills, liver, bile and plasma were relatively close. It indicated that during the 7d absorption kinetics experiment, Climbazole had reached the equilibrium of absorption/clearance kinetics in fish. The comparison showed that the bioaccumulation level of Climbazole in the liver was higher, and the bioaccumulation level in the gill and plasma was lower. According to the previous investigation results, the average value of logBAF of the log BAF in the liver of wild tilapia in the Yangtze and Pearl River basins was 2.42. In comparison, the bioaccumulation level of Cambium in tilapia under laboratory exposure conditions was lower than that in tilapia under field exposure. This may be due to the contamination of Cambium in surface water and algae. , Wild fish are passively ingested by predation of lower aquatic animals and plants, and actively absorbed by gill respiration, while ingesting calabasin from food and surface water. Due to the continuous excretion of Climbazole into the receiving environment, Climbazole persists in the environment and is continuously ingested by wild fish, while the removal rate of pollutants by organisms is limited, resulting in the continuous accumulation of Climbazole in fish, which eventually led to field investigations. The logBAF was higher than the logBCFss of Climbazole in fish exposed to a single water body in the laboratory.
