Bioconcentration and elimination of avermectin B1 in sturgeon

The bioconcentration and elimination of avermectin B1 in sturgeon muscle were investigated with high-performance liquid chromatography. Mean concentrations of 0.2 and 1 ng x ml(-1) in water were maintained for a 22-d exposure period. The concentrations of avermectin B1alpha in muscle tissues reached steady state within 14 to 18 d. The level of avermectin B1 concentrations in the fish muscles was 7.75+/-0.88 and 38.29+/-1.65 ng x g(-1) for the low and high concentrations, respectively, on day 22. The half-life (t1/2) of the concentrations for the two treated groups was 4.95 and 4.33 d for the low and high concentrations, respectively. Greater than 95% of the tissue concentrations were eliminated from the exposed fish after the 14- and 18-d elimination periods. The estimated values of the bioconcentration factor were 42 L/kg for the low-concentration group and 41 L/kg for high-concentration group, and these values were not significantly different (alpha = 0.05). Avermectin B1alpha does not strongly bioconcentrate in individual aquatic organism and would not be expected to biomagnify in the food chain.