Wja. Vandenheuvel et al., BIOCONCENTRATION AND DEPURATION OF AVERMECTIN B-1A IN THE BLUEGILL SUNFISH, Environmental toxicology and chemistry, 15(12), 1996, pp. 2263-2266
A dynamic 42-d study was conducted to evaluate the bioconcentration of
[H-3]avermectin B-1a in the bluegill sunfish (Lepomis macrochirus). A
mean water concentration of 0.099 mu g/L was maintained for a 28-d ex
posure period. Radioassay throughout the exposure period indicated a g
radual uptake of radioactivity that reached steady state at about 10 t
o 14 d; the day 28 tissue residue values were 6.8, 3.0, and 11 mu g/kg
, in whole fish, fillet, and viscera, respectively. Following this 28-
d uptake period, fish were placed in control water for 14 d to permit
monitoring of elimination of radioactivity. Radioassay indicated 91 to
95% clearance, with the tissue residues dropping by day 14 of the dep
uration period to 0.32, 0.27, and 0.53 mu g/kg, respectively. A one-co
mpartment kinetic model was used for analysis of the uptake-depuration
data and yielded for whole fish an uptake rate constant of 12 L kg(-1
) d(-1), a depuration rate constant of 0.21 d(-1) (t(H) of 3.3 d), and
a steady-state residue concentration of 5.5 mu g/ kg. The correspondi
ng bioconcentration factor (BCF) for whole fish was 56 L/kg. Uptake an
d depuration rate data for fillet and viscera were not significantly d
ifferent (alpha = 0.05) than the values for whole fish. The BCF values
for fillet and viscera were 28 and 84 L/kg, respectively. The data ar
e consistent with rapid depletion of abamectin (and the structurally r
elated anthelmintic ivermectin) from the tissues of other animals (rat
s, sheep, cattle). Abamectin does not strongly bioconcentrate in aquat
ic organisms and would not be expected to biomagnify.