Toxicity of the synthetic pyrethroids,permethrin and AC 222, 705 and their accumulation in early life stages of fathead minnows and snails

Early life stages of fathead minnows (Pimephales promelas) were exposed to permethrin and AC 222, 705 and snails (Helisoma trivolvis) were exposed to permethrin in continuous flow-through exposures for approximately 30 days. Saturated solutions of each pesticide were used to avoid the use of solvents.Survival of newly hatched larvae and early juveniles was found to be the most sensitive measure of effect on fathead minnows of both pesticides. AC 222, 705 was approximately 20 times more toxic to fathead minnows than permethrin by the end of the test period. Based on the chronic limits, as defined in these tests, the predicted chronic no-effect concentrations for fathead minnows were between 0.66 and 1.4 μ/l for permethrin and 0.03 and 0.07 μ/l for AC 222, 705. The no-effect concentration for permethrin and snails was ≥ 0.33 μg/l. The chronic values for these compounds were approximately one-sixteenth and one-fourth of the corresponding 96-h LC₅₀ values, respectively, for fathead minnows in Lake Superior water.The mean bioconcentration factors (BCFs) for permethrin were 2800 for fathead minnows and 800 for snails. The mean BCF for AC 222, 705 and fathead minnows was 4000. Residue concentrations for both pesticides increased with increased water concentrations.