Distribution and depletion of radioactivity in hens treated dermally with 14C-labeled permethrin.

The 25/75 cis-trans mixture of permethrin (BW21Z), one of the new broad-spectrum pyrethroid insecticides, was labeled with 14C in the alcohol methylene carbon moiety and mist sprayed at two rates (3.77 or 11.94 mg/hen) on 28 hens. Peak permethrin equivalents in both treatment groups were found in the skins, .414 and l.69 ppm, respectively. Total permethrin equivalents peaked 3 days after treatment, but permethrin equivalents in eggs peaked 5 days after treatment.