Fate of mirex and its major photodecomposition product in rats

Abstract

Rats receiving single oral doses of radiolabeled mirex (0.5 µ , 0.2 mg/kg) eliminated about 18% of the administered radiocarbon during a 7-day period.Of the total quantity eliminated, 85 % was excreted in the feces within 48 hr after administra- tion.Only trace amounts of radioactivity were detected in the urine.Essentially all of the excreted radioactivity was as unmetabolized mirex.Prefeeding rats with unlabeled mirex resulted in a slight decrease in intestinal absorption of a single oral dose of the 14C material.A major mirex photoproduct was prepared, and its chemical nature and fate in rats were evaluated.This product ex- hibited almost identical behavior to mirex after oral administration to rats, in that it was not metabolized by the animal to any appreciable extent.Both mirex and its photoproduct showed strong lipophilic tendencies, with concentrations of mirex equivalents in fat 7 days after treatment being 0.9 and 1.1 ppm, respectively.Mirex levels in fat did not decline below the 7-day level when the experimental period was extended to 28 days.