DEVELOPMENTAL TOXICITY OF DINITROANILINE HERBICIDES IN RATS AND RABBITS .1. TRIFLURALIN

The potential developmental toxicity of trifluralin was evaluated in r ats and rabbits, Pregnant rats and rabbits were dosed once daily by ga vage on Gestation Days 6-15 and 6-18, respectively, Doses for rats wer e 0, 100, 225, 475, or 1000 mg/kg; doses for rabbits were 0, 100, 225, or 500 mg/kg. Cesarean sections were performed on rats and rabbits on Gestation Days 20 and 28, respectively. In rats, maternal toxicity wa s indicated in the 475 and 1000 mg/kg treatment groups by depression o f body weights and food consumption. Fetal viability and morphology we re not adversely affected at any dose level. Developmental toxicity wa s indicated at the 1000-mg/kg dose level by depression of fetal weight , The NOAEL for maternal toxicity in the rat was 225 mg/kg; the NOAEL for developmental toxicity in the rat was 475 mg/kg. In rabbits, mater nal toxicity was indicated at the 225 and 500 mg/kg dose levels by abo rtions and/or deaths in conjunction with anorexia and cachexia. Develo pmental toxicity was indicated at the 500 mg/kg dose level by depresse d fetal viability and weight. Fetal morphology was not adversely affec ted at any dose level. The NOAELs for maternal and developmental toxic ity in the rabbit were 100 and 225 mg/kg, respectively. Based on these data, trifluralin did not exhibit selective toxicity toward the devel oping conceptus. (C) 1995 Society of Toxicology.