The prenatal inhalation toxicity of acrylic acid in rats.

Pregnant Sprague-Dawley rats (5 per groups) were exposed in a pretest to 0, 225, and 450 ppm acrylic acid (AA) and in a main study (30 per group) to 0, 40, 120, and 360 ppm acrylic acid. Exposures were for 6 hr/day, during Days 6 to 15 of gestation (period of organogenesis), with further observation up to Day 20 after mating. Maternal toxicity occurred in animals exposed at 450 and 225 ppm in the pretest. At 360 ppm in the main study maternal toxicity consisted of sensory irritation (discharge from the eyes, snout wiping, and restless behavior) with significant reductions in body weight (p less than 0.01), body weight gain (p less than 0.01), and food consumption (p less than 0.01) relative to that of chamber controls. Effects on body weight and body weight gain were dose-related and when corrected for uterus weight were significant in animals exposed to 120 ppm (p less than 0.01), with an effect on body weight gain also at 40 ppm (p less than 0.05), indicating a minimal maternal toxic effect. There were no signs of group-related trends or significant differences between groups in terms of numbers of preimplantation losses, live fetuses, or resorptions, and no signs of group-related differences in the incidences of abnormalities, variations, or retardations in the fetuses in terms of general appearance and the condition of the internal organs or the skeletons. It is concluded that under the experimental conditions of the main study acrylic acid vapor at concentrations between 40 and 360 ppm had no embryotoxic teratogenic effects on Sprague-Dawley rats. Maternal toxicity was minimal at 40 ppm, clearer at 120 ppm, and more pronounced at 360 ppm.