Evaluation of subchronic toxicity of n-butyl acetate vapor

The subchronic toxicity of n-butyl acetate (nBA), a common industrial solve nt, was tested in rats in a 13-week inhalation study. Male and female Sprag ue-Dawley (SD) rats were exposed to concentrations of 0, 500, 1500 or 3000 ppm nBA for 6 h per day, 5 days per week for 13 consecutive weeks. Transien t signs of sedation were observed only during exposure to the 1500 and 3000 ppm concentrations. Body weights for the 1500 and 3000 ppm groups were sig nificantly reduced. Feed consumption values for the 1500 and 3000 ppm group s were significantly lower than the control group. Weights of the liver, ki dneys and spleen were significantly lower for the 3000 ppm male group: test es and adrenal gland weights for the 1500 and 3000 ppm groups and the lung weight for the 3000 ppm male group were significantly higher than for the c ontrol group. Signs of irritation of the glandular stomach and necrosis in the non-glandular stomach were observed in 3000 ppm female rats. Degenerati on of the olfactory epithelium along the dorsal medial meatus and ethmoturb inates of the nasal passages of some 1500 and all 3000 ppm rats was also se en. The severity was mild to moderate for the 3000 ppm group and minimal to mild for the 1500 ppm group. No effects were observed in the lungs of any group. The no-observed-effect level (NOEL) for this study is considered to be 500 ppm. The data presented here are relevant to the toxicity risk asses sment of n-butanol due to the rapid hydrolysis of nBA in vivo. (C) 2001 Els evier Science Ltd. All rights reserved.