Nasal and pulmonary toxicity of glutaraldehyde in mice

A concentration-dependent expiratory bradypnea, indicative of sensory irritation, occurred during a 15-min oronasal exposure of mice to glutaraldehyde in the concentration range of 0.7-4.5 ppm. The level of exposure which led to a 50% decrease in the respiratory rate (RD50) was found to be 2.6 ppm. For assessment of nasal toxicity, mice were exposed to glutaraldehyde vapours with concentrations of 2.6, 1.0, 0.3 ppm for periods of 6 h/day over the course of 4, 9 and 14 days and were immediately killed. Recovery was studied with another group of mice exposed to 1.0 ppm for 14 days and sacrificed after 1, 2 and 4 weeks rest time. Control groups were concurrently exposed to clean filtered air. The earliest lesions were observed in the respiratory epithelium of the septum, the naso- and maxilloturbinates, after 4 days of exposure to 0.3 ppm. Severe histopathological changes were still observed 2 weeks after the end of the exposure to 1.0 ppm. No exposure-related histological abnormalities were detected in the trachea and lungs. In conclusion, this experiment demonstrates that repeated exposure to 1/10 RD50 is associated with upper respiratory tract damage in mice, and this value does not seem to be an acceptable concentration limit for occupational exposure.