© 1987 Oxford University Press
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Acute, 9-Day, and 13-Week Vapor Inhalation Studies on Ethylene Glycol Monohexyl Ether
Bushy Run Research Center, Union Carbide Corporation Export, Pennsylvania 15632
Acute, 9-Day, and 13-Week Vapor Inhalation Studies on Ethylene Glycol Monohexyl Ether. KLONNE, D. R., DODD, D. E., PRITTS, I. M., TROUP, C. M., NACHREINER, D. J., and BALLANTYNE, B. (1987). Fundam. Appl. Toxicol. 8, 198–206. At ambient conditions, the low vapor pressure of ethylene glycol monohexyl ether (EGHE) allows for a maximum vapor concentration of approximately 85 ppm. In an acute inhalation study on Wistar albino rats, a 4-hr exposure to 83 ppm EGHE produced no clinical signs, body weight effects, mortality, or macroscopic lesions in thoracic or abdominal organs. Fischer 344 rats exposed for 9 days (6 hr/day) over an 11-day period, to 0 (control), 19, 41, or 84 ppm EGHE had decreased body weight gains and increased liver to body weight values at 84 ppm EGHE. No alterations of the hematology parameters or the morphology of the testes or liver were observed. In a subsequent study, rats were exposed to mean EGHE concentrations of 0 (control), 20, 41, or 71 ppm for 6 hr/day, 5 days/week, for 13 weeks. Urogenital wetness was observed in all EGHE-exposed groups of females and in males of the 71-ppm group. Decreased body weight gains were observed in both sexes of the 71-ppm group, and a slight decrease was also observed in females of the 41-ppm group. Increased absolute and/or relative liver weights were observed in both sexes of the 71-ppm group and to a lesser extent in the 41-ppm group. Possibly related to these findings in the liver were decreases in serum transaminases (aspartate and alanine aminotransferase) and sorbitol dehydrogenase, with an increase in alkaline phosphatase observed in the 71-ppm group of female rats. However, there were no gross or histopathologic lesions found to indicate impairment of the liver. Increases in absolute and/or relative kidney weights were primarily observed in the 41-and 71-ppm groups of males but no gross or histopathologic lesions were found to explain these findings. The principal EGHE-related effect observed in animals maintained for a 1-month recovery period after cessation of exposures was a continued increase in the absolute and/or relative liver weights of the 71-ppm group. Hematologic abnormalities and testicular atrophy observed with some shorter chain alkyl glycol ethers were not observed with EGHE. Based on the data from the 13-week inhalation study, subchronic inhalation exposure to 71 ppm EGHE produced minimal but biologically significant toxicity, while exposure to 41 ppm EGHE is considered to be a concentration at which no biologically significant toxic effects were observed.