A one-generation reproductive toxicity study of ethyl tertiary butyl ether in rats.

A one-generation reproductive toxicity study was conducted to evaluate the effects of ethyl tertiary butyl ether (ETBE), a bio-fuel, on reproduction of parental rats, as well as development and growth of their offspring at dose levels of 0, 100, 300 and 1000 mg/kg-d by gavage. No treatment-related changes were observed in either F0 parents or their F1 offspring in the 100 and 300 mg/kg groups in any parameters examined. Some parental animals in the 1000 mg/kg group exhibited transient salivation, possibly a reflex to a bitter taste of ETBE, immediately after dosing, although their body weights, food consumption, reproductive parameters, and gross pathological findings were not affected. Their absolute and relative liver weights increased significantly in the 1000 mg/kg group, suggesting enhanced activities of metabolic enzymes. Pup viability was slightly reduced during the early lactation period in the 1000 mg/kg group. These results lead to the conclusion that the no-observed-adverse-effect-level (NOAEL) of ETBE on both parental rats and their offspring is 300 mg/kg-d under the current study condition.