Assessment in rats of the reproductive toxicity of gasoline from a gasoline vapor recovery unit

Gasoline (CAS 86290-81-5) is one of the world's largest volume commercial p roducts. Although numerous toxicology studies have been conducted, the pote ntial for reproductive toxicity has not been directly assessed. Accordingly , a two-generation reproductive toxicity study in rats was conducted to pro vide base data for hazard assessment and risk characterization. The test ma terial, vapor recovery unit gasoline (68514-15-8), is the volatile fraction of formulated gasoline and the material with which humans are most likely to come in contact. The study was of standard design. Exposures were by inh alation at target concentrations of 5000, 10 000, and 20 000 mg/m(3). The h ighest exposure concentration was approximately 50% of the lower explosive limit and several orders of magnitude above anticipated exposure during ref ueling, There were no treatment-related clinical or systemic effects in the parental animals, and no microscopic changes other than hyaline droplet ne phropathy in the kidneys of the male rats. None of the reproductive paramet ers were affected, and then were no deleterious effects on offspring surviv al and growth. The potential for endocrine modulation was also assessed by analysis of sperm count and quality as well as time to onset of development al landmarks. No toxicologically important differences were found. Therefor e, the NOAEL for reproductive toxicity in this study was greater than or eq ual to 20 000 mg/m(3). The only systemic effects, in the kidneys of the mal e rats, were consistent with an alpha-2 u-globulin-mediated process. This i s a male rat-specific effect and not relevant to human health risk assessme nt. (C) 2000 Elsevier Science Inc. All rights reserved.