Summary of the Public Health Goal for Ethylbenzene
A Public Health Goal (PHG) of 0.3 mg/L (300 ppb) is developed for ethylbenzene in drinking water. U.S. EPA determined that ethylbenzene is not classifiable as to human carcinogenicity (Group D). Therefore, the PHG calculation is based on noncarcinogenic effects observed in experimental animals. The National Toxicology Program (NTP) study cited in the development of the PHG provides evidence of hepatotoxicity in mice exposed to 250 ppm ethylbenzene in air for two years. This type of effect is consistent with other reports on the toxicity of ethylbenzene. A no-observed-adverse-effect-level (NOAEL) for hepatotoxicity was determined to be 75 ppm from the NTP study, corresponding to a daily dose of 49 mg/kg. For the calculation of the PHG, factors accounting for uncertainty in inter-species extrapolation, potentially sensitive human subpopulations and the potential for a severe effect (cancer) were incorporated, for a cumulative uncertainty factor of 1,000. Based on these considerations, OEHHA calculates a PHG for ethylbenzene of 0.3 mg/L (300 ppb).
- Ethylbenzene