Transcriptomic dose response assessment of 1H,1H-heptafluorobutyl epoxide

Given the vast number of chemicals in commerce and the environment, state and federal regulatory agencies are frequently faced with making important and timely decisions on chemicals with limited or no toxicity data. To provide supporting information to inform human health impacts in a relatively short time frame, the US Environmental Protection Agency’s (EPA) Transcriptomic Assessment Process (ETAP) was implemented by the Agency as an efficient and cost-effective method to begin assessing chemicals that lack traditional toxicity testing data. The method involves short-term oral in vivo study in adult rats, followed by transcriptomic dose-response assessment in twelve tissues to determine a point of departure (POD). The ETAP POD identifies the dose at which there are no coordinated transcriptional changes that would indicate a potential toxicity of concern. However, this approach does not explore any specific association with hazard or mechanism. Reported here is ETAP results for 1H,1H-heptafluorobutyl epoxide (HFBE). The transcriptomic points of departure associated with the tested chemicals, as assessed via ETAP and allometrically scaled to human equivalent doses, was 0.00022 (HFBE) mg/kg-day.