On February 28, 2014 the U.S. Environmental Protection Agency (EPA) opened draft documents on the health effects of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) for public comment. In these draft documents, the U.S. EPA identifies the peroxisome proliferator activated receptor (PPAR), constitutive androstane receptor (CAR), farnesoid receptor (FXR), and pregnane X receptor (PXR) as relevant target receptors of PFOA and concludes upon an RfD of 0.02 mg/kg/day based on liver weight as an endpoint. The EPA states that scientific evidence on PFOS is “suggestive of carcinogenicity”, but the identified human equivalent dose (HED) for Leydig cell tumors was 30 000 fold higher than the RfD. Thus, the RfD was considered protective. Also for PFOS, the US EPA identified liver weight as the critical health effect. The agency concluded upon an RfD of 0.00003 mg/kg/day based on liver and developmental toxicity observed in rodent studies. Under the EPA 2005 cancer guidelines, evidence for carcinogenicity of PFOS is suggestive, but was judged to be too limited to support a quantitative cancer assessment.
PFOA is authorized in Europe for the use in plastic food contact materials for repeated use, e.g. for non-slip surfaces on metal (Teflon™) pans and both PFOS and PFOA are thought to be used in grease and water repellent applications in food contact. The public comment period on the two EPA draft documents ends on April 29, 2014.
US EPA (February 28, 2014). “Notice of public comment period.”