A new study published online on December 12, 2014 in the peer-reviewed journal Chemosphere investigates the release of perfluoroalkyl carboxylic acids (PFCAs) from heated polytetrafluoroethylene (PTFE) surfaces. Thermal decomposition of PTFE, best known by its brand name Teflon®, may serve as a source of PFCAs emission. Further, some PTFE products use substances containing perfluorooctanoic acid (PFOA, CAS 335-67-1) as emulsifying agents. To date, only limited information is available on possible emissions of PFCAs from PTFE-coated food contact materials (FCMs) and consumer goods. Schlummer and colleagues from the Fraunhofer Institute for Process Engineering and Packaging (IVV), Germany measured PFCAs from PTFE-coated products considering ordinary usage as well as an overheating scenario for frying pans. Four pans (claimed to be PFOA-free), three waffle irons, a sandwich maker, and three types of PTFE-coated consumer goods (electric irons, an iron sole plate, and an electric hair straightener) were tested. The results show that PFCAs, with carbon chain lengths from C4 to C12, were emitted from PTFE surfaces at temperatures over 180°C. Emission was found to decrease with increasing chain length. Under normal use conditions total emissions of PFCAs accounted for 4.75 ng/h. Emission increased with temperature. Overheated pans released far higher amounts with up to 12190 ng PFCAs/h at 370°C. Under worst-case exposure conditions (an 8 hour application of a PTFE-coated product per day, 200 days a year) human exposure estimates for PFCAs would be far below the tolerable daily intake (TDI) of 1500 ng/kg body weight/day for PFOA, the authors concluded. However, they also stated that the emitted PFCAs will be present in indoor house dust and therefore will add to the aggregate human exposure in indoor environments.
Schlummer, M. et al. (2014). “Emission of perfluoroalkyl carboxylic acids (PFCA) from heated surfaces made of polytetrafluoroethylene (PTFE) applied in food contact materials and consumer products.” Chemosphere (published online December 12, 2014)