Perfluorinated Alkyl Substances

Perfluorinated alkyl substances have been in use for over sixty years, and these highly stable substances were at first thought to be virtually inert and of low toxicity. Toxicity information slowly emerged on perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). More than 30 years ago, early studies reported immunotoxicity and carcinogenicity effects. The substances were discovered in blood samples from exposed workers, then also in the general population and in community water supplies near U.S. manufacturing plants. Only recently has research publication on PFOA and PFOS intensified. While the toxicology data base is still far from complete, carcinogenicity and immunotoxicity now appear to be relevant risks at prevalent exposure levels. Existing drinking water limits are based on less complete evidence that was available before 2008 and may be more than 100-fold too high. As risk evaluations assume that untested effects do not require regulatory attention, the greatly underestimated health risks from PFOA and PFOS illustrate the public health implications of assuming safety of incompletely tested industrial chemicals