Ecological Risk and Bioremediation of Per- and Polyfluoroalkyl Substances

Per- and Polyfluoroalkyl substances (PFAS) have become widely recognized as environmental hazards due to concerns over human health effects, but the potential importance of ecological interactions of PFAS are increasingly being recognized. Numerous uncertainties persist, but indications are that PFAS are not likely to be directly toxic to aquatic organisms except in cases of concentrated releases to surface water near heavily contaminated sites. Several so-called “long-chain” PFAS, notably including perfluorooctane sulfonic acid (PFOS), have been found to bioaccumulate in aquatic systems and potentially pose indirect risks to predatory species through food chain exposure. Similarly, terrestrial species with limited feeding ranges may be at risk near concentrated areas of PFAS releases such as sites where PFAS-containing aqueous film-forming foam (AFFF) has been used. The ability of the environment to self-cleanse by breaking down PFAS is questionable, as many stable compounds resist biodegradation. Active efforts are underway to identify specific microbes capable of breaking the strong carbon-fluorine bonds in PFAS in the hope of developing bioremediation technologies for in situ applications. Not many PFAS have been studied, however, and significant data gaps exist regarding the toxicity, bioconcentration, and biodegradation of compounds such as PFOS that have been investigated. Substantial research is needed to understand the risks that PFAS present to the environment and to promote degradation of these persistent compounds.

Keywords: PFAS; PFOA; PFOS; Perfluorinated substances; Ecological risk, Bioremediation