Evaluating full environmental impacts of “low concern” polymeric PFAS

The estimated 4,730 PFAS compounds can be divided into two main categories; polymeric and non-polymeric.

Non-polymeric PFAS are small molecules, more easily absorbed by wildlife, humans, and soil. Non-polymeric PFAS are more reactive and considered to be more harmful than polymeric PFAS. Industries consider most types of polymeric PFAS to be of “low concern” because these molecules are too large to be absorbed by people and wildlife, however manufacturers use non-polymeric PFAS to produce the more stable, less harmful polymeric PFAS, and these smaller components can be released into the environment when polymeric PFAS break down.

A recent op-ed from STEEP Director Rainer Lohmann, PhD, and Robert Letcher, National Wildlife Research Centre, Ontario, details the current state of research on fluorinated polymeric PFAS, their uses, chemical properties, and concerns surrounding their environmental and human health impacts. The “extreme stability” of fluorinated polymers means they behave similarly to microplastics in that they persist in the environment for a very long time and can still be ingested. Thus, long, stable polymers have been found in fish, whales, and humans. The article points to two main mechanisms of fluorinated polymer breakdown and the release of harmful non-polymers:

Mechanism A: fluorinated polymers are degraded in the environment by microbes or weathering, much like plastics, and release non-polymeric PFAS.

Mechanism B: non-polymeric PFAS are released from fluorinated polymer fibers in treated textiles (i.e. microfiber cloth) during washing.

Designating fluorinated polymers as “low concern” focuses solely on the stability of ready-to-use polymeric PFAS, which have been tested to be biosafe, and fails to integrate “the environmental full life cycle considerations” of these materials, which includes production, manufacture, and disposal. These early and late aspects of the chemical life cycle pose the most risk to environmental and human health, and as the authors concluded, many of these risks still warrant further study.

Lohmann, R. and Letcher, R. (2023) The universe of fluorinated polymers and polymeric substances and potential environmental impacts and concerns. Current Opinion in Green and Sustainable Chemistry, 41:100795. DOI: https://doi.org/10.1016/j.cogsc.2023.100795