An article released as preprint at the ChemRxiv website on November 6, 2018, focuses on the environmental behavior of highly persistent chemicals and proposes a new approach to risk assessment and management of such substances. Ian Cousins from the Department of Environmental Science and Analytical Chemistry, Stockholm University, Sweden, together with three other scientists from the U.S. and Switzerland, argue that “the higher the persistence of a chemical, the greater the emphasis that it should be given in chemicals assessment and decision making.”  

The authors discuss three case studies to demonstrate that there are unique problems shared by all highly persistent chemicals, regardless of their other properties. Namely, a continuous release of a highly persistent chemical “will lead to continuously increasing contamination irrespective of the chemical’s physical-chemical properties.” This in turn “will result in increasing probabilities of the occurrence of known and unknown effects.” The associated problem is that “once adverse effects are identified, it will take decades, centuries or even longer to reverse contamination and therefore effects.”  

Due to these considerations, the authors “propose that high persistence should be established as a sufficient basis for regulation of a chemical.” They term this a “P-sufficient approach.” In current chemical assessment schemes, persistent chemicals may receive special emphasis only if they have other known hazardous properties relating to bioaccumulation and toxicity, and “persistence is largely ignored in risk assessment.” A P-sufficient approach, on the contrary, would mean “that high persistence is sufficient for a chemical to be flagged for subsequent management actions.”  

The authors bring up the examples of certain “fluorochemicals” and “synthetic polymers” as compound groups that would come into light using the P-sufficient approach to regulation. They argue that “regulation on high persistence alone is not over-precautionary given the historical problems that persistent chemicals . . . have caused,” because such regulation “would serve to prevent poorly reversible future impacts.” The P-sufficient approach is “in line with . . . classifying plastic waste as hazardous” (FPF reported) and with it recently “being flagged as a planetary boundary threat.”  


Cousins, I.T, et al. (2018). “Why is high persistence alone a major cause of concern?” ChemRxiv DOI: 10.26434/chemrxiv.7299992.v1 (published November 6, 2018) (pdf) 

Villarrubia-Gomez, P., et al. (2018). “Marine plastic pollution as a planetary boundary threat – The drifting piece in the sustainability puzzle.” Marine Policy 96:213-220. 

Rochman, C.M., et al. (2013). “Classify plastic waste as hazardous.” Nature 494:169-171.