To be or not to be degraded: in defense of persistence assessment of chemicals

Abstract

Characterizing the degradation behavior of chemicals in the environment is a key component of chemical hazard and risk assessment. Persistence has been successfully characterized for readily and for slowly degradable...

Are Ready Biodegradation Tests Effective Screens for Non-persistence in All Environmental Compartments?

“…Modi cations to the test systems, such as use of lower sediment-water ratios in OECD 308 test systems to signi cantly reduce variability have recently been successfully demonstrated bySeller et al (2021). Given the stringent nature of the RBT and the di culties in performing simulation testing, a repeat of a well-conducted RBT could offer a more reliable, pragmatic, and e cient step before a simulation test.As expected, signi cant variability in degradation half-lives for a substance can result in ambiguous outcomes in Persistence assessment, most notably for those substances with degradation half-lives closer to the cut-off criteria for Persistence/non-Persistence(Seller et al 2020;Schäffer et al 2022). The variable outcomes in degradation testing even when conducted according to standardised test guidelines, combined with the large body of degradation data generated from non-standardised tests, highlights the value of transparent and systematic weight-of-evidence determination to account for all available evidence in Persistence assessment.…”

Addressing chemical pollution in biodiversity research

“…Of particular concern is the persistence of pollutants in the environment (Cousins, Ng, et al, 2019; Schaeffer et al, 2022). For example, PFASs remain in the environment for at least centuries after their initial emission, a property for which they are often referred to as “forever chemicals” (Cousins et al, 2022).…”

Silylation: a reproducible method for characterization of non-extractable residues (NER) of organic chemicals in the assessment of persistence

“…29 If type III/bioNER and type II NER have been identied, these fractions should be considered as 'safe sink', 29 since (i) biomolecules are of no environmental concern and (ii) covalently bound NER have a very low remobilisation potential due to stable chemical bonds, 30,31 unless evidence for remobilisation has been provided. Whether or not type I NER have to be considered in the persistence assessment of chemicals, is currently under debate 32 and the European Chemicals Agency seems in favour of. 33 A standardized and reliable technology is needed to clearly differentiate the type I and II fractions and to unroll the safe sink vs. hidden hazard presumption of NER in environmental risk assessment.…”