Release of flame retardants from microplastics in the environment are very low and unlikely to pose significant risk, is the conclusion of a review of nearly 200 publications. Extremely slow diffusion in the plastic matrix is identified as the limiting factor for release. However, this could be accelerated by reduction of microplastic particle size with weathering over time, or degradation of the polymer after ingestion by aquatic organisms. It should be noted that the data supporting this paper conclusions concerns only halogenated FRs. pinfa suggests that studies are needed on PIN flame retardant losses from microplastics and also that the study conclusions are not applicable for degradable polymers.
“Release kinetics as a key linkage between the occurrence of flame retardants in microplastics and their risk to the environment and ecosystem: A critical review”, H. Cheng et al., Water Research 185 (2020) 116253 https://doi.org/10.1016/j.watres.2020.116253