Preventing brominated flame retardants from occurring in recycled expanded polystyrene: comparing Norwegian visual sorting with advanced screening methods

There is international interest to increase recycling rates of expanded polystyrene foam (EPS). Extensive use of brominated flame retardants (BFRs), however, presents a hinder to this. If uncontrolled, hazardous BFRs could persist in recycled EPS leading to new exposure routes, including in materials such as EPS packaging where no flame retardants are required. This study looked at EPS foam collected from Norwegian Municipal Waste Sorting Facilities, visually sorted as white EPS foam, mostly derived from packaging. Bromine was analysed by X-ray fluorescence (XRF), and selected BFRs including hexabromocyclododecane (HBCDD) were analysed by targeted gas chromatography-mass spectrometry analysis. Results were compared with EU and UNEP low persistent organic pollutant concentration limits (LPCLs). One out of 120 samples contained HBCDD over established LPCLs, likely attributable to missorted insulation EPS. Further, no false negatives occurred, as all samples in which target BFRs were quantified had XRF-detectable bromine. Visual sorting of white EPS packaging foam, with the use of XRF in uncertain cases has the potential of minimizing hazardous BFRs in recycled EPS. The context of national sorting infrastructure and compliance should be a central feature of future studies investigating how BFRs or other hazardous substances enter the global circular economy.

Automated summary

This study analyzed bromine and selected BFRs in EPS foam and compared the results with EU and UNEP concentration limits. It found hazardous BFRs in recycled EPS, emphasizing the importance of national sorting infrastructure and compliance in future research on how these substances enter the global circular economy.