On May 12, 2021, peer-reviewed journal Resources, Conservation, and Recycling published an article by Qi-Zhi Su and other chemists from the University of Zaragoza, investigating the migration of volatile organic compounds from recycled high-density polyethylene (rHDPE) into food simulants. The authors collected post-consumer HDPE pellets and flakes from three recyclers in Spain and tested for migration of 58 volatile organic compounds into ethanol and acetic acid food simulants. Poorly sorted rHDPE from one recycler was “contaminated with several pesticides and one polychlorinated biphenyl, which are of very high concern. Besides, many prioritized migrants were only detected in this set of samples and some of them had migration values several times higher than their [EU] set migration limit.” The other two Spanish recyclers sorted rHDPE from milk bottles better than the third and ultimately created a recycled plastic with “rather consistent chemical composition between batches” and only two of the 58 chemicals tested, octocrylene (CAS 6197-30-4) and 2-ethylhexyl-4-methoxycinnamate (octinoxate, CAS 5466-77-3), reached a level of concern.
Octocrylene and octinoxate have high molecular weights, which make them difficult to remove from HDPE through the washing and extra decontamination procedures used by the Spanish recyclers (and recyclers more broadly). Both chemicals are listed in the Food Packaging Forum’s Food Contact Chemicals Database (FCCdb, FPF reported) as “substances of potential concern” for being a putative endocrine disrupting chemical and predicted health hazard, respectively. According to Su et al., “HDPE milk bottles are well-distinguished from others in the mixed plastic waste collection and therefore could have less contamination from non-food grade plastics.” Through enhancing the sorting and decontamination process of rHDPE, milk bottles “could be the first [non-PET plastic] candidate for closed-loop recycling.”
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Qi-Zhi Su, et al. (May 12, 2021). “Decontamination efficiencies of post-consumer high-density polyethylene milk bottles and prioritization of high concern volatile migrants.” Resources, Conservation and Recycling
