Targeted and non-targeted analysis of chemical contaminants in recycled plastics for food packaging.

Abstract

In order to address concerns with the use of recycled plastics for food packaging, Health Canada, in collaboration with Environment and Climate Change Canada (ECCC) and Agriculture and Agri-Food Canada (AAFC), recently investigated various chemical contaminants in food-grade recycled plastic materials including beverage bottles, reusable water bottles, and plastic resin pellets. Methods were developed to extract samples with acetonitrile and for non-targeted analysis of volatile and semi-volatile organic chemicals, and also for targeted analysis of bisphenols, phthalates, and volatile organic chemicals. Bisphenol A (BPA) was detected in all recycled polyethylene terephthalate (PET) beverage bottles with concentrations ranging from 4.26 ng/g to as high as 283 ng/g. BPA levels in virgin PET beverage bottle samples are very low, either not detected or at levels close to detection limits. Flavouring chemicals (e.g. D-limonene, γ-terpinene, benzaldehyde) were also detected in the recycled PET beverage bottles. Toluene was detected in all recycled reusable water bottles at levels as high as 26,077 ng/g in addition to a few unidentified characteristic peaks. Several peaks were identified as chemicals associated with dyes (e.g. solvent orange 60, solvent red 179, disperse red 9, solvent yellow 33) used in coloured water bottles. Among the 12 pellet samples analysed, the two PET pellet samples showed comparatively low levels of detectable chemical constituents, while the other 10 pellet samples exhibited higher concentrations and a greater diversity of detected compounds. Plasticisers, such as di-(2-ethylhexyl) adipate (DEHA) and several phthalates (e.g. di-(2-ethylhexyl) phthalate (DEHP), isomers of di-iso-nonyl phthalate (DiNP) and di-iso-decyl phthalate (DiDP), were identified in the four polyethylene (PE) and polypropylene (PP) pellet samples in addition to numerous tentatively identified and unidentified peaks. Styrene was also detected in all polystyrene (PS) pellet samples (virgin and recycled) as expected in addition to numerous tentatively identified and unidentified peaks.