Revealing contaminants in China's recycled PET: Enabling safe food contact applications

Abstract

The lack of data on chemical contamination in recycled polyethylene terephthalate (rPET) in food contact applications, impedes the legalization of rPET in food contact applications in China. This study offers a comprehensive analysis of contaminants in hot-washed rPET flakes, identifying 1011 compounds. While most substances were detected infrequently, some i.e., bis(2-ethylhexyl) phthalate and mineral oil aromatic hydrocarbons stood out for their relatively high average concentrations. Limonene emerged as the most frequently detected flavorants. Rare genotoxic compounds like safrole and diethyl sulfate were detected at low levels, emphasizing the importance of adopting a conservative evaluation approach. Molecular descriptor analysis guided the proposal of four new surrogates, i.e., dimethyl pentanedioate, 2-tridecanone, bis(2-ethylhexyl) terephthalate, and 2,2-dimethoxy-1,2-diphenylethanone, for challenge tests, aiming to better capture the chemical diversity of rPET contaminants. This research unveils the contamination profile of Chinese rPET and suggests adjustments to evaluation protocols, potentially facilitating its high-value applications and minimizing potential harms.