Leaching of endocrine disrupting chemicals from plastic food packaging – In vitro toxicity and chemical composition

Plastics are chemically highly complex materials. More than 10,000 substances are used in the production of plastics (e.g., plasticizers, antioxidants) and even more non-intentionally added substances (e.g., reaction byproducts, impurities) are associated with them. While there is abundant scientific evidence that some compounds used in plastics, such as bisphenols and phthalates, are endocrine disrupting chemicals, little is known about the composition and toxicity of the complex mixtures of chemicals leaching from everyday plastic products. Therefore, this study aims at characterizing the in vitro toxicity and the chemical composition of leachates from plastic food contact articles (FCAs) as relevant sources of human exposure. Fourteen plastic FCAs covering the seven polymer types with the highest global market share were leached into water and a water-ethanol mixture for 10 days at 40°C according to European Regulation 10/2011/EU. The leachates were analyzed with reporter gene assays for a set of nuclear receptors relevant to human health, including pregnane X receptor (PXR), peroxisome proliferator-activated receptor gamma (PPARγ), estrogen receptors alpha (ERα), and androgen receptor (AR). Further, these plastic mixtures were analyzed using non-target high-resolution mass spectrometry to quantify the number of chemical features and tentatively identify the chemicals leaching from the FCAs. Thirteen of the fourteen FCA leachates interfered with at least one of the nuclear receptors. PXR and PPARg were the predominant targets of the plastic chemicals, but both steroid receptors were also activated or inhibited by several samples. The water leachates were less toxic than the water-ethanol leachates and none of the latter was estrogenic. Also, lower numbers of chemicals were leaching into water as compared to water-ethanol mixture. To identify the active compounds in these complex mixtures, an effect-directed analysis will be performed. This research shows that plastic FCAs leach endocrine disrupting chemicals into food simulants and highlights the importance of analyzing whole mixtures of finished plastic products to cover the toxicity of unknown compounds and mixtures.

Acknowledgment - This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 860720.