Endocrine and metabolism disrupting chemicals in plastic food packaging: Addressing the unknowns

Abstract

Over 16,000 chemicals are used in or present in plastics, with more than a quarter known to be hazardous and over 10,000 lacking basic data on identity, functionality, and toxicity. In addition, plastics contain numerous chemical impurities, reaction byproducts, or degradation products with largely unknown identities. These chemicals can leach into the environment, and humans can take them up via the consumption of foods. Some well-known plastic chemicals, such as bisphenols and phthalates, have been linked to non-communicable diseases, including reproductive disorders or obesity. However, the chemical mixtures leaching from plastics and their cellular targets remain poorly characterized. This thesis focuses on the interference of plastic chemicals from real-world food packaging with various cellular receptors, particularly those related to the metabolic and endocrine systems. We found that most plastic food contact articles (FCAs), made from common polymers, contain chemicals that activate receptors involved in hormone regulation and metabolism. These chemicals also migrate into food simulants, indicating their potential for human exposure. Specifically, chemicals from low-density polyethylene, polyvinyl chloride, and polyurethane were more likely to interfere with the receptors, while high-density polyethylene and polyethylene terephthalate were less toxic. Advanced analytical techniques revealed that plastic FCAs can contain many chemicals (up to 10,000 chemical features) and have diverse chemical compositions, with most chemicals remaining unidentified. However, certain known toxic chemicals, such as triphenyl phosphate, were detected, and parabens and aromatic amines – known for their hormone disruption and toxicity – were linked to receptor activity. The study highlighted that fewer chemicals in FCAs correlated with less receptor activity, suggesting that reducing the number of chemicals in plastics could improve safety. Overall, the thesis emphasizes the need for a better understanding of the chemicals used and present in plastics and the need to reconsider the way plastics are being designed and produced.