Unbottling the risk: Microplastic release and health hazards from bottled drinks

The widespread use of plastic packaging has raised global concern about microplastic (MP) contamination in bottled beverages and its potential human health implications. This study investigates the occurrence, release mechanisms, and toxicological risks of MP in bottled drinks under varied conditions. Fourteen commercial beverages, including water, milk, cola, juice, vinegar, and oral hygiene solutions, were analyzed for MP content and polymer composition. Experiments simulated storage scenarios at -18, 4, 22, and 45 °C, alongside beverages with differing pH profiles. Results revealed that extreme temperatures, both freezing and heating, substantially increase MP release, with polyethylene terephthalate (PET) and polypropylene (PP) as the dominant polymer types. Low-pH beverages, particularly fizzy drinks and vinegar, also exhibited elevated MP loads, driven by acid-catalyzed degradation of packaging materials. Unexpected polymers such as polyether sulfone, polyvinylidene fluoride, and polytetrafluoroethylene were detected, indicating additional contamination sources from processing equipment. A probabilistic human health risk assessment showed that while average hazard index (HI) values for adults remain below the safety threshold (HI < 1), children frequently exceeded this limit at the 95th percentile, particularly when consuming heat-exposed water. Risk decomposition revealed that although PP is less abundant, it poses a disproportionately high risk due to its low reference dose. PET dominates under thermal stress due to accelerated degradation. These findings demonstrate that MP exposure from bottled beverages is non-trivial, particularly for children and under poor storage conditions. This study highlights the need for stricter manufacturing standards, improved packaging resilience, and public awareness to minimize MP ingestion risks through common consumer products.