Microplastics and other harmful substances released from disposable paper cups into hot water

Disposable paper cups are popular for consuming beverages. These paper cups have an interior that is laminated with a hydrophobic film made of mostly plastic (polyethylene) and sometimes of copolymers. The objective of this study was to evaluate the degradation of these films as a result of exposure to hot water (85–90 °C). Due to deterioration of the films, ions like fluoride, chloride, sulfate, and nitrate were released into the water contained in the paper cups. Microplastic particles leaching into the liquid were identified and quantified. Fluorescence microscopy indicated the release of approximately 25,000 micron-sized microplastic particles into one cup of hot water in 15 min (100 ml) while scanning electron micrographs indicate 102 + 21.1 × 106 sub-micron-sized particles/ml into the same volume of liquid. Toxic heavy metals like Pb, Cr, and Cd were detected in the films which can be transferred into hot water. Elemental analysis shows a decrease in the percentage of elements like C, H, and N (by weight) due to exposure to hot water. Ingestion of microplastics, ions, and heavy metals regularly while consuming our daily dose of hot beverages like tea and coffee can expose us to potential health risks in the future.