Exposure to hot liquid for 15 minutes makes plastic-coated disposable paper cups release tiny plastic particles, harmful ions and heavy metals into liquid, a study reveals1.

Sipping hot beverages from such paper cups could result in the ingestion of these contaminants, increasing the risk of developing reproductive defects, cancer and even neurological disorders, says a team of researchers from the Indian Institute of Technology, Kharagpur.

Despite the presence of plastic particles in salt, branded milk, fish and seafood, their leaching from food-packaging materials have rarely been quantified.

To detect such leaching from paper cups, the IIT scientists poured hot ultrapure water into 100ml paper cups, allowing the hot water to reside in the cups for 15 minutes. They then added a specific dye to detect and quantify plastic particles in the water samples collected from the cups.

The researchers, led by Sudha Goel, found that each paper cup could release around 25,000 tiny plastic particles into hot water after 15 minutes. Thus, they say, a person drinking three cups of tea or coffee daily might ingest 75,000 tiny plastic particles that are invisible to the human eye.

The researchers also detected ions such as fluoride, chloride, nitrate and sulfate, and toxic heavy metals such as lead, chromium, cadmium and arsenic in the water samples. However, no plastic particles and ions were found in paper cups that held water at room temperature, indicating that the contaminants came from the cups.


1. Ranjan, V. P. et al. Microplastics and other harmful substances released from disposable paper cups into hot water. J. Hazard. Mater. 404, 124118 (2020)