05/09/2026
Disposable paper cups, commonly used for hot beverages, feature a thin plastic lining, typically polyethylene, to prevent leakage and maintain structural integrity.
When filled with hot liquid around 85 to 90 degrees Celsius, this lining degrades rapidly.
Within just 15 minutes, the heat causes the plastic film to break down, releasing approximately 25,000 micron-sized microplastic particles into a standard 100-milliliter serving.
Far more numerous sub-micron particles are also liberated, along with various ions including fluoride, chloride, sulfate, and nitrate.
Toxic heavy metals such as lead, chromium, and cadmium present in the lining material can migrate into the drink as well.
These contaminants enter the beverage through physical and chemical deterioration of the hydrophobic film under thermal stress. Room-temperature liquids do not produce the same effect, confirming that heat is the primary driver.
Regular consumers who drink several cups of tea or coffee daily may therefore ingest tens of thousands of these invisible particles along with associated chemicals.
While the long-term health consequences of chronic low-level exposure remain under investigation, the particles and leachates raise concerns about potential accumulation and biological interactions in the body.
Switching to reusable alternatives made of stainless steel, ceramic, or glass eliminates this pathway of contamination entirely.
Source: Ranjan, V. P., Joseph, A., & Goel, S. Microplastics and other harmful substances released from disposable paper cups into hot water. Journal of Hazardous Materials, 404, 124118.