This article was updated on July 16, 2021.
In it, researchers, Ved Prakash Ranjan, Anuja Joseph, and Sudha Goel from the Indian Institute of Technology, determined that drinking hot beverages from paper cups can release 25,000 micron-sized plastic particles into your drink after just 15 minutes. These potentially harmful materials are apparently invisible to the naked eye.
What’s wrong with drinking coffee from paper cups?
The authors estimate that an average person drinking three regular cups of tea or coffee out of paper cups daily ultimately exposes themselves to 75,000 micro-plastic particles.
“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 authors wrote in the new paper. “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.”
“We could confirm the release into the MilliQ water of microplastic particles using a scanner. A disposable paper cup exposed to hot liquid for 15 minutes will have approximately 10.2 billion submicron-sized particles.”
The results revealed that exposure of paper cups to hot water triggers the release of microplastics that contain heavy metals in them.
The plastic linings extracted from cups exposed to hot water were subsequently analyzed for changes in physical, chemical, and mechanical properties.
Four out of every five cups featured in the analysis were lined with HDPE grade plastic, which means they were designed o resist chemical agents. Yet surface properties of the liners reliably deteriorated after exposure to hot water.
“Micro-plastics act as carriers for contaminants like ions, toxic heavy metals such as palladium, chromium and cadmium, as well as organic compounds that are water-repelling and can cross over into the animal kingdom,” the authors explained in a release. “When ingested regularly over time, the health implications could be serious.
“This study shows careful consideration needs to be done before the promotion of replacements for bio-hazardous products and environmental pollutants,” Institute director Professor Virendra Tewari says. “We have been quick to replace plastics cups and glasses with disposable paper cups.”
Although the authors can only theorize about the impact their findings will have on the long-term health of those who habitually drink hot beverages out of paper cups, the team is concerned about the wide-spread use of these products in commercial markets.
For most vendors, paper cups are simply a cheap alternative to potentiaally safer carry-wear.
“There is definitely a push factor from the companies that install and maintain coffee or tea vending machines that are ubiquitous in offices,” a spokesman for the environmental charity Ecolife said on the back of the new report. “Apart from ingesting microplastics, as outlined in the study, paper cups leave behind thin plastics that contaminate the environment. Disposable paper cups do not decompose in a landfill and cannot be recycled. There is a continuous and growing demand for them that can only be met by further deforestation.”