SYDNEY, Aug. 27 (Xinhua) -- Single-use paper cups used for takeaway coffee and other hot beverages can release millions of microplastic particles when exposed to hot liquid, new research reveals.
Researchers from Australia's University of Queensland (UQ) examined single-use cups lined with fossil-based polyethylene (PE) and polylactic acid (PLA), a biodegradable plastic, finding that PLA-lined cups released a total particle mass approximately 12 times higher than PE-lined cups in experiments, according to a UQ statement released Thursday.
"A cup made mostly of paper does not mean that the cup is plastic-free because many contain a thin plastic lining that provides water resistance and structural integrity," said UQ research fellow Elvis Okoffo, noting that single-use paper cups are used worldwide for coffee, tea and other hot drinks.
The study, published in ACS Food Science & Technology, measured approximately 4.3 million nanoparticles per milliliter from PLA-lined cups, compared with 2.7 million nanoparticles per milliliter from PE-lined cups. The nanoparticles are around a thousand times thinner than a human hair.
The findings added to growing evidence that plastic products used for food storage and preparation represent a significant yet often overlooked source of human exposure via ingestion, Okoffo said.
However, he said the results did not necessarily mean people should stop using paper cups or that PLA was inherently unsafe, noting that the impact of plastic particles on human health remains unclear.
Researchers called for regulators to consider safety guidelines or warning labels for food-contact materials and said manufacturers could develop cup linings that release fewer plastic particles when exposed to hot liquids. ■
