Plastic waste pollution represents a critical environmental challenge with increasing implications for the well-being and health of future generations. Food packaging is one of the main sources of contamination by microplastics and nanoplastics (MNPLs) and its inhalation and ingestion is the main route of human exposure.
A study of Mutagenesis Group of the Department of Genetics and Microbiology of the Autonomous University of Barcelona (UAB) has successfully obtained and characterized microplastics and nanoplastics derived from several types of commercially available tea bags.
UAB researchers have observed that when using these sachets to prepare an infusion, enormous quantities of nanometric-sized particles and nanofilamentous structures are released, which represents an important source of exposure to MNPLs.
The tea bags used for the research were made from the polymers nylon-6, polypropylene and cellulose.
The study shows that, when making an infusion, polypropylene releases approximately 1.2 billion particles per milliliter, with an average size of 136.7 nanometers; cellulose releases about 135 million particles per milliliter, with an average size of 244 nanometers; while nylon-6 releases 8.18 million particles per milliliter, with an average size of 138.4 nanometers.
To characterize the different types of particles present in the infusion, a set of advanced analytical techniques were used such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (ATR-FTIR), dispersion (DLS), laser Doppler velocimetry (LDV) and nanoparticle tracking analysis (NTA).
“We have managed to characterize these contaminants in an innovative way with a set of cutting-edge techniques, which constitutes a very important tool to advance research on their possible impacts on human health,” highlights UAB researcher Alba García.
Interaction with human cells
The particles were stained and first exposed to different types of human intestinal cells to evaluate their interaction and possible cellular internalization. The novel biological interaction experiments showed that mucosa-producing intestinal cells had the highest absorption of microplastics and nanoplastics, with the particles even entering the cell nucleus that houses the genetic material.
The result suggests a key role of the intestinal mucosa in the absorption of these polluting particles and underlines the need for more research on the effects that chronic exposure can represent on human health.
«It is essential develop standardized test methods to evaluate contamination by MNPLs released by plastic materials in contact with food and formulate regulatory policies to mitigate and minimize this contamination effectively. As the use of plastic in food packaging continues to increase, it is vital to address contamination by MNPLs to ensure food safety and protect public health,” the researchers add.
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