Researchers found that microwaving plastic baby food containers released, in some cases, over two billion nan plastics and four million microplastics for every square centimeter of the container. Plastic food containers in the microwave can release billions of tiny toxic plastic particles.
Technology also found that three-quarters of cultured embryonic kidney cells died after two days of introduction into the same particles.
Kazi Albab Hussain, lead author of the study and a PhD student at the University of NebraskaLincoln, US says “It’s really important to know how much micro and nanoplastic, show that the toxicity of micro- and nanoplastics is closely related to the level of exposure”.
The team conducted experiments with two baby food containers made of polypropylene and a reusable bag made of polyethylene, both plastics approved by the US Food and Drug Administration.
In one experiment, researchers filled containers with either deionized water or 3% acetic acid, which was designed to simulate dairy products, fruits, vegetables, and other relatively acidic consumables, and then heated them at full power for three minutes in a 1,000-watt microwave oven.
They then analyzed the liquids for evidence of micro- and nanoplastics: microparticles at least 1/1000th of a millimeter in diameter, nanoparticles smaller. The actual number of each particle released by the microwaves depended on many factors, including the plastic container and the liquid inside.
However, based on a model that took into account particle emissions, body weight and per capita consumption of various foods and beverages, the team estimated that infants drinking microwaved water products and toddlers consuming microwaved milk products ingested the greatest relative concentrations of plastic.
Instead of just measuring the number of particles released by a single container, the researchers instead exposed the cells to concentrations of particles that can accumulate over days or from multiple sources in infants and toddlers.
After two days, only 23 percent of the kidney cells exposed to the highest concentrations managed to survive a much higher mortality rate than that observed in earlier studies of micro- and nanoplastic toxicity.
The team suspects that kidney cells may be more sensitive to the particles than other cell types examined in previous research.
Regardless of their experimental conditions, the team found that polypropylene containers and polyethylene bags generally released about 1,000 times more nanoplastics than microplastics.