In all, infants consume as many as 1.6 million polypropylene microplastic particles on average every single day.
Not even newborns are spared from this as microplastics have made their way into babies’ feeding bottles, according to two scientists.
The researchers, Dunzhu Li and Yunhong Shi, both of whom work at Trinity College Dublin, have found that polypropylene-based products, which are commonly used for making and storing food, can release large amounts of microplastics during use.
“To estimate the potential global exposure to infants up to 12 months old, we surveyed 48 regions, finding values ranging from 14,600-4,550,000 particles per capita per day, depending on the region,” the scientists explain in a study.
“We demonstrate that infant exposure to microplastics is higher than was previously recognized due to the prevalence of PP-based products used in formula preparation and highlight an urgent need to assess whether exposure to microplastics at these levels poses a risk to infant health,” they add.
The scientists say that infant feeding bottles made of polypropylene release large quantities of microplastic particles per liter especially because sterilization and exposure to hot water both increase microplastic release in these plastic products.
“This is an astoundingly large increase on previous estimates. Earlier studies had suggested that adults and children in the US were exposed to between 74,000 and 211,000 particles over the course of an entire year, through the food they eat, the water they drink and the air they breathe,” they write in an article.
The researchers started investigating how microplastics release after observing a colleague preparing instant noodles in a plastic container. “The container looked rigid to start with, but after he poured hot water in it, it changed to become more malleable and soft. We were curious and wondered whether microplastics might be released in the process,” they recall.
They did a test in their lab and found that the plastic container released more than 1 million microplastics in every liter of hot water. “We began testing other polypropylene containers, such as plastic bottles, with liquids at room temperature and found very few microplastic particles were released with each litre, from none at all to a few hundred. Heat, it seemed, was the problem,” they elucidate.
Troublingly, after a survey of bottles used for feeding babies in 48 regions that cover 78% of the world’s population, the two scientists discovered that bottles made of polypropylene account for 83% of the global market. They then tested how many microplastics were released through cleaning, sterilizing and mixing liquids in each of 10 bottles available on the market globally.
“[We] found that they released up to 16 million particles per litre of 70°C water. The majority of these microplastics were smaller than 20 micrometres and were flake-like with a coarse surface, and an average thickness one-tenth of their width,” they observe.
“When the temperature of the water was raised from the recommended 70°C to 95°C – the temperature of recently boiled water – the release of microplastics increased from six million particles per litre to 55 million,” the scientists note. “The sterilisation process alone – in which the bottle is disassembled and placed in a pan full of 95°C water – increased microplastics release by at least 35%.”
In all, the researchers estimate that infants consume as many as 1.6 million polypropylene microplastic particles on average every single day. It remains little understood what effects all those microplastics have on the developing bodies of babies, but the researchers are now seeking to find that out.
In the meantime, parents can follow steps to reduce their offspring’s exposure to microplastics, the researchers say: 1) Rinse sterilized feeding bottles with cool water; 2) Always prepare baby formula in a non-plastic container; 3) After the formula has cooled to room temperature, transfer it into the cooled and sterilized feeding bottle; 4) Avoid rewarming prepared formula in plastic containers, especially with a microwave oven.