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Nanoplastics are the smallest pieces of plastic, less than one micrometer in size, formed as a side effect of many industrial processes and as a result of the degradation of large plastic products. Until now, our methods for detecting nanoparticles have been limited to volumetric evaluation, but the new technique not only distinguishes individual particles but also allows their identification.

Nanoplastic particles can be very harmful to our body. Some of them can overcome the body’s biological barriers and reach internal organs. Scientists have already found them in the heart, lungs and other parts of the body. Therefore, we desperately need the ability to measure the amount of plastic in our bodies to assess toxicity.

With a technique called stimulated Raman scattering microscopy, the team used a pair of lasers that can be tuned to resonate with specific molecules. This allowed them to determine the chemical composition of target particles using cross-referencing algorithms against chemical resonance databases.

Because some bottles contained less plastic and others contained more, the researchers determined the average amount to be 240,000 nanoplastic particles per liter. 100 times higher than previous estimates.

Surprisingly, the most common plastic they found was not the material the bottles are made from, but a compound called polyamide. Ironically, filters used to purify bottled water are made from it. In fact, we pollute our water with nanoplastics while purifying it from all other pollutants. The plastic bottle material PET also turned out to be as common as expected.

The researchers noted that previous estimates mostly only considered larger particles, but they found that: Smaller particles made up about 90 percent of the plastic they found.

Although micro- and nanoplastics are not immediately toxic once they enter the body, there are concerns about their long-term effects as they accumulate in various tissues of our body, from the brain to the placenta. We still don’t know what the consequences might be. Plastic also has a bad habit of attracting potentially harmful companions, from antibiotic-resistant bacteria to toxic molecules like flame retardants and phthalates.

A new imaging technique can show potentially toxic clusters and help identify them with more chemical identification data.

Scientists also hope that the new method can show the interaction between these particles and our biological tissues.