The brands considered by the study included Aquafina, Bisleri and Nestle Pure Life among others.
It found that 93% of the samples were contaminated with plastic particles.
If you included the smaller particles (6.5-100 μm), the average rose up to 325 microplastic particles per litre.
Researchers came to the conclusion that “contamination is at least partially coming from the packaging and/or the bottling process itself.” The study found that the polymers found in the water (54%) matched the make of common plastic used to make the cap of the water bottles.
“Averaging across lots by brand, Nestle Pure Life and Gerolsteiner showed the highest average densities at 930 and 807 MPP/L, respectively, while San Pellegrino and Minalba showed the lowest microplastic contamination with 30.0 and 63.1 MPP/L, respectively,” the study says.
Interestingly, when the researchers studied samples of the same brand which came in glass bottles instead of plastic, there was considerably less plastic contamination in the water packaged in glass bottles.
“This indicates that some of the microplastic contamination is likely coming from the water source, but a larger contribution might be originating from the packaging itself,” the study says.
“We found roughly twice as many plastic particles (>100 um) within bottled water as compared to tap water on average (10.4 vs. 5.45 particles/L).
While fibers made of 97% of the microplastics within the tap water study, they only composed 13% of the particles within bottled water,” the study says.
“[…] the data seems to suggest that at least some of the plastic contamination may be coming from the industrial process of bottling the water itself.