A study published in the Proceedings of the National Academy of Sciences (PNAS) in January has been used for a media wave of scaremongering about plastic residue in bottled water. Its results are based on a system developed by researchers at Columbia University and Rutgers University that uses a "hyperspectral stimulated Raman scattering (SRS) imaging platform with an automated plastic identification algorithm that allows micro-nano plastic analysis." That sounds impressive, and it really is, relying on an immersive tank, lasers, and advanced computational techniques.
The study's major contribution to science was actually not in coming up with an estimate of the amount of plastic in bottled water, but in inventing a technique that could detect nanoplastics at all. Nanoplastics, as the name implies, are much smaller than already tiny microplastics. Microplastics can be as small as one micron in size, 1/83rd the width of a strand of hair.
