> The brain samples, all derived from the frontal cortex, revealed substantially higher concentrations than liver or kidney, at 3,057 μg/g in 2016 samples and 4,806 μg/g (0.48%, by weight) in 2024 samples, ranging as high as 8,861 μg/g.
Brains were 0.5% plastic by weight? The highest value was nearly 1% plastic.
Yup. They're extrapolating from uncalibrated GC/MS curves, and normalizing by mass of pre-processed sample. They also don't give any of the un-normalized data. I have zero faith in the accuracy of these numbers, but some faith in the inter-group comparisons.
The sensitivity of the GC/MS method makes me hypothesize that the stated values are massively inflated. Whatever error there was in that original measurement is probably amplified like crazy in scaling up to ug/g estimates.
> Micro- and Nanoplastics Breach the Blood–Brain Barrier (BBB): Biomolecular Corona’s Role Revealed
> The blood–brain barrier (BBB) is an important biological barrier that protects the brain from harmful substances. In our study we performed short term uptake studies in mice with orally administered polystyrene micro-/nanoparticles (9.55 µm, 1.14 µm, 0.293 µm). We show that nanometer sized particles—but not bigger particles—reach the brain within only 2 h after gavage. To understand the transport mechanism, we performed coarse-grained molecular dynamics simulations on the interaction of DOPC bilayers with a polystyrene nanoparticle in the presence and absence of various coronae. We found that the composition of the biomolecular corona surrounding the plastic particles was critical for passage through the BBB. Cholesterol molecules enhanced the uptake of these contaminants into the membrane of the BBB, whereas the protein model inhibited it.
So, in theory, a diet higher in protein and lower in cholesterol ought to be somewhat protective against nanoplastics crossing the blood brain barrier.
They found some brains have 1% of plastic in them by weight. 1% of the human brain by weight is 14g. A solid 14g plastic ball is 1.2 inches in diameter which is about the size of a golf ball.
You'd only be off by a factor of 3 instead of 4, then.
In any case, comparing it to a solid ball isn't so useful. Even the idea of "density" for something that is dispersed as small particles isn't too useful; proportion of mass is really the only useful metric.
This is not correct. A golf ball is closer to 1.7 inches in diameter, which is nearly three times the size of a 1.2 inch diameter ball in terms of volume.
Brains were 0.5% plastic by weight? The highest value was nearly 1% plastic.
That seems hard to believe.