Re: What fraction of a gram ?
"For a substance to be absorbed from the digestive system it needs to be dissolved"
Not true. Small enough bits can pass through the gaps in between the cells lining the digestive tract.
"Microplastics that are inhaled (a tiny fraction of the total) will be trapped in mucus in the lungs and eventually be removed"
Probably true for the larger bits, but still there is a certain size where particles will be absorbed, just like tiny soot particles can be absorbed. (Think about it - if our lungs had the capacity to clear out all tiny particles, people wouldn't have lung problems from living next to a coal power station, working in coal mines etc)
"What should be shown in the studies ... is what fraction of the particles is actually absorbed into the body"
Yes, that would be a more useful measure (but also probably much harder to determine)
Biting the hand that feeds IT
