@neauoire This is alarming indeed. I'd like to point out that this quote requires more context though.
The referenced report states this (page 89):
> Eleven percent of total plastics [...] comes from the four key sources [...]
... and then continues to break down these four key sources into 78% from tyres, etc.
So we're talking about 78% of 11%, which is more like 8.6% of measured microplastics.
... But these numbers are from 2016 and are may be higher by now.