> A not insignificant part of the plastic thrown in rivers in South East Asia is consumed in Europe and the USA
I've heard this repeated many times, but every time I go searching for details I always come back with the same results: This is not true.
The garbage in rivers is local.
No one is shipping waste from Europe or USA, but some countries do buy recycling. But of course since they paid for the recycling, they have no interest in then dumping it.
If you have some source showing different I'd be interested in seeing it.