The worst thing plastic waste does is to kill birds and marine life. An Australian town has implemented a solution: they bag the outflows, then deal with what they catch.
This is expensive, but they reckon it’s worth it.
The best solution is to stop making and using the stuff. Second best is not to throw it away. This is third best, but still a long way better than letting it loose.
Thank you, Angela Archer, for sending me the link.