It is likely a fraction of a fraction of an already small fraction. Textiles, tires and food packaging are the biggest contributors. It has yet to be proven that microplastics are directly linked to any harm, it is mostly unknown.
If you care about that kind of stuff the best thing you could do is stop driving.
Interesting. I will do more research on this, thanks. But at the end of the day, even though it's tough for us to see the PLA poop, etc from our prints (I still generally don't like it), my point is that hobbyist plastic waste is basically negligible and making nearly zero difference.
I don't want people to see plastic waste from 3D printing and be discouraged to try it out as a hobby. I just got my first 3d printer 6 months ago (and I did all this biodegradable research mostly so my wife would feel comfortable with it). But the benefits of rewiring your brain in a manufacturing mindset, having the ability to create things, solve custom problems, etc, far outweigh the negligible (in the grand scheme of things) amount of waste compared to all the other plastic shit (toys, etc) the masses buy on amazon. That was my main point.
But it's good to know that it could still take 80 years, and is not as quickly biodegradable as originally thought.
But once it's fragmented, it's rapidly degraded. So it doesn't contribute to persistent microplastics.
It also does not take 80 years in normal environmnets.