Where did plastic come from?
Take a look around nowadays and you can see garbage everywhere. Plastic is a real part of that mass and some to lots are non-biodegradable. Though nowadays more and more we find ways to lessen the impact the struggle is too hard. Years have done this not a little bit here and there. With mass dumps and great hills going nowhere fast, plus the ocean filling with the waterproof substance.
... and disable advertisements! No kidding :)