In the world of the unseen, the law of unintended consequences dominates.
Our pervasive use of plastics... which don't biodegrade well, if at all... has inundated the environment with plastic waste. It's unsightly... and when we see it we're sometimes dismayed, even though by now the sight of it is so common that we've developed a sort of visual immunity, whereby we edit it out of our vision. This enables the vast majority of people to walk right past most plastic waste without picking it up.
It's always someone else's responsibility.
What most of us don't understand in the least is that plastic, like all other materials in the environment, is subject to mechanical forces that steadily erode it. Abrasion takes place as plastic is transported by wind or water; it rubs against branches, grinds against sand and stones, and creates smaller and smaller particles... which, as it happens, aren't really much more biodegradable than the larger pieces the plastic first came from.
The net effect, over the past city or more years, has been the creation of a steadily increasing sand-like substrate of plastic nano particles, tiny little bits of plastic that are so small as to be nearly invisible to the naked eye.
No big deal, you might think; but it IS a big deal, as scientists at Plymouth University reveal in the link. Plastics assist in the transfer of toxic chemicals into small marine organisms who ingest them; and these small, uninteresting organisms form some of the foundational elements in the food chain on shorelines—and, of course, in many other cases.
Not only are plastic nano particles present on shorelines, they are becoming increasingly abundant in suspension in water, where they affect aquatic food chains all over the world. Imagine living in a world where you began to have to inadvertently eat pieces of plastic with your spaghetti, your hamburgers, your bagel; these tiny organisms are already in that world. they can't escape the consequences of our polluting activity and they aren't able, as we are, to discriminate between plastic particles and food particles. It's absolutely certain that because of this, nanoplastic pollution is already wreaking havoc on food chains and biodiversity in the microsphere; and it's all taking place out of sight. the long term effects are likely to be severe, but the phenomenon is drastically understudied and the public is (as usual) not just uninformed, but completely ignorant—and, let's admit it, probably won't care anyway, at least not until it impacts their lifestyle.
Treating issues of this kind with a shrug of the shoulders and a "who cares" is not good enough. Much stronger environmental controls need to be placed on the production and use of plastics, which will take a major rethinking on the part of both producers and consumers.