It is not surprising to learn that the Hudson River is filling with plastics. But scientists are discovering that the plastic we can’t see — tiny particles, or microplastics, created when larger pieces break down or are inserted into cosmetics as exfoliants — are easily absorbed into fish and humans. What is the effect? Scientists aren’t sure yet, but no one thinks it’s good.

You can find the pieces in the deepest trenches of the ocean, nearly 7 miles down. You can find them in the most desolate parts of the Arctic, in the rain over the mountains, in the fish, in the water. And, yes, you can find them in your poop, because you inhale and consume tens of thousands of pieces each year, which is probably a gross underestimate because scientists haven’t yet inventoried all the animals and food that can absorb them.

Microplastics are defined by scientists as objects that are 5 millimeters or smaller. They are created when larger pieces of plastic, such as water bottles, are broken down by sunlight or the rocking of waves. Others are included as exfoliants in cosmetics such as facial scrubs and whitening toothpastes — they’re often visible beads.