At Curtis Cove here in Biddeford, Maine, 95% of the material that I find washed in has actually come from the sea floor, not the surface. Of all the varieties of consumer plastic out there, only polyethylenes and polypropylenes float. All the rest sink. #1 PET bottles, vinyls, nylons, toys -- which are mostly made of styrenes, related to #6 plastics.
I've just written a new article for Scientific American online, "Plastics in the Ocean: How Dense Are We?" that lays out a bit more of what I've found.
Globally, the mass of hidden, sunken plastic now raining down onto the floor of the deep ocean is a huge chunk missing from the bigger picture. For all we've learned about what plastic is doing to our environment, there's the devil we know -- and the devil we don't.
|Image from the Rozalia Project of a plastic bag found on|
the New England sea bed recently