Oceanographer Curtis Ebbesmeyer, Ph.D., an expert on marine debris, agrees. “If you could fast-forward 10,000 years and do an archaeological dig…you’d find a little line of plastic,” he told The Seattle Times last April. “What happened to those people? Well, they ate their own plastic and disrupted their genetic structure and weren’t able to reproduce. They didn’t last very long because they killed themselves."
from the article Our Oceans Are Turning Into Plastic - Are We?. Which, frankly, you should go read as soon as you have time.
Here's a shorter article that introduces the topic: The world's rubbish dump: a garbage tip that stretches from Hawaii to Japan
And some info on Bisphenol A (the type of plastic with the number 7 inside its recycling triangle icon), and how Canada is banning it.
Canada to ban bisphenol-A...
...especially from baby bottles