HARI SREENIVASAN:

Plastic pollution is more than bags and bottles and things we can see. A good deal of plastic pollution exists in things we can't see. They're called microplastics and new scientific research is underway to find out what impact they might have on humans and the environment. This coming week PBS NewsHour is launching the series "The Plastic Problem," a deep dive into the dangers of plastics and possible solutions to the problems they present.

I spoke recently with Andrea Thompson, Associate Editor for sustainability at Scientific American about her series on microplastics.

Andrea Thompson, thanks for joining us. We've heard these stories about whales beaching up on shore with 17 pounds of plastic in their belly and we've heard about the damage that plastic does in the oceans. What you're focusing on something much more interesting, which is microplastics on a very, very small scale. Tell us, first of all, what is a microplastic and why is it dangerous?