I'm thoroughly enjoying this fellowship but it can sometimes be a real downer. There's dying species and acidification of the ocean, rising sea levels - there's a sense that some scary stuff lies ahead and not a lot of obvious solutions in the works.

And every now and then, we learn something totally terrifying, like the day that Michael SanClements came to our seminar. He's an ecologist affiliated with the Institute of Arctic and Alpine Research. In 2011, he decided to go two weeks without creating any plastic waste, a challenge that was way harder than he'd ever expected. He blogged his experience for grist.org - an environmental website - and then that blog became the foundation for a book called Plastic Purge: How To Use Less Plastic, Eat Better, Keep Toxins Out Of Your Body, and Help Save The Sea Turtles!

What he found was that we use a helluva lot more plastic than we probably realize. It's in everything, some good - like medical supplies - and some bad - like plastic water bottles. While we benefit tremendously from many plastic products, there are some obvious problems - like the damage plastic does to the environment. And then there's the other problem of what's IN plastics, the chemicals that make them up.

By now, most people have heard of a substance called BPA. That's the acronym for bisphenol-A, which Mike defines in his book as "...an industrial chemical used in the production of hard, clear plastics." It showed up in everything from reusable water bottles to the linings of metal food cans to baby toys to cosmetics. In short, it was everywhere.

BPA is what's called an endocrine disrupter - these are chemicals that may have an effect on the body's endocrine system, which regulates our hormones. Research suggests endocrine disrupters can have adverse effects on development, reproduction and immunity - just to name a few. There are all kinds of other things that BPA may contribute to as well - Mike goes into those in detail in his book.

So here's this potentially dangerous chemical that's present in all kinds of things we use in our everyday lives and there's not a whole lot of regulation. The FDA and EPA haven't done much, aside from requiring plastics makers to remove BPA from baby bottles and sippy cups. And there are a lot of companies that have removed BPA from their products - like Nalgene, which makes hard plastic water bottles, and ConAgra Foods - under pressure from consumers.

But you can avoid BPA, right? Switch to glass and BPA-free containers and steer clear of foods that use lots of plastic packaging. Easy peasy. This is where the terrifying part comes in. BPA is actually found - in really high quantities - in something you handle all the time: receipts.

Receipts that use BPA technology have 250 to 1000 times more of the chemical than the amount found in a can of food, according to one study. And unlike the other items on the list of BPA-infused products, you're generally not putting these in your mouth - you're just touching them, briefly, but long enough to absorb quite a bit through your skin.

So, no. I don't want my receipt. And if you insist on it, please don't be surprised when I pick it up with a pair of tweezers.