Perhaps the most common manifestation of our urge to be "green" these days is recycling.

After all, it makes intuitive sense to get the most use out of any given object. And when it’s applied, recycling generally works as designed, turning waste paper into fresh paper or old aluminum cans into new ones.

But how much of our waste really gets recycled? According to the EPA, roughly one third of our total trash is reused, a percentage that has grown every year since the first Earth Day in 1970--and really took off in the 1990s.

The most recycled product? It's not aluminum cans--only half are recycled. Or even office paper, at more than 70 percent. It's the lead acid batteries from your car. More than 99 percent of such batteries wind up recycled, keeping toxic lead out of landfills and waterways.

That's a good thing as long as the recycling is done properly. Unfortunately, dismantling old lead acid batteries incorrectly is one of the 10 worst pollution problems for the globe, according to the Blacksmith Institute. And that's no way to celebrate Earth Day.

—David Biello