Going Green - Vocabulary

As some of you have seen, I'm participating in the Earth Hour 2 Earth Day Challenge. As part of that, I've said I'll post things here to help educate you and me about ways to go green in our lives. Since I'm one of those that always seems behind on the vocabulary of things, I decided to start out by posting a vocab lesson. Don't worry, there won't be a spelling test or anything later!

So, today's term is....

Half-Life : The time it takes for a half portion of a substance (any substance, but the term is typically used in reference to drugs, radioactive materials or pesticides) to be eliminated or disintegrated by natural processes from an organism or ecosystem. Some simple examples: The half-life of water in a human body is about 7 to 10 days; the half-life of lead in animal bones is about 10 years.

So now we'll know what they mean when they say the half-life of something in a landfill is x amount of time!