Does anyone know if this is true, about 1 pound of Plutonium???

I was watching a video on the internet, and at approx 23:25, it states that just 1 pound of Plutonium dust in the atmosphere would kill all of the plants and animals on Earth, and yet there is 50 pounds of Plutonium in satellites.

Surely this can't be true?

link to vid...

video.google.com...#

That is kind of scary to think about that one might reenter the atmosphere and explode, breaking apart and spreading the dust. But then, there are countless ways the world could come to an end. Personally, I think the Earth as a whole is protected by unseen forces. That doesn't mean that a whole city or even continent could vanish. I mean, we've have disasters before and will continue to have them. There is evidence that the Earth has survived meteor strikes, ice ages, and other such things. I believe people and animals can adapt over time to many things. Animals even live where Chernobyl happened, and have adapted to the radiation. Maybe people could do so as well, over many generations, becoming adapted to the levels of radiation.

The plutonium that could kill the earth and the plutonium that powered the satellites are two different isotopes. Plutonium 238 isn't as dangerous, which is why it was used as a power source.