That means the atmospheric bomb testing gave cancer to 44 billion people (10 metric tons released). The alpha radiation released by Pu239 is stopped by a piece of paper or a few inches of air.
nice try. Pu239 plutonium a fission byroduct, has a halflife of 24,110 years.
It has been estimated that a pound (454 grams) of plutonium inhaled as plutonium oxide dust could give cancer to two million people.
Apples and oranges. marktwain is writing about the hazard from ionizing radiation. You can sit next to a chunk of Pu and it will not harm you much from the alpha emission. You'd be better off swallowing a gram of Pu than a gram of arsenic.
You are writing of metal toxicity and alpha emission in the lungs. Pu dust in the lungs is a bad place for alpha emitters, causing radiation induced cancers. Pu is also a toxic metal on its own, able to be taken up by cells.
Now compare Pu to polonium-210 with a half life of 140 days. It too is an alpha emitter, but at a much higher rate than Pu. It also gets taken up by cells, but is not chemically toxic. The alpha emission is spread throughout your body and you die from radiation poisoning.
The best way to get rid of Pu is to consume it in a reactor. But society doesn't want nations accumulating Pu-239. The next best way is to stick in a cask and store underground, the best place would be a subduction zone (but tricky).