Pink Tentacle has a post about Pluto-kun, created by Japan's Power Reactor and Nuclear Fuel Development Corporation in the 1990s. The helium-voiced fellow stars in a "pro-nuclear PR cartoon entitled 'Pluto-kun, Our Reliable Friend.' The aim of the animated film, which features the company mascot Pluto-kun, is to dispel some of the fears surrounding plutonium."
[4:00] Misconception #2 — Pluto-kun addresses the fear that plutonium is deadly and causes cancer. Plutonium's danger to the human body stems from the alpha radiation it emits. Because alpha radiation is relatively weak, it does not penetrate the skin, and plutonium is not absorbed into the body if it comes into contact with skin. He explains that you would not die instantly if you were to drink plutonium. If swallowed, the vast majority simply passes through the digestive tract without being absorbed. If it enters the blood stream (through a cut, for example) it cannot be removed easily from the body. It accumulates in the lymph nodes before ending up in the bones or liver, where it continues emitting alpha radiation. Plutonium can also get into the liver or bones if it is inhaled into the lungs. It is important not to breathe it in or allow it to enter the blood stream.
[6:00] No human is ever known to have died because of inhaling or ingesting plutonium.
[7:00] Pluto-kun explains what would happen if criminals dumped plutonium into a reservoir that provides our drinking water. Plutonium is heavy and it does not dissolve easily in water, so most of it would sink to the bottom. Even if you were to drink plutonium-laced water everyday, the vast majority of it would simply pass through the digestive system without being absorbed by the body.