Seraph: Wouldn't the elimination rate depend on whether the radioactive substance was ingested in pure metallic form or as a salt? I would assume that finely powdered metallic Po would be passed very quickly in the feces, but a polonium salt might be significantly absorbed by the digestive system, with less going out in the feces and more going out in the urine and sweat.

But anyway, if your main point is that the UK public health service spent a lot more money on "polonium clean-up" after the Litvinenko poisoning than was "logically necessary", then I would agree. But humans aren't Vulcans, and a lot of people in the general people have difficulty accepting that their risk from a low dose of polonium because they sat next to Litvenenko on the bus is going to "fade into the background" of the normal environmental polonium levels.