>>
> In terms of alphas specifically, I'd say under the threshold of detection
> is the way to be. Alphas are nasty things to be eating.

Forgive my ignorance but alpha particles can be blocked with a piece of
paper, they are nothing but helium nuclei. They have the propensity of
ionising cells, as they are very heavy. In order to get damage from them
you need to ingest them. Geiger counters are probably a bad tool for
detecting them.

Beta particles and gamma radiation are a different kettle of fish, but
they ionise much less and need to be administered in large doses. Eating
Ceasium and Strontiom is bad, as those elements substitute calcium in your
bones and are then permanent radiation sources.

Granite is a strong source of beta radiation, very few people hesitate to
touch granite though.

In my opinion eating, or drinking, something with a large dose of
chemicals on it is much worse than radiation. For instance, there was a
time when teas from China and Ceylon were very high in DDT content, due to
crop spraying. Don't know how the situation is now. Dioxins would be
another major worry, but not radiation.

Just my tuppence

JB