The Linear No Threshold Hypothesis: Battling Risks Already Below Background
If the (hypothetical) risk posed by radiation from drinking water is already less than the (hypothetical) risk posed by radiation exposure from the earth's crust, cosmic rays, etc does it make any sense to spend a lot of time and money worrying about it? Only if you're hoping to gain power or money by leading to safety a "populace alarmed ... by an endless series of hobgoblins ..." And when it comes to instigating and propagating public health panics two things work best when conjuring hobgoblins: 1) recasting one side of a normal distribution of disease into a "disease cluster"; and, 2) the linear no threshold (LNT) hypothesis.
As we recently noted, there's a bill in Congress that rejects (or perhaps implicitly repeals) the stochastic nature of biochemistry and aims for a future in which every community has either average or above average health outcomes. The bill is a response to the fact that none of the hundreds of cancer cluster investigations, conducted at enormous expense, have produced evidence to support the charges brought against the various industrial chemical hobgoblins claimed to have been responsible. About the only cluster to actually be a non-random event, that of childhood leukemia in Fallon, NV, turned out to be due to a virus. Outraged activists are lobbying hard to ensure that nothing other than putatively man-made causes can be investigated in the future.
A similar codification of the LNT hypothesis may be needed to rescue it from obsolescence. Not only is the hypothesis wholly evidence-free, there's sound evidence to support the claim that in the case of radiation low levels cause adaptive responses that make you less likely to develop cancer. An excellent summary of the evidence against LNT and for adaptation is available free online in "Human Health and the Biological Effects of Tritium in Drinking Water: Prudent Policy Through Science - Addressing the ODWAC New Recommendation". It's a discussion about whether or not people ought to worry about tritium in drinking water that produces less radiation than the ground on which we walk and the buildings in which we live. The answer is "no". To paraphrase one of my son's favorite Chuck Norris jokes (don't know how or why these suddenly became popular) 'before getting in bed, hobgoblins check their closets for Canadian health scientists'.
