The Low-Level Radiation Puzzle

In the Bulletin of the Atomic Scientists this month, "...guest editor, Jan Beyea, an environmental scientist who has opposed nuclear reactors for decades and worked on epidemiological studies at Three Mile Island, takes a hard look at the power industry.

"Dr. Beyea challenges a concept adopted by American safety regulators about small doses of radiation. The prevailing theory is that the relationship between dose and effect is linear – that is, that if a big dose is bad for you, half that dose is half that bad, and a quarter of that dose is one-quarter as bad, and a millionth of that dose is one-millionth as bad, with no level being harmless.

"The idea is known as the “linear no-threshold hypothesis,’’ and while most scientists say there is no way to measure its validity at the lower end, applying it constitutes a conservative approach to public safety.

"...Dr. Beyea contends that small doses could actually be disproportionately worse.

"[He] proposes that doses spread out over time might be more dangerous than doses given all at once. He suggests two reasons: first, some effects may result from genetic damage that manifests itself only after several generations of cells have been exposed, and, second, a “bystander effect,” in which a cell absorbs radiation and seems unhurt but communicates damage to a neighboring cell, which can lead to cancer. New York Times