‘Contamination,’ ‘exposure’ differ

Tokyo

Some news stories do not seem to distinguish between “contamination” and “exposure” when referring to radioactive matter leaking from the Fukushima No. 1 nuclear power plant. A May 11 Kyodo dispatch (“Evacuees briefly return home in no-go zone“) stated that evacuees returning to Kawauchi in order to retrieve their personal belongings wore “suits, masks, goggles and gloves for protection against radiation exposure.”

While such measures will likely prevent “contamination” by alpha and beta particles, they offer no protection from “exposure” to gamma rays emitted by radioactive matter. The fact is that the temporary returnees were exposed to increased levels of radiation during their brief foray into the “hot zone.”

Gamma rays would have gone right through their protective gear; hence the reported two-hour limit.

While lead plates will stop gamma rays in their tracks, it’s not something that is readily available in your local hardware store. Avoidance seems to be the only realistic protection from radiation exposure to gamma rays, including staying indoors in case of a nuclear emergency.

The opinions expressed in this letter to the editor are the writer’s own and do not necessarily reflect the policies of The Japan Times.

william ireton