Understandably, there has been quite a bit of discussion, and controversy, regarding possibly false Fukushima meltdowns fallout detections because of the phenomenon called radon progeny or radon daughters. The Canadian Coalition for Nuclear Responsibility is one of the few readily available resources that addresses this in layman’s terms in “Introducing the Radon Progeny (formerly called Radon Daughters)“:
An excellent CCNR chart, above, is accompanied by copy explaining the process:
The chart below lists all of the decay products of radon gas (radon-222) in their order of appearance. They are called the “radon progeny” (formerly “radon daughters”). Each radioactive element on the list gives off either alpha radiation or beta radiation — and sometimes gamma radiation too — thereby transforming itself into the next element on the list. Lead-206, the last element on the list, is not radioactive. It does not decay, and therefore has no half-life.
When radon gas is allowed to build up in an enclosed space, such as a mine shaft or basement, the radioactive hazard increases enormously because of the build-up of radon progeny. Conversely, when radon gas migrates through the atmosphere, the solid radon progeny are deposited on the soil and water below, entering into the food chain and hence the bodies of birds, animals, fish and insects.
Looking at the following readings, one might wonder just how harmful radon progeny possibly originating from Fukushima Japan’s triple meltdowns, melt-throughs and melt-outs is:
5:00PM SPOT CHECK SANTA MONICA RAIN: ~118 CPM^ sustained or ~264% of normal higher (Videotaped)
4:55pm 10-minute INTERIOR COMBINED average: 44.7 CPM
4:55pm 10-minute INTERIOR average: 45.1 CPM (Inspector 1)
4:55pm 10-minute INTERIOR average: 44.3 CPM^ (Inspector 2)