Worldwide dose commitment from radioactive fallout from nuclear tests prior to 1970*

source isotope half-life due to bone surfaces (mGy)

external radiation short lived

(e.g., iodine-131) 8 days 360

longer lived

(e.g., cesium-137) 30 years 360

internal radiation strontium-89 and -90 50 days 1,310

cesium-137 28 years 210

carbon-14** 5,730 years 160

total 2,400

*North temperate zones; doses calculated for bone surface.

**Calculated to year 2000 only.