Specific activity converter
Convert radioactivity per unit mass between becquerels and curies per gram or kilogram, as soil, food and isotope reports use.
That's 1.42× as radioactive as a banana, while granite is 5.4× more radioactive.
What it means
How radioactive is that?
Activity says how many atoms decay per second, not the dose they give; that depends on the isotope and the exposure.
Every unit
That activity in every unit
Learn
Three things worth knowing
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pCi/g × 37
1 pCi/g = 37 Bq/kg = 0.037 Bq/g. The US cleanup level for radium in soil, 5 pCi/g, is 185 Bq/kg.
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The Curies’ radium
The curie was set in 1910 as the activity of one gram of radium-226, which Marie and Pierre Curie had isolated. The becquerel, one decay per second, replaced it in SI in 1975.
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Bq/kg vs Bq/g
A factor of 1,000 separates them: 100 Bq/kg in soil is 0.1 Bq/g, not 100.
Shortcuts
Popular radioactivity conversions
Background
About specific activity
Specific activity is radioactivity per mass: how many atoms decay each second in a gram or kilogram of material. Soil and food labs report Bq/kg in Europe and pCi/g in the US; isotope suppliers quote Ci/g or GBq/mg.
One becquerel is one decay per second; one curie is 37 billion, the activity of a gram of radium.