Strontium unit Strontium unit The strontium unit is a unit used to measure the amount of radioactivity from strontium-90, a radionuclide found in nuclear fallout, in a subject's body. Since the human body absorbs strontium as if it were calcium, incorporating it into the skeleton, its presence is very common. One strontium unit is equal to one picocurie from strontium-90 per gram of calcium (37 becquerels per kilogram) in the subject's skeleton. The United States National Academy of Sciences holds that the maximum safe measure of strontium-90 in a person is one hundred strontium units (3700 Bq/kg). The average American is estimated
International System of Units and derived units may be used to express other derived units. For example, the SI unit of force is the newton (N), the SI unit of pressure is the pascal (Pa)—and the pascal can be defined as one newton per square metre (N/m). Prefixes are added to unit names to produce multiples and sub-multiples of the original unit. All of these are integer powers of ten, and above a hundred or below a hundredth all are integer powers of a thousand. For example, "kilo-" denotes a multiple of a thousand and "milli-" denotes a multiple of a thousandth, so there