Strontium unit
Encyclopedia
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; as 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 pico
curie
from strontium-90 per gram
of calcium (37 becquerel
s 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 to have three to four strontium units.
The strontium unit was formerly known briefly as the sunshine unit, a term promoted by the United States Department of Defense
until public ridicule brought about its disuse. (Among the sources of this outcry was a George Carlin
performance, released on the CD "Parental Advisory: Explicit Lyrics
", during a passage on governmental euphemisms for dangerous or unethical activities: "The Pentagon has actually begun measuring nuclear radiation in something they call 'sunshine units'!")
Strontium
Strontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when exposed to air. It occurs naturally in the minerals celestine and...
-90, a radionuclide
Radionuclide
A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma...
found in nuclear fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...
, in a subject's body; as the human
Human
Humans are the only living species in the Homo genus...
body absorbs strontium as if it were calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
, incorporating it into the skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, its presence is very common. One strontium unit is equal to one pico
Pico
Pico- is a prefix in the metric system denoting a factor of 10−12 or .Derived from the Italian piccolo, meaning small, this was one of the original 12 prefixes defined in 1960 when the International System of Units was established....
curie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...
from strontium-90 per gram
Gram
The gram is a metric system unit of mass....
of calcium (37 becquerel
Becquerel
The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...
s per kilogram) in the subject's skeleton.
The United States National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
holds that the maximum safe measure of strontium-90 in a person is one hundred strontium units (3700 Bq/kg). The average American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
is estimated to have three to four strontium units.
The strontium unit was formerly known briefly as the sunshine unit, a term promoted by the United States Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
until public ridicule brought about its disuse. (Among the sources of this outcry was a George Carlin
George Carlin
George Denis Patrick Carlin was an American stand-up comedian, social critic, actor and author, who won five Grammy Awards for his comedy albums....
performance, released on the CD "Parental Advisory: Explicit Lyrics
Parental Advisory: Explicit Lyrics
-Track listing:The order of the album is different from the HBO special.# Offensive Language – 4:48# I Ain't Afraid of Cancer – 1:59# Some People Are Stupid – 2:28# Rape Can Be Funny – 3:52# Feminist Blowjob – 7:28# Good Ideas – 2:29...
", during a passage on governmental euphemisms for dangerous or unethical activities: "The Pentagon has actually begun measuring nuclear radiation in something they call 'sunshine units'!")