strontium 90

American  

noun

Chemistry.

1. a harmful radioactive isotope of strontium, produced in certain nuclear reactions and present in their fallout.

---

strontium 90 Scientific  

1. A radioactive isotope of strontium having a mass number of 90 and a half-life of 28 years. Strontium 90 is the most dangerous component of the fallout from nuclear explosions because it is easily absorbed by the body. It is also used in medicine to treat cancer.

---

Etymology

Origin of strontium 90

First recorded in 1950–55

Example Sentences

See Examples For:

strontium 90

He found his political voice when he encountered the indifference of government authorities to the high levels of strontium 90 in the atmosphere from atomic tests.

From New York Times ● Oct. 1, 2012

The teeth were sent to the laboratory at Washington University, which tested them for strontium 90, one of more than 100 chemicals created in nuclear explosions and reactors.

From New York Times ● Jan. 10, 2011

During a second testing phase, it found a 50 percent decline in strontium 90 in children born in 1968, compared with those born five years earlier, immediately after the treaty went into effect.

From New York Times ● Jan. 10, 2011

"It took the AEC three years to acknowledge that strontium 90 appeared in milk and was a hazard to human health," says Biochemist H. Peter Metzger.

From Time Magazine Archive

Reason: cesium 137 and strontium 90, two radioactive particles spewed by the blaze, decay very slowly.

From Time Magazine Archive