Strontium 90

In their paper published in 1957, “Strontium-90 in Man,” the scientists J. Laurence Kulp, Walter R. Eckelmann, and Arthur R. Schulert argued that the radioactive isotope Strontium 90 could likely be detected in every human on earth. They concluded that this was due to the testing of nuclear weapons that had produced fallout (radioactive elements that “fall out” of the atmosphere) and entered human beings via dairy products and food staples the human body. The study led to widespread concern about the consequences of global radioactive pollution, with protests inspiring the Limited Nuclear Test Ban Treaty of 1963.

Further Readings: 
  • Kulp, J. Laurence, Walter R. Eckelmann and Arthur R. Schulert. "Strontium-90 in Man." Science 8 (1957): 219–225.