By David J. Tenenbaum
Between 1945 to 1980, testing atomic bombs in the atmosphere was a dangerous experiment in spreading carcinogens literally to the four winds. But little noted outside science, the radioactive elements created in the tests became radiologic calendars waiting to be used in any organism that incorporates carbon.
Carbon-14 was one of the many radioactive isotopes formed during the instant of nuclear fission and fusion. An atom of C-14 has two more neutrons than the common C-12.
Because both isotopes are chemically identical, they enter the same biological reactions. And since C-14 decays over time, the level in the sample can be traced back to the high level of C-14 in the air during the atom-bomb tests. The result shows when a living animal was eating food contaminated with bomb fallout.
This technique, called carbon dating, was traditionally used to date archeological sites from long before the nuclear era. Now, the “bomb-pulse” of radiation allows organisms from the modern era to be dated, which could one day identify illegal ivory.
A study published this week shows the potential for carbon-dating teeth and ivory tusks from elephants. Thure Cerling, a professor of geology, geophysics and biology of the University of Utah, an expert on carbon dating, was interested in dating ancient bone and ivory samples from Kenya. More....