Applying Carbon-14 Dating to Recent Human Remains
Measuring carbon-14 levels in human tissue could help forensic scientists determine age and year of death in cases involving unidentified human remains.
Philip Bulman with Danielle McLeod-Henning
Archaeologists have long used carbon-14 dating (also known as radiocarbon dating) to estimate the age of certain objects. Traditional radiocarbon dating is applied to organic remains between 500 and 50,000 years old and exploits the fact that trace amounts of radioactive carbon are found in the natural environment. Now, new applications for the technique are emerging in forensics, thanks to research funded by NIJ and other organizations. In recent years, forensic scientists have started to apply carbon-14 dating to cases in which law enforcement agencies hope to find out the age of a skeleton or other unidentified human remains.
The new method is based on the fact that over the past 60 years, environmental levels of radiocarbon have been significantly perturbed by mid-20th-century episodes of above-ground nuclear weapons testing. Before the nuclear age, the amount of radiocarbon in the environment varied little in the span of a century. In contrast, from 1955 to 1963, atmospheric radiocarbon levels almost doubled. Since then they have been dropping back toward natural levels. Over the past six decades, the amount of radiocarbon in people or their remains depends heavily on when they were born or, more precisely, when their tissues were formed.