Tracing Marijuana Back to its Pot

Chemists at the University of Alaska Fairbanks are using advanced chemical analyses to help pin point the source of marijuana confiscated in the coming years.  The method they are currently developing relies on subtle changes in the atomic composition of different elements, namely oxygen, carbon, nitrogen, and hydrogen.  

These elements naturally exist as 'heavier' and 'lighter' forms, referred to as stable isotopes (compared to radioisotopes that decay and release energy).  As the plants grow and use these elements to make leaves, stems, and roots, they simultaneously incorporate an imprint of the heavy and light forms of the elements.  The ratio of these heavy and light forms might tell the chemists where the plants were grown to a reasonable degree of certainty.

The lab is being provided with marijuana samples from plants confiscated by the federal Drug Enforcement Administration and the Alaska Bureau of Alcohol and Drug Enforcement.