The Science of Busting Illegal Ivory
"It was cool."
Image: Flickr/Benh LIEU SONG
A technique called radiocarbon dating helped Canadian authorities convict a Toronto-based auction house and its owner this week for attempting to sell illegal ivory tusks. It's only the sixth time in the world that the approach has been used to support a conviction for the sale of ivory—and a first in Canada.
Any ivory taken from an animal killed after 1975 is illegal in Canada and in any of the 179 other countries that signed the Convention on International Trade in Endangered Species of Wild Fauna and Flora—an international treaty that controls the sale of endangered plant and animal species.
In November of 2013, Environment Canada, the agency responsible for ensuring Canada complies with international regulations on the sale of illegal animal and plant products from endangered species, learned that Five Star Auctions and Appraisals in Toronto, Ontario, was in possession of two carved ivory tusks each roughly two and a half feet in length, according to a statement.
Officials seized the tusks and then mailed them to Laval University in Quebec City, where scientists there combusted a sample and turned it into ultra-pure CO2 gas. The gas was then shipped to the University of California (Irvine)'s Keck lab, where scientists there turned the gas into graphite and analyzed it. The data from their analysis was then sent back to the Laval lab. At Columbia, Kevin Uno analyzed their results and compiled the final report.
A process called radiocarbon dating was used to measure the amount of radiocarbon—a radioactive isotope of carbon, which is found in all living organisms on Earth—remaining in the collected samples. Because radiocarbon decays at a known rate, the amount of radiocarbon in a sample is a good indicator of a sample's age.
The use of radiocarbon dating to determine whether ivory for sale was obtained after bans on its sale were put in place is a relatively recent practice. In 2013, Uno and his colleagues at at Columbia devised a technique that relies on what's known as the "bomb curve" to determine the age of the tusks. The bomb curve refers to the exploding levels of radiocarbon found in the earth's atmosphere following above-ground nuclear tests carried out during the '50s and '60s. Using the high levels present during this period as a benchmark, researchers can determine whether the sample came from before this time or after.
"When I received the tusks, I had to subsample them because they were pretty big pieces," said Guillaume Labrecque, head technician of Laval's radiocarbon dating lab. "Ivory is processed like a bone sample. The bone is a different process than a regular, organic sample. To subsample it, I took a grinding bit and grinded the tusk to get the fine ivory powder. I then extracted the collagen from the ivory powder and after that, the process was like an ordinary radiocarbon sample [the combustion and subsequent purification of the resulting CO2 gas]."
"It was pretty nice," Labrecque said of being the first scientist in Canada to radiocarbon date a tusk to convict sellers of ivory. "I hope to do it again. It was cool."
The lab results showed that the tusks were from elephants killed between 1977 and 1978. The company and its director, Chun Al Jin, were charged for violating the Wild Animal and Plant Protection and Regulation of International and Interprovincial Trade Act (WAPPRIITA), and pleaded guilty last week. Both Jin and Five Star Auctions were fined $9,375, for a total of $18,750.
When Motherboard contacted Five Star Auctions and Appraisals, a representative declined to comment. A follow-up request made via email was ignored.
In a bit of a cruelly ironic twist, radiocarbon dating was recently used to determine that humans are likely not to blame for the extinction of the wooly mammoth—an ancestor of today's elephants—since they were well on their way to dying out long before humans arrived.
According to estimates from the University of Washington's Center for Conservation Biology, an estimated 50,000 elephants are being killed annually for their ivory. Between 1979 and 1987, according to the center, the population of African elephants plummeted from more than one million to approximately 500,000. Conservation efforts that focus on figuring out how local communities can work to preserve the elephant—which often really means, "How can we make money from elephants without killing them?"—are well underway, yet rampant poaching continues.
At least, in this one case, science was able to help bring the merchants of poached ivory to justice in Canada.
Correction: A previous version of this article stated that Environment Canada mailed the tusks to Laval University and the University of Columbia, leaving out the University of California (Irvine)'s contribution to the work. Moreover, only purified CO2 from the tusks was sent to Irvine and Columbia. These inaccuracies have been corrected. A short description of radiocarbon sample processing was also added.