Arpad Vass, a forensic anthropologist at the Oak Ridge National Laboratory, and his colleagues have suffered the odor of rotting corpses for the past four years to isolate 30 compounds specific to buried bodies. They hope their research will eventually be used to better train “cadaver dogs” or even to make an electronic sniffing device.
Human body odor historically has a bad name, but for ORNL’s Arpad Vass, determining the chemical composition of human body odor after death could lead to the invention of a desirable “electronic nose.” Such a detector could help police more quickly find bodies buried in hidden, shallow graves.
A tool that mimics a cadaver dog’s nose is high on the wish list of law enforcement agencies. The wish is a goal for Vass, who is close to developing a superb training tool for cadaver dogs and eventually a detector of clandestine graves…
At the University of Tennessee Anthropological Research Facility (dubbed the Body Farm), Vass and his colleagues found that donated dead bodies lying on the surface or buried in shallow graves emitted more than 400 different volatile compounds. The researchers are honing in on groups of chemicals that are consistently emitted for each stage of decomposition: fresh, bloated, decayed, and skeletonized.
“We identified fluorinated compounds coming out as vapors from buried bodies,” Vass says. “Since Americans drink fluorinated water, it may be possible that, as dead bodies decompose, fluorine combines with hydrocarbon compounds, generating an odor. We’d like to test whether cadaver dogs key in on these compounds.”
At the UT facility, ORNL researchers collect vapors from a 2.5-ft-deep grave outfitted with perforated pipes, sampling ports, a video camera for visual monitoring of a body as it decomposes, and a capture hood containing a triple-sorbent trap system developed in ORNL’s Chemical Sciences Division–a metal cylinder loaded with carbon granules that bind lightweight, medium-size, and large molecules. The collected vapors are desorbed from the carbon trap and analyzed by a gas chromatograph mass spectrometer at ORNL.
“We found that a human body in a shallow grave decomposes eight times slower than a corpse left on the surface,” Vass says. “Some reasons may be that bacterial decay in the body slows down because of the lack of oxygen, and insect infestation of the body is minimal.”
If the chemicals that attract cadaver dogs can be identified, then one type of detector that ORNL researchers could build would use polymers that react with specific chemical vapors wafting by. A reaction changes each polymer’s electrical conductivity enough to produce an electronic signal. Thus, a specific group of signals from the electronic nose could alert law enforcement that a shallow grave is nearby.
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