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Dogs can detect traces of gasoline down to one billionth of a teaspoon

Posted on May 13, 2020 | Leave a comment

Eza waiting for her handler, Jeff Lunder, to initiate a search of a residential structure fire to check for any indication of ignitable liquid. Photo credit: Joe Towers

Trained dogs can detect fire accelerants such as gasoline in quantities as small as one billionth of a teaspoon, according to new research by University of Alberta chemists. The study provides the lowest estimate of the limit of sensitivity of dogs’ noses and has implications for arson investigations.

“During an arson investigation, a dog may be used to identify debris that contains traces of ignitable liquids—which could support a hypothesis that a fire was the result of arson,” explained Robin Abel, graduate student in the Department of Chemistry and lead author of the study. “Of course, a dog cannot give testimony in court, so debris from where the dog indicated must be taken back to the laboratory and analyzed. This estimate provides a target for forensic labs when processing evidence flagged by detection dogs at sites of potential arson.”

The study involved two dog-and-handler teams. The first was trained to detect a variety of ignitable liquids, while the other was trained primarily with gasoline. Results show that the dog trained on a variety of liquids performed well detecting all accelerants, while the dog trained on gasoline was not able to generalize to other accelerants at extremely low concentrations.

Another outcome of the study was the development of a protocol that can be used to generate suitable ultra-clean substrates necessary for assessing the performance of accelerant-detection dogs for trace-level detection.

“In this field, it is well-known that dogs are more sensitive than conventional laboratory tests,” said James Harynuk, associate professor of chemistry and Abel’s supervisor. “There have been many cases where a dog will flag debris that then tests negative in the lab. In order for us to improve laboratory techniques so that they can match the performance of the dogs, we must first assess the dogs. This work gives us a very challenging target to meet for our laboratory methods.”

So, just how small a volume of gasoline can a dog detect?

“The dogs in this study were able to detect down to one billionth of a teaspoon—or 5 pL—of gasoline,” added Harynuk. “Their noses are incredibly sensitive.”

This research was conducted in collaboration with Jeff Lunder, vice president of the Canine Accelerant Detection Association (CADA) Fire Dogs. Funding was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC).

The paper, “A novel protocol for producing low-abundance targets to characterize the sensitivity limits of ignitable liquid detection canines,” was published in Forensic Chemistry (doi: 10.1016/j.forc.2020.100230).

Source: University of Alberta media release

Making cadaver dogs more efficient

Posted on August 23, 2014 | Leave a comment

A PhD student at the University of Huddersfield (UK) is conducting research to make cadaver and victim recovery (VR) dogs more efficient in their work.

These special dogs are probably not as well known as other working and assistance dogs, because the work they are associated with isn’t pleasant. They are used to recover dead bodies (victims of suicide or murder), plus to find body parts and fluids that can help police track down the perpetrators of crime. VR dogs were used to identify body parts from victims of the 7/7 bombings in London, for example.

Kip, a victim recovery dog from the South Yorkshire Police Department, has been helping in the research (photo courtesy of University of Huddersfield)

In her experiments using Kip, researcher Lorna Irish set out a sequence of vials containing different odours that she had prepared in the lab. These chemicals are known to be produced from the body decomposition process. Alongside these test chemicals were “positive controls” associated with human cadavers, such as human bone – from archaeological sources – and pork at various stages of decomposition. Pork meat is used for training such dogs due to the ethical and legal problems associated with obtaining human material. It is thought to be the closest analogue for human flesh for decomposition studies. There were also “negative controls” – smelly chemicals not associated with decomposition, such as clove oil.

Kip correctly identified the odours derived from decomposition and was not distracted by the “negative control” smells. It was a successful demonstration. In the field, VR dogs can sometimes be distracted by “false positives”, such as dead animals, or even mushrooms, explained Lorna. If she can arrive at a greater understanding of the chemistry of odours from human cadavers, then VR dogs can be extra efficient.

“If you train a dog with a chemical that is specific to human decomposition, you can enhance its ability. It is not about changing the way the dogs do it, but improving it,” she added.

Irish is approximately half-way through the research for her degree; she is traveling widely across the UK to observe dog training methods.

Source: University of Huddersfield media statement