Characterization of the volatile organic compounds present in the headspace of decomposing animal remains, and compared with human remains
ABSTRACT Human Remains Detection (HRD) dogs can be a useful tool to locate buried human remains because they rely on olfactory rather than visual cues. Trained specifically to locate deceased humans, it is widely believed that HRD dogs can differentiate animal remains from human remains. This study analyzed the volatile organic compounds (VOCs) present in the headspace above partially decomposed animal tissue samples and directly compared them with results published from human tissues using established solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) methods. Volatile organic compounds present in the headspace of four different animal tissue samples (bone, muscle, fat and skin) from each of cow, pig and chicken were identified and compared to published results from human samples. Although there were compounds common to both animal and human remains, the VOC signatures of each of the animal remains differed from those of humans. Of particular interest was the difference between pigs and humans, because in some countries HRD dogs are trained on pig remains rather than human remains. Pig VOC signatures were not found to be a subset of human; in addition to sharing only seven of thirty human-specific compounds, an additional nine unique VOCs were recorded from pig samples which were not present in human samples. The VOC signatures from chicken and human samples were most similar sharing the most compounds of the animals studied. Identifying VOCs that are unique to humans may be useful to develop human-specific training aids for HRD canines, and may eventually lead to an instrument that can detect clandestine human burial sites.
- SourceAvailable from: Moshe (Mike) Dalva
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- "Methods to expedite locating clandestine graves have been developed where surface clues are lacking and where the content of a potential grave is unknown              . Changes in soil properties have been examined [5,7,10,13,15–17] and volatile chemical compounds and odors that could indicate the presence of buried remains        have been identified. "
ABSTRACT: Twelve pig carcasses were buried in single, shallow and deep (30 and 90 cm, respectively) graves at an experimental site near Ottawa, Ontario, Canada, with three shallow and three deep wrapped in black plastic garbage bags. An additional six carcasses were left at the surface to decompose, three of which were bagged. Six reference pits without remains were also dug. The objective of this three-year study was to examine the biogeochemistry and utility of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) in grave detection and whether grave depth or cadaver condition (bagged versus bare) affected soil pore air concentrations and emission of the three gases. Graves showed significantly higher (α = 0.05) concentrations and surface fluxes of N2O and CO2 than reference pits, but there was no difference in CH4 between graves and reference pits. While CH4 decreased with depth in the soil profiles, N2O and CO2 showed a large increase compared to reference pits. Shallow graves showed significantly higher emissions and pore air concentrations of N2O and CO2 than deep graves, as did bare versus bagged carcasses.Forensic Science International 12/2014; 247. DOI:10.1016/j.forsciint.2014.12.002 · 2.12 Impact Factor
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ABSTRACT: A fast and simple screening procedure using solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) in full-scan mode for the determination of volatile organic compounds (VOC) is presented. The development of a fast and simple screening technique for the simultaneous determination of various volatiles is of great importance, because of their widespread use, frequent occurrence in forensic toxicological questions and the fact that there is often no hint on involved substances at the crime scene. To simulate a screening procedure, eight VOC with different chemical characteristics were chosen (isoflurane, halothane, hexane, chloroform, benzene, isooctane, toluene and xylene). To achieve maximum sensitivity, variables that influence the SPME process, such as type of fiber, extraction and desorption temperature and time, agitation and additives were optimized by preliminary studies and by means of a central composite design. The limits of detection and recoveries ranged from 2.9 microg/l (xylene) to 37.1 microg/l (isoflurane) and 7.9% (chloroform) to 61.5% (benzene), respectively. This procedure can be used to answer various forensic and toxicological questions. The short time taken for the whole analytical procedure may make its eventual adoption for routine analysis attractive.Journal of Mass Spectrometry 04/2010; 45(4):391-7. DOI:10.1002/jms.1723 · 2.71 Impact Factor
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ABSTRACT: Insects, specifically blowflies (Diptera: Calliphoridae), are often the first to arrive at the scene of a crime and provide crucial information including post mortem interval and whether the body has been moved from its original location, amongst other useful information. History tells us that insects’ association with death was recognised as early as documentation of events could be made (Greenberg and Kunich 2005; Benecke 2001). As we continue to understand this link dramatic advances, such as those mentioned throughout this book, are continually being made in the field of Forensic Entomology in relation to different situations, environments, as well as the incorporation of new approaches. While the methods used to determine the post-mortem interval (PMI), such as larval age determination and arthropod succession, are continually being used and further investigated the mechanism which attracts the flies to the body has not been fully explored. It is well documented that female flies will lay eggs near wounds or natural orifices soon after death so that the larvae may develop in a moist area (Smith 1986; Anderson 2001). However, determining exactly what attracts insects to a decomposing body and cause behavioural responses such as mating and laying eggs (oviposition), has still not been identified.01/2010: pages 205-221;