In addition to estimating the postmortem interval (PMI) insects that feed on carcasses may also represent a reliable specimen for toxicological analyses (entomotoxicology). This is especially so in the absence of tissues and fluids normally taken for such purposes. There are many studies involving the extraction of drugs and chemicals from blowfly larvae (Diptera: Calliphoridae) associated with a corpse, but only a few papers have focused on the analyses of gunshot residues (GSR, generally lead (Pb), barium (Ba) and antimony (Sb)) detection in blowfly larvae. Mostly the detection of GSR elements in blowfly larvae has been conducted using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The focus of these studies was on the detection of Pb, Ba and Sb in larvae as pure chemical elements. The aim of this study was to determine if there are any chemical and/or morphological changes of Pb, Ba and Sb following the uptake of GSR by larvae of Calliphora vomitoria (L.) (Diptera: Calliphoridae). Five pieces of swine meat (500g and 16x16x7cm each) were shot using a Beretta 98f gun. One piece was not shot (control). The ammunitions used were 9x21mm Winchester with Pb contained in the primer and 9x21mm Fiocchi Leadless no Pb in the primer, and two shooting distances of 2 and 40cm. 200 C. vomitoria eggs were placed on each piece of meat as close as possible to the shot hole and allowed to develop until the third instar. 500mg of larvae were analyzed by ICP-MS while a total amount of 50 stubs each one prepared with the stomach contain of a single larva of each experimental groups were analyzed using two different SEMs (Leica StereoScan 420 and Zeiss EVO 50XVP with variable pressure) both coupled with Energy Dispersive X-ray microanalysis (SEM-EDX). The gloves and the hands of the gunman were also analyzed. This study demonstrated the presence of actual GSR particles which was obtained by using variable pressure SEM. The EDX analyses showed that GRS particles were in the stomach content of those larvae feeding on the meat shot at close range (2 cm).
Detection of Gunshot Residues (GSR) in blowfly larvae using Scanning Electron Microscopy equipped with Energy Dispersive X-ray microanalysis (SEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP- MS)
MARTRA, Gianmario;PAZZI, Marco;VINCENTI, Marco;
2014-01-01
Abstract
In addition to estimating the postmortem interval (PMI) insects that feed on carcasses may also represent a reliable specimen for toxicological analyses (entomotoxicology). This is especially so in the absence of tissues and fluids normally taken for such purposes. There are many studies involving the extraction of drugs and chemicals from blowfly larvae (Diptera: Calliphoridae) associated with a corpse, but only a few papers have focused on the analyses of gunshot residues (GSR, generally lead (Pb), barium (Ba) and antimony (Sb)) detection in blowfly larvae. Mostly the detection of GSR elements in blowfly larvae has been conducted using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The focus of these studies was on the detection of Pb, Ba and Sb in larvae as pure chemical elements. The aim of this study was to determine if there are any chemical and/or morphological changes of Pb, Ba and Sb following the uptake of GSR by larvae of Calliphora vomitoria (L.) (Diptera: Calliphoridae). Five pieces of swine meat (500g and 16x16x7cm each) were shot using a Beretta 98f gun. One piece was not shot (control). The ammunitions used were 9x21mm Winchester with Pb contained in the primer and 9x21mm Fiocchi Leadless no Pb in the primer, and two shooting distances of 2 and 40cm. 200 C. vomitoria eggs were placed on each piece of meat as close as possible to the shot hole and allowed to develop until the third instar. 500mg of larvae were analyzed by ICP-MS while a total amount of 50 stubs each one prepared with the stomach contain of a single larva of each experimental groups were analyzed using two different SEMs (Leica StereoScan 420 and Zeiss EVO 50XVP with variable pressure) both coupled with Energy Dispersive X-ray microanalysis (SEM-EDX). The gloves and the hands of the gunman were also analyzed. This study demonstrated the presence of actual GSR particles which was obtained by using variable pressure SEM. The EDX analyses showed that GRS particles were in the stomach content of those larvae feeding on the meat shot at close range (2 cm).
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