Extraction of gunshot residues from the larvae of the forensically important blowfly Calliphora dubia (Macquart) (Diptera: Calliphoridae)

Whole body concentrations of lead (Pb), barium (Ba) and antimony (Sb) were determined in larvae of the blowfly Calliphora dubia (Macquart) (Diptera: Calliphoridae) removed from a piece of beef shot and contaminated with gunshot residue and compared with the concentrations detected within larvae feeding on a control piece of beef. Whole larvae were taken into solution and analysed using inductively coupled plasma-mass spectrometry (ICP-MS). Significantly higher concentrations of Pb, Ba and Sb were detected within the larvae feeding on the shot piece of beef compared with larvae that were feeding on the control piece of beef. Initial results indicate that the concentrations of Pb and Sb within the larvae decrease as the duration of feeding increases, whereas Ba concentrations appear to increase, suggesting a bioaccumulation of Ba within the larvae. The second part of this experiment investigated the depuration of Pb, Ba and Sb from the larvae following removal of the gunshot residue source. A significant reduction in Pb, Ba and Sb concentrations within the larvae was observed following the transfer of larvae from the shot piece of beef to the control piece of beef.