title: The detection of gunshot residues in the nasal mucus of suspected shooters.
abstract: The identification and quantification of metallic residues produced by gunshots, called gunshot residues (GSR), provide crucial elements in forensic investigations. The research has been largely focused on their collection onto the hands of suspected shooters, but the method is often burdened by risks of contamination. This research was focused on the possibility of sampling GSR trapped inside the nasal mucus of consenting shooters. Samples of the nasal mucus of "blank" control subjects and shooters were chemically analysed by Instrumental Neutron Activation Analysis (INAA), for residues of antimony (Sb) and barium (Ba), while lead (Pb) was excluded as ubiquitously environmental contaminant and due to high instrumental quantification limit (IQL) of INAA for this element. Shots were fired using two types of weapons (pistols and revolvers) and different firing sequences. The mucus was sampled at different times: immediately after the shots, after 30-60-120 and 180 min. Different amounts of Sb and Ba were detected between controls and shooters, witnessing the ability of the nasal mucus to retain GSR at concentrations significantly different even from the highest basal levels. Moreover, in order to simulate actual cases, nasal mucus from five groups of shooters was sampled after different shots with the same weapon and cartridges, immediately and after 1, 3, 12, and 24 h. The highest values were always found in the first 3 h from firing, for both weapons. Interestingly, for all the weapons, significant Sb and Ba concentrations were also found up to 12 h after firing, contrary to what occurs on hands, even though a progressive decrease was detected, with values below the detection threshold only after 24 h, thus demonstrating that GSR are persistent in nasal mucus. These first results proving that both Sb and Ba were qualitatively detectable in the nasal mucus of shooters indicate that the chemical analysis of the nasal mucus of suspected shooters may represent a promising tool in the forensic field since it is less burdened by problems related to sampling or contamination than the usual sampling on hand, providing that ammunitions employed contain Ba and Sb.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Pavia, Via Taramelli 12, 27100, Pavia, Italy. daniele.merli@unipv.it.
authors.forename: Daniele
authors.initials: D
authors.lastname: Merli
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Pavia, Via Taramelli 12, 27100, Pavia, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Brandone
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Sezione di Medicina Legale, Università degli Studi di Milano, via Mangiagalli 37, 20133, Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Amadasi
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Sezione di Medicina Legale, Università degli Studi di Milano, via Mangiagalli 37, 20133, Milan, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cattaneo
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Pavia, Via Taramelli 12, 27100, Pavia, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Profumo
mesh_terms: D000965:Antimony / Q000032:analysis*; D001464:Barium / Q000032:analysis*; D016022:Case-Control Studies; D005389:Firearms; D006801:Humans; D007854:Lead / Q000032:analysis*; D009093:Mucus / Q000737:chemistry*; D009297:Nasal Mucosa / Q000737:chemistry*
chemical_list: D001464:Barium; D007854:Lead; D000965:Antimony
keywords: Antimony and barium; Forensic science; Gunshot residues; Instrumental neutron activation analysis; Nasal mucus; Suspected shooters