Gunshot residue preservation in seawater Anne-Christine Lindstro ¨m a, *, Jurian Hoogewerff b,1 , Josie Athens c , Zuzana Obertova d , Warwick Duncan a , Neil Waddell e , Jules Kieser a a Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, PO Box 647, Dunedin, New Zealand b Department of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand c Department of Preventive and Social Medicine, University of Otago, PO Box 56, Dunedin, New Zealand d Waikato Clinical School, University of Auckland, 3240 Hamilton, New Zealand e Sir John Walsh Research Institute, Department of Oral Rehabilitation, University of Otago, PO Box 647, Dunedin, New Zealand 1. Introduction Gunshot residue (GSR) consists of burnt and unburnt residue, derived from the primer, propellant, the bullet or the firearm itself [1,2], which normally can be differentiated by their chemical composition and morphology. Particles characterized as GSR have normally a spherical shape of molten and cold matter with a diameter of 0.1 to 10 mm. In casework involving shootings, inorganic residues originating from the primer, bullet and cartridge are analysed. Pb, Ba and Sb are considered unique to GSR and can be found in different combinations and concentra- tions [3,4]. They can be divided into GSR-unique (i.e. Pb–Ba–Sb) and GSR-indicative (i.e. Pb–Ba or Ba–Ca–Si–Pb) particles of the ammunition used during a shooting incident [5]. Indicative particles are particles that may originate from a cartridge but may also originate from other objects such as industrial tools. SEM–EDX cannot always distinguish between GSR-indicative particles originating from a discharged gun and other inorganic particles that come from other sources such as brake linings [6], fireworks [7] or paints [8]. This can lead to false positive identification of GSR particles. One of the unsolved puzzles of GSR is the question of how long it persists in tissues during the process of decomposition, particu- larly in different environments [9]. There may be a link between the postmortem interval and the retention of GSR [10], but testing this relationship is challenging because of postmortem factors such as decomposition, burial conditions and scavengers. When Forensic Science International 253 (2015) 103–111 A R T I C L E I N F O Article history: Received 17 December 2014 Received in revised form 22 April 2015 Accepted 17 May 2015 Available online 27 May 2015 Keywords: Marine decomposition Gunshot residue Gunshot wound SEM–EDX ICP-MS A B S T R A C T Little is known about the persistence of gunshot residue (GSR) in soft tissue and bones during decomposition in marine environments. For a better understanding, qualitative and quantitative data were obtained on GSR retention on soft tissue and bony gunshot wounds (GSWs). A quantity of 36 fleshed and 36 defleshed bovine ribs were shot at contact range with 0.22 calibre hollow point ammunition using a Stirling 0.22 calibre long rifle. Bone specimens in triplicate were placed in three environments: submerged, intertidal and in supralittoral zone. Sets of triplicates were recovered on day 3, 10, 24 and 38, and analysed with scanning electron microscopy with energy dispersive X-ray spectrometry (SEM–EDX), and inductive coupled plasma mass spectrometry (ICP-MS). The SEM–EDX recorded GSR-indicative particles surrounding the bullet entrance on all bone types (fleshed and defleshed) in all environments throughout the study. GSR-unique particles were only detected on the supralittoral bones. The ICP-MS analysis showed faster GSR loss on submerged than intertidal and supralittoral defleshed specimens. Fleshed specimens showed a faster GSR loss on intertidal than submerged and supralittoral specimens. In conclusion, the GSR disappeared faster from submerged and intertidal than non-submerged specimens. The difference of detection of GSR between analysed specimens (defleshed versus fleshed) disappeared upon defleshing. This study highlights the potential of finding evidence of GSR in a submerged body and the potential of microscopic and analytical methods for examining suspected GSW in highly decomposed bodies in marine habitats. ß 2015 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, PO Box 647, Dunedin, New Zealand. E-mail addresses: anne_christine@me.com (A.-C. Lindstro ¨ m), Jurian.Hoogewerff@canberra.edu.au (J. Hoogewerff), josie.athens@otago.ac.nz (J. Athens), obertovazuzana@yahoo.co.nz (Z. Obertova), warwick.duncan@otago.ac.nz (W. Duncan), neil.waddell@otago.ac.nz (N. Waddell). 1 Faculty of Education, Science, Technology & Maths, University of Canberra, Canberra, Australia. Contents lists available at ScienceDirect Forensic Science International jou r nal h o mep age: w ww.els evier .co m/lo c ate/fo r sc iin t http://dx.doi.org/10.1016/j.forsciint.2015.05.021 0379-0738/ß 2015 Elsevier Ireland Ltd. All rights reserved.