Introduction

1. The Effect of Decomposition and Adipocere Formation: Are these Affected by Body Wrapping?Sheppard, K., Davidson A.R., Cassella J.P.Department of Forensic Science and Crime Science, Faculty of Computing, Science and Engineering, Staffordshire University, U.K Introduction Preliminary Results ADIPOCERE FORMATION AND THE WRAPPING OF BODIES – A USEFUL FORENSIC INDICATOR? Adipocere is a greasy, waxy substance produced as a late post-mortem change that occurs due to putrefactive and hydrolytic enzymes associated with the decomposition process. Enzymes which convert free fatty acids in adipose tissue to saturated fatty acids commonly known to comprise adipocere include myristic, palmitic, stearic and hydroxy stearic acids. Many factors can affect the decomposition process, either increasing or retarding its rate of development, but there is limited research into the effects that wrapping materials and coverings have upon decomposition and adipocere formation in a forensic setting. A study was conducted to investigate the effects of different types of wrapping materials on the rate and extent of adipocere formation on a porcine model in an attempt to aid scientists in crime scene investigations in estimations of post-mortem intervals. Control Sample Qiagen Buccals Chelex Buccal Qiagen Buccals Qiagen Lenses Plastic Bag Adipocere Mechanism Endogenous bacteria hydrolyse triglycerides in the adipose tissue to free unsaturated fatty acids and glycerol. These unsaturated fatty acids include palmitoleic, oleic and linoleic acids and are subsequently hydrogenated into saturated fatty now known to make up the composition of adipocere. The resulting fatty acids that are formed are acidic and inhibit putrefactive bacteria, preventing further decomposition, thus preserving the body. Figure 5: Proportions of main components in Porcine sample Control (Unwrapped) and porcine sample wrapped in Plastic Bag over the 14 week decomposition period Figure 5 demonstrates the change in proportions of the components of the collected porcine samples, particularly the saturated fatty acids that comprise adipocere; with the amount of palmitic acid and stearic acid increasing throughout the 14 weeks, proving the hydrogenation into adipocere has occurred. Table 1: The visual decompositional changes over the 14 week period, comparing the Control sample and the Porcine sample wrapped in Shower Curtain , respectively Figure 1:The mechanism of adipocere formation Materials & Method • Pig cadavers were used as a proxy for human cadavers due to the Human Tissue Act (2004) [Pringle et al. 2010] • 9 belly pork samples were wrapped in different types of household materials: • Non permeable - black sac, plastic bag, shower curtain • Permeable – duvet, blanket, fabric curtain, rug, pillowcase • 1 sample was left unwrapped as a control • All samples left to decompose indoors for 14 weeks • Tissue samples were obtained weekly and were frozen. Conclusions Figure 2: Belly Pork wrapped in Duvet :Week 1 • The results suggest that wrapping materials generally, accelerate the rate of adipocere formation, in non aqueous environments. Confirming previous studies which state that water content within the porcine tissue is sufficient enough to induce adipocere formation • Results demonstrated the hydrolysis of triglycerides in fatty tissue to unsaturated fatty acids, oleic acid and palmitoleic acid. The further hydrogenation into saturated fatty acids, comprising palmitic acid and stearic acid were present confirming adipocere formation. Figure 3: Belly Pork wrapped in Duvet: Week 14 Further work • Tissue samples were subjected to a derivatisation step using HMDS: • 2mg of the porcine sample was weighed into a sterilised tube • 1ml of Chloroform was added and the mixture sonicated for 15 minutes • Chloroform layer was drawn off and placed into new tubes • 250 μL of Hexamethlydisilizane (HMDS) – Derivatising agent – was added • Solution heated at 70 ˚C for 15 minutes • An aliquot was placed into vials for injection into the GC-MS • Determine the effect of more different types of wrapping materials, that mimic body disposal in criminal investigations, on the formation of adipocere. • Allow a much longer decomposition period • Identify any characteristic chemical components formed in adipocere and use these to help aid in creating a method of estimating post-mortem interval References • Forbes, S.L. Stuart, B.H. Dent, B.B. (2005) The effect of the method of burial on adipocere formation. Forensic Science International. 154. 44-52 • Gupta, M. Jain, GV. (2011) Importance of Adipocere in Determining the Cause of Death. Journal of Indian Acadmia Forensic Medicine. 33 (3). Figure 4: GC-MS equipment. Week 1 Week 7 Week 14 Week 2 Week 14 Week 8