Cadaver decomposition processes

This chapter reviews the processes in soils associated with cadaver decomposition (i.e., gravesoils). A portion of this review also concerns insects and scavengers, because the activity of these organisms can regulate the introduction of cadaver material to soil. However, these topics are dealt with in greater detail by Amendt, Krettek, and Zehner (2004) and DeVault, Brisbin, and Rhodes (2003). The hope is that this chapter will provide a greater understanding of the processes associated with cadaver decomposition and their potential for forensic application. 

Carter, D. (2005). Forensic taphonomy Processes associated with cadaver decomposition in soil. Ph.D. thesis, James Cook University, Townsville, Australia. 

A cadaver exposed to the environment is subject to degradation by various types of animals, of which insects are often the most predominant. Insects can affect the breakdown of the corpse by augmenting the internal decomposition process (Campobasso, Di Vella, and Introna 2001). The succession and development of some insects that visit a corpse can be used to estimate PMI. Succession data are useful in providing a minimum and maximum estimate of time since death. However, biotic and abiotic factors are known to influence carrion insect growth and activity and need to be considered when estimating PMI (Wells and Lamotte 2001). 

Because cadavers comprise 60%-80% water their breakdown has been described as a competition between desiccation and decomposition (Auf-derheide 1981). The relationship between these processes is important because rapid desiccation can inhibit decomposition and result in the natural preservation of a cadaver for thousands of years, such as the natural mummies observed in Egypt (Ruffer 1921) and Peru (Allison 1979). Sledzik and Micozzi (1997) distinguished three types of mummification natural, intentional, and artificial. Dryness, heat, or absence of air may cause natural mummification. Intentional mummification is the result of exploitation or enhancement of natural mummification processes. Artificial mummification may be the result of evisceration, fire, or smoke curing and the application of embalming substances. 

Tooth enamel represents one of the most resistant skeletal tissues to post-depositional decay in a burial environment (Duric, Rakocevic, and Tuller 2004), and, as a result, teeth are often the only identifying feature of a skeleton to remain. As decomposition proceeds, the loss of soft tissue around the mandible allows the exposed teeth to become dislodged from their original anatomical position. Postmortem tooth loss has been described as a possible indicator of PMI and appears to be dependent on age, periodontal health, seasonality, and location of the body placement (McKeown and Bennett 1995). Cadavers that are deposited in the summer months will undergo a more rapid process of soft-tissue decomposition and thus lose teeth more rapidly than bodies that decompose in the autumn or winter months. Similarly, a cadaver exposed to direct sunlight, or even deposited in a shaded area, will decompose and lose teeth more rapidly than a cadaver that has been buried. The... 

Forensic taphonomy is an applied discipline that is coming of age. To date, however, the major advances in the field have been captured in publications that deal primarily with the cadaver and associated items rather than the grave itself. This book provides, for the first time, a collection of chapters from leading scientists in their fields that deal primarily with the burial environment. Our focus is on the processes of decomposition in soils, the decomposers in the soil, and the basic physiochemical composition of the soil as it relates to forensic science and taphonomy. 

The terrestrial environment has been much studied as a decomposition environment for materials of little forensic value, such as leaf litter or dead roots. These provide the basic methods and framework for studying and understanding decomposition of materials in soils. It is only in recent years that this has been applied to forensic taphonomy, in which studies have been conducted with mammalian tissues and cadavers. The burial environment is a complex and dynamic system of interdependent chemical, physical, and biological processes. These processes influence, and are influenced by, the inclusion of a body and its subsequent decay. Though this book deals with what is known in this context, much still remains to be discovered, understood, and applied to forensic science. 

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