Decomposition studies using animal models in contrasting environments: Evidence from temporal changes in soil chemistry and microbial activity

Abstract

Traditionally, soil evidence in forensic science has focused predominantly on the transference of soil particles from a victim or suspect and a crime scene. However, a recent increase in forensic taphonomy research has highlighted the potential of soil to provide key information to an investigation involving decomposed remains. A decomposing carcass can release a significant pulse of nutrients into the surrounding soil (gravesoil) resulting in the retention of decomposition products in the soil for a considerable period of time. In order to understand the complex associations between a decomposing carcass and the soil system, research must be conducted in both controlled laboratory environments and outdoor field environments. This chapter discusses two contrasting decomposition studies which aimed to investigate the cadaver/soil interaction. The first study investigated the decomposition of small mouse carcasses buried in soil and was conducted within a controlled laboratory environment in Western Australia. The second study investigated the decomposition of large pig carcasses placed on the soil surface and was conducted in an outdoor field environment in southern Ontario. Both studies investigated a range of decomposition products particularly focusing on carbon-based, nitrogen-based and phosphorus-based compounds as these were considered to offer the most valuable information to address the research questions. The results of both studies provide the opportunity to comment on the effect of carcass size, soil type and decomposition environment on the influx of decomposition products into the soil.