An Investigation of Model Forensic Bone in Soil Environments Studied Using Infrared Spectroscopy

Abstract

Infrared spectroscopy has been used to examine changes to bone chemistry as a result of soil burial. Pig carcasses were buried as part of a controlled field study, and pig bone was used in soil environments established in the laboratory. The variables of species type, bone pretreatment, soil type and pH, moisture content, temperature, and burial time were investigated. The crystallinity index (CI) and the organic and carbonate contents of the bones were monitored. The data revealed decreasing trends in the organic and carbonate contents and an increase in the CI of the bone with burial time. An acidic soil environment and soil type are the factors that have the most influence on bone chemistry as a result of burial. The study demonstrates the potential of infrared spectroscopy as a straightforward method of monitoring the changes associated with aging of bones in a variety of soil environments.

The Analysis of Heat-Induced Crystallinity Change in Bone

“…For example, King et al (2011) used a combination of crystallinity indices (CI and C/P) to successfully distinguish archaeological from modern bone material; Weiner et al (1993) and Stiner et al (2001) have also used this to examine differences between Lebon et al (2010) bone samples from Israel, Sillen and Morris for samples from Southern Africa (1996). More recently, Howes et al (2013) have used them to examine diagenetic changes over shorter timescales.…”

Heat-induced Bone Diagenesis Probed by Vibrational Spectroscopy

“…A clear increase in recent years has been observed in its application within the forensic 15 and archaeological 21 – 24 sciences. For example, its potential for discriminating between fossilised, archaeological and modern bones 24 – 26 or for estimating the postmortem interval in forensic cases 27 – 30 , has been demonstrated by evaluating bone crystallinity, as well as carbonate and organic contents. Nonetheless, devising a method capable of quantifying diagenetic changes in burned skeletal remains is still an unmet challenge.…”

Alteration of the metal content in animal bones after 2.5-year experimental exposure to sediments

“…The time duration of this experiment was not long, especially when compared to fossil materials, which have spent hundreds or thousands of years in sediment. However, the time interval was similar to the 2-year burial time tested by Howes et al (2012), which was enough time to produce structural and bulk chemical changes in bones, and shorter than the 15 years reported by Trueman et al (2004), which was enough time to create an alteration of some metal contents in the bones exposed to weathering on the soil surface. Nevertheless, the bones in this study clearly show visible, macroscopic signs of multidirectional alterations.…”

“…Howes et al (2012) showed that acidic soils promote the structural ordering in bone apatite, and this process may stay behind the accelerated incorporation of bivalence cations during apatite recrystallization. Conversely, Ba and Sr exhibit positive correlations with the pH (Table 2).…”