Detection of structural degradation of porcine bone in different marine environments with Raman spectroscopy combined with chemometrics

Abstract

The investigation of time since exposure and taphonomic alteration of bone in marine environments is crucial in forensic sciences. In this study, we explored the diagenetic changes to juvenile porcine bone in two different environmental marine contexts (submerged and intertidal) and how seasonal variation at time of deposition impacted on the pattern of taphonomic alteration in bone during early stages of exposure, from 6 to 24 weeks. The analysis was conducted using Raman spectroscopy combined with chemometrics. Principal component analysis of the Raman data of the recovered bones (either summer or winter season in 2014) showed that the main chemical changes occurred in the bioapatite (phosphate band, ν1(PO43−) at 961 cm−1) and organic constituents in the bones and depended on the exposure environment. Support vector machine (SVM) classification analysis classified the samples based on bone type, exposed environment and season, with high accuracy (>80%), but exposure time was less accurate (56%), although still higher than chance. When applying a SVM regression, time since exposure could be predicted with a ±5‐week uncertainty. This study illustrated the potential and limitations of using Raman spectroscopy to detect structural degradation of bone in different marine environments for forensic purposes.

Innovative Vibrational Spectroscopy Research for Forensic Application

“…They demonstrated that Nile Red staining enables the identification of fluorescent particles and provides a method for fast analysis at a low cost and with low equipment needs. Garagoda Arachchige et al also used Raman spectroscopy in combination with chemometrics to detect the structural degradation of porcine bone in different marine environments . This research is timely since the exposure and taphonomic alterations of bone in environments like marine conditions are a crucial area of investigation for environmental forensics.…”

“…Bones were also not misclassified between the control group and the environmental study. SVM analysis was used to classify bone type, exposed environment, and season with >80% accuracy . The researchers also investigated other applications of this method, such as the identification of specific algal markers in aquatic environments, which would be helpful for determining seasonal deposition of bones .…”

“…SVM analysis was used to classify bone type, exposed environment, and season with >80% accuracy . The researchers also investigated other applications of this method, such as the identification of specific algal markers in aquatic environments, which would be helpful for determining seasonal deposition of bones . Visual inspection of bones can determine some information about the environmental impacts on the degradation of the sample, but this technique is prone to bias among investigators and can only reveal a partial picture of the scene.…”