Inductively coupled plasma – atomic emission spectroscopy (ICP-AES) as a method of species differentiation of bone fragments

Abstract

During criminal investigations relating to buried human remains, mass graves, or poaching, human and animal bones may be comingled, highly fragmented, or burned. Misidentification of skeletal elements may result in animal bones being sent to forensic laboratories and human bones sent to a zoologist for identification, creating unnecessary work and further investigative problems. To determine the origin of skeletal remains this research will examine the trace element signature in bone from several different species. The animals of interest in this study included beaver, cat, coyote, deer, fisher, fur seal, mouflon, pig, raccoon, and rat. Bone fragments of each species were collected, prepared, and analyzed using inductively coupled plasma – atomic emission spectroscopy (ICP-AES) to measure the concentrations of aluminum, boron, calcium, iron, lead, potassium, magnesium, and sodium. Significant differences were observed between the various experimental elements and feeder types. Carnivores had significantly higher levels of aluminum, iron, potassium, magnesium, and sodium than both herbivores and omnivores. Significantly higher levels of aluminum, potassium, magnesium, and sodium were detected in domestic species. Discriminant analysis of the species showed that it may be possible to distinguish bone fragments by feeder type, species, and domestication status.

Keywords:

• poaching
• chemical analysis
• forensics, species identification

Acknowledgements

The authors would like to thank Dyann Powley, Dr Graham Crawshaw, and the Toronto Zoo for supplying several of the specimens. Furthermore, the authors would like to acknowledge Dr Shari Forbes for use of her lab, and Mike Allison for providing training on ICP-AES.