Topic: metal wipes/smear on bone surface

[jrathman]

Greetings, I am a student in the Master of Forensic Science program at Nebraska Wesleyan University and am working on research that applies forensic toolmark examination to an archaeological situation.  I'm attempting to identify the tool type on ancient butchered remains (cut marks on bone).

One idea that came to mind during my research is to attempt identify metal within the cut mark (metal wipes or smear).  Has anyone experimented or know research on identifying metal elements in order to associate/link a tool used on a bone surface?  I have read about bullet wipes/smears but wondering if research has been done on bone surfaces.

Thanks,

Jeff Rathman

[Mike Scanlan]

I use x-ray fluorescence spectrometry (XRF) mapping to analyze bones for bullet impact.  Copper/zinc (from bullet jackets) and lead are readily identifiable.  Iron will show up from blood/tissue on the bone, so might be more problematic for interpretation.

[Ron Fazio]

You can submit sub-samples of the cut surface and sub-samples of the non-cut areas for ICP (or ICP-MS) testing. Its fairly cheap (most environmental labs have this instrumentation) and requires only a very small sample.

You can compare the identified metals on the cut surface and non-cut surface to determine tool metal. There may be matrix interference issues do to the likely high levels of calcium, so you may want to check with the lab first.

It is a destructive test.

[Rachel B-K]

Hi Jeff,

I am not sure whether this would work on your samples, or if you have access to the equipment, but thought I would raise the idea.

If you could pick up the metal residues or particulates from the bone with a small sticky stub, you could put the stub into and analyse them with a surface analysis method called SIMS (Secondary Ion Mass Spectrometry). I have used this technique to identify batches of metal components successfully with just a timy amount of material created with sandpaper. This website will give you the basic principle from a lab in the UK:

http://www.lpdlabservices.co.uk/analytical_techniques/surface_analysis/sims/index.php

This does not completely destroy the particles like ICP, but will remove the surface layer from the analysed particles.

Rachel