Reinstating soil examination as a trace evidence sub-discipline

In the past, forensic soil examination was a routine aspect of forensic trace evidence examinations. However, the apparent need for soil examinations has diminished and with it the capability of forensic laboratories to carry out soil examination has been eroded. In recent years, due to soil examinations contributing to some high profile investigations, interest in soil examinations has been renewed. The need for, and suggested pathways to, the reinstatement of soil examinations as a trace evidence sub-discipline within forensic science laboratories is presented in this chapter. An examination procedure is also proposed that includes: appropriate sample collection and storage by qualified crime scene examiners; the preliminary examination of soils by trace evidence scientists within a forensic science laboratory; and the higher-level examination of soils by specialist geologists and palynologists. Soil examinations conducted by trace evidence scientists will be facilitated if the examinations are conducted using the instrumentation routinely used by these examiners. Trace evidence scientists routinely use a microspectrophotometer (MSP) for the colour analysis of forensic samples, including paint, fibres, inks and toners. This chapter also presents how a microspectrophotometer can be used to objectively measure the colour of forensic-sized soil samples as a demonstration as to how the proposed examination procedure can incorporate both trace evidence scientists within a forensic laboratory and specialist soil scientists.