Soil as a tool of revelation in forensic science: a review

Soil contains diverse and complex natural elements having physical, chemical, mineralogical and biological components. Soil being a transferable physical component (it can be transferred from one location to another with the help of shoes, tires, clothes, tools etc.), acts as a tool of forensic investigation to correlate a specific crime scene with criminal suspects. A variety of techniques and combinations of methods can be used to discriminate soil from different geographical locations. The present review highlights various analytical techniques (ATR-FTIR, pyGC-MS, SEM-EDX, ICP-MS/OES and XRD) for soil analysis (colour comparison, texture and particle size determination, density gradient methods and organic matter estimation) and discusses some of the famous cases solved with soil trace evidence. The objective of the present study is to provide an overview of the importance of soil as physical evidence in forensic science based on literature analysis that will help forensic scientists and researchers to select appropriate methods to discriminate different soil samples. This article reviews various analytical techniques used to differentiate soils and provides compiled information regarding soil as trace evidence in order to help academicians, researchers and forensic soil scientists.