Development of a searchable major and trace element database for use in forensic soil comparisons

Forensic soil comparisons are normally undertaken on the basis of several physical, chemical and biological properties, but in all cases the interpretation of results is dependent on the availability of relevant contextual information. This paper summarises the results of major and trace element analyses performed using inductively coupled plasma atomic emission spectrometry and inductively coupled plasma-mass spectrometry on the < 150 microm size fraction of 1896 soil samples collected in connection with forensic investigations in England and Wales between 1999 and 2007. A number of new methods are described which facilitate inter-sample comparison. Although the available data do not provide uniform geographical coverage they do provide useful information which can assist police search investigations and they provide valuable contextual information which aids the evidential assessment of soil evidence when used in court. There is considerable scope to improve the database by increasing the geographical coverage and increasing the number of soil attributes which are included.