New Guide for Polarized Light Microscopy in the Forensic Examination and Comparison of Soils
1. Scope
1.1 This guide covers the use of polarized light microscopy (PLM) for the identification and comparison of the mineralogical components of soils (to include unconsolidated geological materials) for forensic applications.
1.2 Soils are often complex mixtures of a variety of components. This guide is tailored to the microscopical examination and comparison of the geological components of soils in grain mounts.
1.3 This standard is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (refer to Practice E2917), and demonstrated proficiency to perform forensic casework.
1.4 The values stated in SI units are to be regarded as standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This standard aims to provide guidance for examination of soils as trace evidence by means of polarized light microscopy. This examination method is typically used within a larger examination scheme. Those who might perform this examination include scientists in forensic laboratories or geoscientists in research institutions asked to assist in a forensic case. This document provides a framework for interpreting PLM results for forensic interpretation.
