Micro- to Nanoscale Morphologies and Chemical Components of Soils Investigated by SEM-EDS for Forensic Science

Yingzi Liu,Qiang Li,Zhiwen Zhao,Yumei Li,Jie Bao,Zhiheng Hu,Dakui Hao,Jiajia Wang,Dongxue Song

doi:10.1155/2015/734560

Abstract

As a kind of microscale physical evidence, soil can provide significant assistance to forensic science. In this study, soil samples that were collected from eighteen different regions of Shandong Province, China, were examined by scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The homogeneities and diameters of the samples were evaluated by SEM which has been applied to observe objects at nanoscale. The soil from Jiaxiang, a city in Eastern Shandong Province, showed the maximal particle diameter and the sample from Liaocheng, another Eastern city in Shandong Province, showed the best homogeneity. The mass fraction and molar percentages of nine inorganic elements in all samples were analyzed by EDS. Oxygen and silicon showed the highest content in all of these samples. However, different samples exhibited their own characteristic elements, which can help to discriminate them from other samples. In this regard, SEM-EDS-based homogeneity and element analysis might be used as a fast and reliable technique for the soil criminological analysis in Shandong Province.

Highlights

Soil provides the nutrients and water required by terrestrial plants growth and exchange energy
Before they were subjected to the scanning electron microscopeenergy dispersive spectrometer (SEM-Energydispersive X-ray spectroscopy (EDS)) analysis, samples were coated with a layer of gold using a goldplated machine for 120 s
Objects can be observed in the limit of 0.1 nm (10−10 m)

Summary

Introduction

Soil provides the nutrients and water required by terrestrial plants growth and exchange energy. Soil is influenced by various biotic and biological factors, such as climate, early formation of texture, microbial environment, and human activities. The soil from various regions has tremendous differences in the components of metal, minerals, and the microbial communities [1, 2]. There is a strong connection between the soil and people’s lives. Soil on the body or belongings of a person could be used as trace evidence in a large amount of criminal cases. As a kind of trace evidence, soil has played an important role in forensic science [3,4,5,6]

Methods

Results

Conclusion