What Is Soil Evidence? [#1 Answer]

Soil samples can be collected in different ways depending on where the sample is being collected from 😁 If samples are being collected indoors or from a vehicle vacuuming is generally used 🙌 If the sample is outdoors it’s collected by placing a teaspoon of soil into a plastic vial. When found on a tool, it is wrapped in plastic and then sent to the lab for testing. Collecting soil samples off of a body isn’t any harder than collecting a sample from anywhere else but it takes more work and care so that the evidence doesn’t get contaminated. When collecting samples from a body, samples should be taken at regular intervals and a different spoon should be used each time. [1]
Soil can provide important information to criminal investigations as transfer evidence because many criminal cases take place under circumstances such that soil transfers to a criminal or victim. The variation in soils from place to place makes soil valuable evidence to prove linkage between a suspect and a crime scene. Soil is a complex mixture with a variety of mineralogical, chemical, biological, and physical properties. Considering such complexity, a variety of methods have been developed for forensic science purposes. Because minerals are an important component of soils, mineralogical examination is essential in forensic soil identification. Additionally, many other methods can be applied to raise the discriminating power, but not all kind of methods need to be used. What is important is that examiners select an appropriate combination of methods by considering the context of the soil samples. This report summarizes a wide range of reports on the analysis of soil components and of closely related materials such as plant fragments, pollen and spores, and diatoms, with emphasis on the importance of screening tests consisting of several simple techniques. The soil formation process involves parent materials, temperature, water condition, vegetation, time, and the chemical processes of solution, oxidation, reduction, and even human activities. The history of a soil’s development as the results of such complex soil formation process is strongly reflected in soil colourr. The systematic observation of multiple soil colors is especially useful for screening. (emended by Ruth P. From Yichang, China on July 6, 2020) [2]
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The current approach to analyzing forensic soil evidence is to focus on profiling the chemistry of the soil to indicate a possible origin. Because of this focus, police photographs are not generally taken of soil mark/pattern evidence on suspects/victim’s clothing at the crime scene; before the body is moved or clothing removed. Instead, soil evidence is generally ignored until specific items are chosen for analysis by either police forensic investigators or forensic soil experts. This soil analysis begins once as much soil as possible is rigorously removed from clothing fabric. This removal may involve shaking soil particles from clothing into collection bags or even cutting out sections of soiled material. Not since Locard’s experiments in 1930 has anyone published methods to help police use soil marks/patterns on clothing to interpret what happened to a victim during or after a crime. [3]
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As per the experts at pubs.rsc.org, 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 (colorcomparison, 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. (last modified 13 days ago by Atasha Tobin from Jhansi, India) [4]
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Article References

  1. https://www.crimemuseum.org/crime-library/forensic-investigation/forensic-soil-analysis/
  2. https://www.jstage.jst.go.jp/article/jasti/7/2/7_2_95/_article
  3. https://munsell.com/color-blog/color-analysis-forensic-application-crime-scene/
  4. https://pubs.rsc.org/en/content/articlelanding/2020/ay/d0ay01634a
Mae Chow

Written by Mae Chow

Passionate about writing and studying Chinese, I blog about anything from fashion to food. And of course, study chinese! I'm a passionate blogger and life enthusiast who loves to share my thoughts, views and opinions with the world. I share things that are close to my heart as well as topics from all over the world.

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