FINAL by: OSAC Program Office; Version 2, January 13, 2020 1 

OSAC RESEARCH NEEDS ASSESSMENT FORM

Title of research need: Assessing Heterogeneity of Soils at a Site

Describe

the need:

The variability of soils at a crime scene or suspect location affects the collection of known 

reference soils and evaluation of the evidence.

Keyword(s): Soil, Heterogeneity, Interpretation, Comparison, Variability, Urban, Rural, Land Use

Submitting subcommittee(s): Trace Materials Date Approved: September 19, 2023

Background Information:

1. Does this research need address a gap(s) in a current or planned standard? (ex.: Field identification system 

for on scene opioid detection and confirmation)

This research need is a fundamental study that would impact reference soil collection and the interpretation of soil as 

forensic evidence. ASTM E3272 − 21 “Standard Guide for Collection of Soils and Other Geological Evidence for 

Criminal Forensic Applications” provides some guidance on collection of known soil exemplars. The spatial 

heterogeneity of soils with respect to commonly characterized properties in forensic examinations should inform how 

many soil exemplars are sufficient to represent the properties within the area of interest and demonstrate differences 

outside of that area of interest. 

2. Are you aware of any ongoing research that may address this research need that has not yet been published 

(e.g., research presented in conference proceedings, studies that you or a colleague have participated in but 

have yet to be published)?

There are small-scale limited studies of the spatial variability of surface soil properties relevant for forensic 

examination. There are no large-scale, systematic studies that address soil heterogeneity, both across the landscape 

and with depth, in a forensic context, using the methods commonly employed in forensic soil examinations. Ideally, 

this assessment should use methods that are analogous to those commonly used in forensic soils analysis (not bulk 

chemical methods i.e., de Caritat et al 2021).

3. Key bibliographic references relating to this research need: (ex.: Toll, L., Standifer, K. M., Massotte, D., eds. 

(2019). Current Topics in Opioid Research. Lausanne: Frontiers Media SA. doi: 10.3389/978-2-88963-180-3)

1. Graham, R.C. and O’Geen, A.T. (2009) Soil mineralogy trends in California landscapes. Geoderma, 

doi:10.1016/j.geoderma.2009.05.018 

2. Lark, R.M. and Rawlins, B.G. (2008) Can we predict the provenance of a soil sample for forensic purposes by 

reference to a spatial database? European Journal of Soil Science, 59: 1000–1006 

3. Morrison, A.R. et al. (2009) Characterization and Discrimination of Urban Soils: Preliminary Results from the Soil 

Forensics University Network. In Ritz, K. et al. (Eds) Criminal and Environmental Soil Forensics, Springer.

4. Suarez MD, Southard RJ, Parikh SJ. Understanding Variations of Soil Mapping Units and Associated Data for 

Forensic Science. J Forensic Sci. 2015 Jul;60(4):894-905. doi: 10.1111/1556-4029.12762. Epub 2015 Mar 24. PMID: 

25808848.
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5. Idrizi, Hirijete, Metodija Najdoski, and Igor Kuzmanovski. "Classification of urban soils for forensic purposes using 

supervised self-organizing maps." Journal of Chemometrics: e3328. https://doi.org/10.1002/cem.3328

6. Pirrie, D., Ruffell, A., Dawson, L. and J. McKinley “Crime Scenes: Geoforensic Assessment, sampling and 

examination” Chapter 4: of A Guide to Forensic Geology Edited by Donnelly, L.J., Pirrie, D., Harrison, M.A., Ruffell, 

A., and Dawson, L., Geological Society, London, 2021 pp. 87-110. DOI.org/10.1144/GFG.4

7. ASTM E3272 − 21 Standard Guide for Collection of Soils and Other Geological Evidence for Criminal Forensic 

Applications

8. “Collection of Forensic Soil Evidence” 2019, https://youtu.be/o9dWZOj1U5A

9. Min, Jisook, et al. "Forensic comparison of soil samples." Soil in Criminal and Environmental Forensics: Proceedings 

of the Soil Forensics Special, 6th European Academy of Forensic Science Conference, The Hague. Springer 

International Publishing, 2016.

10. McKinley, J. , Ruffell, A. “Contemporaneous spatial sampling at scenes of crime: Advantages and 

disadvantages” Forensic Science International 172 (2007) 196–202

11. McKinley, J. 2013. How useful are databases in environmental and criminal forensics? Geological Society, 

London, Special Publication, 384, 109-119.

12. de Caritat, P., et al. (2021). Forensic soil provenancing in an urban/suburban setting: A sequential 

multivariate approach. Journal of Forensic Sciences, 66(5), 1679-1696.

13. Pitts, K. M., & Clarke, R. M. (2020). The forensic discrimination of quartz sands from the Swan Coastal Plain, 

Western Australia. Forensic Science International: Reports, 2, 100130.

14. Testoni, Samara Alves, et al. "Can analysis of a small clod of soil help to solve a murder case?." Science & 

Justice 59.6 (2019): 667-677.

15.Pye, K., Blott, S. J., Croft, D. J., & Carter, J. F. (2006). Forensic comparison of soil samples: assessment of small-scale 

spatial variability in elemental composition, carbon and nitrogen isotope ratios, colour, and particle size 

distribution. Forensic Science International, 163(1-2), 59-80.

4. Review the annual operational/research needs published by the National Institute of Justice (NIJ) at 

https://nij.ojp.gov/topics/articles/forensic-science-research-and-development-technology-working-groupoperational#latest? Is your research need identified by NIJ?

This research addresses: 

“Scientific foundations for expert conclusions of forensic evidence”; “Practical statistical approaches for the 

interpretation of forensic evidence”

5. In what ways would the research results improve current laboratory capabilities?

This research would provide guidance to crime scene professionals on the number of reference (known) soil samples 

to collect to sufficiently represent the heterogeneity of soils in and around a crime scene. Collection of sufficient 

known soils from the vicinity of a crime scene that includes both exemplars lacking exclusionary differences and those 

with exclusionary differences soils, will enable the examiner to demonstrate both that soil evidence could have come 

from the crime scene but the methods used are capable of demonstrating exclusionary differences. The sufficient 

number and density of known soils to capture these differences will likely vary based on human (land use) and 

pedological (parent material, geomorphic position, landscape age, vegetation, and climate) factors. In addition, better 

collection of known soils and a better understanding of spatial heterogeneity will provide context for soil examination 

conclusions (associations, exclusions, inconclusive findings) for cases involving soil from different land use types, 

geomorphic position, landscape age, and bedrock/parent material characteristics. Appropriate limiting statements 

could be inserted into reports and findings could be qualified in court testimony in more rigorous ways than simply 

based on examiner experience. For example, if research demonstrates that soil tends to be more homogeneous 

across certain types of settings (i.e., prairie underlain by granitic bedrock), this would be important for a soil examiner 

to know as they evaluate the significance of a soil association in a case involving this type of setting.
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6. In what ways would the research results improve understanding of the scientific basis for the 

subcommittee(s)?

This research would provide those performing forensic soil examinations with a better understanding of the 

significance of soil examination results to enable better conclusions (associations, exclusions, inconclusive findings) 

for cases involving soil from different land use, geomorphic position/age, and bedrock characteristics. It would also 

assist the subcommittee in developing a statistical approach to estimating population size for comparisons. This 

would enable the subcommittee to make informed interpretation and report writing recommendations to forensic 

practitioners in future standards and/or guidelines.

7. In what ways would the research results improve services to the criminal justice system?

It would improve the assessment of the probative value of any particular soil comparison result. It would aid in 

appropriate testimony and reporting. This research is needed to address the strength of a comparison, assessment of 

inconclusive, or exclusion.

8. Status assessment (I, II, III, or IV): I

Major gap in 

current 

knowledge

Minor gap in 

current 

knowledge

No or limited

current research is 

being conducted I III

Existing current 

research is being 

conducted II IV

This research need has been identified by one or more subcommittees of OSAC and is being provided as an 

informational resource to the community.