Private sector in soil examination:
- International Union of Geological Sciences Initiative on Forensic Geology.
- Working on Guide to Forensic Geology and Code of Conduct.
Potential benefits of soil materials as trace evidence:
Soil can be collected by non-specialists at a particular position or place where something occurs or is situated.
Forensic soil examination:
Often comparative rather than being focused on identifying on a particular soil.
Laboratory recovery is relatively simple:
This cannot be said of soil sampling at the scene of the crime.
Team approach to crime scenes:
Careful consideration needs to be given to the sequence of examination and sampling by specialists to maximize potential for each to ensure their work is not compromised and to minimize potential negatives for other specialists.
Principle responsiblities of crime scene examiner:
Recognize, record and recover.
Critical skill of Crime Scene Examiner or any specialist:
Recognize anomalies or inconsistencies which may indicate a potential evidence discovery.
Geologist:
Interpret location and anomalies which might indicate burial site.
Most significant challenge:
Sampling
Crime scenes:
Vary by their nature; differ greatly
Samples should be:
Sufficient (adequate) and representative of possible variation.
Specific considerations for packaging:
- Place in folded paper and sealable plastic container. 2 Moist samples need to be passively dried. 3. Plastic bottles found in aqueous environments (river/swamp).
Spatial scale:
Geographical extent of an area.
Spatial resolution:
Resolution or spacing for a sampling strategy.
No simple rules with respect to number or size of samples to meet criteria:
- Specialist should consider classic crime scene search patterns. 2. Samples should have accurate geolocation recorded.
Forensic geology contributes to:
Development of the potential location for an incident.
May need to:
Conduct aerial examination, analysis of geology of area and ecology.
Human remains involved:
= 3D Layer Perspective
Soil classification help to:
Organize knowledge about soils and soil surveys.
Two international soil classification system:
- World Reference Base (WRB). 2. Soil Taxonomy.
Soil maps produced at different scales to depict soils over:
- Large areas such as the world, countries and regions (1: 100,000 or larger scale). 2. Detailed areas such as farms (1:10.000 or larger scale).
Countries sometimes have internal databases:
Parent material, climate, organisms, and amount of time it takes for these properties to interact wil vary worldwide.
Diversity of Human Made Soils. Human made and urban soils general terms used to indicate soils under strong human influence in urban - suburban areas:
Characterized by strong spatial heterogeneity: Brick fragments, compost, toxic wastes, mixing of original (natural) soil material. Mine soils. Characterized by diversity, heterogeneityand complexity.
Soils Categories in Forensic Investigations:
- Questioned samples whose origin is unknown or disputed (suspect or victim). 2. Control samples whose origin is known, usually from specific sites directly related to investigation such as known or proposed crime scene. 3. Alibi samples whose origin is known and provide a measure of the uniqueness of the questioned / controlled samples.
