Developing a new scoring method to evaluate human decomposition in a humid, continental (Dfb) climate in Quebec

Area of Science:

• Forensic Science
• Taphonomy
• Thanatology

Background:

• Limited methods exist for evaluating human decomposition and estimating post-mortem interval (PMI) in humid continental (Dfb) climates like Quebec.
• Existing decomposition scoring methods may not be suitable for controlled experimental conditions in this climate.

Purpose of the Study:

• To address the knowledge gap in human decomposition patterns and PMI estimation in Dfb climates.
• To provide the first controlled experimental observations of human decomposition in Quebec.
• To develop and apply a novel scoring system for macromorphoscopic changes in decomposing human remains.

Main Methods:

• A 12-month study using six human donors at Canada's first human taphonomy facility.
• Donors were deposited in spring, summer, and autumn 2021.
• A new scoring system based on observed macromorphoscopic changes was developed and applied.

Main Results:

• All donors exhibited comparable decomposition trajectories irrespective of deposition season.
• 85% of taphonomic patterns emerged within 25 experimental days or 5000 Kelvin accumulated degree days (350 ADD).
• Extensive tissue desiccation was observed at a median of 21 days, leading to a decomposition plateau without extensive skeletonization.

Conclusions:

• The developed scoring system effectively evaluates decomposition in a Dfb climate.
• Decomposition patterns in this climate are season-independent and characterized by early desiccation.
• This study offers crucial data for forensic investigations in southern Quebec and similar climates.