[Diatoms in drowned and postmortem immersed rabbits' lungs]

Area of Science:

• Forensic Science
• Microbiology
• Toxicology

Background:

• Diatoms are microscopic algae found in aquatic environments.
• Their presence and distribution in lung tissue can indicate the circumstances of death, particularly drowning.
• Distinguishing between true drowning and postmortem submersion is crucial in forensic investigations.

Purpose of the Study:

• To investigate the quantitative and qualitative distribution of diatoms in rabbit lungs.
• To differentiate between drowning and postmortem immersion using diatom analysis.
• To assess the utility of diatom analysis in forensic testing.

Main Methods:

• Sixty-two rabbits were divided into drowning, postmortem immersion, and land death groups.
• Lung tissue samples were analyzed using microwave digestion and scanning electron microscopy.
• Diatom numbers, sizes, and types were quantitatively and qualitatively assessed.

Main Results:

• Diatoms were detected in all lung lobes of the drowning group, predominantly Cyclotella and Melosira.
• Cyclotella was the dominant diatom in the postmortem immersion group, with some lung lobes lacking diatoms.
• Significant differences in diatom detection rates were observed in specific lung lobes between the drowning and postmortem immersion groups (P < 0.05).

Conclusions:

• Microwave digestion and scanning electron microscopy are effective methods for analyzing diatom distribution in lung tissue.
• Diatom analysis, including numbers, sizes, and types, can provide valuable references for forensic testing.
• The findings support the use of diatom analysis to differentiate drowning from postmortem immersion.