The length and width of diatoms in drowning cases as the evidence of diatoms penetrating the alveoli-capillary barrier.

Forensic diatom test has been considered as a significant tool for diagnosis of drowning. Most of the studies in this field discussed the methodology of extracting, enriching and detecting diatoms from different tissues and drowning media. There are few studies on the basic principle of diatom test which was based on the theory developed by forensic scientists many years ago. This study was designed to analyze the length and width of diatoms in different organs and drowning medium samples of drowning cases. This study is designed to find evidence of diatoms penetrating the alveoli-capillary barrier. Samples from 100 drowning cases were analyzed using the methodology we developed: the Microwave Digestion-Vacuum Filtration-Automated Scanning Electron Microscopy method (MD-VF-Auto SEM method). The results showed that the length and width of diatoms in the liver and kidney tissues are smaller than that of the lung tissues and water samples. Our studies also found that the pennate diatoms are easier to penetrate through the alveoli-capillary barrier, travel in the blood stream and finally deposit in the distant tissues including liver and kidney. These findings provided evidences to support the process of diatoms penetrating the alveoli-capillary barrier.