Role of Diatoms in the World of Forensic Science

Abstract

This article reviews the forensic aspects of Diatoms analysis and acid digestion method for diatoms extraction. A body recovered from the water does not necessarily imply that death was due to drowning. If the person is still alive when entering the water, diatoms will enter the lungs if the person inhales water and drowns. The diatoms are then carried to distant parts of the body such as the brain, kidneys, lungs and bone marrow by circulation. If the person is dead when entering the water, then there is no circulation and the transport of diatom cells to various organs is prevented because of a lack of circulation and diatoms cannot enter the body. When a body is recovered from water, there is usually a suspicion whether it was a case of ante-mortem or post-mortem drowning i.e. whether the body was drowned before or after death. In these medico legal cases, presence of diatoms in the body tissues is very useful evidence. In drowning related death cases, a correlation between the diatoms extracted from bone marrow and liver/lungs) samples and the samples obtained from drowning medium have to be established for the successful determination of drowning site in Forensic laboratories. Diatom analysis should be considered positive when number of diatoms is above a minimal established limit; 20 diatoms/ 100 µl of pellet obtained from 10 gm of lung samples and 50 diatoms from other organs and further matching of diatoms from bone marrow and drowning site can strengthen this supportive evidence and a positive conclusion can be drawn whether person was living or not when drowned. Detection of diatoms in the bone marrow is a proof that the individual was alive when entered the water.

Light Manipulation by Single Cells: The Case of Diatoms

“…Nowadays, the fossilized remain of diatom frustules, the socalled diatomite or diatomaceous earth, is routinely used in toothpaste and in some facial scrubs due to its abrasive property and in infiltration of water due to the submicron porosity of the material. Application of living diatoms include environmental monitoring and assessment of seas and freshwaters [51] and forensic science (starting from the analysis of the diatom content of dead bodies recovered from water) [52].…”

Diagnosis of Drowning and the Value of the Diatom Test in Veterinary Forensic Pathology

“…Diatoms are unicellular, photosynthetic and autotrophic organisms that live both in fresh water and saltwater. Usually, the size range of diatoms (between 20 and 200 μm) and their morphology allow them to percolate through the alveolo-capillary barrier and subsequently enter into the bloodstream during the pre-agonic state of drowning (8, 10, 12). Although the diatom test is a valid test to support the diagnosis of drowning, its sensitivity and specificity is still controversial; the main limitation is based on the potential post-mortem contamination of the organs due to the ubiquitous distribution of diatoms.…”

Enhancing Percolation in Phosphatic Clay Using Diatoms under Laboratory Conditions

“…Diatoms are photosynthetic single-celled algae with siliceous shells called frustules found in fresh and marine waters (12). Their ubiquitous distribution in the environment provides a significant impact on the carbon and silicon cycles.…”

“…Their ubiquitous distribution in the environment provides a significant impact on the carbon and silicon cycles. The unique properties of its porous frustules have been explored for a variety of applications to include ecological monitoring (13, 14), drug delivery, (15), heterogeneous catalysis (16), gene transfection carriage (17), and forensic research (12). Geological timeline indicates that diatoms have been depositing their siliceous skeletal remains in the sediment since the early Triassic period (18) as soft, granular, component called diatomaceous earth (19).…”