Study of Diatom Flora of Kaalesar Ghat of Rapti River at Gorakhpur for Forensic Consideration

Diatoms are unique algae. They are scientifically known as Bacillariophyceae. Diatoms have been used in forensic science in a variety of ways, the most frequent being the diagnosis of death by drowning. When a person drowns, water will enter the lungs and then enter the bloodstream through ruptures in the peripheral alveoli before being carried to the other organs such as the liver and heart. Naturally, the microscopic contents of the water, which will include diatoms, will pass into the blood as well. The detection of diatoms in the organs can contribute to a diagnosis of death by drowning, a process referred to as the ‘diatom test’. A study was conducted in the department of Forensic Science, SHUATS, Prayagraj which included the extraction and identification of diatoms from the collected water samples from three different sites of Kaalesar Ghat of Rapti River in Gorakhpur. The acid digestion method was used for diatom extraction. And, after analysis total 13 diatom species were found. The identified diatoms were of great ecological assessment that plays an important role in criminal investigations related to premortem or ante-mortem drowning. Keywords: Diatom, Drowning, D-mapping, Rapti-River

Comparison of Diatoms Which Were Obtained from The External Surface of The Body and Internal Organs in the Corpses Pulled Out of Water Using Colloidal Silica Gradient Centrifuge Method

Objective: Diatom analysis is a valuable tool in forensic science and it is useful in diagnosis of drowning and determination of the drowning site. The basic principal of the “diatom test” in investigation of drowning is based on correlation between diatoms are present in the medium where the possible drowning took place and inhalation of water causes penetration of diatoms into the alveolar system and blood stream and consequently their deposition into brain, kidneys and other organs, like the bone marrow of large bones. There are various extraction methods that are used to isolate diatoms from water and tissues. Nitric acid digestion is a worlwide known method for the extraction of diatoms. In this study, instead of acid digestion method, colloidal silica gradient centrifuge method was used to extraction diatom and the advantages of this technique has been aimed to be discussed. Materials and Methods: Therefore, 30 visceral and body fluid samples that have been obtained from corpses which were removed from the water and brought to the Council of Forencic Medicine to perform autopsy, were examined and diatom were obtained from samples of 19 cases. Moreover, the diatoms that were obtained from the swab samples taken from the outer body surfaces and the diatoms obtained from the visceral organs were compared. Results: When the diatoms which were obtained from internal organs tissues and body fluids were evaluated numerically, it was seen that the diatoms that were obtained lungs were in high numbers and it was followed by pleural liquid...

Does occurrence of diatoms in internal organs always prove a case of drowning

Diatoms (Bacillariophyta) are unicellular algae inhabiting in aquatic ecosystems and marsh habitats on the entire Earth. This group of algae, variable in terms of species, comprises both cosmopolitan ones but also those whose occurrence is limited to specific environmental conditions, i.e. stenotopic species. Diatoms are distinguished by unique cell walls making so-called, frustules, whose structures constitute the bases for differentiation between species. Frustules are resistant to the majority of environmental conditions that destroy other algae. Due to the above characteristics diatoms have been incorporated in forensic investigations and they can be the conclusive component of the proceedings by indicating drowning as the cause of death. In those cases, it is important to answer the question whether finding diatoms in internal organs of corpses found in water always proves drowning. The publication uses reports from forensic medical examinations of corpses and reports from detecting presence of diatoms in internal organs performed in years 2013-2017 in the Institute of Forensic Medicine of Warsaw Medical University, which is presently the only centre in Poland that routinely performs the diatom test. It has been demonstrated that a positive result of the diatom test generally coincides with the conclusive indications of the cause of death in the forensic medical autopsy reports. Only in few individual well-explainable cases the results of the diatom tests did not confirm conclusions from the forensic autopsies, which excluded drowning as the cause of death.