Evaluation of the Effectiveness of an Alternate Diatom Extraction Procedure in Diatomological Study

Abstract

Background: The “Diatom Test” is based on the recovery of diatoms in high concentration in the organs of drowned persons because diatoms pass through the alveoli into the great circulation. Acid digested extracts of various internal organs and water collected from waterbodies demonstrate the presence of diatoms. If quantitatively and qualitatively these diatoms match to each other, that is the confirmatory diagnosis of death due to drowning in that drowning medium. This study was conducted to analyze the effectiveness of alternate method of diatom extraction using diluted Sulphuric acid solution and to compare its effectiveness with the traditional method of extraction of diatoms using concentrated nitric acid.Methods: It was a prospective study. Samples were collected from ten different water bodies which included lakes,rivers, canals and reservoirs, for a period of one year in all the seasons. The pH and temperature of water were recorded during sampling. From each of water samples, diatoms were extracted using both classical and alternate method. And then compared by observing the diatoms at 100X magnification under compound microscope. Total 22 genera of diatoms were identified. Most of them were pennales and few were centrales. The time demanded for complete digestion of samples with strong acids like concentrated nitric acid was much lesser time than with diluted acids as it hasstronger digestive capability in comparison to diluted sulphuric acid. The structures of different diatoms specifically Cyclotella, Cybella, Navicula were better found in almost intact state with clear background after digestion by diluted sulphuric acid.Conclusion: Depending on different criterion, digestion by diluted sulphuric acid has procured better result than concentrated nitric acid digestion method. Therefore, for qualitative and quantitative diatom analysis alternate diatom extraction method is a better choice than traditional method.