Abstract

Diatoms are eukaryotic, unicellular algae that belong to a Bacillariophyceae family and it exists in water. Diatom is important in determining whether or not a person died as a result of drowning. When a corpse is retrieved from the water, it is generally believed that the death was caused by drowning, and that the body was drowned either before or after death. In such circumstances, the existence of diatoms in body tissues is a very useful evidence in determining the cause of death. Various types of diatoms found in dead body tissues are related to the types of diatoms present in bodies of water that are recovered from the body. The objective of this study was to find out which types of Diatom are present in different freshwater bodies around Patna district of Bihar, India. In this research, freshwater samples were collected by Random Sampling Technique from 17 different water habitats of Patna, during January to February, 2021. For diatom analysis, samples from ecological niches like river Ganga, ponds, and lakes were collected in clean water bottles with tight-fitting caps.Extraction of diatoms is done in two ways: The H2O2 method and the HNO3 method. The aim is to determine which extraction procedure — H2O2 or NHO3 — is best for diatom extraction. After the extraction of diatoms, the examination and photography of diatoms species is performed by compound microscope (Leica DM750 with Leica ICC50 E camera). Different Diatoms species found in various water environments at different location were investigated in this research. Some of their names are Cymbella sp., Fragiliaria sp., Ehrenbergiulva granulosa, Coscinodiscus radiates, Cyclotella sp., Melosira sp., Actinoptychus sp., Triceratium sp., Nietzsche sp., Actinocyclus sp. The information from this experiment will help in forensic science laboratories to identify diatoms, criminal investigation and locating drowning sites or place of crime. In this analysis we found that nitric acid digestion method give better extraction as compare to hydrogen peroxide extraction method.

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