Extraction methods of diatoms-A review

Detection of diatoms in tissues has been applied as an important sign of drowning since the beginning of 20th century and utility of diatoms for the diagnosis of drownings cases was debated soon after they were first found in lung exudates. Hard bones (sternum and femur) and soft tissues (lungs and liver etc) of drowned bodies are usually sent to the Forensic Science Laboratories for the detection of diatom. Dissolution of these samples is not very difficult but complete extraction of diatoms frustules from these samples needs great care, attention and expertise. While solving drowning cases, a correlation between the diatoms extracted from these tissue samples and the samples obtained from putative drowning medium has to be established for the successful determination of drowning site. Therefore, it needs proper method for extraction of diatoms from tissues and water samples to avoid even minor contamination. In the present study, literature related with various extraction methods of diatoms from postmortem and water samples has been reviewed.