The transferability of marine diatoms to forensic evidence in different materials and evaluation of various extraction methods

Diatoms are important creatures that have been studied for the purpose of elucidating drowning cases. These creatures can cling to the body, clothes or belongings of the person or persons involved in the forensic incident. The presence of diatoms in the evidence collected by crime scene investigation teams is used to illuminate the forensic event. In this study, it is aimed to determine the appropriate extraction method in order to analyze the diatoms attached to the fabric in a more efficient and short way in criminal analysis. Compared with previous studies, different fabric types and different incubation times were studied. Again, in order to work on local diatom species, diatoms in the Marmara Sea were provided to cling to fabrics. This study, carried out in a natural aquatic environment, gains importance in terms of its applicability to criminal cases. In the thesis study, polyester added viscose fabric, polyester added tencel fabric and 100% viscose fabric type were kept in the Marmara Sea. Fabrics were incubated for 4 hours, 24 hours and 96 hours. Then, the isolation of diatoms was ensured by applying the methods of washing with water, washing with alcohol and disintegration with hydrogen peroxide on the fabric samples brought to the laboratory. The obtained diatoms were counted under the light microscope. Statistical analysis of the counting results was made and it was determined that the highest adhesion was to viscose fabric, and the least adhesion was to tencel and polyester blended fabric. While the open and rough texture of viscose fabric made it easier for diatoms to adhere to the fabric surface, the shiny, smooth and semi-open texture of polyester made it difficult for diatoms to adhere to the fabric surface. In the study, more diatoms were counted in long-term (96-hour) incubations than in short-term (4-hour and 24-hour) incubations. As the incubation time increased, the number of diatoms attached to the fabric increased. In diatom extraction from fabric, more diatoms were obtained with the H2O2 method and it was determined that this method gave results in a shorter time compared to other water and alcohol methods.