Diatoms from inland aquatic and soil habitats as indestructible and nonremovable forensic environmental evidence

J Forensic Sci. 2022 Jul;67(4):1490-1504. doi: 10.1111/1556-4029.15017. Epub 2022 Mar 2.

Abstract

Environmental analysis of soil, water, and plants plays a key role in the criminal investigation process, as it not only provides information about the course of the crime, but it can also elucidate the connection between the offender, the victim, and the environment. One particularly useful way of linking the victim and offender to a specific environment is by analyzing their clothing for the presence of diatoms. The present research was conducted upon field experiments. Firstly, it examines the variability of diatom and the quantitative analysis of diatom communities in designated places, each at an increasing distance from the aquatic ecosystem. Secondly, it analyses the differentiation of the structure of diatom communities in designated environments located close to each other. Thirdly, it examines the diatom colonization of selected substrates: cotton, chamois leather, and sponge. Finally, it confirms whether the diatoms which transfer to socks after contact with the selected environment reflect the structure of the diatom communities in that environment, even after the socks had been washed. Our findings indicate that diatom communities vary considerably, even between environments separated by short distances, and that objects placed in a particular environment are colonized by diatoms that reflect the environmental samples, irrespective of the substrate. In addition, after contact with a specific aquatic ecosystem, sock material retained diatom collections that reflected the environment samples, even though the time of exposure was very short and after the socks had been washed. This provides valuable information that can be used as forensic evidence.

Keywords: crime scene geolocation; diatoms transfer; environmental trace; forensic ecology; freshwater crime scenes; persistence of diatom traces.

MeSH terms

  • Diatoms*
  • Ecosystem
  • Forensic Medicine
  • Soil
  • Water

Substances

  • Soil
  • Water