Bone and Tooth: Substrates for determining Drowning: A new diagnostic procedure in forensic medicine Practice?

Diatom tests are rarely used during autopsy to confirm drowning as the cause of death (COD) because of limitations of the current literature involving these techniques. Instead, experts rely on physical examination by the pathologist. Due to interpretive concerns regarding Diatom tests, they are often insufficient in establishing a diagnosis, but offer the potential to be an extremely useful diagnostic tool with further understanding. The aim of study is to optimize "Diatom Tests" for use in forensic medicine in Bosnia and Herzegovina.

A randomized prospective experimental study was conducted, using albino Wistar rat models (Rattus norvegicus), at the Veterinary Facility, University of Sarajevo. Thirty-two adult albino rats, were used and distributed into groups as follows: Group A (6 deceased rats with COD other than drowning, but due to mechanical asphyxia, which were then submerged for 1 h after death); Group B (6 deceased rats with COD other than drowning, but due to mechanical asphyxia, which were then submerged for 72 h after death); Group C (6 rats that were immediately autopsied after drowning, with COD determined as drowning); Group D (6 rats that underwent a 48-hour postmortem period after drowning); Group E (COD: drowning, post-mortem 72hrs after death, remained submerged in water until PM). Live algological material was collected for the research of the systematics of algae from the Bosna river, Sarajevo, and transported to the University of Sarajevo (Department of Biology, Faculty of Science). Periphyllon, epiphyllon and epipelon were used to collect phytobenthos. The material was fixed with 4% formalin solution. Laboratory processing of diatoms was performed using the methods described by Hustedt (16). In the process of obtaining pure diatom valves, part of the material is digested with potassium permanganate (KMnO4), sulfuric acid (H2SO4), and oxalic acid (C2H2O4). In the next step, the cleaned diatom valves were mounted in Canadian balsam. A light microscope under 1000x magnification (Best Scope 2020) was used to evaluate and analyze the species. The identification of diatoms was performed using the reference of Cantonati et al (17). The nomenclature of diatom species was performed according to Guiry & Guiry's worldwide electronic internet database.

No diatoms were found in Groups A and B. However, Navicula sp. and Sellaphora sp. cf., were discovered during bone analysis of Group C where rats were immediately autopsied after drowning. Hantzschia amphioxus taxon was present in Group D, which underwent a 48-hour postmortem period after drowning and before samples were taken. In Groups C and D, where drowning was the COD, Diatoma vulgaris i Pinnularia major, Achnanthidium minutissimum i Melosira varians were present in the tooth samples.

Optimization of the "Diatom Test" method could potentially lead to its future use as a routine method within experimental settings. This experimental study is a starting point that guides forenscic medicine pracitioners towards the optimization of tests and sampling in cases of unexplained etiology, where preserved soft tissue structures is not available. In these cases, teeth and bones serve as accessible materials for diagnosing COD, alongside standardized nonspecific findings in the absence of organs for micro- and macroanalysis.