Using measures of water quality to narrow down the postmortem submersion interval (PMSI) in water

The purpose of this study was to explore the use of water quality parameters as proxy variables for establishing a timeline for the postmortem submersion interval (PMSI). This research was conducted using mice in water samples collected from the Schuylkill river in Philadelphia, US, as well as deionized water for control. Parameters were monitored from initial placement of the specimens in water to the completion of the experiment three months later. These parameters included pH, dissolved oxygen (DO), turbidity, conductivity, total organic carbon (TOC), nitrite, nitrate, and heterotrophic bacteria. In addition, qualitative observations of the specimens were made using Total Aquatic Decomposition Score (TADS). Peak changes in conductivity, turbidity, and TOC parameters coincided with a TADS of 7–9, indicating a partially decomposed carcass. These results preliminarily suggest that standard, easy to measure water quality parameters could serve as potential indictors in estimating PMSI in surface water bodies, however more experimental and field studies are needed to replicate results and validate findings.