Adipocere is a late-stage postmortem decomposition product that forms from the
lipids present in soft tissue. Its formation in aquatic environments is typically related to the presence of a moist, warm, anaerobic environment, and the effect of decomposer microorganisms. The ideal temperature range for
adipocere formation is considered to be 21-45°C and is correlated to the optimal conditions for bacterial growth and enzymatic release. However,
adipocere formation has been reported in cooler aquatic environments at considerable depths. This study aimed to investigate the chemical process of
adipocere formation in a cold freshwater environment in Lake Ontario, Canada. Porcine tissue was used as a human tissue analogue and submerged at two depths (i.
e., 10 and 30 feet) in the trophogenic zone of the lake. Samples were collected at monthly postmortem submersion intervals and analysed using diffuse reflectance infrared Fourier transform spectroscopy to provide a qualitative profile of the
lipid degradation and
adipocere formation process. Early stage
adipocere formation occurred rapidly in the cold water environment and proceeded to intermediate stage
adipocere formation by the second month of submersion. However, further
adipocere formation was inhibited in the third month of the study when temperatures approached the freezing point. The depth of submergence did not influence the chemical conversion process as similar stages of
adipocere formation occurred at both depths investigated. The study demonstrated that
adipocere can form rapidly, even on small amounts of soft tissue, which may be representative of dismembered or disarticulated limbs discovered in an aquatic environment.