Design and evaluation of a bioreactor with application to forensic burial environments. (December 2015)

• Record Type: Journal Article
• Authors: Dunphy, Melissa A.; Weisensee, Katherine E.; Mikhailova, Elena A.; Harman, Melinda K.
• Is Part Of: Forensic science international. Volume 257(2015)
• Page Start: 242
• Page End: 251
• Publication Date: 2015-12
• Subjects: Artificial aging -- Bioreactor -- Bone -- Decomposition -- Postmortem interval -- Soil analysis; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2015.08.014
• Languages: English
• ISSNs: 0379-0738

Abstract

Highlights: The forensic bioreactor accounted for forensically relevant environmental factors. Environmental variables were characterized in a soil science context. The bioreactor design controlled variables known to impact bone decomposition. Bone weathering varied after 90-day exposure to different soils and temperatures. The bioreactor advances forensic taphonomy methods for analyzing skeletal remains. Abstract: Existing forensic taphonomic methods lack specificity in estimating the postmortem interval (PMI) in the period following active decomposition. New methods, such as the use of citrate concentration in bone, are currently being considered; however, determining the applicability of these methods in differing environmental contexts is challenging. This research aims to design a forensic bioreactor that can account for environmental factors known to impact decomposition, specifically temperature, moisture, physical damage from animals, burial depth, soil pH, and organic matter content. These forensically relevant environmental variables were characterized in a soil science context. The resulting metrics were soil temperature regime, soil moisture regime, slope, texture, soil horizon, cation exchange capacity, soil pH, and organic matter content. Bioreactor chambers were constructed using sterilized thin-walled polystyrene boxes housed in calibrated temperature units. Gravesoil was represented using mineral soil (Ultisols), and organic soil proxy for Histosols, horticulture mix. Gravesoil depth was determined using mineral soil horizons A and Bt2 to simulate surface scatter and shallow grave burial respectively. A total of fourteen different environmental conditions were created and controlled successfully over a 90-day experiment. These results demonstrate successful implementation and control of forensic bioreactor simulating precise environments in a single research location, rather than site-specific testing occurring in different geographic regions. Bone sections were grossly assessed for weathering characteristics, which revealed notable differences related to exposure to different temperature regimes and soil types. Over the short 90-day duration of this experiment, changes in weathering characteristics were more evident across the different temperature regimes rather than the soil types. Using this methodology, bioreactor systems can be created to replicate many different clandestine burial contexts, which will allow for the more rapid understanding of environmental effects on skeletal remains.