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Biomarkers of Human Decomposition Ecology and the Relationship to Postmortem Interval

NCJ Number
Date Published
September 2012
91 pages
This final report presents the results of a study aimed at providing baseline physicochemical and bacterial community data for developing methods to postmortem interval estimation.
The goals of this study were to answer two main questions: 1) what is the physicochemical and microbial composition of human decomposition in the terrestrial landscape; and 2) do the physicochemical and microbiological data associated with human decomposition conform to a pattern that has the potential to improve postmortem interval (PMI) estimation. Data for the study were obtained from comparison of soil samples taken from different areas within the University of Tennessee Anthropology Research Facility (ARF) to soil samples collected outside the facility. Using one-way ANOVA, six significant grave soil parameters were evaluated for each soil sample: soil moisture content, soil organic content, soil pH, total nitrogen, carbon to nitrogen ratio, and lipid-bound phosphorus. The analysis found that significant differences were noted between the samples taken within the facility and those taken outside the facility for the parameters of soil pH, moisture content, and organic content. The samples from within the facility were also analyzed to determine any differences in soil composition for those areas with high, medium, and low levels of decomposition. The analysis found that areas within in the facility that had higher rates of decomposition (areas where bodies are constantly decomposing) showed significant changes in the underlying bacterial community. The study also analyzed the bacterial community in grave soils taken from directly underneath actively decomposing corpses. The analysis found that as postmortem interval increased, the relative distribution of the individual bacterial changed and appeared to follow time since death, becoming more similar in composition to that observed in the non-facility normal soil samples. Implications for future research are discussed. Tables, figures, and references
Date Published: September 1, 2012