Bone weathering patterns of metatarsal v. femur and the postmortem interval in Southern Ontario

Twenty-five defleshed pig femora and 25 metatarsals were placed outdoors and observed over 291 days to establish: (1) bone weathering patterns for use in estimating time since death in Southern Ontario and (2) whether larger (femora) or smaller (metatarsals) bones provide a better indicator of time since death. Pig hind limbs were observed to determine a timeline for decomposition of soft tissues during the fall and winter. Ambient air temperature, humidity, precipitation, sunlight, soil pH, and freezing and thawing were considered as factors affecting the breakdown of bone. Weathering patterns were observed based on the extent of bleaching, amount of periosteum and soft tissues present, as well as the appearance of greasiness, cracking and flaking of cortical bone. Both entomological activity and climatic conditions affected soft tissue decomposition. Animal activity affected both the process of bone weathering and soft tissue decomposition, causing variability in sample decomposition and bone breakdown. The variation in microenvironment, partially caused by soil composition, introduced variability in bone weathering rates. Four bone weathering stages were established based on patterns observed. Femora proved to be more resilient and showed more degrees of change due to weathering, thus proving to be a better indicator of time since death than metatarsals.     

Modelling the buried human body environment in upland climes using three contrasting field sites

Despite an increasing literature on the decomposition of human remains, whether buried or exposed, it is important to recognise the role of specific microenvironments which can either trigger or delay the rate of decomposition. Recent casework in Northern England involving buried and partially buried human remains has demonstrated a need for a more detailed understanding of the effect of contrasting site conditions on cadaver decomposition and on the microenvironment created within the grave itself. Pigs (Sus scrofa) were used as body analogues in three inter-related taphonomy experiments to examine differential decomposition of buried human remains. They were buried at three contrasting field sites (pasture, moorland, and deciduous woodland) within a 15 km radius of the University of Bradford, West Yorkshire, UK. Changes to the buried body and the effect of these changes on hair and associated death-scene textile materials were monitored as was the microenvironment of the grave. At recovery, 6, 12 and 24 months post-burial, the extent of soft tissue decomposition was recorded and samples of fat and soil were collected for gas chromatography mass spectrometry (GCMS) analysis. The results of these studies demonstrated that (1) soil conditions at these three burial sites has a marked effect on the condition of the buried body but even within a single site variation can occur; (2) the process of soft tissue decomposition modifies the localised burial microenvironment in terms of microbiological load, pH, moisture and changes in redox status. These observations have widespread application for the investigation of clandestine burial and time since deposition, and in understanding changes within the burial microenvironment that may impact on biomaterials such as hair and other associated death scene materials.     

Characterization of adipocere formation in animal species

Adipocere is a soft white substance formed postmortem from fatty tissue in a decomposing body. In this preliminary study the formation of adipocere in soil was investigated for a number of animal species. Adipocere was formed from the fatty tissue of pig, cattle, sheep and rabbit. It was found that adipocere did not form from the fatty tissue of chicken or kangaroo in the time frame investigated. The issues being considered are relevant to the forensic examination of remains whose origin is otherwise uncertain or which are, in some way, related to human remains. Infrared spectroscopy and gas chromatography-mass spectrometry were used to characterise the composition of adipocere formed in the various species after different burial durations. Adipocere was observed to form at different rates among the species, but there was no distinct evidence of the fundamental composition varying between species.     

The effect of body coverings on the formation of adipocere in an aqueous environment

Adipocere is a postmortem decomposition product that consists of a mixture of fatty acids. The rate of formation of adipocere from pig adipose tissue in an aqueous environment has been monitored. The effect of various clothing and carpet material types on the process was investigated. The fatty acid composition of the adipocere was determined at regular intervals using gas chromatography-mass spectrometry. Examination of the changes to fatty acid concentrations allowed the degree of adipocere formation in the different environments to be estimated. The study demonstrated that the rate at which adipocere forms is particularly accelerated by the presence of coverings produced from natural materials. Elemental analysis by inductively coupled plasma-mass spectrometry revealed, for the most part, little change to the cations present in the adipocere formed. However, an increase in Ca concentration was observed for tissue wrapped in acrylic carpet, which was associated with a CaCO(3) additive used in the carpet manufacture.     

Time since death. An entomological study on corpses

After death, during disintegration, various environmental conditions and fauna play an important role, indicating "time since death." The natural openings of the host body provide the most important breeding place for an agent which could consume the body very quickly, e.g., flies. Wounds are preferred over the natural openings by this agent. In such cases, antemortem wounds become unidentifiable. This paper presents the study of 25 cases in which inferences relating to the maturation of blow fly life stages and the total developmental time of an adult blow fly in breeding experiments in the prevailing environment are drawn. These can be used to help estimate the "time since death" of infested bodies.     

Fatty degeneration in renal tubule epithelium in accidental hypothermia victims

The diagnosis "death due to hypothermia" is mainly based on circumstances and gross autopsy findings like frost erythema and gastric erosions. Up to now, there are no reliable histologic criteria available to confirm the diagnosis "death due to hypothermia." However, fatty changes of organs have been reported already in the literature as a histological finding contributing to the diagnosis "death due to hypothermia." To evaluate these reports, cases with well-documented hypothermia (study-group; n=83), cases with other causes of death (control-group; n=25) and additionally also seven cases with a past medical history of diabetes mellitus were investigated. Renal tissue autopsy samples were taken from both the left and the right kidney and investigated for signs of fatty degeneration within the renal tubule epithelium. The results were compared with regard to macroscopic signs of hypothermia (Wischnewski-ulcers, erythema), as reported in the autopsy protocols. The results lead to the conclusion, that fatty degeneration is a very reliable histologic diagnostic criterium in cases of hypothermia, comparable to the significance of Wischnewski-ulcers.     

A report of decomposition rates of a special burial type in Edmonton, Alberta from an experimental field study

Regional studies that examine decomposition rates of certain faunal remains can help to determine time since death. Forensic anthropologists have long used qualitative decomposition data, but linking these to more quantitative data could improve time since death estimations. Experiments were developed in which domestic pigs (Sus scrofa) were buried with varying characteristics then excavated and observed over a period of 15 months in Edmonton, Alberta. Data recorded after two weeks, five weeks, three months, one year, and 15 months were correlated with stages of decomposition as well as time since death, climate data, grave type, clothing, burial depth, and other factors. Results from these experiments provide useful regional information about stages of decomposition in a burial context. Pigs buried in June were skeletonized by approximately three to five weeks, while those buried in May were skeletonized between five weeks and three months. Climate data, insects, and grave type contributed the most to advanced decomposition, mainly in the form of mummification, and skeletonization.     

Odor analysis of decomposing buried human remains

This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), lists and ranks the primary chemical constituents which define the odor of decomposition of human remains as detected at the soil surface of shallow burial sites. Triple sorbent traps were used to collect air samples in the field and revealed eight major classes of chemicals which now contain 478 specific volatile compounds associated with burial decomposition. Samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and were collected below and above the body, and at the soil surface of 1.5-3.5 ft. (0.46-1.07 m) deep burial sites of four individuals over a 4-year time span. New data were incorporated into the previously established Decompositional Odor Analysis (DOA) Database providing identification, chemical trends, and semi-quantitation of chemicals for evaluation. This research identifies the "odor signatures" unique to the decomposition of buried human remains with projected ramifications on human remains detection canine training procedures and in the development of field portable analytical instruments which can be used to locate human remains in shallow burial sites.     

Marine taphonomy: adipocere formation in a series of bodies recovered from a single shipwreck.

Taphonomy of marine environments has been studied mostly from individual cases. The formation of adipocere, or "grave-wax," is an important indicator of the postmortem interval. In the present paper, the conditions and the timing of adipoceric formation are observed in a series of 15 cadavers recovered at different times, over a period of 433 days, from the same contained environment. Initial foci of adipocere on the subcutaneous tissue of the cadavers were detected as early as 38 days from the time of immersion in cold (10-12 degrees C) sea water. The discrepancies between our findings and previous reports on the correlation between time since death and decomposition stages in marine environments are discussed.     

Decomposition of buried bodies and methods that may aid in their location

This is the second report on an ongoing study conducted to collect data on the decompositional rates of human cadavers and the first on buried cadavers. Six unembalmed human cadavers were buried separately in unlined trenches of various depths and allowed to naturally decompose for a time period ranging from a month to a year. During the period of burial, data were collected daily on the air, soil, and cadaver temperature at each burial site. At the end of each specified burial period the cadavers were exhumed and examined for the degree of decomposition which had taken place as well as changes in the soil pH, surface vegetation, and carrion insect activity. Analysis of the data shows that the decomposition rate of buried cadavers is highly dependent on the depth of burial and environmental temperatures. The depth at which the cadaver was buried also directly affected the degree of soil and vegetational changes as well as access by carrion insects. Application of this information can contribute to a more accurate estimation of time since death of a buried corpse and may aid in the location of such corpses.     

Detection of Gunshot Residue in Blowfly Larvae and Decomposing Porcine Tissue Using Inductively Coupled Plasma Mass Spectrometry (ICP‐MS)*

Abstract: Blowfly larvae and porcine tissue contaminated with gunshot residue (GSR) were collected during summer and winter months, over a 37‐day and a 60‐day sampling period, respectively. Wound samples were microwave‐digested and analyzed by inductively coupled plasma mass spectrometry (ICP‐MS) for the detection of antimony, barium, and lead. During summer, the 37‐day sampling period encompassed all stages of decomposition, except skeletonization. The three elements were detected in larvae only on days 3 and 4 after death but were detected at significant levels in tissue samples throughout the entire sampling period. In winter, no significant decomposition was observed throughout the 60‐day sampling. Although temperatures were too low for blowfly activity, the three elements were detected in the tissue samples at relatively constant, significant levels. Hence, GSR determination in tissue was more dependent on decomposition stage rather than time since death.     

Unusual hanging deaths

Four unrelated hanging deaths involving young white males, all in enlisted status in the United States military, are presented. Taken in a military context, one scene served as a suicide note equivalent with the unmistakable message of extreme defiance toward military regulations. In two cases, the elaborate attire of the decedents could have lead to the misclassification of the manner of death if investigative information had not been considered. Extensive background investigation and review of medical records in the fourth case disclosed that the victim had an eight- to ten-year history of compressing his neck to cause unconsciousness. He left an extensive suicide note in which he concluded that "hanging would be good." Each case has certain unique features, as a group, the cases all demonstrate a continuum from obvious suicide to cases where the manner of death is, at first, equivocal.     

The Effect of Repeated Physical Disturbance on Soft Tissue Decomposition—Are Taphonomic Studies an Accurate Reflection of Decomposition?*

Although the relationship between decomposition and postmortem interval has been well studied, almost no studies examined the potential effects of physical disturbance occurring as a result of data collection procedures. This study compares physically disturbed rabbit carcasses with a series of undisturbed carcasses to assess the presence and magnitude of any effects resulting from repetitive disturbance. Decomposition was scored using visual assessment of soft tissue changes, and numerical data such as weight loss and carcass temperature were recorded. The effects of disturbance over time on weight loss, carcass temperature, soil pH and decomposition were studied. In addition, this study aimed to validate some of the anecdotal evidence regarding decomposition. Results indicate disturbance significantly inversely affects both weight loss and carcass temperature. No differences were apparent between groups for soil pH change or overall decomposition stage. An insect-mediated mechanism for the disturbance effect is suggested, along with indications as to why this effect may be cancelled when scoring overall decomposition.     

The Initial Changes of Fat Deposits During the Decomposition of Human and Pig Remains

Abstract:  The early stages of adipocere formation in both pig and human adipose tissue in aqueous environments have been investigated. The aims were to determine the short-term changes occurring to fat deposits during decomposition and to ascertain the suitability of pigs as models for human decomposition. Subcutaneous adipose tissue from both species after immersion in distilled water for up to six months was compared using Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and inductively coupled plasma-mass spectrometry. Changes associated with decomposition were observed, but no adipocere was formed during the initial month of decomposition for either tissue type. Early-stage adipocere formation in pig samples during later months was detected. The variable time courses for adipose tissue decomposition were attributed to differences in the distribution of total fatty acids between species. Variations in the amount of sodium, potassium, calcium, and magnesium were also detected between species. The study shows that differences in total fatty acid composition between species need to be considered when interpreting results from experimental decomposition studies using pigs as human body analogs.     

The effect of the burial environment on adipocere formation

Adipocere is a decomposition product comprising predominantly of saturated fatty acids which results from the hydrolysis and hydrogenation of neutral fats in the body. Adipocere formation may occur in various decomposition environments but is chiefly dependent on the surrounding conditions. In a soil burial environment these conditions may include such factors as soil pH, temperature, moisture and the oxygen content within the grave site. This study was conducted to investigate the effect of these particular burial factors on the rate and extent of adipocere formation. Controlled laboratory experiments were conducted in an attempt to form adipocere from pig adipose tissue in model burial environments. Infrared spectroscopy, inductively coupled plasma-mass spectrometry, and gas chromatography-mass spectrometry were employed to determine the lipid profile and fatty acid composition of the adipocere product which formed in the burial environments. The results suggest that adipocere can form under a variety of burial conditions. Several burial factors were identified as enhancing adipocere formation whilst others clearly inhibited its formation. This study acts as a preliminary investigation into the effect of the burial environment on the resultant preservation of decomposing tissue via adipocere formation.     

Food labeling: trans fatty acids in nutrition labeling,nutrient content claims,and health claims. Final rule

The Food and Drug Administration (FDA) is amending its regulations on nutrition labeling to require that trans fatty acids be declared in the nutrition label of conventional foods and dietary supplements on a separate line immediately under the line for the declaration of saturated fatty acids. This action responds, in part, to a citizen petition from the Center for Science in the Public Interest (CSPI). This rule is intended to provide information to assist consumers in maintaining healthy dietary practices. Those sections of the proposed rule pertaining to the definition of nutrient content claims for the "free" level of trans fatty acids and to limits on the amounts of trans fatty acids wherever saturated fatty acid limits are placed on nutrient content claims, health claims, and disclosure and disqualifying levels are being withdrawn. Further, the agency is withdrawing the proposed requirement to include a footnote stating: "Intake of trans fat should be as low as possible." Issues related to the possible use of a footnote statement in conjunction with the trans fat label declaration or in the context of certain nutrient content and health claims that contain messages about cholesterol-raising fats in the diet are now the subject of an advance notice of proposed rulemaking (ANPRM) which is published elsewhere in this issue of the Federal Register.     

Macroscopic observations of the effects of varying fresh water pH on bone

Little is known about the decomposition of remains in aquatic environments of varying pH, and even less is known about the specific effects of these environments on bone. Bovine bones were placed in solutions of pH 1, 4, 7, 10, and 14 and observed over a period of 1 year. All solutions eventually removed or dissolved the soft tissues from the external surface of the bone. The pH 7 and pH 10 solutions had little effect on the bone, but the other solutions affected the bone to varying degrees. Extreme pH levels were the most destructive, while more moderate pH levels had lesser but significant and interesting effects. Empirical data on postmortem aquatic changes may be extremely useful in forensic contexts for both improving time since death estimates and also for providing better information to underwater recovery experts thereby potentially increasing the quantity and quality of remains recovery.     

A preliminary investigation of the stages of adipocere formation

Adipocere is a postmortem decomposition product which forms from a body's adipose tissue. This study aimed to chemically demonstrate the process of conversion from adipose tissue to adipocere. Samples of adipocere were collected from pig cadavers that were allowed to decompose for varying intervals. Samples of soil were collected from beneath the cadavers and analyzed to determine the leaching effect of adipocere. Gas chromatography/mass spectrometry (GC/MS) was used to quantify the fatty acid composition of pig adipocere. Fourier transform infrared spectroscopy (FTIR) was used as a confirmatory test and to identify other components such as triglycerides and calcium salts of fatty acids. The study demonstrates the process of adipocere formation and the stages of formation through which the process passes using chemical techniques.     

An Analysis of Systematic Elemental Changes in Decomposing Bone

The aim of this pilot study was to investigate compositional changes in bone during decomposition. Elemental concentrations of barium, calcium, iron, potassium, magnesium, zinc and phosphorus in porcine bone (as an experimental analog for human bone) were analyzed by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The samples were taken from porcine bone subjected to shallow burial and surface depositions at 28‐day intervals for a period of 140 days. Results indicated that ICP‐OES elemental profiling has potential to be developed as a forensic test for determining whether a bone sample originates from the early stages of soft tissue putrefaction. Significant changes in iron, sodium and potassium concentrations were found over 140 days. These elements are known to be primarily associated with proteins and/or tissue fluids within the bone. Changes in their respective concentrations may therefore be linked to dehydration over time and in turn may be indicative of time since deposition.     

Evaluation of the correlation between time corpses spent in in-ground graves and findings at exhumation

To determine how long pathological findings persist after burial and which factors play a role in decomposition of a corpse, we evaluated all bodies exhumed under the auspices of the Institute of Legal Medicine at the Hannover Medical School between 1978 and 1997. A total of 87 exhumations (54 men, 33 women) were performed in this period. The time bodies remained buried varied between 5 days and 16.8 years (mean 1.5 years, median 2.3 months). Fifty-six percent of the bodies were exhumed after at most 3 months, 10% remained buried for greater than 3 years. Pathomorphological changes of the soft tissues and the internal organs remained evident after several months, in some cases after several years of burial. Overall, it was possible to evaluate internal organs after 5 years of burial. Bodies became mostly decomposed after approximately 8 years at the earliest, although it was still possible to evaluate some soft tissue remnants after 16.8 years. In stepwise logistic regression, both the length of time the body was buried (p < 0.00005) and the time of year (p < 0.0019) clearly affected the rate of physical change. The variables of sex (p = 0.33), age (p = 0.61) and changes in the integrity of the body before burial (trauma, autopsy before burial; p = 0.15) did not influence the physical state of the body after exhumation. Our data show that much information may be gained from an exhumation even after significant time has passed since burial.