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Decomposistion

Characterization Of The Volatile Organic Compounds Present In The Headspace Of Decomposing Human Remains

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ABSTRACT

Law enforcement agencies frequtly use canines trained to detect the odor of human decomposition to aid in detuermining the location of clandestine burials and human remains deposited or scattered on the surface. However, few studies attempt to identify the specific volatile organic compounds (VOCs) that elicit an appropriate response from victim recovery (VR) canines. Solid-phase microextraction (SPME) War combined with gas chromatography mass spectrometry (GC–MS) to identify the VOCs released into the headspace associated with 14 separate tissue samples of human remains previously used for VR canine training. The headspace was found to contain various classes of VOCs, including acids, alcohols, aldehydes, halogens, aromatic hydrocarbons, ketones, and sulfides. Analysis of the data indicates that the VOCs associated with human decomposition share similarities across regions of the body and across types of tissue. However, sufficient differences exist to warrant VR canine testing to identify potential mimic odor chemical profiles that can be used as training aids. The resulting data will assist in the identification of the most...

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Forensic Entomology Decay

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Forensic entomology is the study of insects for medico-legal purposes. There are many ways insects can be used to help solve a crime, but the primary purpose of forensic entomology is estimating time since death.Once a person dies his or her body starts to decompose. The decomposition of a dead body starts with the action of microorganisms such as fungi and bacteria, followed by the action of a series of insects (arthropods). Bodies decompose slowly or fast depending on weather conditions, if they have been buried or are exposed to the elements, if there is presence of insects or if they have a substance in their bodies that prevents their fast decomposition such as body size and weight, clothing,The dead body goes through constant changes allowing investigators to estimate how long that person has been dead. Generally speaking, there are 5 basic stages of decomposition:Fresh, putrefaction, fermentation, dry decay and skeletonization. Every stage attracts different kinds of organisms...

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Forensic Evaluation of Soils for Presence of Decaying Flesh

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I. Introduction

I.1 Forensic Searches for Human Remains The nature of police work is such that sometimes only vague clues are available regarding the location of a clandestine grave (e.g., “in farmer Brown’s bottom field.”). However,oftentimes without information of this type even the best available forensic tools have little hope of finding a grave. A variety of forensic tools can be used to locate clandestine graves. These are more efficient once the general location of a suspected grave site is identified. The forensic methods range from non-invasive techniques to extremely invasive techniques, and include aerial photographic surveys of suspected areas, ground level photographic surveys, magnetometer and metal detectors, dogs trained to search for cadavers, ground penetrating radar, infrared photography, vegetation differential (pioneer plants), and penetro meter. Treatments such as wetting the site and then using ground penetrating radar and/or magnetometer, plowing the siteand looking for color differential or other evidence of disturbances, and finally perform the actual forensic exhumation are also performed [1].

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Effect Of Alcohols On Decomposition Temperature Of Chloroform Hydrate

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INTRODUCTION

In connection with the work being done on hydrocarbon hydrates in the physical chemistry laboratories of the University of Oklahoma, it became desirable to know what effect 2-propanol m1Iht have on the decomposition temperature of chloroform hydrate. The decomposition effect for ethanol had been 'determined by sampson (6).

Deaton and Prost (2) report the use of alcohols as inhibltors of hydrate formation In high-pressure natural las Unes. Alcohols are Injected into the Une to decompose any hydrate present or to inhibits formation and subsequent closure of the pipes by solid hydrate.

In some preliminary experiments with the l)'Stem water-chlorotorm-2- propanol, the question arose as to Whether or not 2-propanol would form a hydrate or inhib1its formation. Bampeon (6) had determined the decomposltion effect ethanol had on chloroform hydrate. Since literature searches and current investigations have indicated that ethanol does not form a lattice type hydrate, it was assumed that a...

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Decomposition And Insect Succession On Cadavers Inside A Vehicle Environment

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Abstract

This study presents differences in rate of decomposition and insect succession between exposed carcasses on the soil surface and those enclosed within a vehicle following carbon monoxide (CO) poisoning. Nine 45-kg pigs were used as models for human decomposition. Six animals were sacrificed by CO gas, half of which were placed within the driver’s side of separate enclosed vehicles and half were placed under scavenger-proof cages on the soil surface. A further three animals were sacrificed by captive head bolt and placed under scavenger proof cages on the soil surface. The pattern of insect succession and rate of decomposition were similar between surface carcasses within trials regardless of the mode of death. Progression through the physical stages of decomposition was 3–4 days faster in the enclosed vehicle due to higher temperatures there compared to external ambient temperatures. Patterns of insect succession also differed between the vehicle and surface treatments. Carcass attendance by representatives of the Calliphoridae was delayed within the vehicle environment by 16–18 h, while oviposition...

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The Effect of Various Coverings on the Rate of Human Decompositioin

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Abstract

A multitude of factors can affect the decomposition process, increasing or decreasing its rate. Some of the most frequently observed variables are temperature, moisture, insect activity, and sun or shade exposure. Coverings can impact the decomposition process, and are found frequently in forensic cases. In a survey of New Mexico cases, Komar (2003) reported that sixteen individuals were found wrapped in plastic, and twenty were noted as wrapped in a cloth or blanket. In a survey conducted of eighty-seven cases, fifty-four of the bodies were wrapped in some type of covering. Plastic was most common, but a variety was noted, including rugs, sleeping bags, and blankets, (Manhein, 1997). In order to document how coverings affect early decomposition an experiment was designed to mimic a forensic setting. Three human cadavers were used in each of two repetitions of this experiment. Two of the cadavers were covered, one in plastic tarp, the other in a cotton blanket, while the third was left uncovered as a control...

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Analytical Separations Of Mammalian Decomposition Products For Forensic Science: A Review

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Abstract

The study of mammalian soft tissue decomposition is an emerging area in forensic science, with a major focus of the research being the use of various chemical and biological methods to study the fate of human remains in the environment. Decomposition of mammalian soft tissue is a postmortem process that, depending on environmental conditions and physiological factors, will proceed until complete disintegration of the tissue. The major stages of decomposition involve complex reactions which result in the chemical breakdown of the body’s main constituents; lipids, proteins, and carbohydrates. The first step to understanding this chemistry is identifying the compounds present in decomposition fluids and determining when they are produced. This paper provides an overview of decomposition chemistry and reviews recent advances in this area utilising analytical separation science.

1. Introduction

The study of mammalian soft tissue decomposition is an emerging area in forensic science, with a major focus of the research being the use of various chemical and biological methods to study the fate of human remains in the environment. Such techniques have major roles to play in locating clandestine gravesites assisting in the estimation of postburial interval...

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Beyond The Grave – Understanding Human Decomposition

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Human decomposition begins approximately 4 minutes after death has occurred. The onset is governed by a process called autolysis – or self-digestion. As cells of the body are deprived of oxygen, carbon dioxide in the blood increases, pH decreases and wastes accumulate which poison the cells. Concomitantly, unchecked cellular enzymes (lipases, proteases, amylases, etc.) begin to dissolve the cells from the inside out, eventually causing them to rupture, and releasing nutrient-rich fluids. This process begins and progresses more rapidly in tissues that have a high enzyme content (such as the liver) and a high water content such as the brain, but eventually affects all the cells in the body. Autolysis usually does not become visually apparent for a few days. It is first observed by the appearance of fluidfilled blisters on the skin and skin slippage where large sheets of skin slough off the body. Meanwhile, the body has acclimated to ambient temperature (algor mortis), blood has settled in the body causing discoloration of the skin...

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Decompositional Odor Analysis Database – Phase I

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ABSTRACT: This study, conducted at the University of Tennessee’s Anthropological Research Facility (ARF), describes the development of the Decompositional Odor Analysis (D.O.A.) Database and seeks to establish the chemical basis for canine’s scenting ability when detecting human remains. This database is composed of chemicals that are liberated during the decompositional process from buried human remains. This ‘living’ database currently spans the first year and a half of burial, providing identification, chemical trends and semi-quantitation of chemicals liberated below, above and at the surface of 1.5 – 2.5 ft graves for three individuals (two males and one female). A fourth male individual (buried in 1990) was also sampled to provide possible ‘endpoint’ information. In-ground, in-corpse thermocouples provided temperature information which can be used to correlate accumulated degree days (ADDs) to surface decompositional events and indicated an approximate 12 hour lag between equilibration of grave temperature with the surface air. Clear, sealed, hollow pipes were also placed in the grave vault providing viewing ports by which the burial...

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The Effects Of Temperature On The Decomposition Rate Of Human Remains

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Forensic anthropologists are frequently called upon to assist in the recovery and analysis of recently-deceased individuals. Estimating postmortem interval, or PMI, is an important part of a forensic anthropologist's job. The PMI serves two functions. First, estimating PMI can narrow down the potential pool of missing persons and ultimately help to identify the remains. Second, in homicide cases, law enforcement personnel use the PMI to exclude possible assailants. Forensic scientists use many methods to estimate the PMI, but anthropologists tend to emphasize the decay and decomposition of soft tissues. Qualitative "stages" of decomposition that broadly correspond to the PMI have served as rough guides for most estimates made by anthropologists. However, nearly all previous studies have considered decomposition as a thing to be described, not as a process to be scored and used statistically to estimate the PMI. Forensic anthropology might benefit from applying quantitative methods to the study of decomposition. Fly larvae (maggots) associated with decomposing remains grow and develop at a rate...

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Dead Body Decomposition Model

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Stella® model and case study by Bob GotwalsView the case study for this model.

Below you will find an image of a model of dead body decomposition. This model was created using Stella® software and was converted to Java for the web using Stella2Java©2001-2003.

Please note that in order to view this Java applet you must use a Java-enabled browser.

As with any model, this one has been simplified in order to demonstrate change in body weight over time. This model could be added to in such a way that it would more closely represent real decay processes in a given geographic area. Manipulate the variables below to see how they change the rate of decomposition.

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