Hot and Dry, Cold and Wet, High and Dry, Bogs and Adipocere: Toward a Green Burial Taphonomy, Part 1

Taphonomy is the study of the fossilization process, but more generally is the study of the process of decay of remains and those factors that promote longer term preservation. Forensic taphonomy is the study of the decay of human remains. We need a conservation burial taphonomy: one that integrates landscape-level land protection and with burial services, while ensuring that the remains are recycled to nurture new life.

Photo courtesy of ancient-origins.net

Slow Recycling Can be a Problem for Buried Remains
Bodies that are not buried decay quickly-related to aerobic (oxygen dependent) processes, temperature and the action of animals (vertebrates and invertebrates). The Body Farm in Tennessee studies these processes to assist with forensic analysis of crime scenes, accidents, etc.

When bodies are buried quickly, the chance of long-term preservation of tissue goes up dramatically, and this is an outcome we want to avoid with conservation burial.

Hot and Dry, Cold and Wet, High and Dry, Bogs and Adipocere
Most of us are familiar with mummies high in the Andes, those in the coastal Atacama desert, the incredibly preserved bog-bodies from iron-age northern Europe and the 5000 year old “iceman”, Otzi.

These finds are remarkable and fascinating in part because of their rarity. However, shorter-term body preservation (decades or even a century or more) could be much more common than we think.

Fiedler and Graw (2003) reported that some 30-40 % of cemeteries in Germany (where they generally re-use graves after 25 years) have a problem with persistent preservation of remains. The chief culprit in dramatically slowing the recycling of buried human remains is adipocere.

Adipocere (or “grave wax”) forms from body fat. After death, fat liquefies and saturates the surrounding muscle and skin tissue. Bacteria change the liquefied fat to fats with much higher melting points, including palmitic acid ( 142 degrees f) and 10-hydroxysteric acid (178 degrees f). These waxy fats are very resistant to further degradation and can preserve parts of the body for decades (several studies documented adipocere lasting 130-140 years).

Factors that seem to promote adipocere include those specific to the body (a high percent of body fat, for example), certain soil conditions including heavy clay soils and high soil moisture, depth of burial, the type of clothing (burial suits?) and sealed caskets. My best guess is that most of these conditions have to do with slowing the decomposition of soft tissue other than fat, and many of them create anaerobic or near anaerobic conditions. In fact, adipocere translocated to or near the surface degrades relatively quickly. The degradation of 1 kg of steric acid requires almost 3 kg of oxygen (Schoenen, 2002, cited in Fiedler and Graw 2003).

What factors seemed to promote prompt recycling? Lighter soils, higher temperatures, less depth, “ventilated” caskets, delay between death and burial and vegetative bedding in the bottom of a coffin (or the bottom of a grave in shroud burial). Interestingly, the extra oxygen present in a casket can make decomposition go faster (Forbes, in Tibbett and Carter). The straw or other material could help recycling in a couple of ways. It can provide some insulation to hold onto some of the heat released as a body decays (it is an exothermic process in technical terms); it could provide additional micro-organism contact with the skin, and could absorb some of the fluid being purged from the body. “Ventilated caskets” means lighter unsealed materials, but also refers to a finding that accidentally perforating caskets with tomb-stone anchors prevented adipocere (in an area where adipocere is a major problem).

So how can we use this information to design site specific burial techniques to ensure that the body is recycled back to the living forest or grassland? That is the subject of Part 2: graves as one-use composting machines.

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