The amount of time required for buried animal carcasses (or human corpses) to decompose depends on many factors including temperature, moisture, burial depth, soil type and drainability, species and size of carcass, humidity/aridity, rainfall, and possibly other factors (McDaniel, 1991). The factors of most significance will likely be temperature, moisture level, and burial depth. Warm temperatures hasten decomposition by the body’s natural enzymes found in many of the body’s cells and in the digestive juices (Iserson, 2001, p. 384). A carcass left on the surface of the ground generally decays much more quickly than a buried carcass due in large part to destruction of much of the soft tissue by insects, carnivores, and rodents (Micozzi, 1991; Mann, Bass, & Meadows, 1990; Iserson, 2001; Rodriguez & Bass, 1985). In ideal conditions (warm to hot weather), a human corpse left exposed to the elements can become skeletonized in a matter of two to four weeks (Mann, Bass, & Meadows, 1990; Iserson, 2001, p. 384). However, an unembalmed adult human corpse buried six feet deep in ordinary soil without a coffin requires approximately 10 to 12 years to skeletonize (UK Environment Agency, 2002a; Pounder, 1995; Munro, 2001; Iserson, 2001). Other sources indicate that even longer may be required: Scottish lore held that a grave was ‘ripe’ for twenty years after burial, meaning that it was likely more than bones would turn up if the grave was reopened before twenty years had passed. Since the Scots frequently reused gravesites, this maxim was well founded. (Iserson, 2001, p. 391) Given relatively equal factors (temperature, body size, etc.), a corpse placed in water (with no fish or reptiles present) will generally decompose about four times faster than a corpse that is buried (Iserson, 2001, p. 390). One source indicates that a buried whale carcass remained largely intact and putrid after 10-20 years (Gaudet, 1998). In addition to the lengthy persistence of actual carcass material in a burial site, leachates or other pollutants may also be long-lived. Although much of the pollutant load would likely be released during the earlier stages of decomposition (i.e., during the first 1-5 years) (UK Environment Agency, 2001b; McDaniel, 1991; UK Environment Agency, 2002a; Munro, 2001), several reports suggest that mass burial sites could continue to produce both leachate and gas for as long as 20 years (UK Environment Agency, 2001b; Det Norske Veritas, 2003).