Centro de Geologia do Porto, Faculdade de Ciências da Universidade do Porto, R. Campo Alegre 687, 4169-007 Porto, Portugal.
Forensic Sci Int. 2010 Feb 25;195(1-3):168.e1-6. doi: 10.1016/j.forsciint.2009.11.010. Epub 2009 Dec 14.
Four typical soils of the Porto (Portugal) area were characterized and used to study the decomposition of buried pieces of pork meat under controlled laboratory experiments (an 8 month experiment with a relatively high soil moisture and a 1 month experiment with relatively low soil moisture). The soils types were: organic, sandy, gravel and clay-gravel soils. Soils were characterized for their grain size distribution, pH, water content, organic matter percentage and mineral composition. Four free fatty acids (myristic, palmitic, oleic and stearic) were analysed (using a methodology based on an extraction step followed by a derivatization reaction and high performance liquid chromatography analysis) in soil samples as a sign of adipocere formation. The direct sensorial analysis of the buried sample residues and the free fatty acids profiles of the sampled soils showed that sandy and clay-gravel soils (in a low moisture environment) slowed the normal decomposition process promoting the formation of adipocere. Nevertheless, this apparent soil effect is indirect and a consequence of the different water retention and permeability of the soils. Thus, the water content of the soils is a crucial factor for adipocere formation.
四种典型的波尔图（葡萄牙）地区土壤进行了特征描述，并用于研究在控制实验室条件下（相对高土壤湿度下的 8 个月实验和相对低土壤湿度下的 1 个月实验）埋藏猪肉的分解情况。土壤类型为：有机土、沙土、砾石土和砾岩土。对土壤的粒径分布、pH 值、含水量、有机质含量和矿物组成进行了特征描述。对土壤样本中四种游离脂肪酸（肉豆蔻酸、棕榈酸、油酸和硬脂酸）进行了分析（采用基于提取步骤，然后进行衍生化反应和高效液相色谱分析的方法），以作为形成尸蜡的标志。对埋藏样品残留物的直接感官分析以及采样土壤的游离脂肪酸图谱表明，沙土和砾岩土（在低湿度环境下）减缓了正常的分解过程，促进了尸蜡的形成。然而，这种明显的土壤效应是间接的，是土壤持水和渗透性不同的结果。因此，土壤的含水量是形成尸蜡的关键因素。
