Gradient analysis of relationships between soil, decomposition of human remains, and external factors in graves in four Norwegian municipalities

Based upon a dataset collected from 61 graves directly by cemetery workers, incorporated in their daily practice, two decomposition gradients of coffin and human remains were found using Principal Component Analysis (PCA). The first main gradient represented variation in decomposition from poor to good and was tentatively interpreted as a result of oxygen availability, for which soil texture and drainage properties were particularly important. The second main gradient was tentatively interpreted to represent variation in decomposition processes from bacterial decomposition of soft tissue and textiles to decomposition of the coffin by fungi and chemical degradation of skeletal remains. Cemetery management choices of irrigation, grave depth, and treatment with lime were also shown to impact decomposition in the graves. Shallow redoximorphic features in soil seem to be a reliable indicator of soil unsuitable for coffin graves, which may prove a useful tool in daily practice and cemetery management, by reducing exposure of the cemetery workers to poorly decomposed human remains.