Steroids aid in human decomposition fluid identification in soils of temporary mass graves from World War II

Abstract

Steroids are widely used for the detection of faecal matter and also – in recent years – for characterising human decomposition in the terrestrial environment. Until now it was not clear whether all commonly used faecal (i.e. 5β-stanols, 5β-stanones and bile acids) and tissue derived steroids (i.e. cholesterol, 5α-cholestanol and 5α-cholestanone) could reveal the presence of human decomposition products in temporary graves. In this study, soil was sampled from three putative mass graves where concentration camp prisoners were temporarily buried for 10 months at the end of World War II (1944 – 45). We hypothesised that soil from the putative temporary mass graves exhibits elevated concentrations of faecal and tissue steroids compared to reference samples, thereby reflecting the former input of human decomposition products. Steroids (Δ5-sterols, 5β-stanols, 5α-stanols, stanones and bile acids) from soil samples from three soil pits suspected to be putative mass graves, as well as reference soil samples, were extracted and analysed with gas chromatography-mass spectrometry (GC–MS). Cholesterol, 5α-cholestanol and 5α-cholestanone were ubiquitously present in all soil pits and reference samples and therefore not indicative for the former input of human decomposition products. Compared to the reference, increased concentrations of selected faecal steroids (coprostanol, 5β-stigmastanol, 5β-cholestanone, lithocholic acid, isolithocholic acid) provided a strong indication of the former input of human decomposition products for one soil pit (pit 2). Additionally, epicoprostanol and isolithocholic acid were unique components for soil pit 2 as they were found neither in the other pits nor in the reference soil. In combination with earlier findings, steroid and bile acid patterns indicate an input of faecal and tissue constituents from former buried bodies in at least one of the three soil pits.